HomeMy WebLinkAbout20093772.tiffErie Substation
Weld County Use by Special Review Questionnaire
Substation Expansion and Telecommunications Facilities
Appendix M:
Soils Report
Erie Substation
Weld County Use by Special Review Questionnaire
Substation Expansion and Telecommunications Facilities
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f
USDA
0
•
United States
Department of
Agriculture
N RCS
Natural
Resources
Conservation
Service
0
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
369ft
•
Custom Soil Resource
Report for
Weld County,
Colorado,
Southern Part
Erie Substation Expansion
- VI -
Preface
Soil surveys contain information that affects land use planning in survey areas. They
highlight soil limitations that affect various land uses and provide information about
the properties of the soils in the survey areas. Soil surveys are designed for many
different users, including farmers, ranchers, foresters, agronomists, urban planners,
community officials, engineers, developers, builders, and home buyers. Also,
conservationists, teachers, students, and specialists in recreation, waste disposal,
and pollution control can use the surveys to help them understand, protect, or enhance
the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil properties
that are used in making various land use or land treatment decisions. The information
is intended to help the land users identify and reduce the effects of soil limitations on
various land uses. The landowner or user is responsible for identifying and complying
with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some cases.
Examples include soil quality assessments (http://soils.usda.gov/sqi/) and certain
conservation and engineering applications. For more detailed information, contact
your local USDA Service Center (http://offices.sc.egov.usda.gov/locator/app?
agency=nrcs) or your NRCS State Soil Scientist (http://soils.usda.gov/contact/
state_offices/).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic
tank absorption fields. A high water table makes a soil poorly suited to basements or
underground installations.
The National Cooperative Soil Survey is a joint effort of the United States Department
of Agriculture and other Federal agencies, State agencies including the Agricultural
Experiment Stations, and local agencies. The Natural Resources Conservation
Service (NRCS) has leadership for the Federal part of the National Cooperative Soil
Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Soil Data Mart Web site or the NRCS Web Soil Survey. The Soil
Data Mart is the data storage site for the official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs
and activities on the basis of race, color, national origin, age, disability, and where
applicable, sex, marital status, familial status, parental status, religion, sexual
orientation, genetic information, political beliefs, reprisal, or because all or a part of an
individual's income is derived from any public assistance program. (Not all prohibited
bases apply to all programs.) Persons with disabilities who require alternative means
2
for communication of program information (Braille, large print, audiotape, etc.) should
contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a
complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400
Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272
(voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and
employer.
3
Contents
Preface 2
How Soil Surveys Are Made 5
Soil Map 7
Soil Map 8
Legend 9
Map Unit Legend 10
Map Unit Descriptions 10
Weld County, Colorado, Southern Part 12
66 —Ulm clay loam, 0 to 3 percent slopes 12
79 —Weld loam, 1 to 3 percent slopes 13
References 15
4
How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous areas
in a specific area. They include a description of the soils and miscellaneous areas and
their location on the landscape and tables that show soil properties and limitations
affecting various uses. Soil scientists observed the steepness, length, and shape of
the slopes; the general pattern of drainage; the kinds of crops and native plants; and
the kinds of bedrock. They observed and described many soil profiles. A soil profile is
the sequence of natural layers, or horizons, in a soil. The profile extends from the
surface down into the unconsolidated material in which the soil formed or from the
surface down to bedrock. The unconsolidated material is devoid of roots and other
living organisms and has not been changed by other biological activity.
Currently, soils are mapped according to the boundaries of major land resource areas
(MLRAs). MLRAs are geographically associated land resource units that share
common characteristics related to physiography, geology, climate, water resources,
soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically
consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that is
related to the geology, landforms, relief, climate, and natural vegetation of the area.
Each kind of soil and miscellaneous area is associated with a particular kind of
landform or with a segment of the landform. By observing the soils and miscellaneous
areas in the survey area and relating their position to specific segments of the
landform, a soil scientist develops a concept, or model, of how they were formed. Thus,
during mapping, this model enables the soil scientist to predict with a considerable
degree of accuracy the kind of soil or miscellaneous area at a specific location on the
landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented by
an understanding of the soil -vegetation -landscape relationship, are sufficient to verify
predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them to
identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character of
soil properties and the arrangement of horizons within the profile. After the soil
scientists classified and named the soils in the survey area, they compared the
5
Custom Soil Resource Report
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that have
similar use and management requirements. Each map unit is defined by a unique
combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components of
the map unit. The presence of minor components in a map unit in no way diminishes
the usefulness or accuracy of the data. The delineation of such landforms and
landform segments on the map provides sufficient information for the development of
resource plans. If intensive use of small areas is planned, onsite investigation is
needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape, and
experience of the soil scientist. Observations are made to test and refine the soil -
landscape model and predictions and to verify the classification of the soils at specific
locations. Once the soil -landscape model is refined, a significantly smaller number of
measurements of individual soil properties are made and recorded. These
measurements may include field measurements, such as those for color, depth to
bedrock, and texture, and laboratory measurements, such as those for content of
sand, silt, clay, salt, and other components. Properties of each soil typically vary from
one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists interpret
the data from these analyses and tests as well as the field -observed characteristics
and the soil properties to determine the expected behavior of the soils under different
uses. Interpretations for all of the soils are field tested through observation of the soils
in different uses and under different levels of management. Some interpretations are
modified to fit local conditions, and some new interpretations are developed to meet
local needs. Data are assembled from other sources, such as research information,
production records, and field experience of specialists. For example, data on crop
yields under defined levels of management are assembled from farm records and from
field or plot experiments on the same kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on such
variables as climate and biological activity. Soil conditions are predictable over long
periods of time, but they are not predictable from year to year. For example, soil
scientists can predict with a fairly high degree of accuracy that a given soil will have
a high water table within certain depths in most years, but they cannot predict that a
high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
identified each as a specific map unit. Aerial photographs show trees, buildings, fields,
roads, and rivers, all of which help in locating boundaries accurately.
6
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of soil
map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
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MAP INFORMATION
MAP LEGEND
Map Scale: 1:3,710 if printed on A size (8.5" x 11") sheet.
Very Stony Spot
The soil surveys that comprise your AOI were mapped at 1:24,000.
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Map Unit Legend
Weld County, Colorado, Southern Part (CO618)
Map Unit Symbol
Map Unit Name
Acres in AOI
Percent of AOI
66
79
Totals for Area of Interest
Ulm clay loam, 0 to 3 percent slopes
Weld loam, 1 to 3 percent slopes
Map Unit Descriptions
40.2
3.3
43.5
The map units delineated on the detailed soil maps in a soil survey represent the soils
or miscellaneous areas in the survey area. The map unit descriptions, along with the
maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the landscape,
however, the soils are natural phenomena, and they have the characteristic variability
of all natural phenomena. Thus, the range of some observed properties may extend
beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic
class rarely, if ever, can be mapped without including areas of other taxonomic
classes. Consequently, every map unit is made up of the soils or miscellaneous areas
for which it is named and some minor components that belong to taxonomic classes
other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They generally
are in small areas and could not be mapped separately because of the scale used.
Some small areas of strongly contrasting soils or miscellaneous areas are identified
by a special symbol on the maps. If included in the database for a given area, the
contrasting minor components are identified in the map unit descriptions along with
some characteristics of each. A few areas of minor components may not have been
observed, and consequently they are not mentioned in the descriptions, especially
where the pattern was so complex that it was impractical to make enough observations
to identify all the soils and miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the usefulness
or accuracy of the data. The objective of mapping is not to delineate pure taxonomic
classes but rather to separate the landscape into landforms or landform segments that
have similar use and management requirements. The delineation of such segments
on the map provides sufficient information for the development of resource plans. If
intensive use of small areas is planned, however, onsite investigation is needed to
define and locate the soils and miscellaneous areas.
92.4%
7.6%
100.0%
10
Custom Soil Resource Report
An identifying symbol precedes the map unit name in the map unit descriptions. Each
description includes general facts about the unit and gives important soil properties
and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major horizons
that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity,
degree of erosion, and other characteristics that affect their use. On the basis of such
differences, a soil series is divided into soil phases. Most of the areas shown on the
detailed soil maps are phases of soil series. The name of a soil phase commonly
indicates a feature that affects use or management. For example, Alpha silt loam, 0
to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps. The
pattern and proportion of the soils or miscellaneous areas are somewhat similar in all
areas. Alpha -Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present or
anticipated uses of the map units in the survey area, it was not considered practical
or necessary to map the soils or miscellaneous areas separately. The pattern and
relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha -
Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas that
could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion of
the soils or miscellaneous areas in a mapped area are not uniform. An area can be
made up of only one of the major soils or miscellaneous areas, or it can be made up
of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil material
and support little or no vegetation. Rock outcrop is an example.
11
Custom Soil Resource Report
Weld County, Colorado, Southern Part
66 —Ulm clay loam, 0 to 3 percent slopes
Map Unit Setting
Elevation: 5,070 to 5,200 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 46 to 48 degrees F
Frost -free period: 105 to 120 days
Map Unit Composition
Ulm and similar soils: 85 percent
Minor components: 1 percent
Description of Ulm
Setting
Landfomr: Plains
Down -slope shape: Linear
Across -slope shape: Linear
Parent material: Alluvium and/or eolian deposits derived from shale
Properties and qualities
Slope: 0 to 3 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum content: 15 percent
Maximum salinity: Nonsaline (0.0 to 2.0 mmhos/cm)
Available water capacity: High (about 10.4 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability (nonirrigated): 4e
Ecological site: Clayey Plains (R067BY042CO)
Typical profile
0 to 5 inches: Clay loam
5 to 19 inches: Clay
19 to 60 inches: Clay loam
Minor Components
Aquic haplustolls
Percent of map unit: 1 percent
Landform: Swales
12
Custom Soil Resource Report
79 —Weld loam, 1 to 3 percent slopes
Map Unit Setting
Elevation: 4,850 to 5,000 feet
Mean annual precipitation: 13 to 17 inches
Mean annual air temperature: 46 to 55 degrees F
Frost -free period: 100 to 155 days
Map Unit Composition
Weld and similar soils: 80 percent
Minor components: 1 percent
Description of Weld
Setting
Landform: Plains
Down -slope shape: Linear
Across -slope shape: Linear
Parent material: Eolian deposits
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum content: 6 percent
Maximum salinity: Nonsaline (0.0 to 2.0 mmhos/cm)
Available water capacity: High (about 10.2 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability (nonirrigated): 3e
Ecological site: Loamy Plains (R067BY002CO)
Typical profile
0 to 8 inches: Loam
8 to 15 inches: Clay
15 to 60 inches: Silt loam
60 to 64 inches: Silt loam
Minor Components
Aquic argiustolls
Percent of map unit: 1 percent
Landform: Swales
13
•
References
American Association of State Highway and Transportation Officials (AASHTO). 2004.
Standard specifications for transportation materials and methods of sampling and
testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep -water habitats of the United States. U.S. Fish and Wildlife Service
FWS/OBS-79/31.
S/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt. G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils
in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S.
Department of Agriculture Handbook 18. http://soils.usda.gov/
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making
and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service,
U.S. Department of Agriculture Handbook 436. http://soils.usda.gov/
Soil Survey Staff. 2006. Keys to soil taxonomy. 10th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://soils.usda.gov/
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://soils.usda.gov/
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.glti.nrcs.usda.gov/
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430 -VI. http://soils.usda.gov/
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States, the
Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.
http://soils.usda.gov/
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Custom Soil Resource Report
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210.
16
CTLITHOMPSON
INCORPORATED
GEOTECHNICAL INVESTIGATION
ERIE 230 KV SUBSTATION
WELD COUNTY, COLORADO
Prepared for:
TRI-STATE GENERATION &
TRANSMISSION ASSOCIATION, INC.
1100 West 116th Avenue
Westminster, Colorado 80234
Attention: Ms. Kelly Beal, PE
Project No. FC04773-125
February 18, 2009
351 Linden Street I Suite 140 I For[ Collins, Colorado 80524
Telephone: 970-206-9455 Fax: 970-206-9441
TABLE OF CONTENTS
SCOPE
SUMMARY OF CONCLUSIONS
SITE CONDITIONS
PREVIOUS INVESTIGATIONS
PROPOSED CONSTRUCTION
EXPLORATORY INVESTIGATIONS
SUBSURFACE CONDITIONS
GEOLOGIC HAZARDS
FILL PLACEMENT
EXCAVATIONS
FOUNDATIONS
Drilled Piers Bottomed in Bedrock
Laterally Loaded Piers
CORROSION PROTECTION
Resistivity
Water -Soluble Sulfates
SURFACE DRAINAGE
LIMITATIONS
FIGURE 1 - LOCATIONS OF EXPLORATORY BORINGS
FIGURE 2 - SUMMARY LOGS OF EXPLORATORY BORINGS
FIGURE 3- WENNER 4 -PIN RESISTIVITY LOG
APPENDIX A - RESULTS OF LABORATORY AND FIELD TESTING
APPENDIX B - SAMPLE SITE GRADING SPECIFICATIONS
TRI-STATE GENERATION 13 TRANSMISSION ASSOCIATION
ERIE 2301W SUBSTATION
CTL I T PROJECT NO. FC04773-125
1
1
2
2
2
3
3
4
4
5
6
6
8
9
9
10
11
11
SCOPE
)
This report presents the results of our geotechnical investigation for the proposed
substation to be located southeast of the intersection of County Road 6 and County
Road 11 in Weld County, Colorado (Figure 1). We were retained to investigate the
subsurface conditions at the site and to provide geotechnical design criteria for
engineering and construction of the substation facility.
)
The discussions in this report are based on our understanding of the planned
construction, subsurface conditions encountered by exploratory drilling, site
observations, results of laboratory tests, engineering analysis of field and laboratory
data, and our experience. Our main conclusions and recommendations are summarized
in the following paragraphs. A more detailed description of the subsurface conditions,
results of our field and laboratory investigations and our opinions, conclusions and
recommendations are included in the subsequent sections of this report.
) SUMMARY OF CONCLUSIONS
1. No geologic hazards were encountered at this site that would preclude
the proposed construction.
2. In general, our borings penetrated approximately 2 to 4-1/2 feet of clayey
sand underlain by claystone bedrock. The upper 4 to 8 feet of bedrock is
highly weathered. Ground water was measured at depths ranging from
approximately 12 to 16 feet below existing grades. Existing groundwater
levels are not expected to significantly affect site development, but may
affect drilled pier installation.
3. Due to the presence of highly expansive bedrock at this site, we
recommend using drilled pier foundations to support all structures.
Design and construction criteria for drilled pier foundations are presented
in this report.
1
4. The results of resistivity testing at the site indicate the soils and bedrock
have a severe potential for corrosion.
)
TRI STATE GENERATION & TRANSMISSION ASSOCIATION
ERIE 230 KV SUBSTATION
CTL I T PROJECT NO. FC04773-125
)
1
SITE CONDITIONS
The project site is located south of Weld County Road 6 and west of the Union
Pacific railroad tracks in Weld County, Colorado (Figure 1). The site is bounded to the
south by the Bull Canal. The property is occupied by an existing 115kV substation,
various single -story buildings, transmission poles, and assorted other structures.
Several unpaved roads are present in the project area. Vegetation consists of sparse
prairie type grasses and weeds. The area is generally flat with a slight slope toward the
north.
PREVIOUS INVESTIGATIONS
CTLIThompson conducted a Geotechnical Investigation for the existing 115kV
substation at this site (Project No. FC-2693, dated May 23, 2003). The substation
station is located east of the proposed substation. The report from this previous
investigation was reviewed prior to the preparation of this report. Subsurface conditions
encountered during this previous investigation were similar to those encountered during
this investigation. In our previous investigation, our borings did not encounter any coal
beds. Several coal bed were encountered during our most recent investigation. Drilled
pier foundations were recommended in our previous report due to the highly expansive
nature of the near surface bedrock.
PROPOSED CONSTRUCTION
Based on conversations with our client, we understand the proposed construction
will consist of a 230kV substation with an approximate footprint of 260 feet by 500 feet.
The substation will include a communication tower approximately 185 feet tall supported
by a four drilled piers, busses approximately 25 to 35 feet tall, switches, and a
prefabricated, steel -framed operation and maintenance building. We understand that
drilled piers 30 inches in diameter are typically used to support the planned structures.
Smaller diameter piers may be used to support the proposed building and ancillary
structures. No below grade construction or paved areas are planned at the site. Up to
two feet of fill may be added to realize desired grades.
TRISTATE GENERATION &TRANSMISSION ASSOCIATION
ERIE 230 KV SUBSTATION
CU T PROJECT NO. FC04773-125
J
2
EXPLORATORY INVESTIGATIONS
Subsurface conditions at the site were investigated by drilling four borings at the
approximate locations shown on Figure 1. The borings were drilled using a truck -
mounted drill rig and 4 -inch diameter continuous -flight augers. Samples were obtained
using a 2.5 -inch O.D. modified California sampler. The sampler was driven into the soils
and bedrock recording the number of blows with a 140 -pound hammer falling 30 inches.
Our representative was on -site during drilling to log the soil and bedrock found in the
borings and to obtain samples. Graphical logs of the borings and results of field
penetration resistance tests are presented in Figure 2.
The samples were returned to our laboratory for further classification and select
testing. Laboratory testing included moisture content and dry density, swell -
consolidation, unconfined compressive strength, Atterberg limits and water-soluble
sulfate tests. Results of laboratory testing are presented in Appendix A and summarized
in Table A-1. Electrical resistivity testing was performed at the site using the Wenner 4 -
pin method. Resistivity results are presented in Figure 3.
SUBSURFACE CONDITIONS
Our borings penetrated up to approximately 4'r4 feet of clayey sand over
claystone bedrock. The upper 4 to 8 feet of bedrock is highly weathered. Coal beds up
to 3 feet thick were encountered in all of our borings at various depths. We anticipate
additional coal beds may be encountered during foundation construction at the site.
Ground water was encountered at depths of approximately 12 to 16 feet. A more
complete description of the subsurface conditions is presented on our boring logs and in
our laboratory testing.
TRI-STATE GENERATION & TRANSMISSION ASSOCIATION
ERIE 230 NV SUBSTATION
CTL I T PROJECT NO. FC04773-125
3
GEOLOGIC HAZARDS
As part of this investigation our engineering geologist conducted a site visit to
evaluate potential geologic hazards at the site. Other than expansive soil and bedrock,
we did not identify any potential geologic hazards that will affect the proposed
construction. Expansive soil and bedrock can be mitigated by proper design of
foundation systems that support the proposed structures. Our recommendations for
foundations systems to support the proposed structures over expansive soils and
bedrock are presented in the FOUNDATIONS section of this report.
FILL PLACEMENT
The existing on -site overburden soils are suitable for re -use as fill material
provided debris or deleterious organic materials are removed. If import material is
required, we recommend importing granular soils. Import fill should contain 10 to 40
percent silt and clay sized particles (percent passing No. 200 sieve) and exhibit a liquid
limit less than 30 percent and a plasticity index less than 15 percent.
Areas to receive fill should be scarified, moisture -conditioned and compacted to
at least 95 percent of standard Proctor maximum dry density (ASTM D 698). The
properties of the fill will affect the performance of slabs -on -grade. Sand soils used as fill
should be moistened to within 2 percent of optimum moisture content. Clay fill soils
placed below structures should be moisture conditioned to 1 to 4 percent above optimum
moisture content. Clay fill placed exterior to the structures can be moistened to between
optimum and 3 percent above optimum moisture content. The fill should be moisture -
conditioned, placed in thin, loose lifts (8 inches or less) and compacted as above.
Placement and compaction of fill should be observed and tested by a representative of
our firm during construction. Fill placement and compaction activities should not be
conducted when the fill material or subgrade is frozen.
Site grading in areas of landscaping where no future improvements are planned
can be placed at a dry density of at least 90 percent of standard Proctor maximum dry
TRI-STATE GENERATION & TRANSMISSION ASSOCIATION
ERIE 230 NV SUBSTATION
CTL I T PROJECT NO. FC04773-125
4
density (ASTM D 698). Example site grading specifications are presented in Appendix
B.
EXCAVATIONS
The soils penetrated by our borings can be excavated using conventional heavy
earth moving equipment and large excavators. Excavations into bedrock may require
ripping and/or blasting.
Excavations in the upper soils and bedrock may need to be sloped or braced.
Excavations should be sloped or shored to meet local, State and federal safety
regulations. Based on our investigation and OSHA standards, we believe the sand and
clay soils classify as Type C soils. Type C soils require a maximum slope inclination of
1.5:1 in dry conditions. We believe that the bedrock would classify as Type A soils.
Type A soils require a maximum slope inclination of 3/4:1 in dry conditions. Excavation
slopes specified by OSHA are dependent upon types of soil and groundwater conditions
encountered. The contractor's "competent person" should identify the soils encountered
in the excavation and refer to OSHA standards to determine appropriate slopes.
Stockpiles of soils and equipment should not be placed within a horizontal distance
equal to one -halt the excavation depth, from the edge of excavation. Excavations
deeper than 20 feet or excavations not in strict accordance with OSHA, should be
designed by a professional engineer should design the slopes.
The width of the top of an excavation may be limited in some areas. Bracing
may be necessary where slopes cannot be laid back. Bracing systems include sheet
piling, steel struts, soldier piles, trench boxes, and others. Lateral loading of bracing
depends on the depth of excavation, slope of excavation above the bracing, surface
loads, hydrostatic pressures, and allowable movement. For trench boxes and bracing
allowed to move enough to mobilize the strength of the soils with associated cracking of
the ground surface, the "active" earth pressure conditions are appropriate for design. If
movement is not tolerable, the "at rest' earth pressures are appropriate. We suggest an
equivalent fluid weight of 45 pcf for "active" earth pressure and 60 pcf for "at rest' earth
pressure, assuming level backfill. These pressures do not include factors of safety,
TRI-STATE GENERATION 6 TRANSMISSION ASSOCIATION
ERIE 230 KV SUBSTATION
CTI. I T PROJECT Na FC04773-126
5
allowances for surcharge loading, or hydrostatic loads. We are available to assist further
with bracing design if desired.
Utility trenches should be backfilled using the materials and criteria discussed in
the FILL PLACEMENT section of this report. Free draining, crushed gravel can be
placed in the bottom of utility trenches around pipes, but should be compacted as much
as practical. Ground water or saturated soils may be encountered in excavations within
three feet of the measured groundwater levels presented on Figure 2. We have
assumed that cuts at the site will be minimal. If ground water is encountered,
dewatering may be required. Dewatering may consist of a series of trenches with
sumps. If requested, we can provide additional recommendations for dewatering.
FOUNDATIONS
Based on the subsurface conditions encountered during our investigation,
structures will be supported on expansive bedrock. To reduce the risk of potential
movement of the structures, we considered several foundation options for the planned
construction. These included footing or mat foundations and over -excavation as well as
drilled piers. We believe that constructing the structures over a deep over -excavation
and replacement would likely be cost prohibitive and would likely not reduce potential
movements to acceptable levels.
We recommend drilled pier foundations be used to support the proposed
structures for the substation facility. Design and construction criteria are presented
below. These criteria were developed from analysis of field and laboratory data and our
experience. The recommended foundation can be used provided all design and
construction criteria presented in this report are followed.
Drilled Piers Bottomed in Bedrock
1. Piers should bottom in competent bedrock and have a minimum length of
at least 38 feet. Piers should not bottom in weathered bedrock or coal.
2. Piers should be designed for a maximum allowable end pressure of
30,000 psf and an allowable skin friction of 3,000 psf for the portion of the
TRISTATE GENERATION 8 TRANSMISSION ASSOCIATION
ERIE 230 KV SUBSTATION
CTL I T PROJECT NO. FC04773-125
6
pier in bedrock. Skin friction should be neglected for the portion of the
pier in overburden soils or within 3 feet of grade beams.
3. Axial tension loads can be resisted using a skin friction value of 3,000 psf
for the portion of pier in bedrock.
4. Piers should be designed with a length/diameter ratio less than 30.
5. Shear rings should be installed in the lower portion of piers. We
recommend provision of shear rings that extend about 3 inches beyond
the pier shaft to increase the load transfer through skin friction. These
shear rings should be spaced about 2 feet on -center for the bottom 10
feet of pier in bedrock.
6. Pier drilling should produce shafts with relatively undisturbed bedrock
exposed. Excessive remolding and caking of bedrock cuttings on pier
walls should be removed.
7. Piers should be reinforced their full length and the reinforcement should
extend into grade beams or foundation walls. A minimum steel -to -pier
cross-sectional area ratio of 0.005 using Grade 60 steel is recommended.
More reinforcement may be required by structural considerations.
8. A 12 -inch continuous void should be constructed beneath grade beams,
between piers, to concentrate structural deadload on the piers.
9. Grade beams should be well reinforced. The structural engineer should
design the reinforcement.
10. Piers should have a center -to -center spacing of at least three pier
diameters when designing for vertical loading conditions, or they should
be designed as a group. Piers aligned in the direction of lateral forces
should have a center -to -center spacing of at least six pier diameters.
Reductions for closely spaced piers are discussed in the following
section.
11. Concrete should have a slump of 6 inches (+/- 1 inch). Concrete should
be ready and placed in the pier holes immediately after the holes are
drilled, cleaned, observed and the reinforcing steel is set.
12. Ground water was encountered in our borings. Where ground water is
encountered during drilling, pump or tremie pipe placement of concrete
may be required for proper cleaning, dewatering and placement of
concrete during pier installation. Concrete should not be placed by free
fall in pier holes containing more than 3 inches of water.
13. Due to shallow ground water, casing may be required for piers. Concrete
should be ready and placed in the pier holes immediately after the holes
are drilled, cleaned and observed and reinforcing steel set. At least 5 feet
of concrete should be maintained above the ground water level prior to
TRI-STATE GENERATION & TRANSMISSION ASSOCIATION
ERIE 230 KV SUBSTATION
cm I T PROJECT NO. F004773-125
7
(and during) casing removal.
14. Some pier -drilling contractors use casing with an O.D. equal to the
specified pier diameter. This results in a pier diameter less than
specified, typically on the order of 2 inches smaller in diameter. The
design and specification of piers should consider the alternatives. If full
size casing is desired (I.D. of casing equal to specified pier diameter) it
should be clearly specified. If design considers the potential reduction in
diameter, then the specification should include a tolerance for a smaller
diameter for cased piers.
15. Some movement of the drilled pier foundation is anticipated to mobilize
the skin friction. We estimate this movement to be on the order of less
than 1 -inch. Differential movement may be equal to the total movement.
16. The installation of the drilled pier foundations should be observed by a
representative of our firm to confirm the piers are bottomed in the proper
bearing material and to observe the contractor's installation procedures.
Laterally Loaded Piers
Several methods are available to analyze laterally loaded piers. With a pier
length to diameter ratio of 7 or greater, we believe the method of analysis developed by
Matlock and Reese is most appropriate. The method is an iterative procedure using
applied loading and soil profile to develop deflection and moment versus depth curves.
The computer programs LPILE and COM624 were developed to perform this procedure.
Suggested criteria for LPILE analysis are presented in the following table.
TABLE A
SOIL INPUT DATA FOR LPILE or COM624
J II
Effective Unit Weight (pci) 0.07
0.06
Cohesive Strength, c (psi) -
40
Friction Angle 35
Degrees
-
Soil Strain, E0 (in/in) -
0.003
p -y Modulus ks (pci) 90
2,000
The Eso represents the strain corresponding to 50 percent of the maximum
principle stress difference.
TRISTATE GENERATION 8 TRANSMISSION ASSOCIATION
ERIE 230 KV SUBSTATION
CM I T PROJECT NO. FC04773-125
8
CORROSION PROTECTION
As a part of our testing program, a corrosion test was performed to provide
guidance in material selection for the subsurface structures on this project. We
recommend this test data be provided to a corrosion engineer for evaluation.
Resistivity
Soil electrical resistivity was measured in the field at one boring location (TH-3)
using the Wenner 4 -point method, developed by the National Bureau of Standards. In
this procedure, four electrodes are driven into the soil at equal distances from each other
and in a straight line. The electrodes are connected to an ohm meter via a set of wires
to measure resistance as a low voltage current is generated. According to the Wenner
theory, the average soil resistivity is measured over a depth equivalent to the distance
between two adjacent pins (electrodes). By measuring the resistance at varying pin
spacing, a soil resistivity profile can be established for a location. Two profiles were
measured at the location at pin spacing's of 5, 10, 15, and 20 feet. The average field
resistivity measurement for both profiles was 195 ohms -cm. Resistivity logs are
presented in Figure 3.
The City of Denver Water Department has, over a period of years, established
apparent resistivity versus corrosion potential of the subsurface soil and bedrock for their
underground pipelines. They concluded from their studies that apparent resistivity
measurements of 0 ohm -cm to 1,000 ohm -cm indicates severe corrosion potential of
metal pipes, 1,000 ohm -cm to 2,500 ohm -cm indicates moderate corrosion potential, and
greater than 2,500 ohm -cm indicates low corrosion potential. Many other sources
including FHWA and The Corrosioneering Journal have similar guidelines with soil
resistivity measurements of less than 1,000 ohm -cm considered corrosive to very
corrosive and between 1,000 and 2,000 ohm -cm considered moderately corrosive.
Generally, resistivity measurements greater than 2,000 ohm -cm are considered mildly
corrosive and above 10,000 ohm -cm is essentially non -corrosive. Based on these
guidelines, the soils testing would be classified in the severely corrosive category.
TRI-STATE GENERATION & TRANSMISSION ASSOCIATION
ERIE 230 KV SUBSTATION
cm I T PROJECT NO. FC04773-125
9
Water -Soluble Sulfates
J
Concrete that comes into contact with soils and bedrock can be subject to sulfate
attack. We measured water-soluble sulfate concentrations in two samples from this site.
Concentrations were measured to be 0.18 and 0.30 percent. Water-soluble sulfate
concentrations between 0.2 and 2 percent indicate Class 2 exposure to sulfate attack for
concrete that comes into contact with the subsurface soils, according to the American
Concrete Institute (ACI). For this level of sulfate concentration, ACI recommends using
a cement meeting the requirements for Type V (sulfate resistant) cement or the
equivalent, with a maximum water-to-cementitious material ratio of 0.45 and air
entrainment of 5 to 7 percent. As alternative, ACI allows the use of cement that
conforms to ASTM C 150 Type II requirements, if it meets the Type V performance
requirements (ASTM C 1012) of ACI 201, or ACI allows a blend of any type of portland
cement and fly ash that meets the performance requirements (ASTM C 1012) of ACI
201. In Colorado, Type II cement with 20 percent Class F fly ash usually meets these
performance requirements. The fly ash content can be reduced to 15 percent for
placement in cold weather months, provided a water-to-cementitious material ratio of
0.45 or less is maintained. ACI also indicates concrete with Class 2 sulfate exposure
should have a minimum compressive strength of 4,500 psi.
Sulfate attack problems are comparatively rare in this area when quality concrete
is used. Considering the range of test results, we believe risk of sulfate attack is lower
than indicated by the few laboratory tests performed. The risk is also lowered to some
extent by damp -proofing the surfaces of concrete walls in contact with the soil. ACI
indicates sulfate resistance for Class 1 exposure can be achieved by using Type II
cement, a maximum water-to-cementitious material ratio of 0.50, and a minimum
compressive strength of 4,000 psi. We believe this approach should be used as a
minimum at this project. The more stringent measures outlined in the previous
paragraph will better control risk of sulfate attack and are more in alignment with written
industry standards.
TRISTATE GENERATION & TRANSMISSION ASSOCIATION
ERIE 230 NV SUBSTATION
CTL I T PROJECT NO. FC04773-125
10
SURFACE DRAINAGE
Performance of foundations and concrete flatwork is influenced by the moisture
conditions existing within the foundation soils. The risk of wetting foundation soils can
be reduced by carefully planned and maintained surface drainage. Surface drainage
should be designed to provide rapid runoff of surface water away from the proposed
structures. We recommend the following precautions be observed during construction
and be maintained at all times after the construction is completed.
1. The ground surface surrounding the exterior of the foundations and slabs
should be sloped to drain away from the foundation in all directions. We
recommend a minimum slope of at least 10 percent in the first 5 to 10 feet
in landscape areas. Paved surfaces should be sloped to drain away from
the foundation. A minimum slope of 2 percent is suggested.
2. Backfill around grade beams should be moistened and compacted to the
criteria in FILL PLACEMENT section.
3. Landscaping should be carefully designed to minimize irrigation. Plants
close to foundation walls should be limited to those with low moisture
requirements. Irrigation should be limited to the minimum amount
sufficient to maintain vegetation; application of more water will increase
likelihood of slab and foundation movement.
4. Downspouts with extensions and/or splash blocks should be used to
conduct roof runoff well away from any backfill areas.
5. Any below grade spaces should have a foundation drain.
LIMITATIONS
Although our borings were spaced to obtain a reasonably accurate picture of
subsurface conditions, variations in the soils and bedrock not indicated in our borings
are always possible. We should observe pier hole drilling and foundation excavations to
confirm soils or bedrock are as we anticipated from our borings. Placement and
compaction of site grading fill, backfill, subgrade and other fills should be observed and
tested by a representative of our firm during construction.
TRI-STATE GENERATION & TRANSMISSION ASSOCIATION
ERIE 230 KV SUBSTATION
CTL I T PROJECT NO. FC04773-125
11
This report was prepared from data developed during our field exploration,
laboratory testing, engineering analysis and experience with similar conditions. The
recommendations contained in this report were based upon our understanding of the
planned construction. If plans change or differ from the assumptions presented herein,
we should be contacted to review our recommendations.
We believe this investigation was conducted in a manner consistent with that
level of skill and care ordinarily used by engineering geologists and geotechnical
engineers currently practicing under similar conditions in the locality of this project. No
warranty, express or implied, is made. If we can be of further service in discussing the
contents of this report or in the analysis of the project from the geotechnical point -of -
view, please contact the undersigned.
CTL I THOMPSON, INC.
fau ve,
Rae Doner, E.I.
Staff Engineer
Reviewed by:
Eric D. Bernhardt,
Project Manager
TRI-STATE GENERATION & TRANSMISSION ASSOCIATION
ERIE 23O KV SUBSTATION
CTL I T PROJECT NO. FO04773-125
Robin Dornfest, PG
Geotechnical Department Manager
12
a
APPROXIMATE
SCALE: 1' = 200'
0 100' 2W
VICINITY MAP
-CRB
53
EXISTING BUILDINGS
III II;'�I�!G
IYG�f IIIII I'I
•
■ TH-1
1 I j'lli!ii III 11 il,I I' I'd
•
TH-2
PROPOSED SUBSTATION
•
TH-3
•
TH-4
0
a
BULL CANAL
EXISTING SUBSTATION
TRI.STATE GENERATION & TRANSMISSION ASSOCIATION
ERIE 2001(N SUBSTATION
CTL I T PROJECT NO. FCW77S125
(ERIE AREA)
NOT TO SCALE
LEGEND:
TH-1
•
INDICATES APPROXIMATE
LOCATION OF EXPLORATORY
BORING.
Locations of
Exploratory
Borings
FIGURE 1
g
W
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r=
re.:'.1
0
t
s
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gg
a
2
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= q M
l33!'NOISY/SA
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0
0
0
0
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MIR m wenn iarnwNuml Ina 1-3,,11 wMwuwwI• iz
WENNER 4 -PIN RESISTIVITY LOG
Nilsson 400 Solt Resistance Meter
Project Number:
Project Name:
Test ID:
Test Location:
FC04773-125
ERIE 230 KV SUBSTATION
TH-3
WELD COUNTY
Bate:
118/2009
Test Orientation A
Pin
Spacing
a (ft)
Meter
Resistance
(ohms)
Wenner
Spacing Factor
(191.5*Pin Spacing)
Sod
Resistivity
(ohms -an)
5
0.5
957.5
479
10
0.1
1915
192
15
0.01
2872.5
29
20
NR
3830
-
Test Orientation B
Resistivity Average:
230
Pin
Spacing
a (ft)
Meter
Resistance
(ohms)
Wenner
Spacing Factor
(191.5'Pin Spacing)
Soil
Resistivity
(ohms -cm)
5
0.28
957.5
268
10
0.1
1915
192
15
0.01
2872.5
29
20
NR
3830
-
Resistivity Average:
160
600
..500
E
E 400
a�
m 200
m
CC too
0
0
5
Orient A
—2—Orient B
10 15 2D
Pin Spacing (ft)
25
30
Note: Soil Resistivity (aims -cm). )9).5 • Spacing In Feat Resistance in Mms
Tfl4STATE GENERATION & TM1b4SSICN ASSOCIATION
ERIE 2YI KV SUBSTATION
CIL IT Pr10JECr NO. FCd773I2S
FIGURE 3
APPENDIX A
RESULTS OF LABORATORY AND FIELD TESTING
TRI-STATE GENERATION A TRANSMISSION ASSOCIATION
ERE 22OKV SUBSTATION
CR I T PROJECT NO. F004713-125
2
Z D
0
NZ
A. 41
W
O -x
O
yfA
A. a
6
0
U
-4
0.1
APPLIED PRESSURE-KSF
Semple of CLAYSTONE
From TH-1 AT FEET
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
3
0 -2
N
W
K
6 4
V
-4
0.1
APPLIED PRESSURE - KSF
Semple of CLAYSTONE
From TH-1 AT 19 FEET
ID
DRY UNIT WEIGHT=
MOISTURE CONTENT=
119
13.3
103
PCF
EXPANSION UNDER CONSTANT
P • ESSURE DUE TO WETTING
TRINTATE REITERATION & TRANSMISSION ASSOCIATION
ERIE MANN SUBSTATION
CTLI TPROJECT ND. FCMn3-IPS
10
DRY UNIT WEIGHT..
MOISTURE CONTENT=
115
13.3
1DE
Per
Swell Consolidation
Test Results FIGURE Al
3
2
z o
0
N
Z
a. -1
W
O s
N
CC a
O
U
-4
. ; EXPANSION UNDER CONSTANT
-:. PRESSURE DUE TO WETTING
APPLIED PRESSURE - KSF
Sample of CLAYSTONE. WEATHERED
From TH-2 AT4FEET
3
O a
(O
Q
a
x n
w
3E
2
EO -x
m
w
2 a. cr 0
U
e
10
DRY UNIT W EGHT-
MOISTURE CONTENT=
109
17.3
100
PCF
0
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
J J
0.1
APPIJED PRESSURE - KSF
Sample of CLAYSTONE
From TH-2 AT FEET
TRI-STATE GENEMTION & TPANSMISSION ASSOCIATION
ERIE 230W SUBSTATION
CHI T MQIECT Na FCW nS123
Is
ORY UNIT WEIGHT= 108
MOISTURE CONTENT= 20.9
1%
PCF
%
Swell Consolidation
Test Results FIGURE A2
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0
-1 -
ar
11
0.1
APPLIED PRESSURE - KSF
Sample of CLAYSTONE
From TR-2 AT 14 FEET
1.0
TRI-STATE GENERATION 8 TRANSMISSION ASSOCIATION
ERIE 230KV SUBSTATION
CIL T PROJECT NO. FCMTl3-I25
10 IOC
DRY UNIT WEIGHT. 118 POP
MOISTURE CONTENT- 18.1 %
Swell Consolidation
Test Results
FIGURE A3
a
2
a
rei
A
W
ae
Z
p -5
y
Co
W
C
<
2 s
a
U
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
T 'r
0.1 .0
APPLIED PRESSURE - KSF
Sample of CLAYSTONE
From TR-2 AT 19 FEET
TRI-STATE OENEAAT ON A TMNSMISSION ASSOCIATION
ERIE 3301N SUBSTATION
CR I T PROJECT NO. FLOC /3125
10
IW
DRY UNIT WEIGHT= 101 PCF
MOISTURE CONTENT= 23.1 %
Swell Consolidation ..
Test Results
FIGURE A4
2
4
.1
8a
Z
Q
o
03
T
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
APPLIED PRESSURE - KSF
Sample of CLAYSTONE
From TH•2 AT 34 FEET
TRISTATE GENERATION & TRANSMSSION ASSOCIATION
ERIE 20BKV SUBSTATION
CTL I T PROJECT NO. FC04T:L125
10
100
CRY UNIT WEIGHT_ 113 PCP
MOISTURE CONTENT= 18.4 %
Swell Consolidation
Test Results
FIGURE A5
9F
7
4
.1
2
2
K 3
W
Z
O 4
2
W
6
O
O
U
0.1
1.0
10
APPLIED PRESSURE - KSF
Sample Of CLAYSTONE, WEATHERED
From TH • 3 AT 4 FEET
TRI-STATE GENERATION & TRANSMISSION ASSOCIATION
ERE ZOKV SUBSTATION
CTL IT PROJECT NO. FC04773.1]S
100
DRY UNIT WEIGHT. 115 PCF
MOISTURE CONTENT. 15.8 %
Swell Consolidation
Test Results
FIGURE A6
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
z
a
X
2
O a
y
W
6
O
O
U
Bi
APPLIED PRESSURE- KSF
Sample of CLAYSTONE
From TH-3 AT 29 FEET
TRFSTATE GENERATION & TRANSMISSION ASSOGATON
ERIE 230 K SUBSTATION
CrL I T PROJECT Na FW4TT3.125
0
100
DAY UNIT WEIGHT. 116 PCP
MOISTURE CONTENT- 16.3 %
Swell Consolidation
Test Results
FIGURE A7
6
5
4
3
2
0
O4
i
a
K -5
W
Z
O c
N
W
2
6 -7
E
O
U
b
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
.1
LL
rr
T
0.I
1.0
APPLIED PRESSURE - KSF
Sample of CLAYST0NE, WEATHERED
From TH-4 AT FEET
TAI -STATE GENERAT1ON &TRANSMISSION ASSOCIATION
ERIE YYV(V SUBSTATION
CTLI T PROJECT NO. P000773-125
10
100
DRY UNITWEIC HT= 102 PCF
MOISTURE CONTENT- 26.5 E.
Swell Consolidation
Test Results
FIGURE A8
12
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
rT
0
-------------
0
z
a
0 B
0. -I
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TRISTATE GENERATION a TRANSMISSION ASSOCIATION
ERE 2]0W SUBSTATION
CR I T PRC ECT NO. FC04773-126
0 100
DRY UNIT WEIGHT.. 114 PCF
MOISTURE CONTENT*. 18.0 %
Swell Consolidation
Test Results
FIGURE A9
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APPLIED PRESSURE - KSF
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TRI-STATE GENERATION & TRAN4RGSION ASSOCIATION
ET4E 230XV SUBSTATION
CT.I T PROJECT NO.. F004773125
10
ISO
DRY UNIT WEIGHT= 107 PCF
MOISTURE CONTENT= 23.2 %
Swell Consolidation
Test Results
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APPENDIX B
SAMPLE SITE GRADING SPECIFICATIONS
TRISTATE GENERATION &TRANSMISSION A SVLAT10N
ERIE 2300/ SUBSTATION
CTI IT PROJECTNO. FCUa2T3125
SAMPLE SITE GRADING SPECIFICATIONS
1. DESCRIPTION
This item shall consist of the excavation, transportation, placement, and compaction of
materials from locations Indicated on the plans, or staked by the Engineer, as necessary
to achieve building site elevations.
2. GENERAL
The Soils Engineer shall be the Owner's representative. The Soils Engineer shall
approve fill materials, method of placement, moisture contents, and percent compaction,
and shall give written approval of the completed fill.
3. CLEARING JOB SITE
The Contractor shall remove all trees, brush, and debris before excavation or fill
placement is begun. The Contractor shall dispose of the cleared materiel to provide the
Owner with a clean, neat appearing job site. Cleared material shall not be placed in
areas to receive fill or where the material will support structures of any kind.
4. SCARIFYING AREA TO BE FILLED
All topsoil and vegetable matter shall be removed from the ground surface upon which
till is to be placed. The surface shall then be plowed or scarified to a depth of B Inches
until the surface is free from ruts, hummocks or other uneven features, which would
prevent uniform compaction by the equipment to be used.
5. COMPACTING AREA TO BE FILLED
After the foundation for the fill has been cleared and scarified, it shall be disked or
bladed until it is free from large clods, brought to the proper moisture content and
compacted to provide a firm base for fill placement.
6. FILL MATERIALS
On -site materials classifying as CL, SC, SM, SW, SP, GP, GC, and GM are acceptable.
Fill soils shall be free from organic matter, debris, or other deleterious substances, and
shall not contain rocks or lumps having a diameter greater than three (3) Inches. Fill
materials shall be obtained from the existing till and other approved sources.
7. MOISTURE CONTENT
Fill materials shall be moisture treated. Clay soils placed below the building envelope
should be moisture -treated to between 1 and 4 percent above optimum moisture content
as determined from Standard Proctor compaction tests. Clay soil placed exterior to the
TRI$TATE GENERATION &TRAN9NSSION ASSOCIATION
ERIE STOKE SUBSTATION
CR I T PROJECT NO. kdTTYI25
B-1
building should be moisture treated between optimum and 3 percent above optimum
moisture content. Sand soils can be moistened to within 2 percent optimum moisture
content. Sufficient laboratory compaction tests shall be made to determine the optimum
moisture content for the various soils encountered In borrow areas.
The Contractor may be required to add moisture to the excavation materials in the
borrow area if, in the opinion of the Soils Engineer, it is not possible to obtain uniform
moisture content by adding water on the fill surface. The Contractor may be required to
rake or disk the fill soils to provide uniform moisture content through the soils.
The application of water to embankment materials shall be made with any type of
watering equipment approved by the Soils Engineer, which will give the desired results.
Water jets from the spreader shall not be directed at the embankment with such force
that fill materials are washed out.
Should too much water be added to any part of the fill, such that the material is too wet
to permit the desired compaction from being obtained, rolling and all work on that section
of the fill shall be delayed unit the material has been allowed to dry to the required
moisture content The Contractor will be permitted to rework wet material in an
approved manner to hasten Its drying.
8. COMPACTION OF FILL AREAS
Selected fill material shall be placed and mixed in evenly spread layers. After each till
layer has been placed, it shall be uniformly compacted to not less than the specified
percentage of maximum density. Fill materials shall be placed such that the thickness of
loose material does not exceed 8 inches and the compacted lift thickness does not
exceed 6 inches.
Compaction, as specified in the report, shall be obtained by the use of sheepsfoot
rollers, multiple -wheel pneumatic -tired rollers, or other equipment approved by the
Engineer. Compaction shall be accomplished while the fill material is at the specified
moisture content. Compaction of each layer shall be continuous over the entire area.
Compaction equipment shall make sufficient trips to insure that the required density is
obtained.
9. COMPACTION OF SLOPES
Fill slopes shall be compacted by means of sheepstoot rollers or other suitable
equipment. Compaction operations shall be continued until slopes are stable, but not
too dense for planting, and there Is no appreciable amount of loose soil on the slopes.
Compaction of slopes may be done progressively in increments of three to five feet (3' to
5') in height or after the fill is brought to its total height Permanent fill slopes shall not
exceed 3:1 (horizontal to vertical).
TRISTATE GENERATION & TWNSKSSION ASSOCIATION
ERIE 2301W SUBSTATxIN
Cit I T PROJECT NO. FCGITT.12i
B-2
10. DENSITY TESTS
Field density tests shall be made by the Soils Engineer at locations and depths of his
choosing. Where sheepsfcot rollers are used, the soil may be disturbed to a depth of
several inches. Density tests shall be taken In compacted material below the disturbed
surface. When density tests indicate that the density or moisture content of any layer of
fill or portion thereof Is below that required, the particular layer or portion shall be
reworked until the required density or moisture content has been achieved.
11. COMPLETED PRELIMINARY GRADES
All areas, both cut and fill, shall be finished to a level surface and shall meet the
following limits of construction:
A. Overlot cut or fill areas shall be within plus or minus 2/10 of one foot.
B. Street grading shall be within plus or minus 1/10 of one foot.
The civil engineer, or duly authorized representative, shall check all cut and fill areas to
observe that the work is in accordance with the above limits.
12. SUPERVISION AND CONSTRUCTION STAKING
Observation by the Soils Engineer shall be continuous during the placement of fill and
compaction operations so that he can declare that the fill was placed in general
conformance with specifications. All site visits necessary to test the placement of fill and
observe compaction operations will be at the expense of the Owner. All construction
staking will be provided by the Civil Engineer or his duly authorized representative.
Initial and final grading staking shall be at the expense of the owner. The replacement of
grade stakes through construction shall be at the expense of the contractor.
13. SEASONAL LIMITS
No fill material shall be placed, spread or rolled while it is frozen, thawing, or during
unfavorable weather conditions. When work is interrupted by heavy precipitation, fill
operations shall not be resumed until the Soils Engineer indicates that the moisture
content and density of previously placed materials are as specified.
14. NOTICE REGARDING START OF GRADING
The contractor shall submit notification to the Soils Engineer and Owner advising them
of the start of grading operations at least three (3) days In advance of the starting date.
Notification shall also be submitted at least 3 days in advance of any resumption dates
when grading operations have been stopped for any reason other than adverse weather
conditions.
TRI STATE GENERATION a TRANSMISSION ASSOCIATION
ERIE 220(V SUBSTATION
CO. I T PROJECT NO. FCWln125
B-3
15. REPORTING OF FIELD DENSITY TESTS
Density tests made by the Soils Engineer, as specified under 'Density Tests' above,
shall be submitted progressively to the Owner. Dry density, moisture content, of each
test taken, and percentage compaction shall be reported for each test taken.
16. DECLARATION REGARDING COMPLETED FILL
The Soils Engineer shall provide a written declaration stating that the site was tilled with
acceptable materials, or was placed in general accordance with the specifications.
TRISTATE GENERATION & TRANSMISSION ASSOCIATION
ENE 23CI(V SLBSTAT.ON
CR I T PROJECT NO. FCOIT/SI25
B-4
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