HomeMy WebLinkAbout20151365.tiff cgG-MILLER ENGINE_
`NB
inberg-miller.corn MEMO
To: Andy Siegfried,Zion Engineering
From: Glen M. Bobnick, P.E.
Date: January 29, 2015
Re: Preliminary Geotechnical Findings, Milton Terminal Project, IME Project No. 17872 ZX
MESSAGE:
This memorandum summarizes the preliminary results of subsurface exploration that we performed
for the proposed Milton Terminal in Weld County, Colorado.
lnberg-Miller Engineers drilled a total of 6 test borings to depths of between 26.5 and 76.5 feet
below ground surface. We encountered essentially two soil strata during our exploration, which
included an overburden alluvium layer and sedimentary bedrock.
The overburden consists of loose to medium dense, fine to medium sand to clayey fine sand.
Overburden extends from ground surface to depths of between 7 and 13 feet below ground surface.
Overburden is characterized by low to moderate strength and moderate compressibility.
All 6 test borings were terminated in sedimentary bedrock below the overburden layer. Sedimentary
bedrock is highly weathered below the overburden as indicated by Standard Penetration Test blow
counts in the 20 to 50 range, but becomes less weathered through depth, particularly below depths
of 50 to 60 feet. Sedimentary bedrock is substantially comprised of claystone, with inter-bedded
sandstone layers. Sedimentary bedrock is characterized by moderate to high strength and moderate
to low compressibility.
Groundwater was encountered in only the 2 deepest soil borings at depths between approximately
20 and 40 feet. Groundwater is likely present within more permeable sandy layers or fractures
within the sedimentary bedrock.
We are in the process of performing laboratory testing to determine certain engineering properties
to support analysis and recommendations for our report. At this juncture the following issues are
being considered:
1. Clay or claystone may be expansive and testing is underway to evaluate this.
2. Overburden may be suitable for support of structures, provided there is adequate separation
between structures and any expansive soil. Subgrade preparation consisting of compaction
may be required to address loose zones or areas.
Page 1 of 2
3. Tank bearing pressure will likely induce settlement within the overburden and upper
sedimentary bedrock, and this will be estimated. Tank ring-walls may require some subgrade
preparation to provide uniform support within the overburden around the tank perimeter.
The above information is provided to help with initial project planning as we proceed through
laboratory testing and report preparation. Detailed design and construction information will be
provided in our final report which may differ or add to the information provided above.
Page 2 of 2
Hello