HomeMy WebLinkAbout1977-08-24 Prelim Soil Boring ReportfP
LOG OF BORINGS
PROJECT: 77-423 Preliminary Soil Burings S Percolation DATE: 8/24/77
Tests Proposed Subdivision
SE Quadrant Watertown S Willow SCALE: 1"-4'
)rono. Minnesota
BORING: B-1 LOCATION: ORING: B-2 LOCATION:
U . See Attached Sketch. UR See Attached Sketch.
1002.5+ 1007.0+
Depth DescA on o erlaIs A WL e t Doses Lion o Materials D WL
SANDY CLAY, with lenses SILTY CLAYEY SAND, fine
0 of SILTY CLAYEY SAND, CL to medium -grained, with S11-SC
..., with fine to medium with fine to medium Gravel,
.°tee Gravel, dark brown to SM-SC dark brown to brown, `!`
V4 brown, dry to moist. moist, i
d (Glacial Till) I 4 _ (Glacial Till)
u ,1 CLAYEY SILT, fine-
grained, brown mottled
> ,` 1'� U with gray, moist. ML
(Lacustrine)
b
c - —
SAND, fine to medium -
grained, with lenses SP
a of SILTY SAND, with fine wSMt' 13
to medium Gravel, brown, SANDY CLAY, brown,
moist to wet. moi�r. CL
c (Coarse Alluvium) (Glacial. Till)
w
m
v
u
P.
M 20 10
v
to Water level down 16' 10 Water level not encountered to
v� minutes after completion of cave-in depth of 18' immediatel
boring. after withdrawal of auger.
v
c
ro Water level down 14' 24 hours Water level not encountered
u after completion of boring. when probing boring 24 hours
aafter completion of boring.
A
Surface elevations -interpolated —
41 from topographic site plan
v provided.
1
Cal
h
0 A
0
0
1*
77-423
Georgc Jackson & Assoc. -4 - Aii,;ust 31, 1977
type can be questionable when wet and should be more
thoroughly investigated at a later time. Although power
auger borings do not provide information relative to the
strength parameters of the various soil types encountered,
mineral soils of the types brought to the surface by the
auger generally are of sufficient strength to support single
family dwellings without detrimental settlement. The black
mineral soils encountered in the majority of the borings
near the surface are likely quite soft and would not provide
an adequate foundation. These soils will likely have to be
removed in their entirety from the building areas prior to
construction.
The acceptable rate for percolation tests is 60 mpi; there-
fore, all of the tests conducted indicate rates of a magnitude
which would be considered acceptable. At the time of lot
developrent and when drainfield locations are establ=shed,
it is suggested that a more thorough check of soil *ptivity
rates be conducted.
Uf necessity, the area of the power auger borings and perco-
lation tests in relation to the areaof the subdivision and
the depth of the borings are limited. Suggestions and/or
recommendations of this report are opinions based on the
data obtained from the borings and percolation tests performed.
If we can be of further assistance in evaluating these data,
or in taking additional borings or percolation tests as the
development of the site progresses, kindly contact us at
your convenience.
Very truly yours,
113 4UN ENGINEERI G TESTING, INC.
Dennis M. Rietschel
Engineering Ass*stani
C. G. Krusc, P.E.
Tice President - l:nl;in�eri►to
DAllt/CGh: skf
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w. •n l...�. • l r .. fit .1-11 1116 .1\\..inr .11 1-111.111.t1...1, 1• •111, .r1 •.fir P,••trl•\ r1 .J,lr V•' •l ". 1 r :.Irril
BRAUR"
ENGINEERING TESTING
77-423
George Jackson & Assoc. -3-
August 31, 1977
that groundwater levels were completely stabilized at the
times the water level checks were made. 3) There is a
possibility that some of these areas contained "perched"
water levels. Water levels should be expected to show
normal seasonal and annual fluctuations. At the current
time, groundwater levels are at or slightly below the
normal.
Percolation tests indicated soil absorptivities, in minutes
per inch (mpi) as follows:
Test #
Surface
Elevation
Soil At
Test Depth
Rate
m i
P-1
1002.0±
Silty
Clayey Sand
(SM-SC)
13
P-2
1003±
Silty
Clayey Sand
SM-
15
-
-
i
e
P-4
1007.0±
Silty
Clayey Sand
(SM-SC)
8
P-5
995±
Silty
Clayey Sand
(SM-SC)
15
P-6
994.5±
Silty
Clayey Sand
(SM-SC)
17
Y-7
995±
Silty
Clayey Sand
(SM-SC)
12
P-8
994.5±
Silty
Clayey Sand
(SM-SC)
12
P-9
967±
Silty
Clayey Sand
(SM-SC)
7.5
P-10
967.5*_
Silty
Clayey Sand
(SM-SC)
20
P-11
953±
Silty
Sand (SM)
20
P-12
949±
Silty
Sand (SM)
IS
P-13
974.5±
Silty
Clayey Sand
(SM-SC)
15
P-14
970.5
Silty
Clayey Sand
(SM-SC)
12
P-15
983±
Silty
Clayey Sand
(SM-SC)
ZO
P-16
984±
Silty
Clayey Sand
(SM-SC)
30
PRELIMINARY
RECOMMENDATIONS:
You have indicated that current plans call for developing
this site as a single family, residential area. The total
size of the site is 23 acres; however, individual lot size
is not known at this time. You did, however, indicate that
it is desirable for each dwelling to have an individual
sanitary disposal system.
Borings were taken at random across the site and provide
preliminary information relative to the general soil types
encountered in this area. The borings did not encounter any
highly organic soils such as peat or muck; however, some
black mineral soils were encountered over the majority of
the tract, ranging in depth from 6 inches to 3 feet. Also,
a clayey silt lacustrire deposit was also encountered in
boring B-2 between the 4 and 13-foot depth. Soils of this
Bmut
ENGINEERING TESTING
77-423
George Jackson F, Associates -2- August 31, 3977
Percolation tests were run
to a depth of 36 inches, in
normally used on lots that
In accordance with standard
permitted to soak overnight
in 6-inch diameter holes, drilled
accordance with procedures
will be developed residentially.
procedures, the holes were
before conducting the tests.
Each of the borings were probed immediately after completion
to check for the presence of groundwater.
RESULTS:
The log of soils encountered in the borings and the water
level observations are shown on the attached Log of Bor.;ig
sheets.
Boring B-1 encountered a sandy clay glacial till from the
surface to the 11-foot depth, underlain by coarse alluvium
sands and silty sands to the 20-foot termination depth in
this boring.
Boring encountered a silty clayey sand glacial till from
the surface to the 4-foot depth, which was immediately
underlain by a clayey silt lacustrine deposit from the 4 to
the 13-foot depth. Sandy clay glacial till was then encoun-
tered to the 20-foot termination depth in this boring.
The balance of the borings, B-3 through B-8, all encountered
glacial tills consisting of silty clayey sands in the upper
Iportions of the borings to sandy clays at depth.
In probing the borings immediately after completion, it was
noted that cave-ins had occurred in all of the borings
betty and 18�-foot de the he exception being
ring B-1 where roun ncounter 6-foot
�dep pproxima e y hours later, a rec eck of eac
re holes indicated no groundwater occurrence in borings
B-2 and B-8. red at a depth of 7 feet in
boring B-5 14 feet in boring B- 15 feet in boring B-7, 16
feet in bor at the 17-foot depth in
boring B-6. Water level readings vary considerably, ranging
from elevation 936, as indicated by boring B-6, taken in the
far southeastern corner of the site in what appears to be
the lowest area on the site, to elevation 988, indicated by
boring B 1 and taken in the upland area in the southwestern
portion of the site. These water level variations can be
attributed to several factors. 1) The undulating topographic
features of the site indicate that water levels are following
the contours and subsequent drainage patterns developed in
this area. 2) Because of the cohesive nature of the soils
encountered, considerable time is required in order for the
groundwater to stabilize in the borings. It does not appear
BRAUR"
ENGINEERING TESTING
An Expansion of Soil Engineering; Services, Inc
IINNEAPILIS/ST. ►AUL I= S. County Rd.18, ► 0. Buff 35108, Mph_ Ms. SS4351012.541 ON
ORTHERII NINNESOTA 3211 E. IhbAruffuu, Hibbing, Me. 55141 121I.263-INS
August 31, 1977
George Jackson & Associates
Suite 1760 Shelard Tower
Minneapolis, MN S5426
Attn: Mr. Bob Tyler
Mr. Tyler:
Braun'
ENGINEERING TESTING
S ffeau�. [ .
w A:A11:.M. Vn. h.. gor.rwnr
C G . .'IS[ P [ . Va. P_ f.yn....ry
Re: 77-423 PRELIMINARY SOIL BORING
PERCOLATION TESTS
Proposed Subdivision
S.E. Corner of Watertown
Road & Willow
Orono, Minnesota
As requested, we have recently conducted a preliminary soils
investigation consisting of 8 power auger borings and 16
percolation tests. These borings were taken to determine
general soil and water conditions over the above referenced
subdivision. The percolation tests were conducted to pro-
vide preliminary information relative to the soil absorptivity
rates. The borings and percolation tests were taken at the
locations as shown on the attached sketch. Field locations
were determined by you and our crew chief as determined by
topographical features as shown on the topographical survey
provided by you. Surface elevations were interpolated from
the contour elevations shown on this same survey.
1NVESTIGATION METHODS:
Power auger borings were completed using a CME-45 truck -
mounted power auger unit. The soil classifications and
depths as shown on the attached logs were inferred from the
soils brought to the surface by the continuous flight feature
of the auger and are thus somewhat approximate,
Mineral soils encountered in the borings were classified in
accordance with the Unified Soils Classification System. A
copy of that chart is attached. Representative sampples of
the soils brought to the surface by the auger will be retained
in this office for a period of 60 days to be available for
your examination.
CONSULTING ENGINEERSIMLS AND MATERIALS
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