HomeMy WebLinkAboutB12-0318 / B12-0319 SOILS REPORT HN.E��e��nli-I',n�l:ik (�c��tr�hnir:�l, In�.
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HE WORTH-PAWLAK GEOTECHNICAL F�\:y_��y�� ���{
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Septe ber 17, 2012
Sunde , Inc.
Attn: J hn Sunderland
P. O. ox 1393
Edwar s, Colorado 81632
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Job No. 112 252A
Subjec : Interim Findings of Subsoil Study and Partial Observation of Excavation,
Proposed Zuckerman Duplex, Lot 3, Bighorn Subdivision Second
Addition, 3807 Lupine Drive, Vail, Colorado
Dear J .
This le er provides interim findings of the subsoil study we are cutrently performing for
founda ion design of the proposed residence at the subject site. The letter also provides
results f our partial excavation observation of the northwestern portion of the proposed
buildin to evaluate the soil bearing conditions exposed. Additional information will be
provid in our project report.
An exis ing residence on the lot has been removed for the new construction. There has
been so ne fill placed on the lot for the previous construction. The terrain is strongly
sloping down to the northeast towards Gore Creek which borders the north side of the lot.
We obs rved two exploratory pits (Pits 1 and 2) at the site to evaluate the subsoil
conditi ns. Pit 1 was located to the northwest and Pit 2 was located to the southeast of
the pro sed building. The subsoils encountered in Pit 1, below about 4 feet of fill,
consist of 1%2 feet of stiff, very sandy silty clay underlain by relatively dense, slightly
silty sa dy gravel and cobbles. Results of swell-consolidation testing perfonned on
samples of the very sandy silty clay and the clayey silty sand soils indicates moderate
coinpre sible under conditions of loading. Free water was encountered in Pit 1 at a depth
of 7 fee at the time of excavation and no free water was encountered in Pit 2 at the time
of exca ation.
A sprea footing foundation bearing on the natural coarse granular soils designed for an
allowab e bearing pressure of 2,000 psf appear feasible for foundation support of the
building� All fill, topsoil and fine grained clay and sand soils should be removed below
footing reas. Groundwater is expected to be encountered in the foundation excavation in
the nort western portion of the building. The groundwater should be removed from the
excavati n prior to the footing construction. It should be feasible to dig a sump pit
outside t e footing area and pump the groundwater for shallow draw-down. About 6 to
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Sund r, Inc.
Septe ber 17, 2012
Page
12 in �hes of minus 1% inch screened rock can be placed in the bottom of the excavation
to aid in the dewatering and allow construction of the footings in the dry.
On S ptember 14, 2012, we observed the foundation excavation for the northwestem
porti n of the building. The excavation had been cut in two leve(s from about 6 to 10 feet
belo the adjacent ground surface. The soils exposed in the bottom of this portion of the
exca tion consisted of relatively dense, slightly silty sandy gravel and cobbles. The
excav tion was observed to be adequately dewatered by a sump and pump placed outside
of the footing area. About 8 inches of minus 1'/2 inch size screened rock had been placed
in the excavation bottom. The bearing soils and constructed conditions are suitable for
supp of spread footings designed for an allowable bearing pressure of 2,000 psf.
The ater seepage into the excavation should continue be collected and diverted away
from he footing areas and any softened soils and mud removed before concrete
place ent. We should observe the remaining portion of the excavation when completed.
We w 11 forward our project report when completed. In the meantime, if you have any
questi ns or need further assistance, please contact us.
If you have any questions or need further assistance, please call our office.
Since ely,
HEP ORTH — PAWLAK�R���'HNICAL, INC.
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Job No. 12 252A
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