HomeMy WebLinkAboutSTOLLE Subsurface Investigation S-4878
MEMORANDUM
~) A T E:
March ~'0, 1981
TO:
FROM:
SUBJECT;
Planning DeparLment
Health and Environment. al Protection
S-4878: Stolie Subd~!~ision
The new subdivision design of larger lots and satisfactorty
percolations tests will support on-site septic systems. The
submittal is now approved by this department.
Les N. Buchholz, R.S.
Senior Environmental
LNB/ljw
Specialist
DATE:
TO:
FROM:
SUBJECT:
AAu , pa:lity of Anchorage
MEMORANDUM
Referencing Case #S-4878 - Stolle Subdivision - additional sub-surface
investigation for on-site sewer disposal system appears to be adequate
as submitted, but Test Hole 5 and Test Hole 7 indicate shallow bedrock.
This Department recommends putting in Test Holes at Lot 6 and Lot 4 in
Block 1, and Lot 6 in Block 2 to establish the bedrock depth strata.
Three Percolation Tests in T;~ l, 2, & 4 indicate 150 square feet per
bedroom. This Department also requests Percolation Tests on new Test
Holes referred to on locations shown above.
/Si ncerel~,, .x~
/// Environmental E.ngi neerl.ng
JWL: 1 mp
91-010 (4/76)
Subdivision Plat Reviews
July 18, 1978
Page 2
S-4868
Contracting Engineers and Associates for Peaceful Acres Subdivision located
in the NW 1/6 NE 1/4 SE 1/4 and NE 1/4 NW 1/4 SE 1/4 Sec 27 T12N R3W, S.M. Ak
containing 20.00 acres ~ore or less.
Public ~ater not available. Public sewer not available to service petition area. This
Department requests inspections on Lots l, 2, 6, 7, &8 prior to construction. Soils en
balance of Lots are adequate as submitted in soils report.
~'S-4878 ~Tryck N~an & Hayes for Plat of Stolle Subdivision located within SE 1/~ NE 1/4
.... -/ Sec 6, TllN, R2W, S.M. Ak., containing 40 acres, 2~ Lots.
Public water not available. Public sewer not available to service petition area. This
Department must have soils test Profile of Plat; Note Soils t_s~ hole to 16'.
S-4880 Tryck N~nan & Hayes for Plat of Youngs Subdivision located within SW 1/4 '-
Sec 3, TllN, R3W, S.M. Ak, containing 20 ~acres, 14 Lots.
Public water not available. Public sewer not available to service petition area. This
Department must have soils tests on Profile of Plat; Note - soils test holes to 16'
in depth.
S-4885
DOFIL for Resource Investments Subdivision No. 1 Preliminary Plat located in
SW 1/4 Sl.l 1/4 Sec 17, T12N, R3W, S.M. Ak.
Public water not available. PUblic sewer not ava~loble to service petition area. This
Department must have soils test on lots prior to approval of subdivision.
S-4895
Tryck N~an & Hayes for Plat of Iliamna Acres Subdivision Tracts SA, 5B, 5C &
5D - a subdivision of Tr 5, Iliamna Acres Subdivision located ~ithin NE 1/6
Sec 34, T12N, R3W, S.M. Ak., containing 10~ acres & 4 Tracts.
Public water not available. Public sewer not available to service petition area.
Resolve soils tests~d Da'ca on location of well.
/ / J~-~. Ly~n
~ Environmental Engineering
~ JI'~L: lmp
4040 'B" STREET
ANCHORAGE, ALASKA 99503
(907) 278-1551
August 17, 1978
W.O. A18586
Mr. Mike Stolle -- {(
814 W. 2nd Avenue v~; Z ~' ~ [Y
Anchorage, AK 99501
Subject:
Subsurface Investigation to Ascertain Suitability
of Placing On-Site Sewage Disposal Systems in
Stolle Subdivision located with the NE 1/4, Section
6, T. 11 N., R. 2 W., Seward Meridian, Alaska.
Dear Mr. Stolle:
We have preformed the subsurface investigation on'the above
referenced parcel to ascertain suitability for placement'of
on-site seware disposal systems on' the individual lots With
an anticipated R-6 development (1-1/4 acre lots). We have'
used as our basis for this exploration, ~he preliminary plat
prepared, and provided to us by Tryck, Nyman & Hayes Engineers.
The data from that subsurface investigation is presented as
follows:
Test Hole Location Sketch Figure 1
Test Hole Logs -' Table A
Individual Lot Percolation Ratings Table B
Grain Size Distribution Sheets 1-4
Standard Explanatory Information Sheets 5-7
CONCLUSIONS
The site soils are granular in nature; generally fairly
Clean gravelly sands and sandy gravels. Every lot in
the subdivision should have soil conditions such that
its percolation rating will fall range of 100 to 200
sf/bedroom A detailed listing of the estimated and
actual ratings for all the lots within the subdivision
is included in this report as Table B.
Little shallow, subsurface water was encountered on the
site. Water in sufficent quantities was not detected
in any of the test holes that would preclude development
of a disposal system. However, any small streams,
Mr. Mike stolle
August 17, 1978
Page 2
springs, or natural drainage paths should be avoided.
It should also be remembered that the water level will
fluctuate with seasonal and climatic changes~ This summer
water levels have been.quite high.
Bedrock was encountered in test hole ~3 at 15.3', test
hole #5 at 10.5' and in test hole #7 at i2.5'. Though
the bedrock is relatively shallow on this site, we do
not anticipate it precluding the development of systems
on subject lots. The lots are big enough that if
bedrock is encountered above the.12' level it should be
possible to move the system to a more desirable location
(i.e. bedrock bel6w 12.').
DISCUSSION
'The exploration consisted of the placing of eight test holes
as located on Figure 1. The holes were drilled using a
tract mounted Mobile Drill B-50' drill rig owned and operated
by Denali Drilling, Inc. The. test holes were logged and the
drilling supervised by ~. T.L~ Barber, staff geologist with
Alaska Testlab.
The holes were drilled using solid, continuous flight auger.
Grab samples were taken driectly off the drill bit as the
auger was raised to the surface. As samples were recovered,
they were placed in sealed plastic bags and transported to
the laboratory where their natural moisture content and dry
strength were determined. Each sample was then visually
classified with samples of similar color, texture, and grain
size distribution being given an arbitrary group designation.
Further testing was then performed on a composite sample
from the group rather than on individual samples.
A total of five groups were encountered and are described
below:
Group A
Group B
is a brown Silty Sandy Gravel that is moderately frost
susceptible, being rated F-1. Its unified classifica-
tion is GM and its gradation is shown on Sheet 1.
This is generally the predominant soil on the site.
is a brown Silty Sand'that is moderately frost
susceptible, being rated F-2. Its unified classification
is SM.
Group C
is a bro~ Silty Gravelly Sand that is moderately
frost suscept~e, being rated F-2. Its unified
classification is SM and its gradation is'shown on
Sheet 2.
Mr. Mike Stolle
~ugust 17, 1978
Page 3
Group D
Group E
is a brown Silty Gravelly Sand that is mo.derately
frost susceptible, being rated F-2. Its unified
classification is SM/SW and its gradation is shown
on Sheet 4.
is a brown Silty Sandy Gravel that is moderately
to highly frost susceptible, being rated F-l/F-3.
Its unified classification is GM. .
We hope this information is sufficient for your present
needs. If we can be of further assistance or help in interpreting
any data, please do not hesitate to contact us.'
.Very sincerely,
Laboratory Manager
MR~]:rb
Enclosures
Test Hole #1
Table A
WO #A18586
Logged By~ T.L. Barber
Date: August 11, 1978
Depth in Feet
From To
0.0' - 1.5'
1.5' - 2.5'
2.5' - 16.0'
Soil Description __'
Brown Organic Overburden, wet to saturated,
soft.
F-4, brown Sandy Silt, ML, topsoil, wet,
soft, NP.
F-l, brown Silty Sand~ Gravel, GM, wet,
medJtnr, to high density, particles to 1~1/2",
Group A.
Bottom of Test Holt:
Frost Line:
Free Water Level:
16.0' Remarks:
None Observed
None Observed
Perc test run in this hole
5.0 min/inch
SamFl__e Dept~k
1 2.5'
2 5.0'
3 10.0'
4 15.0'
Blows/6'__' M__%
Type of Dry
Sample Strength-- Grou~ Unified
23.9 G L -- ML
11.0 G N-L A GM
9.3 G N-L A GM
14.9 G .~ L ' A GM
Remarks: 1.
3.
4.
5.
6.
Type of Sample, G=Grak., SP = Standard Penetratien,
U = undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=Higb.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole 92
Table A
WO #A18586
Logged By: T.L. Barber
Date: August 10, 1978
Depth in Feet
From To
0.0' - 3~5'
Soil Description
F-2, brown Silty Gravelly Sand,
to medium density, Group B.
SM, damp, iow
F-l, brown Silty Sandy Gravel, GM, Group A.
Bottom of Test Hole:
FrOst Line:
Free Water Level:
16.0' Remarks:
None Observed
None Observed
Perc~ test run in this
2.5 min/inch
hole
Sample Depth
1 2.5'
2 5.0'
3 10.0'
4 16.0'
Type of Dry
Blows/6" M% Sample ~trength Group Unified
- 11.7 G N B SM
- 10.5 G N-L A GM
- 6.8 G N-L A GM
- 8.2 G N-L A GM
Remarks: 1.
3.
4.
5.
6.
Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=14edium, H=High.
Group refers to similar material, this study only.
General Information, see Sheet 7.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole ~3
Table A
WO ~A18586
Logged By: T.L. Barber
Date: August 10, 1978
Depth in Feet
From To
Soil Description
0.0' - 2.0'
2.0' 15.3'
F-4, brown Sandy Silt, ML, wet..
F-l, brown Silty Sand~ Gravel,' GM~ damp,
medium to h~h density, pa-~cles to 3/4",
Group A.
Bottom of Test Hole:
Frost Line:
15.3' Remarks:
None Observed
Fractured bedrock encountered
at 15.3'
Free Water Level:
None Observed
Sample
!
2
3
Depth
3.0I
5.0'
10.0'
Type of Dry
Blows/6" M% Sample Strength Group Unified
12.3 G N-L A G.X!
7.1 G N-L A GM
7.3 G N-L A GM
Remarks: 1.
3.
4.
5.
6.
Type of Sample, G=Grab, SP = Standard. Penetration,
U = undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole
Table A
WO #A18586
Logged By: T.L.. Barber
Date: August 10, 1978
Depth in Feet
From To
0.0' - '1.5'
1.5' 5.0'
5.0' - 16.0'
Soil Description
F-4, brown Sandy Silt, ML, damp, soft.
F-l, brown Silty Sandy Gravel, GM, damp to
wet, medium'denSity, partlcl--~-es to 1", Group A.
F-2, brown Silty Gravelly Sand, SM/SW, wet,
low to medium density, particles to 3/8",
Group D.
~ottom of Test Hole:
Frost Line:
Free Water Level:
16.0' Remarks:
None Observed
None Observed
Perc, test run in this hole
3.3 min/inch
Sample Depth
1 2.5'
2 5.0'
3 10.0'
4 16.0'
Blows/6"
Type. of Dry
M% Sample Strength Group Unified
7.1 G N A GM
-- G - A GM
11.3 ~ L. C SM
-- G .' - D SM/$W
Remarks: 1.
3.
4.
5.
6.
Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium,. H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole #5
Table A
W0 #A18586
Logged By: T.L. Barber
Date: August 10, 1978
Depth in Feet
From To
0.0' - .1.0'
1.0' - 10.5'
Soil Description
F-4, brown Sandy Silt, M_L, damp, soft, NP.
F-2/Fr3,
to wet,
and E.
brown Silty Gravelly Sand, SM, damp
high density, particles to 1", Groups C
Bottom of Test Hole:
Frost Line:
Free Water Level:
Sample Depth
1 2.5'
2 5.0'
3 10.0'
10.5' Remarks:
None Observed
None Observed
Bedrock encountered at 10.5'
Type of Dry
Blows/6" M% Sampl¢ · Strength Group Unified
- 9.8 G
- 11.7 G
- 9.3 G
N'L E GM
N-L E GM
L C SM
Remarks: 1.
3.
4.
5.
6.
Type of 'Sample, G=~rab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=High.
Group refers to similar material, {his study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole ~5A
Table A
WO ~A18586
Logged By: T.L. Barber
Date: August t0, 1978
Depth in Feet
From To
0.0' 0.5'
0.5' 16.0'
Soil Description
F-4, brown Sandy Silt, ML, damp, soft.
F-l, brown Silty Sandy Gravel, GM, damp,
to wet, Group A.
Bottom of Test Hole:
Frost Line:
Free Water Level:
16.0'
None Observed
None Observed
Sample
Depth
I 2.5'
2 5.0'
3 10.0'
4 16.0'
Blows/6" M%
8.
5.
7.
.Type of
.sample
Dry
Strength Group Unified
G N A GM
G N-L A GM
G N-L A GM
G N D SM/SW
Remarks: 1.
3.
4.
5.
6.
Type of Sample, G=Grab, SP = Standard Penetration~
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
· Test Hole #6
Table A
WO #A18586
Logged By: T.L. Barber
Date: August 10, 1978
Depth in Feet
From To
O.0'- 3.0'
3.0.' -' 8.0'
8.0' - 16.0'
Soil Description
F-2/F-4, brown Silty Sandy/Sandy Silt, SM/ML
damp.
F-2, brown Silty Gravelly Sand, SM, wet,
particles to 3/4", Group C.
F-l, brown Silty Sandy Gravel, GM, wet, medium
to high density, particles to 1", Group A.
Bottom of Test Hole:
Frost Line:
Free Water Level:
16.0''
None Observed
None Observed
Sample Depth
3.0'
5.0'
10.0'
16.0'
Type of Dry
Blows/6" M% Sample Strength Group Unified
- 24.9 G N - /~L
- 18.5 G L C SM
- 12.4 G N A GM
· - 7.4 G N A GM
Remarks:
1. Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
2. Dry Strength, N=None, L=Low, M=Medium, H=High.
3. Group refers to similar material, this study only.
4. General Information, see Sheet 1.
5. Frost and Textural Classification, see Sheet 2..
6. Unified Classification, see Sheet 3.
Test Hole #7
Table A
WO #A18586
Logged By: T.L. Barber
Date: August 11, 1978
Depth in Feet
From To
0.0' - 3.0'
3.0' - 12.5'
Soil Description
F-2, brown Silty Gravelly Sand, SM, wet,
particles to 3/~", Group C.
F-2, brown Silty Gravelly ~and, SM/SW,
wet, medium to high density, particles to 1",
· Group D.
Bottom of Test Hole:
Frost Line:
Free Water Level:
Sample Depth
1 2.5'
2 5.0'
3 10.0'
12.5' Remarks:
None Observed
None Observed.
Bedrock encountered at 12.5'
· - Type of Dry
Blows/6" Mt' Sample · Strength Group Unified
- 25.5 G L C SM
- 10.5 G N D SM/SW
- 11.5 G L D SM/SW
Remarks: 1.
3.
4.
5.
6.
Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classificatioq, see Sheet 2.
Unified Classification, see Sheet 3.
TABLE B
Based on the exploration and the laboratory analysis that we
have performed, we estimate that i% should be possible to
find an area on each lot within the subdivision that'can
have a percolation rating of 15 minutes/inch or leds. Based
on the data we have collected, this should be a conservative
figure.
Furthermore, the following lots can be given an even better
rating as noted at this time.
'Lot 1, Block t: 10.0 minutes/inch visual rating
Lot 9, Block 1: 10.0 minutes/inch visual rating
.Lot 12, Block 1: 10.0 minutes/inch visual rating
Lot 15, Block 1:
Lot 5, Block 2:.
Lot 2~ Block 2:
2.5 minutes/inch actual percolation test
12.0 minutes/inch visual rating'
10.0 minutes/inch visual rating
Lot 5, Block 2:
Lot 6, Block 2:
3.3 minutes/inch actual percolation test
3.3 minutes/inch ~ctual percolation test
Lot 1, Block 3:, 5.0 minutes/inch actual percolation'test
It is intended that the value of 15.0.'minutes/inch be a
conservative one. It may well prove economic in overall
reduction of the cost of building the on-site system to
perform an actual percolation test on the lots with the 15.0
minutes/inch estimated percolation rating. The test hole
data, the gradation, and the percolation tests run indicate
that generally the soils on the site are far better than
this.
We would like to caution, though, that the test holes only
look at an area of about 9 inches in diameter.. Though the
soils on the site appear to be generally granular, significant
changes can occur very quickly both for the better and for
the worse. We, therefore, feel that it is important that
the absorption trench when it is opened up, be carefully
inspected. If the existing soil conditions are found to vary
substantially from those shown in this report, it may be
economic to reduce the size of the trench, if the soils are
better, or it may be necessary to increase the size of the
trench if the soils prove worse. With the size of the.lots,
it should be possible to move to another location if a
pocket of silt is encountered.
o ~
4040 "B" STREET
ANCHORAGE, ALASKA 99503
(907) 278-1551
August 23, 1978
W.O. A18586
Mr. Mike Stolle
814 West 2nd Avenue
Anchorage, AK 99501
Re: Gravel Availability - Stolle Subdivision
Dear Mr. Stolle:
Per the request of Mr. Dave Grenier of Tryck Nyman Hayes, we
have ex~mined more closely the availability of on-site gravel
for use within the subdivision.
The most promising extraction area is on the ridge to the south-
east in the area of test hole 5A. We re-examined the samples from
that test hole and ran a mechanical analysis of these soils. They
proved to be marginally non-fro~t susceptible (NFS).
The field geologist .feels the samples may not be entirely represent-
ative of actual in-place soils, which is often the case in gravels.
To truly assess the quality and quantity of the material, we feel
a series of approximately 6 to 10 backhoe pits should be placed
in the area. It does look promising at this point.
We have enclosed the gradation for the samples.
If you have any questions, please let us know.
Sincerely,
ALASKA
T E S T L A B
Melvin R. 'Nichols, PE
Laboratory Manager
MRN:mfm
cc: Mr. Dave Grenier, Tryck Nyman & Hayes
Enclosures
'Test Hole Lo9 - Description Guide
~he soil descriptions shown on the Ings are the best estimate of the ~oil's
,recision of a laboratory testing procedure. If thc log includes soils samples,
,, verify the field examination..
f'he logs often include the following items:
Depth Interval - usually shown to 0.1 foot, within that zone no '
significant change in soil type was observed through drill action, dh'cee
observation or sampling.
Frost Classification - NFS, FI, F2, Fa, F4, see "Soil Classification
Texture of Soil - An engineering classification of the soils by particle
size and prcJpurtion, see "Soil Classification Chart", note the
d~, n. or little apparent surface moisture.
~. moisture forms portion of color, less than plastic limit,
wet. no free water, often soft, if cohesive soil,
sand. (The moisture content is further defined by reference to PI,
LW, NP. M%or dilatency.}
Density - refers to more-or-]ess non-cohesive soils, such as sand gravel
mixt~--'es with or without a fine fraction, derived from drilling action
and/or sample data: u~ually describeda's: very loose, loose, medium
dense, very dense. General intent is-.to portray earthwork
characteristics.
Stiffness - refers to more-or-less cohesive soils and fine grained silts of
the clay-sih groups. Derived from drill action and[or sample data, Very
s~ft, soft. stiff, very stiff and hard are commonly used terms.
Palticle size - Thc largest particle recovered by the split spoon is
1-3/8", Shelby tube 3". auger flights (min0te-man} 2", Auger flights
{B-S0 hollow stem} 6"-g". Larger particles are described indirectly by.
action of the drilling and are referred to aa cobbles. 3" to 8", or
boulders 8"+. Theref~ore when reviewing tile gradation sheets, if any,
the description on thc hole log must be considered for an indication of
larger p~r titles.
Unified Soil Classificatinn - This is a two letter code. See Unified
~2}assificatinn sheet I~r further definition. [n some cases AASHO and/or
FAA soil classifications may be shown as well as thc unified.
Atterbeeg Limiis - useful for fine grained and other plastic softs.
PI; natural moisture content believed to be less than plastic ~mit
PI~-; natural moisture content believed to be between plastic and liquid
limits
L.~; natural moisture content believed to be greater than liquid limit
HP; non-plastic, useful as a modifying description of some silty
Dilatencv - is the abdity of water to migrate to the surface of ·
~aturated or nearly saturated ~oil sample when vibr·ted orj0hcd - used
as an ~id to determine if a fine grained soil is · slightly or non-phstic
Rock flour - finely ground soil that is not plastic but other, vise appears
Organic Content - usually described as Peat, PT. sometimes includes
soil, Quantity described as; trace, or an estimate of volume, or. in case
Muck -- a modifier used to describe very sof~, semi-organic dcposil~
Amorphus peat - organic particles nearly or I~ully disintegrated.
samples at the time of drilling.
Frozen Ground - other than frost line. described by samples, usually
permafrost studies.
BIowl6," - Thc number of blows of a 140 weight free falling 30" to
by definition, the. standai~d penctj'ation.
Type of Sample -
C. cut ~ample. undisturbed sample from wall of trench.
Dry Streni'.tb - a useful indicator of asoil's clayey fraction, N--None,
L=LOW, M~Medium, H=Higb
Group -- The samples are placed into apparently simdar groups based
selationship, etc. may be performed on the group and are assumed to
SOIL CLASSIFICATION CHART
30o/,
GRAVEL
0 10 20 30 40 50 60 70 80 90. 1 00
GRAVEL (+#4 SCREEN) % BY WEIGHT
NONFROST SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN 3% FINER THAN 0.02 mm.
GROUPS OF FROST-SUSCEPTIBLE SOILS:
GRAVELLY SOILS CONTAINING BETWEEN 3 AND 20% FINER THAN 0.02 mm,
F2 SANDY SOILS CONTAINING BETWEEN 3 AND 15% FINER THAN 0.02 mm.
F3 a. GRAVELLY SOILS CONTAINING MORE THAN 20% FINER THAN 0.02 mm. ANO SANDY SOILS
(EXCEPT FINE SILTY, SANDS) CONTAINING MORE THAN 15% FINER THAN 0,02 mm.
b, CLAYS WITH PLASTICITY INDEXES OF MORE THAN 12. EXCEPT VARVED CLAYS,
F4 a, ALL SILTS INCLUDING SANDY SILTS.
b. FINE SILTY SANDS CONTAINING MORE THAN 15% FINER THAN 0.02 m~,
c. LEAN CLAYS WITH PLASTICITY INDEXES OF LESS THAN
d. VARVED CLAYS.
Bole No._ 1
Location Top o~ r~d~e alonq
N pro__perty line of 40 acre
parcel
Top Elev. Exist in~
Depth CLASSIF{~ATION
Feet SYSTE,~
sheet __1_ of ~
W.O. No ....... Operator-~M-DP
Date _ 9/25/76
Client~l]~? ..-~
Project__SE 1/4 N.E 1/4 Sec 6
TllN R2W S.M.
1
2 Brown Silty Sands,
moist to wet
3 (SP/SM)
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21-
22
23
24
25
26
Dense Gravelly Sandy Silts
(SM/ML)
Bedrock
Note: Sands would provide
perco'lation for on-site
leach fields on ~tre~¢ sized
lots. No groun~encountere~-
Bedrock was verified at the~ .
minus 9.5 ft depth by ~
drilling 2 test holes approx-
imately 50 feet apart.
SAMPLE
DATA
LEGEND
GRAVEL
SAND
SILT
CLAY
ORGANIC
CONTENT
PEAT
.FROST
WAT ER
TABLE
Hole No. 2
Location Located in drainages__
area in the vicinity of Litq~e
Rabbit Creek (above the ro~_q~J
Top Elev. E,j is ~in~
Depth CLASSIFICATION
Feet SYSTEM .........
2
3 ~!!iGravelly Silty Sand, wet
4 (SP/SM)
5
7f
8 .
9 . Gr~vell'y Silts with water,
10. bearing sandier layers
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Bottom of Test Hole
Note: No bedrock encountere,
Ground water in layers
throughout depth of test
hole. On site sewage syster
would require package treat-
ment type sewage plants with
chlorinators a minimum of
100 feet away from Little
Rabbit Creek drainage area.
25
SAMPLE
DATA
'Sheet -
W.O. No.__ _Operator JM-DP
Date '9/25/76
Client
Project__SE 1__/4 N~ 1l! Sec
. TllN R2W S.M.
LEGEND
GRAVEL
SAND
SILT
CLAY
ORGANIC
CONTENT
PEAT
FROST
WATER
TABLE
3
Hole No._
Location.__ADmrox · % 5-~] ~>!'~
Homestead Cabin on the ....
access road
Top Elev. Ex~ist~nq .
Depth
Feat
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
CLASSIFICATION
.SYSTE~4
Gravelly Silty Sand, dry
(SM)
Silty Sandy Gravel, dry
(GP/GM)
Sandy .Silts (SM/ML)
silty Sands & Sandy Silts
with angular gravel
Bottom of Test Hole
Note: No bedrock or ground
water encountered. Soils
are suitable for on-site
sewage system.
S~'*PLK.
DATA
Sheet l__ of ~
W.O. No. _OperatoL JM-DP
Date 9/25/76 ,,~.
-~. ~ Mike Stolle _
Project. SE 1/4 NE 1/~.~ec
TllN R2W S.M.
LEGEND
GRAVEL
SAND
SILT
CLAY
ORGANIC
CONTENT
PEAT
FROST
WATER
TABLE
r~
Mr. Mike Stolle
814 W. 2nd Avenue
A~chorage, AK 99501
4040 "B" STREET
ANCHORAGE, ALASKA 99503
(907) 278-1551
August 17, 1978
Subject:
Subsurface Investigation to Ascertain Suitability
of Placing On-Site Sewage 9isposal Systems in
Stolle Subdivision located with the NE 1/4, Section
6,~T. 11 N., R. 2 ~., Seward Meridian, Alaska.
Dear Mr. Stolle:
We have preformed th~ subsurface investigation on the above
referenced parcel to ascertain suitability for placement of
on-site seware disposal systems on the individual lots with
an anticipated R-6 development (.1-1/4 acre lots). We have
used as our basis for this exploration, ~he preliminary plat
prepared, and provided to us by Tryck, Nyman & .Hayes Engineers.
The data from that subsurface, investigation is presented as
follows:
Test Hole Location Sketch
Test Hole Logs
Individual Lot Percolation Ratings
Grain Size Distribution
Standard Explanatory Information
Figure 1
Table A
Table B
Sheets 1-4
Sheets 5-7
CONCLUSIONS
The site soils are granular in nature, generally fairly
Clean gravelly sands and sandy gravels. Every lot in
the subdivision should have soil conditioms such that
its percolation rating will fall range of 100 to 200
sf/bedroom A detailed listing of the estimated and
actual ratings for all the.lots within the subdivision
is included in this report as Table B.
Little shallow, subsurface water was encountered on ~he
site. Water in sufficent quantities was not detected
in any of the test holes that Would preclude development
of a disposal system. However, any small streams,
Mr. Mike Stolle
August 17, 1978
Page 2
springs, or natural drainage paths should be avoided.
It should also be remembered that the water level will
fluctuate with seasonal and climatic changes. This summer
water levels have been quite high.
Bedrock was encountered in test hole ~3 at 15.3', test
hole #5 at 10.5' and in test hole'#7 at 12.5'. Though
the bedrock is relatively shallow on this site, we do
not anticipate it precluding the developmen~ of systems
on subject lots. The lots are big enough that if
bedrock is encountered above the 12' level it should be
possible to move the system to a more desirable location
'(i.e. bedrock below 12.').
DISCUSSION
The exploration consisted of the placing of eight test holes
as located on Figure 1. The holes were drilled using a
tract mounted Mobile Drill B-50 drill rig owned and operated
by Denali Drilling, Inc. The test holes were logged and the
drilling supervised by Mr. T.L. Barber, staff geologist with
Alaska Testlab.
The holes were drilled using solid, continuous flight auger.
Grab samples were taken driectly off the drill bit as the
auger was raised to the surface. As samples were recovered,
the~ were placed in sealed plastic bags and transported to
the laboratory where their natural moisture content and dry
strength were determined. Each sample' was then visually
classified with samples of similar color, texture, and grain
size distribution being given an arbitrary group designation.
Further testing was then performed on a composite sample
from the group rather than on individual samples.
A total of five groups were encountered and are described
below:
Group A
is a brown Silty Sandy Gravel that is moderately frost
susceptible, being rated F-1. Its unified classifica-
tion is GM and its gradation is shown on Sheet 1.
This is generally the predominant soil on the site.
Group B
Group C
is a brown Silty Sand that is moderately frost
susceptible, being rated F-2. Its unified classification
is SM.
is a brown Silty Gravelly Sand that is moderately
frost suscept---f~e, being rated F-2. Its unified
classification is SM and its gradation is shown on
Sheet 2.
Mr. Mike Stolle
August 17, 1978
Page 3
Group D
Group E
is a brown Silty Gravell~ Sand that is moderately
frost suscept-~e, being rated F-2. Its unified
classification is SM/SW and its gradation is shown
on Sheet 4.
is a brown Silty Sandy Gravel that is moderately
to highly fr--~ susceptible, being rated F-l/F-3.
Its unified classification is GM.
We hope this information is sufficient for your present
needs. If we can be of further assistance or help in interpreting
any data, please do not hesitate to contact us.
Very sincerely,
A~SKA TES~AB /
/
~f4elvin/R. ~ichols, P.E.
Laboratory Manager
~IP~%: rb
Enclosures
/
,1, ,
· Test Hole #1
Depth in Feet
From To
0.0' -~ 1.5'
1.5' - 2.5'
2.5' ' 16.0'
Bottcm of Test Holt:
Frost Line:
Free Water Level:
Table A
WO #A18586
Logged By~ T.L. Barber
Date~August 11, 1978
Soil Description
Brown Org6nic Overburden, wet to saturated,
soft. ~
F-4, browD SaD6.~y silt, ML, topsoil, wet,
soft, NP.
F-l, brown Silty ~ Gravel,, GM, wet,
· ~ · ~ I I 2"
medium to high density, particles to - / ,
Group. A.
16.0' Remarks~
None Observed
Perc test run
5.0 min/iDch
in this hole
None Observed
~ample Deptk
1 2.5'
2 5.0'
3 10.0'
4 15.0'
Type· of Dry
Blows/6" M% SamplE Strength Group Unified
23.9 G L ML
11.0 G N-L A GM
9.3 G N-L A GM
1419 G L A GM
Remarks:
2.
3.
5.
6.
Type of Sample, G=Gzak., SP = StaDdard Penetrat~en,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=Higb.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classificatmon, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole #2
Table A
WO #A18586
Logged By: T.L. Barber
Date: August 10, 1978
Depth in Feet
From To
0.0' 3.5'
3.5' 16.0'
Soil Description
F-2, brown ~ Gravelly Sand, SM, damp, low
to medium density, Group Bi
F-l, brown S$1ty Sandy Gravel, GM, Group A.
Bottom of Test Hole:
Frost Line:
Free Water Level:
16.0' Remarks:
None Observed
None Observed
Perc. test run in this hole
2.5 min/inch
Sample Depth
I 2.5'
2 5.0'
3 10.0'
4 16.0'
Type of Dry
Blows/6~' M% Sample Strength Group Unified
11.7 G. N B SM
10.5 G' N-L A GM
6.8 G N-L A GM
8.2 G N-L A GM
Remarks:
1. Type of Sample, G=Grab, SP Standard Penetration,
U = Undisturbed.
2. Dry Strength, N=None, L=Low, M=Medium, H=High.
3. Group refers to similar material, this study only.
4. General Information, see Sheet 1.
5. Frost and'Textural Classification, see Sheet 2.
6. Unified Classification, see Sheet 3.
Test Hole #4 Table A
WO #A18586
Logged By: T.L. Barber
Date: August 10, 1978
Depth in Feet
From To Soil Description
0.0' 1.5' F-4, brown Sandy Silt, ML, damp, .soft.
1.5' 5.0' F-l, brown Silty Sandy Gravel, GM, damp to
wet, medium density, partes to 1", Group A.
5.0' 16.0' F-2, brown Silty Grav~ll~ Sand, SM/SW, wet,
low to medium density, particles to 3/8",
GroupeD.
Bottom of Test Hole:
Frost Line:
Free Water Level:
16.0' Remarks:
None Observed
None Observed
Perc. test run in %his
3.3 min/inch
hole
Sample Depth
2.5'
5.0'
10.0'
16.0'
Type of Dry
Blows/6" M% Sample Strength Group Unified
7.1 G N A GM
-- G A GM
11.3 G L C SM
-- G - D SM/SW
Remarks:
2.
3.
4.
5.
6.
Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test ttole #5
Table A
WO ~A18586
Logged By: T.L. Barber
Date: August 10, 1978
Depth in Feet
From To
0.0' 1.0'
1.0' ' 10.5'
Soil Description
F-4, brown Sandy Silt, ML, damp, soft, NP.
F-2/F-3, brown Silty G~avelly Sand, SM, damp
to wet, high density, particles to 1", Groups C
and E.
Bottom of Test Hole:
Frost Line:
Free Water Level:
Sample Depth
2.5'
2 5.0'
3 10.0'
10.5' Remarks: Bedrock encountered at
None Observed
Observed
Type of Dry
Blows/6" M% Sample Strength Grou~ Unified
9.8 G N-L E GM
9.3 G L C SM
Remarks: 1.
2.
3.
4.
5.
6.
Type of Sample, G=Grab., SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification~ see Sheet 3.
Test Hole #5A
Table A
WO #A18586
Logged By: T.L. Barber
Date: August 10, 1978
Depth in Feet
From To
0.0' 0.5'
0.5' 16.0'
Soil Description
F-4, brown Sandy Silt, ML, damp, soft.
F-l, brown Silt~ Sandy Gravel, GM, damp,
to wet, Group A.
Bottom of Test Hole:
Frost Line:
Fre~ Water Level:
16.0'
None Observed
None Observed
Sample Depth
1 2.5'
2 5.0'
3 10.0'
4 16.0'
Type of Dry
Blows/6" M% Sample Strength Group
4.3 G N A
8.1 G N-L A
5.7 G N-L A
7.7 G N D
unified
GM
GM
W
Remarks:
2.
3.
4.
5.
6.
Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=Hiqh.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole~_#6
Table A
WO #A18586
Logged By: T.L. Barber
Date: August 10, 1978
Depth in Feet
From To
0.0' 3.0'
3.0' - 8.0'
8.0' - 16.0'
Soil Description
F-2/F-4, brown Silty Sandy/Sandy Silt, SM/ML
damp.
F-2, brown Silty Gravelly Sand, SM, wet,
particles to 3/4", Group C.
F-l, brown Silty Sandy Gravel, GM, wet, medium
to high density, particles to 1", Group A.
Bottom of Test Hole:
Frost Line:
Free Water Level:
16.0'
None Observed
None Observed
Sample Depth
1 3.0'
2 5.0'
3 10.0'
4 16.0'
Type of Dry
Blows/6" M% Sampl.e Strength Group
- 24.9 G N
- 18.5 G L C
- 12.4 G N A
- 7.4 G N A
Unified
ML
SM
GM
GM
Remarks: 1.
3.
4.
5.
6.
Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, .H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole #7
Table A
WO #A18586
Logged By: T.L. Barber
Date: August 11, 1978
Depth in Feet
From To
0.0' - 3.0'
3.0' - 12.5'
Bottom of Test Hole:
Frost Line:
Free Water Level:
Soil Description
F-2, brown Silty Gravell~ Sand, SM, wet,
particles to 3/~", Group C.
F-2, brown Silty Gravelly Sand, SM/SW,
wet, medium to hi~ density, ~articles to 1",
Group D.
12.5. Remarks./~Bedrock encountered at
None Observed ~~~ ;~o~ ·
None Observed
Sample Depth
2.5'
5.0'
10.0'
Type of Dry
Blows/6" M% Sample Strength Group Unified
- 25.5 G L C SM
- 10.5 G N D SM/SW
- 11.5 G L D SM/SW
Remarks: 1.
3,
4.
5.
6.
Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see 'Sheet 3.
o ~
0
0
0
I
o o
Test Hole Log - Description Guide
The soil descriptions shown on the lugs are the best estimate of the ~oil's
chatacterlsucs at the time of field examination and as such do not achieve the
precision of a laboratory testing procedure. If the log includes soils samples,
those samples receive an independent textural classification in £ne laboratory
to verify the field exammauon.
The logs often include tire following items:
Depth Interval - usually shown to 0.l foot, within that zone no
significant change in soll type was observed through drill acfion, direct
Frost Classification - NFS. Fl. F2. F3. F4. see "Soil Classification
Texture of Soil - An engineering classificafion of the soils by particle
size and propomon see "Soil Classificafion Chart". note tile
prop.trams are approximate dud modifications to the soil group due to
strat ificafion, indusious and changes m properties hre included.
d~y, m, or little ~ pparent surface moisture.
damp, moisture forms portion of color, less than plastic limit.
saturated. Free water may be squeezed out, if a free draining soil:
dilatcnt at natural moisture content ifa non-plastic silt or fine
sand. IThe moisture content is further definedby reference to Pl.
LW, NP. M%or dilatency.I
Density - refers to more-ordess non.cohesive soils, such as sand gravel
mixtures without without a fine fraction derived from drilling actxon
and/or sample data: usuahy described as: very loose, loose, medium
Stiffness- refers to more-ordcss cohesive soils and fine grained silts of
the clay-silt groups. Derived from drill action and/or sample data. Very
soft, soft. stiff, very stiff and hard are commomy used terms.
Particle s~zc The largest particle recovered by the split spoon ~s
1-3/8", Shelb:, tube 3'L auger flights minute-man 2", Auger flights
(I~$0 hollow sceml 6'-8", Larger pamcles are described indirectly by
denon of tl~e drilling ami are referred Id as cobbles, 3" rd 8", or
boulders 8"+. Therefore whcu reviewing die gradation sheets, if any,
the descfipnon on the hole log must be considered for an:indication of
larger particles.
Unified Soil Classification - This is a two etter code. See Unified
Classification sheller ~'~her definition. In some cases AASHO and/or
FAA soil classifications may be shown as well as the unified.
Atterberg Limits - useful for fine grained and other plastic soils.
P_ll natural moisture content believed to be less than plastic limit
PI+: natural momure content believed to be b~tween plastic and liquid
]]-mits
Lw+; natural moisture content believed to be greater than liquid limit
NP: non-p~amc, useful ss a modifying description of some silty
sill ur a volcanic ash.
Rock flour - finely ground soil that is not plastic but otherwise appear~
similar to a clayey sbt.
Organic Content - usually described as Peat. PT, sometimes includes
discrete parfic[es such as wood, coal, etc. as a modifier to an morgamc
soil. Quantity described as: trace, or an estimate of volume, or m case
of all orgamc, - as Peat. This may include tundra muskeg and dug
material.
Muck - a modifier used to describe very soft, semi.organic deposits
usually occuring below a peat deposit.
.~morphus peat -. organic particles nearly or fully disinti'grated
Fibrous Peat - orgamc particles more-ordess intact.
Bottom of T~sthole - includes last sampm interval.
Frost Line -- seasonal frost depth as described by drilling action and/or
sample., at the time of drilling.
Frozen Ground -- other than frost line, described bv samples, usually
includes descriptmn of ice content, often will include modified Unified
Classification for frozen soils - this ~s a specia case related to
permafrost studies,
Free Wattr Level -- The free water level noted during drilling. This is
not necessarily the stauc water table at the time of drilling or at other
seasons. Static water tabk determination in other than very permeable
soils reqmrcs observauon wells oz piezometer installations used only in
special cases.
lilow/6" - The number of blows of a 140 weight free falling 30" to
advance a 2" split spoon 6"~ the number of blows t'or a 12" advance
by definition, the standhrd penetrauon.
M% - natural moisture content of the soil sample, usually not
p~formed on clean sands or gravels below the water table.
Type of Sample -
.,5~, refers to 2" split spoon driven into ~he soil by 140 pound
weight, a disturbed sample,
_S, thin wall tube, "Shelby" used to obtain undisturbed samples
of fine grained soil,
G, "grab" disturbed sample from auger flights or wall of trench.
C, cut sample, undisturbed sample from wall of trench.
Dry StrenlFh - a useful indicat6r of a soil's clayey fraction. N=None.
L=Low. M--Medium. H=High
Group - The samples are placed into apparently similar groups based
reflect the general distrubed characteristics of the so,s assigned lO thc
SOIL CLASSIFICATION CHART
30% GRAVEL
GRA'
0 l 0 20 30 40 50 60 70 80 90 100
GRAVEL (+#4 SCREEN) % BY WEIGHT
NONFROST SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN 3% FINER THAN 0.02 mm,
GROUPS OF FROST-SUSCEPTIBLE SOILS:
Fi GRAVELLY SOILS CONTAINING BETWEEN 3 AND 20% FINER THAN 0.02 mm.
F2 SANDY SOILS CONTAINING BETWEEN 3 AND 15% FINER THAN 0,02 mm.
F3 a. GRAVELLY SOILS CONTAINING MORE THAN 20% FINER THAN 0.02 mm- AND SANDY SOILS
(EXCEPT FINE SILTY, SANDS) CONTAINING MORE THAN ]5% FINER THAN 0.02 mm.
b, CLAYS WlTII PLASTICITY INDEXES OF MORE THAN 12. EXCEPT VARVED CLAYS.
F4 a. ALL SILTS INCLUDING SANDY SILTS. :
b. FiNE SILT~¢ SANDS CONTAINING MORE THAN 15% FINER TNAN 0.02 mm,
¢, LEAN CLAYS WITII ~LASTICITY INDEXES OF LESS THAN ]2.
d. VARVED CLAYS,
IIl~,l~,llllllllllllllh/