Final Clarifier No 3 Slab Repair Geotech Report.pdfHWA GEOSCIENCES INC.
Geotechnical & Pai,ement Engineering • Hydrogeology • Geoeiwiromnental • Inspection U Testing
February 10, 2016
HWA Project No. 2015-003-21
City of Edmonds
200 Second Avenue South
Edmonds, Washington 98020
Attention: Pamela Randolph
Subject: GEOTECHNICAL REPORT
Clarifier No. 3 Slab Repair
City of Edmonds Wastewater Treatment Plant
Edmonds, Washington
Dear Ms. Randolph:
This letter presents the results of the geotechnical investigation and ground water monitoring at
Clarifier No. 3 at the Edmonds Wastewater Treatment Plant. The purpose of this study was to
evaluate the soil and ground water conditions at the project site and provide geotechnical
recommendations for repair of the cracked bottom slab of this clarifier. The location of the site
is provided on Figure 1 (Vicinity Map).
1.0 PROJECT UNDERSTANDING
We understand the bottom slab for Clarifier No. 3 became cracked shortly after it was
constructed in 1988. The City has recently considered methods to repair the cracked slab. As
part of this process, the City requested that HWA install ground water monitoring wells around
the clarifier to observe the soil and ground water conditions at the base of the clarifier. HWA's
scope included installing the wells, supplying transducers to the City for their use in monitoring
the water levels, and discussing our findings within this report. HWA has also visited the site
and observed the exposed cracks in the bottom of Clarifier No. 3 and conducted probing of the
subsurface soils below the bottom slab of the clarifier. Probing was performed through the
pressure relief valves that were installed as part of the design to allow relief of hydrostatic
pressures which were expected due to ground water conditions.
This report summarizes our findings and provides our conclusions and recommendations based
on our observations.
21312 30th Drive SE
Suite 110
Bothell, WA 98021.7010
Tel: 425.774.0106
Fax: 425.774.2714
www.hwageo.com
February 10, 2016
HWA Project No. 2015-003-21
2.0 FIELD AND LABORATORY TESTING
2.1 FIELD EXPLORATIONS
Borings BH-1 through BH-3 were drilled on May 4 and 5, 2015. They ranged in
depth from 31.0 feet to 36.5 feet. The locations of the borings are provided on Figure
2 (Site and Exploration Plan). The boreholes were drilled by Gregory Drilling Inc. of
Redmond, Washington under subcontract to HWA, using a rubber track -mounted
Mudslayer MS 5000 drill rig.
The borings were drilled using hollow -stem auger techniques and employing Standard
Penetration Test (SPT) sampling methods. The SPT sampling was performed using a 2-inch
outside diameter split -spoon sampler, which was driven using a 140 pound automatic -trip
hammer. During the tests, samples were obtained by driving the sampler 18 inches into the soil
with the hammer free -falling 30 inches. The number of blows required for each 6 inches of
sampler penetration was recorded. The N-value (or resistance in terms of blows per foot) was
defined as the number of blows required to drive the sampler the final 12 inches. This resistance
provides an indication of the relative density of granular soils and the relative consistency of
cohesive soils. If a total of 50 blows was recorded within a single 6-inch interval, the test was
terminated, and the blow count was recorded as 50 blows for the number of inches of penetration
achieved.
All subsurface explorations were monitored by an engineering geologist from HWA. Soil
samples obtained from the explorations were classified in the field, and representative portions
were placed in plastic bags to prevent moisture loss and taken to our laboratory in Bothell,
Washington, for further examination and testing.
A Legend of Terms and Symbols Used on Exploration Logs is presented on Figure A-1.
Summary soil exploration logs are presented on Figures A-2 through A-4. It should be noted
that the stratigraphic contacts shown on the individual exploration logs represent the approximate
boundaries between soil types; actual transitions may be gradual. Moreover, the soil and ground
water conditions depicted are only for the specific date and locations reported and, therefore, are
not necessarily representative of other locations and times.
2.2 LABORATORY TESTING
Laboratory tests were conducted on selected samples obtained from the explorations to
characterize engineering and index properties of the project soils. Laboratory tests included
determination of in -situ moisture content and grain size distribution. The tests were conducted in
general accordance with appropriate American Society of Testing and Materials (ASTM)
standards, and are discussed in further detail in the following paragraphs. The results are
presented in Appendix B, or are displayed on the exploration logs in Appendix A.
Clarifier No 3 Slab Repair Geotech Report.doc 2 HWA GEOSCIENCES INC.
February 10, 2016
HWA Project No. 2015-003-21
MOISTURE CONTENT OF SOIL: The moisture content of selected soil samples (percent by dry
mass) was determined in general accordance with ASTM D 2216. The results are shown at the
sampled intervals on the appropriate summary logs in Appendix A.
GRAIN SIZE ANALYSIS OF SOILS: Selected samples were tested to determine the particle size
distribution of material in general accordance with ASTM D422 (either wet sieve method or wet
sieve and hydrometer). The results are summarized on the attached Grain Size Distribution
reports, Figures B-1 and B-5, which also provide information regarding the classification of the
sample and the moisture content at the time of testing.
3.0 SITE CONDITIONS
The site for the Wastewater Treatment Plant (WWTP) is located on the southeast corner of
Edmonds Way (Sunset Avenue) and Dayton Street in Edmonds, Washington, as shown on
Figure 1. The site is near the base of the slope that inclines upward from Puget Sound to form
the plateau to the east. The slope rises from an elevation of about 15 feet at the WWTP to an
elevation of approximately 400 feet over a distance of about 1.5 miles. The slope has been
developed primarily as residential neighborhoods. The area immediately south of the WWTP
has not been developed and is part of the Edmonds Marsh, a saltwater estuary.
3.1 SITE GEOLOGY
The geologic map for the area (Smith, 1975) suggests the project site is underlain by Vashon
glacial till deposits, with modified land (fill) deposits west of the site and Vashon recessional
outwash upslope. Glacial till is a compact, unsorted, mixture of clay, silt, sand, and gravel, and
is known to also contain cobbles and boulders. Vashon glacial till was glacially transported and
deposited during the last advance of ice. Vashon recessional outwash consists of loose to
medium dense, well sorted sand and gravel deposited by water emanating from the receding
glacial ice front. Modified land consists of areas where the original surface topography has been
disturbed by grading and contains fill materials of unknown thickness and composition.
3.2 SUBSURFACE CONDITIONS
The soils observed in the explorations are somewhat in concurrence with the geology indicated
on the geologic map. The upper portions of the explorations encountered fill deposits that
overlie glacially consolidated ice contact/stratified drift deposits. The following are descriptions
of the units encountered during the exploration program, in the order encountered:
• Fill — Material characterized as fill was found in all three borings ranging from 20.8 to
27 feet thick. This unit is composed of local and imported materials that were placed
during or prior to construction of the treatment plant. The fill soils typically consist of
medium dense, olive brown to gray, silty, slightly gravelly, fine to medium sand.
Clarifier No 3 Slab Repair Geotech Report.doc 3 HWA GEOSCIENCES INC.
February 10, 2016
HWA Project No. 2015-003-21
Locally, the base of the fill layer contains wood debris and fine-grained organic soils that
rest directly on native glacial soils or are separated from the native soils by an intervening
layer of geotextile fabric or plastic sheeting (visqueen) and gravel layers.
• Ice Contact/Stratified Drift — Below the fill, soil deposits characterized as ice
contact/stratified glacial drift were encountered in all three borings. This unit is
composed of dense to very dense, gray, gravelly, silty sand that locally is inter -stratified
with slightly silty, fine to medium sand layers. This soil layer ranged from 8.5 to 11 feet
thick in our borings and was not fully penetrated. Ice contact/stratified drift forms sub -
glacially where glacial ice overrides depositional layers that had already been sorted by
flowing water. Locally, this soil unit is water -bearing.
3.3 OBSERVATIONS IN CLARIFIER NO.3
On July 9, 2015, HWA performed a site visit to assess soil and ground water conditions below
the bottom slab of the clarifier. The bottom of the clarifier has a conical shape. The top of the
slab inside the clarifier has an elevation of -4 along the outer edge and an elevation of -6 in the
center near the sump, as shown on Sheet 410 of the Project Plans dated June 1998.
Soil conditions were evaluated by probing the soil through the pressure relief valves of Clarifier
No. 3. The 3-inch diameter holes provided limited access and were either filled with standing
water or had water flowing upward through them. In the eastern and southern valves near the top
of the slab, some of the material within the pressure relief valve was retrieved. In both cases it
consisted of slightly silty, 3/4- to 1/2-inch diameter gravel. This material was similar to the gravel
observed about 20 feet below the ground surface in BH-2, which is at the approximate elevation
of the tank along the outer edge of its foundation. HWA probed the materials below the pressure
relief valves using a T-bar with a helical tip. The probe could typically be advanced about 9 to
12 inches into the gravel. The coring action of the probe indicated it was advancing through
gravelly materials. In each location, the coring action became smooth near the point of refusal.
The helical probe could only be advanced one to two inches once the smooth coring action was
observed. We interpret this to be the ice -contact stratified drift encountered in our borings near
the elevation of the bottom slab of the clarifier.
Each of the four valves located on the outer portion of the slab had standing water in the
depression around the valve. These valves are located about two-thirds the distance from the
center to the outer edge of the clarifier. At the eastern valve the water was below the top of the
pressure valve and air bubbles were forming at the opening. The southern and the western
valves had standing water up to the top of the slab. Some water was slowly trickling out of the
depression at the northern valve. The valves in the lower portion of the slab each had water
flowing out of the depression. The valve with the most flow was the southwestern valve. At the
center of the clarifier, water was also present within the sump. We understand that pumps are
Clarifier No 3 Slab Repair Geotech Report.doc 4 HWA GEOSCIENCES INC.
February 10, 2016
HWA Project No. 2015-003-21
currently running at the bottom of the clarifier, which may be keeping the clarifier from filling
with ground water.
Cracks were observed in both the topping slab and the structural slab. The structural slab is
visible where the topping slab had spalled off. The cracks in the topping slab appear in a lattice-
work like pattern. Some of them appear to be above cracks in the structural slab and are likely
reflective cracks. Ground water was observed to be seeping through the structural slab in the
location of some of the cracks, primarily those observed in the northeast section of the clarifier.
Based on our observation it appears that ground water is able to infiltrate into the space between
the topping slab and the structural slab. Cracks typically extended out radially from the center of
the tank, but some branch off at different angles.
A second visit was made to observe the ground water conditions in the clarifier on October 15,
2015. During this visit, ground water was observed to be seeping through the structural and
topping slabs in several locations where it had not been observed in July. The primary areas
where seepage was observed were in the Southwestern and the northeastern quadrants. In the
Southwestern quadrant, seepage was emanating from cracks observed near the outside edge of
the clarifier. In the northeastern quadrant the seepage was observed in the area where the
topping slab has spalled off.
3.4 GROUND WATER
Ground water was initially encountered in all of the borings at depths ranging from 15 to 27 feet
below the existing ground surface. During drilling groundwater seepage was encountered at or
slightly above the fill/drift contact. Typically, the fill soils were moist, while the underlying
glacial soils were saturated. Static ground water levels were observed on May 8, 2015 and
indicated that the ground water level around the tank ranged between Elevation -1.5 and
-2.5 feet. On May 8, 2015 transducers were installed in each of the three wells. On
December 18, 2015, HWA downloaded the ground water data from the transducers. The data
from these wells are provided on Figure 3.
4.0 CONCLUSIONS AND RECOMMENDATIONS
4.1 GROUND WATER CONDITIONS
Based on the ground water data, it appears that the ground water level outside of the clarifier has
ranged from about Elevation 0 to -3 feet since the transducers were installed in the wells in
May 2015. The top of the slab inside the clarifier ranges from Elevation -4 feet at the outer edge
to Elevation -6 feet near the middle; therefore, the ground water levels range between two and
five feet above the base of the clarifier. During the summer months the ground water remained
relatively constant with occasional increases of about 0.5 to 1 feet. From October to December,
Clarifier No 3 Slab Repair Geotech Report.doc 5 HWA GEOSCIENCES INC.
February 10, 2016
HWA Project No. 2015-003-21
the groundwater levels increased by about 2 feet in response to the increase in precipitation
during this time period.
4.2 RECOMMENDATIONS FOR REPAIR OF THE SLAB
4.2.1 Design
The results of our explorations and analyses indicate that the soils beneath clarifier No. 3 are
relatively dense and suitable for support of the structure. We do not believe poor subgrade soils
were a factor in cracking of the clarifier bottom. In our opinion the native soils beneath the tank
are capable of supporting allowable bearing pressures in excess of 2,500 psf.
Visible cracking patterns in the topping and structural slabs indicate that initially cracking could
have occurred due to shrinkage of the concrete during curing. This is likely in the topping slab
as it is unreinforced. It is also possible that the structural slab could have experienced shrinkage
cracking. Since shrinkage is greater when concrete is dried, Clarifier No. 3, which is often
empty, would be expected to experience much greater shrinkage than Clarifiers No. 1 and No. 2,
which are normally in use. Some cracking could also be due to large uplift forces that may have
been exerted on the slab. As discussed in the report prepare by TetraTech (2014), we understand
that the pressure relief valves were initially blocked by a film membrane left in place during
construction, and were not functional. Significant uplift forces may have been exerted on the
slab due to the upward hydraulic gradient created if the ground water level outside the tank was
significantly higher than the water level in the tank. As the slab was not designed to resist these
forces, this could have caused cracking of the slab. The cracks could easily have been caused by
a combination of these mechanisms.
In our opinion repair of the clarifier should consider both shrinkage and potential uplift
pressures. In addition to proper reinforcing, we recommend that an expanding, fluidizing agent
(such as FX-349 manufactured by Fox Industries of Baltimore, Maryland) be added to the
concrete when a repair slab is installed. This concrete additive will reduce the potential for
shrinkage. The potential for uplift forces can be accommodated by providing adequate drainage
to relieve any potential pressure. It appears that the initial design concept of using pressure relief
valves was adequate for this purpose once the valves were unblocked, and can therefore be
incorporated into the design of a repair slab.
4.2.2 Dewatering
The materials encountered at the base of the clarifier are expected to have relatively low
permeabilities; however, the Contractor should expect to encounter more permeable seams that
produce significant amounts of water during excavation. Wells and well points are not likely to
be effective in lowering the ground water table within the excavation; therefore, we expect
dewatering to be accomplished with sumps and ditching. Effluent from sumps is likely to be
Clarifier No 3 Slab Repair Geotech Report.doc 6 HWA GEOSCIENCES INC.
February 10, 2016
HWA Project No. 2015-003-21
turbid and contaminated with fluids leaked from the clarifiers, and will require treatment before
discharge into the storm water system. We suggest seeking permission to discharge dewatering
effluent into the plant's sewer system for treatment.
4.2.3 Subgrade Preparation
Subgrade preparation for the replacement slab should include the removal of all soft, loosened or
disturbed soils. Where over -excavation is required, structural fill consisting of 100 percent of
particles passing 1-1/2 inches and no more than 10 percent fines (materials passing the No. 200
sieve). We recommend that a woven or non -woven geotextile suitable for separation should be
placed over the prepared subgrade. The geotextile should then be covered with a 6-inch thick
(minimum) layer of I1/z-inch crushed rock. The crushed rock should be a quarry product having
100 percent angular faces. It should contain no more than 5 percent material passing the 3/8-
inch sieve. The crushed drain rock should be placed in 6-inch thick layers and each lift should
be compacted to a dense and unyielding condition. (Note that compaction to a required percent
compaction should not be specified, as reliable testing to determine its unit weight is not
practicable.) The new concrete slab should be cast on the crushed rock.
5.0 CONDITIONS AND LIMITATIONS
We have prepared this letter report for the City of Edmonds for use in design and construction of
this project. The conclusions and interpretations presented herein should not be construed as a
warranty of subsurface conditions. Experience shows that soil and ground water conditions can
vary significantly over small distances. Inconsistent conditions may occur between observations
made during construction.
Within the limitations of scope, schedule and budget, HWA attempted to execute these services
in accordance with generally accepted professional principles and practices in the fields of
geology and geotechnical engineering at the time the report was prepared. No warranty, express
or implied, is made.
The scope of our work did not include environmental assessments or evaluations regarding the
presence or absence of wetlands or hazardous substances in the soil, surface water, or ground
water at this site. HWA does not practice or consult in the field of safety engineering.
Clarifier No 3 Slab Repair Geotech Report.doc 7 HWA GEOSCIENCES INC.
February 10, 2016
HWA Project No. 2015-003-21
We appreciate the opportunity to be of service. If you have any questions or concerns, please do
not hesitate to contact us.
Sincerely,
HWA GEOSCIENCES INC.
JoLyn Gillie, P.E.
Geotechnical Engineer
JLG:rnb:jlg
LIST OF FIGURES
Ralph N. Boirum, P.E.
Geotechnical Engineer, Principal
Figure 1. Vicinity Map
Figure 2. Site and Exploration Plan
Figure 3. Water Level and Precipitation Data for Monitoring Wells around Clarifier No. 3
APPENDIX A — ExPLORATION LOGS
Figure A-1 Legend of Terms and Symbols
Figures A-2 — A-4 Logs of Boring BH-1 through BH-3
APPENDIX B — LABORATORY TESTING
Figure B-1 Summary of Material Properties
Figures B-2 — B-5 Particle -Size Analysis of Soils
Clarifier No 3 Slab Repair Geotech Report.doc 8 HWA GEOSCIENCES INC.
February 10, 2016
HWA Project No. 2015-003-21
REFERENCES:
Smith, Mackey, 1975, Preliminary Surficial Geologic Map of the Edmonds East and Edmonds
West Quadrangles, Snohomish and King Counties, Washington: WDNR Division of
Geology and Earth Resources, Geologic Map GM-14, scale 1:24,000.
TetraTech, 2014, City of Edmonds, Wastewater Treatment Plant Clarifier #3 Slab Repair Final,
prepared for the City of Edmonds, submitted December 2014.
Clarifier No 3 Slab Repair Geotech Report.doc 9 HWA GEOSCIENCES INC.
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APPENDIX A
FIELD EXPLORATIONS
RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-VALUE
COHESIONLESS SOILS
COHESIVE SOILS
Approximate
Approximate
Density
N (blows/ft)
Relative Density(%)
Consistency
N (blows/ft)
Undrained Shear
Strength (psf)
Very Loose
0 to 4
0 - 15
Very Soft
0 to 2
<250
Loose
4 to 10
15 - 35
Soft
2 to 4
250 - 500
Medium Dense
10 to 30
35 - 65
Medium Stiff
4 to 8
500 - 1000
Dense
30 to 50
65 - 85
Stiff
8 to 15
1000 - 2000
Very Dense
over 50
85 - 100
Very Stiff
15 to 30
2000 - 4000
Hard
over 30
>4000
ASTM SOIL CLASSIFICATION SYSTEM
MAJOR DIVISIONS
GROUP DESCRIPTIONS
Coarse
Gravel and
Clean Gravel
&
GW
Well -graded GRAVEL
Grained
Gravelly Soils
(little or no fines)
a
GP
Poorly -graded GRAVEL
Soils
More than
50% of Coarse
Gravel with
a
GM
Silty GRAVEL
Fraction Retained
Fines (appreciable
on No. 4 Sieve
amount of fines)
GC
Clayey GRAVEL
Sand and
Clean Sand
°
SW
Well -graded SAND
More than
Sandy Soils
(little or no fines)
SP
Poorly -graded SAND
50% Retained
50% or More
on No.
of Coarse
Sand with
SM
Silty SAND
200 Sieve
Fraction Passing
Fines (appreciable
Size
No. 4 Sieve
amount of fines )
SC
Clayey SAND
ML
SILT
Fine
Silt
CL
Lean CLAY
Grained
and Liquid Limit
Soils
Less than 50%
Clay
_
OL
Organic SILT/Organic CLAY
MH
Elastic SILT
50% or More
Silt
Liquid Limit
Passing
and
Y 50% or More
CH
Fat CLAY
No. 200 Sieve
Size
OH
Organic SILT/Organic CLAY
.x rr
Highly Organic Soils
-
PT
PEAT
COMPONENT DEFINITIONS
COMPONENT
SIZE RANGE
Boulders
Larger than 12 in
Cobbles
3 in to 12 in
Gravel
3 in to No 4 (4.5mm)
Coarse gravel
3 in to 3/4 in
Fine gravel
3/4 in to No 4 (4.5mm)
Sand
No. 4 (4.5 mm) to No. 200 (0.074 mm)
Coarse sand
No. 4 (4.5 mm) to No. 10 (2.0 mm)
Medium sand
No. 10 (2.0 mm) to No. 40 (0.42 mm)
Fine sand
No. 40 (0.42 mm) to No. 200 (0.074 mm)
Silt and Clay
Smaller than No. 200 (0.074mm)
TEST SYMBOLS
GS
Grain Size Distribution
%F
Percent Fines
CN
Consolidation
TX
Triaxial Compression
UC
Unconfined Compression
IDS
Direct Shear
M
Resilient Modulus
PP
Pocket Penetrometer
Approx. Compressive Strength (tsf)
TV
Torvane
Approximate Shear Strength (tsf)
CBR
California Bearing Ratio
MD
Moisture/Density Relationship
PID
Photoionization Device Reading
AL
Atterberg Limits: PL Plastic Limit
ILL Liquid Limit
SAMPLE TYPE SYMBOLS
®2.0" OD Split Spoon (SPT)
(140 lb. hammer with 30 in. drop)
IShelby Tube
3.0" OD Split Spoon with Brass Rings
OSmall Bag Sample
Large Bag (Bulk) Sample
Core Run
Non-standard Penetration Test
(with split spoon sampler)
COMPONENT PROPORTIONS
DESCRIPTIVE TERMS
RANGE
OF PROPORTION
Clean
< 5%
Slightly (Clayey, Silty, Sandy)
5 - 12%
Clayey, Silty, Sandy, Gravelly
12 - 30%
Very (Clayey, Silty, Sandy, Gravelly)
30 - 50%
GROUNDWATER WELL COMPLETIONS
Locking Well Security Casing
Well Cap
Concrete Seal
Well Casing
Bentonite Seal
Groundwater Level (measured at
time of drilling)
Groundwater Level (measured in
well after water level stabilized)
Slotted Well Casing
Sand Backfill
NOTES: Soil classifications presented on exploration logs are based on visual and laboratory
observation in general accordance with ASTM D 2487 and ASTM D 2488. Soil descriptions MOISTURE CONTENT
are presented in the following general order:
DRY Absence of moisture, dusty,
Density/consistency, color, modifier (If any) GROUP NAME, additions to group name (if any), moisture content. dry to the touch.
Proportion, gradation, and angularity of constituents, additional comments. (GEOLOGIC INTERPRETATION) MOIST Damp but no visible water.
Please refer to the discussion in the report text as well as the exploration logs for a more WET Visible free water, usually
complete description of subsurface conditions. soil is below water table.
CLARIFIER NO. 3 SLAB REPAIR LEGEND OF TERMS AND
=0 EDMONDS WASTEWATER TREATMENT PLANT
SYMBOLS USED ON
JMGEOSaENCESING EDMONDS, WASHINGTON EXPLORATION LOGS
PROJECT NO.: 201 5-003-21 FIGURE: A-1
PZOLEGEND 2015-003.GPJ 1120/16
DRILLING COMPANY: Gregory Drilling Inc. DATE STARTED: 5/4/2015
DRILLING METHOD: HSA, Mudslayer MS 5000 tracked rig DATE COMPLETED: 5/4/2015
SAMPLING METHOD: SPT w/ Autohammer LOGGED BY: B. Thurber
LOCATION: See Figure 2 SURFACE ELEVATION: 17.2 t feet
co
U
O
M v)
a
�°1 a) 0 DESCRIPTION
0 SM Duff over olive brown, gravelly, silty SAND, d to dam
'�:.� :• 9 Y. tY dry P•
5-
10-
15-
20 -
25 -
30 -
35 -
40 -
ly
w
U
W
in
z^
ai
wU
z
F �
Lu Q
y
w
w
a- 0-
30
O
W
W W
as
O
auvi 0
Standard Penetration Test
(140 lb. weight, 30" drop)
♦ Blows per foot
10 20 30 40
Medium dense, olive brown, gravelly, silty, fine to medium
S-1
5-8-11
SAND, moist.
(FILL)
S-2
6-11-12
SM
..........................................................
Medium dense, gray, slightly gravelly, very silty, fine to
.
medium SAND, moist.
S-3
8-8-11
SM
...............................................................
Loose, gray, slightly gravelly, very silty, fine to medium SAND,
S-4
2-2-2 GS
r ... .... .
moist.
XS-5
3-3-2
!
S-6
2-0-4
,.... ....
SM
..............................................................
Medium dense, gray, gravelly, very silty, fine to medium
S-7
1-8-7 GS
SAND, moist.
3 inches of limb wood at approx. 21 feet.
S-8
2-4-10
SP
.................................................................
Medium dense, gray and dark gray, slightly silty, gravelly, fine
SM
to medium SAND, wet.
S-9
3-13-21
SM
Non -woven geotextile fabric at 23 feet.
Dense, gray, gravelly, silty, fine to medium SAND, moist.
. ••
. ••
Stratified.
S-10
22-26-26 GS •�:.
(ICE CONTACT STRATIFIED DRIFT)
Dense, gray, gravelly, silty, fine to medium SAND, wet.
Vaguely stratified.
Very dense, gray, slightly gravelly, slightly silty and silty, fine to
S-11
17-35-47
medium SAND, moist. Vaguely stratified in 3 to 5 inch beds.
Borehole terminated at 31.5 feet.
1-inch PVC standpipe piezometer installed with
machine -slotted screen from 20 to 30 feet.
z
O
wQ)
50 w w
15
....
.... ..............
10
5
0
-5
-10
..:....:....:....:....:....
-15
.
-20
0 20 40 60 80 100
Water Content (%)
Plastic Limit 1 0 Liquid Limit
NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated Natural Water Content
and therefore may not necessarily be indicative of other times and/or locations.
BORING:
CLARIFIER NO. 3 SLAB REPAIR BH-1
ot,g EDMONDS WASTEWATER TREATMENT PLANT
JMGEOSCIENCESINC. EDMONDS, WASHINGTON PAGE: 1 of 1
PROJECT NO.: 201 5-003-21 FIGURE: A-2
PZO-DSM 2015-003.GPJ 1/20/16
DRILLING COMPANY: Gregory Drilling Inc. DATE STARTED: 5/5/2015
DRILLING METHOD: HSA, Mudslayer MS 5000 tracked rig DATE COMPLETED: 5/5/2015
SAMPLING METHOD: SPT w/ Autohammer LOGGED BY: B. Thurber
LOCATION: See Figure 2 SURFACE ELEVATION: 13.5 t feet
0-1 FFF7.sm-
5-
10-
15-
20-
25 -
30-
35 -
40-
w
w
z
Standard Penetration Test
EL
in
2
a)
(140 lb. weight, 30" drop)
Z)
w v
A Blows per foot
O
w
w
0-
w
Of3
w
i¢
a-
Ow
wm
DESCRIPTION a)
Cl)
o
5- s
O
w
a- ai
w
0
10 20 30 40
50
Medium dense, olive gray grading to gray, slightly gravelly, S-1 5-10-9
very silty, fine to medium SAND, moist.
(FILL)
Medium dense, gray, slightly fine gravelly, very silty, fine to S-2 8-8-7
medium SAND, moist.
Softer drilling below approx. 6 feet, per driller.
Medium dense to dense, gray, slightly gravelly, very silty, fine S-3 3-17-29
to medium SAND, moist. Non -stratified.
Broken rock in sampler tip; blow counts overstated.
SM
.......................................
Visqueen layers at 15 and 16.25 feet. Soil between: Loose,
S-4 3-4-3 GS
GP
gray, silty, fine gravelly, SAND, wet_ _ _ _ _ _ _ _ _ -
SM
Loose, clean, fine GRAVEL, wet.
1 (PEA GRAVEL) _ _ _ _ _ _
X
S-5 9-8-3 GS
Medium dense, gray, fine gravelly, silty, fine to medium
GP
SAND,moist._______ ________J
o
Dense, dark blackish -gray, slightly silty, coarse sandy, fine
S-6a 10-35-50/6
SM
AGRAVEL, wet.
S-6b GS
Very dense, olive gray, silty, very fine to coarse gravelly, fine
SP
to medium SAND, wet.
SM................................................................
ICE CONTACT STRATIFIED DRIFT
Very dense, gray, interbedded, slightly silty and silty, fine to
S-7 23-35-45
medium SAND, wet. Scattered fine gravel. Beds from 2 to 5
SM...
inches thick.
................................................................
Very dense, gray, slightly fine gravelly, silty, fine and fine to ® S-8 17-50/6"
medium SAND, moist. r
Borehole terminated at 31 feet.
1-inch PVC standpipe piezometer installed with
machine -slotted screen from 16 to 26 feet.
f
�.... ...�...
.0.
u
10
5
0
-5
-10
-15
».
-20
-25
0 20 40 60 80 100
Water Content (%)
Plastic Limit 1 0 Liquid Limit
NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated Natural Water Content
and therefore may not necessarily be indicative of other times and/or locations.
kL
BORING:
CLARIFIER NO. 3 SLAB REPAIR BH_2
ot,g EDMONDS WASTEWATER TREATMENT PLANT
JMGEOSCIENCESINC. EDMONDS, WASHINGTON PAGE: 1 of 1
PROJECT NO.: 20 1 5-003-21 FIGURE: A-3
PZO-DSM 2015-003.GPJ 1/20/16
DRILLING COMPANY: Gregory Drilling Inc. DATE STARTED: 5/5/2015
DRILLING METHOD: HSA, Mudslayer MS 5000 tracked rig DATE COMPLETED: 5/6/2015
SAMPLING METHOD: SPT w/ Autohammer LOGGED BY: B. Thurber
LOCATION: See Figure 2 SURFACE ELEVATION: 21.4 t feet
m
v
J
J O
M v)
m
0
0 W DESCRIPTION
0
SP
Cuttings to 5 feet: dark yellow brown, clean, fine to medium
SAND, moist.
(FILL)
5
Medium dense, dark yellow brown, clean, fine to medium
SAND, moist.
...........................................................
SP
SM
w
w
z
Standard Penetration Test
in
EL 2 Z)
a)
w v
(140 lb. weight, 30" drop)
A Blows per foot
O
w w
a- 0-
w
Ofy
w
i¢
Ow
Q
a)
o
w
w
W Cl)
5- ,
O
a- uV) 0
10 20 30 40
50 w
XS-1 1-4-6
10
Medium dense, interbedded dark yellow brown, clean to S-2 10-9-10
slightly silty, fine to medium SAND and gray, slightly gravelly,
silty, fine to medium SAND, moist.
15-
20 -
25 -
30 -
35 -
40-
SM
Medium dense, gray, gravelly, silty, fine to medium SAND, S-3 7-15-19 GS
moist.
Rock in sampler tip; blow counts overstated.
Medium dense, gray and greenish gray, slightly gravelly, silty, S-4 5-7-7 GS
fine to medium SAND and fine sandy SILT, moist. With lenses
of slightly silty, fine to medium SAND.
------------------------
ML
SM
Dense, gray and greenish gray, slightly fine gravelly, very silty, S-5 3-11-22 GS
fine to medium SAND and fine sandy SILT, moist. Scattered
SM partly decomposed organics.
Very dense, gray, stratified, slightly gravelly, silty fine SAND, S-6 12-24-32
moist, and slightly silty, fine to medium SAND, wet.
Water on rods at approx. 28 feet after driving sampler.
(ICE CONTACT STRATIFIED DRIFT)
Hard, gravelly drill action from approx. 31 to 33 feet.
Very dense, gray, slightly fine gravelly, slightly coarse sandy, d ® S-7 50/6"
fine SAND, wet.
Borehole terminated at 35.5 feet.
1-inch PVC standpipe piezometer installed with
machine -slotted screen from 24 to 34 feet.
NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated
and therefore may not necessarily be indicative of other times and/or locations.
0 20 40 60 80 100
Water Content (%)
Plastic Limit 1 0 Liquid Limit
Natural Water Content
20 1
15 1
10 1
5
0
-5 1
-10 1
-15 1
BORING:
CLARIFIER NO. 3 SLAB REPAIR BH-3
ot,g EDMONDS WASTEWATER TREATMENT PLANT
JMGEOSCIENCESINC. EDMONDS, WASHINGTON PAGE: 1 of 1
PROJECT NO.: 201 5-003-21 FIGURE: A-4
PZO-DSM 2015-003.GPJ 1/20/16
APPENDIX B
LABORATORY TESTING
U.S. STANDARD SIEVE SIZES
3/4"
3"
1-1/2" 5/8" 3/8" #4 #10 #20 #40 #60 #100 #200
100
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
90
I
I
I
I
I
I
I
I
I
I
II
I
I
I
I
I
80
=
I
I
I
I
I
I
I
I
LD
70
W
I
I
I
I
I
I
I
I
I
60
00
I
I
I
I
I
I
I
I
I
W
I
I
I
I
I
I
I
I
I
50
I
I
I
I
I
I
I
I
I
Z
LL
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
40
z
I
I
I
I
I
I
I
I
I
W
C)Of
I
I
I
I
I
I
I
I
I
30
W
I
I
I
I
I
I
I
I
I
a
I
I
I
I
I
I
I
I
I
20
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
10
I I I I I I I I I I
I I I I I I I I I I
0
50 10 5 1 0.5 0.1 0.05 0.01 0.005 0.001 0.0005
GRAIN SIZE IN MILLIMETERS
GRAVEL
SAND
SILT
CLAY
Coarse
Fine
Coarse
Medium
Fine
SYMBOL
SAMPLE
DEPTH (ft)
CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name
% MC
LL
PL
PI
Gravel
Sand
Fines
•
BH-1
S-4
10.0 - 11.5
(SM) Dark olive gray, silty SAND
10
8.0
56.2
35.8
■
BH-1
S-7
17.5 - 19.0
(SM) Dark gray, silty SAND
10
13.5
56.1
30.3
A
BH-1
S-10
25.0 - 26.5
(SM) Dark gray, silty SAND with gravel
12
16.6
58.3
25.1
901h EDMONDS WASTEWATER TREATMENT PLANT OF SOILS
HMGEOSCIENCESINC. EDMONDS, WASHINGTON METHOD ASTM D422
PROJECT NO.: 2015-003-21 FIGURE: B-�
CLARIFIER NO. 3 SLAB REPAIR PARTICLE -SIZE ANALYSIS
HWAGRSZ 2015-003.GPJ 1/20/16
U.S. STANDARD SIEVE SIZES
3/4"
3" 1-1/2" 5/8" 3/8" #4 #10 #20 #40 #60 #100 #200
I
100
I I I I I I I I
I I I I I I I I
90
I
I I
I
I
I
I
I
I
I
I
I I
I
I
I
I
I
I
80
=
I
II
I
I
I
I
I
70
W
I
I I
I
I
I
I
I
I
co
I
I I
I
I
I
I
I
W
I
I I
I
I
I
I
I
I
50
Z
I
I I
I
I
I
I
I
LL
I
I I
I
I
I
I
I
I
I
I I
I
I
I
I
I
I
40
z
I
I I
I
I
I
I
I
W
C)
I
I I
I
I
I
I
I
30
W
I
I I
I
I
I
I
I
a
I
I I
I
I
I
I
I
I
20
I
I I
I
I
I
I
I
I
I
I
I I
I
I
I
I
I
I
I
10
I I I I I I I I I I
I I I I I I I I I I
0
50 10 5 1 0.5 0.1 0.05 0.01 0.005 0.001 0.0005
GRAIN SIZE IN MILLIMETERS
GRAVEL
SAND
SILT
CLAY
Coarse
Fine
Coarse
Medium
Fine
SYMBOL
SAMPLE
DEPTH (ft)
CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name
% MC
LL
PL
PI
Gravel
Sand
Fines
•
BH-2
S-4
15.0 - 16.5
(SM) Dark olive gray, silty SAND with gravel
12
31.8
44.9
23.4
■
BH-2
S-5
17.5 - 19.0
(SM) Very dark gray, silty SAND with gravel
12
16.3
58.0
25.7
A
BH-2
S-6b
20.8 - 21.5
(SM) Dark olive gray, silty SAND with gravel
8
34.3
45.7
20.0
901h EDMONDS WASTEWATER TREATMENT PLANT OF SOILS
HMGEOSCIENCESINC. EDMONDS, WASHINGTON METHOD ASTM D422
PROJECT NO.: 2015-003-21 FIGURE: B-2
CLARIFIER NO. 3 SLAB REPAIR PARTICLE -SIZE ANALYSIS
HWAGRSZ 2015-003.GPJ 1/20/16
U.S. STANDARD SIEVE SIZES
3/4"
3"
1-1/2" 5/8" 3/8" #4 #10 #20 #40 #60 #100 #200
100
I
rl
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
90
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
80
=
I
I
I
I
I
I
I
I
I
I
70
W
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
60
00
I
I
I
I
I
I
I
I
W
I
I
I
I
I
I
I
I
I
I
50
I
I
I
I
I
I
I
I
I
Z
LL
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
40
z
I
I
I
I
I
I
I
I
I
W
C)Of
I
I
I
I
I
I
I
I
I
I
30
W
I
I
I
I
I
I
I
I
I
I
a
I
I
I
I
I
I
I
I
I
20
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
10
I I I I I I I I I I
I I I I I I I I I I
0
50 10 5 1 0.5 0.1 0.05 0.01 0.005 0.001 0.0005
GRAIN SIZE IN MILLIMETERS
GRAVEL
SAND
SILT
CLAY
Coarse
Fine
Coarse
Medium
Fine
SYMBOL
SAMPLE
DEPTH (ft)
CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name
% MC
LL
PL
PI
Gravel
Sand
Fines
•
BH-3
S-3
15.0 - 16.5
(SM) Dark olive gray, silty SAND with gravel
8
23.8
54.9
21.3
■
BH-3
S-4
20.0 - 21.5
(SM) Olive gray, silty SAND
13
6.3
57.3
36.4
A
BH-3
S-5
25.0 - 26.5
(SM) Dark olive gray, silty SAND
17
11.6
50.1
38.3
901h EDMONDS WASTEWATER TREATMENT PLANT OF SOILS
HMGEOSCIENCESINC. EDMONDS, WASHINGTON METHOD ASTM D422
PROJECT NO.: 2015-003-21 FIGURE: B-3
CLARIFIER NO. 3 SLAB REPAIR PARTICLE -SIZE ANALYSIS
HWAGRSZ 2015-003.GPJ 1/20/16