HomeMy WebLinkAbout201614 17630 108th Ave SE Field Infiltration and Lab Test RptPage 1
Cascade GeotechNW
4957 Lakemont Blvd SE
C-4, #325
Bellevue, WA 98006
June 10, 2020
File No. 201614
Mr. Wentian Lan
17630 - 108th Avenue SE
Renton, WA 98055
Subject: Summary of Field Infiltration Tests and Laboratory Tests
17630 - 108th Avenue SE, Renton, WA
Dear Mr. Lan,
As requested, Cascade GeotechNW conducted three (3) field infiltration tests to verify
the design infiltration rate used in the design, and performed laboratory tests to evaluate
the suitability of the on-site soils as the sand layer below the pavement for pollution
treatment at the above site in the City of Renton, Washington. The following sections
documents the field infiltration testing procedure and rates, and summary of the
laboratory tests.
IN-SITU INFILTRATION TESTING
An engineer from Cascade GeotechNW conducted three verification field infiltration
tests on May 25, 2020. The approximate locations of the infiltration tests are shown on
Figure 2. Plates 1 through 4 on page 2 shows the general infiltration test setup.
The infiltration testing consisted of excavating test pits approximately 2 feet in diameter
and about 18 inches deep. The site soils are already relatively wet due to the rainy
weather. For the testing, water was added to the test pits to about 11 to 12 inches in
depth, and the change in water level is recorded for about every 50 to 60 minutes. This
procedure is repeated 3 times at each location. The field infiltration rate is then calculated
based on the lowest measured water level drop. The test results are summarized in Table
1 on the page 3.
Summary of Field Infiltration Testing and Laboratory Tests
17630 – 108th Avenue SE, Renton, WA
June 10, 2020
201614 17630 108th Ave SE Field Infiltration and Lab Test Rpt Page 2 PanGEO, Inc.
Plate 1 – Infiltration test set-up at PIT-2
Plate 2 – Infiltration test set-up at PIT-2
Plate 3 – Infiltration test set-up at PIT-3
Plate 4 – Infiltration test set-up at PIT-3
Summary of Field Infiltration Testing and Laboratory Tests
17630 – 108th Avenue SE, Renton, WA
June 10, 2020
201614 17630 108th Ave SE Field Infiltration and Lab Test Rpt Page 3 PanGEO, Inc.
IN-SITU INFILTRATION TEST RESULTS
Infiltration testing data and results are summarized in Table 1 below.
Table 1 – Summary of Field Infiltration Test Data
Time Head Loss (Inches) Percolation Rate (Minutes/Inch)
PIT -1
10:26-12:16 11 4.54
11:18-12:06 9 5.33
12:08-13:06 11 5.27
PIT -2
10:10-10:46 12 3.0
10:46-11:20 12 2.83
11:21-11:58 12 3.08
PIT -3
10:55-11:50 12 4.58
11:58-13:06 12 5.66
13:35-14:35 10.5 5.71
Based on three infiltration tests, it is our opinion that a field percolation rate of 6.0
minutes/inch can be conservatively obtained. The current percolation rate is equivalent to
an infiltration rate of 10.0 inches/hour, which is greatly more than 1.0 inch/hour obtained
in the initial testing in 2016. After applying correction factors, the design infiltration rate
from the current testing is 3.15 inch/hour.
We understand that the site grade had been cut down about 2 feet from the original grade
as part of site grading. In our opinion, the much higher field infiltration rates are likely
Summary of Field Infiltration Testing and Laboratory Tests
17630 – 108th Avenue SE, Renton, WA
June 10, 2020
201614 17630 108th Ave SE Field Infiltration and Lab Test Rpt Page 4 PanGEO, Inc.
contributed by testing in the cleaner sandy soils this time in-lieu of silty sand or sand with
silt soils for the 2016 testing.
LABORATORY TESTING
Cascade GeotechNW also collected soil samples and conducted laboratory tests for
Cation Exchange Capacity and Organic Content to evaluate the suitability of the on-site
sand to be used as 6-inch sand layer below the pavement per plan. The soil samples
collected are shown in the attached Figure 2. The soil sample was then transported to the
Fremont Analytical for laboratory testing. The Table 2 below presents the laboratory test
results:
Table 2 – Summary of Laboratory Test Results
Soil Sample Location, Depth
Cation Exchange
Capacity by EPA 9081 (meg/100g)
Organic Content
by ASTM D2974
(%)
#1, 1.5’ 8.15 1.52
#2, 1.5’ 11.2 1.48
#3, 1.5’ 9.54 1.52
#4, 1.5’ 13.1 1.51
#5, 1.5’ 17.0 1.44
Based on the laboratory test results, it is our opinion that the site soils meet the
requirements to use as the 6-inch sand layer for the Permeable Pavement for a pollution-
generating surface.
LIMITATIONS
This report has been prepared for the exclusive use of Mr. Wentian Lan and his other
consultants for specific application to the proposed development. This report is intended
to provide infiltration evaluation and recommendations based on a site reconnaissance,
Summary of Field Infiltration Testing and Laboratory Tests
17630 – 108th Avenue SE, Renton, WA
June 10, 2020
201614 17630 108th Ave SE Field Infiltration and Lab Test Rpt Page 5 PanGEO, Inc.
field infiltration testing, and our understanding of the project. The study was performed
using a mutually agreed-upon scope of work.
Variations in soil conditions may exist between the locations of the explorations and the
actual conditions underlying the site. The nature and extent of soil variations may not be
evident until construction occurs. If any soil conditions are encountered at the site that
are different from those described in this report, we should be notified immediately to
review the applicability of our recommendations. Additionally, we should also be
notified to review the applicability of our recommendations if there are any changes in
the project scope.
The scope of our work does not include services related to construction safety
precautions. Our recommendations are not intended to direct the contractors’ methods,
techniques, sequences or procedures, except as specifically described in our report for
consideration in design. Additionally, the scope of our work specifically excludes the
assessment of environmental characteristics, particularly those involving hazardous
substances. We are not mold consultants nor are our recommendations to be interpreted
as being preventative of mold development. A mold specialist should be consulted for all
mold-related issues.
This report has been prepared for planning and design purposes for specific application to
the proposed project in accordance with the generally accepted standards of local practice
at the time this report was written. No warranty, express or implied, is made.
This report may be used only by the client and for the purposes stated, within a
reasonable time from its issuance. Land use, site conditions (both off and on-site), or
other factors including advances in our understanding of applied science, may change
over time and could materially affect our findings. Therefore, this report should not be
relied upon after 24 months from its issuance. Cascade Group should be notified if the
project is delayed by more than 24 months from the date of this report so that we may
review the applicability of our conclusions considering the time lapse.
It is the client’s responsibility to see that all parties to this project, including the designer,
contractor, subcontractors, etc., are made aware of this report in its entirety. The use of
information contained in this report for bidding purposes should be done at the
contractor’s option and risk. Any party other than the client who wishes to use this report
Summary of Field Infiltration Testing and Laboratory Tests
17630 – 108th Avenue SE, Renton, WA
June 10, 2020
201614 17630 108th Ave SE Field Infiltration and Lab Test Rpt Page 6 PanGEO, Inc.
shall notify Cascade GeotechNW of such intended use and for permission to copy this
report. Based on the intended use of the report, Cascade GeotechNW may require that
additional work be performed and that an updated report be reissued. Noncompliance
with any of these requirements will release Cascade Group from any liability resulting
from the use this report.
CLOSURE
We appreciate the opportunity to be of service and trust that the information outlined in
this letter meets your need at this time. Please call if you have any questions.
Sincerely,
6/10/2020
H. Michael Xue, P.E.
Principal Geotechnical Engineer
Enclosures:
Figure 1 Site and Exploration Plan
Appendix A Summary Laboratory Test Results
Summary of Field Infiltration Testing and Laboratory Tests
17630 – 108th Avenue SE, Renton, WA
June 10, 2020
201614 17630 108th Ave SE Field Infiltration and Lab Test Rpt Page 7 PanGEO, Inc.
REFERENCES:
Booth, D. B., Troost, K. A., and Wisher, A. P., 2007, The Geologic Map of King County,
Washington: scale 1:100,000.
King County Department of Natural Resources and Parks, Surface Water Design
Manual, 2016.
Field Infiltration Tests andLaboratory Tests17630 - 108th Avenue SERenton, WashingtonSITE AND EXPLORATIONS PLAN2016141Original Contours.grf 6/10/20 (12:40) AAEProject No. Figure No.Note:Basemap modified from Civil Utility Plan prepared by Tatu Consulting Engineers dated July 2016.Approx. PIT LocationApprox. Soil Sample LocationLegend:Appro. Scale:1" = 30'#5#2PIT-1#1PIT-1PIT-3PIT-2#1Cascade GeotechNW#4#3
APPENDIX A
SUMMARY LABORATORY TEST RESULTS
Project:17630 108th Ave SE
CLIENT:Cascade GeotechNW
6/9/2020
Analytical Report
2005325
Date Reported:
Work Order:
Client Sample ID:#1
Lab ID:2005325-001 Collection Date:5/25/2020
Matrix:Soil
Analyses Result Qual Units Date AnalyzedDFRL
Cation Exchange Capacity by EPA 9081 Analyst:COBatch ID: R59659
Cation Exchange Capacity 6/5/2020 8:52:18 PM1.00 meq/100g 18.15
Organic Matter of Organic Soils by ASTM D2974 Analyst:SSBatch ID: R59596
Organic Matter 6/1/2020 3:00:00 PM0.500 %11.52
Client Sample ID:#2
Lab ID:2005325-002 Collection Date:5/25/2020
Matrix:Soil
Analyses Result Qual Units Date AnalyzedDFRL
Cation Exchange Capacity by EPA 9081 Analyst:COBatch ID: R59659
Cation Exchange Capacity 6/5/2020 9:14:36 PM1.00 meq/100g 111.2
Organic Matter of Organic Soils by ASTM D2974 Analyst:SSBatch ID: R59596
Organic Matter 6/1/2020 3:00:00 PM0.500 %11.48
Client Sample ID:#3
Lab ID:2005325-003 Collection Date:5/25/2020
Matrix:Soil
Analyses Result Qual Units Date AnalyzedDFRL
Cation Exchange Capacity by EPA 9081 Analyst:COBatch ID: R59659
Cation Exchange Capacity 6/5/2020 9:20:10 PM1.00 meq/100g 19.54
Organic Matter of Organic Soils by ASTM D2974 Analyst:SSBatch ID: R59596
Organic Matter 6/1/2020 3:00:00 PM0.500 %11.52
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Project:17630 108th Ave SE
CLIENT:Cascade GeotechNW
6/9/2020
Analytical Report
2005325
Date Reported:
Work Order:
Client Sample ID:#4
Lab ID:2005325-004 Collection Date:5/25/2020
Matrix:Soil
Analyses Result Qual Units Date AnalyzedDFRL
Cation Exchange Capacity by EPA 9081 Analyst:COBatch ID: R59659
Cation Exchange Capacity 6/5/2020 9:25:44 PM1.00 meq/100g 113.1
Organic Matter of Organic Soils by ASTM D2974 Analyst:SSBatch ID: R59596
Organic Matter 6/1/2020 3:00:00 PM0.500 %11.51
Client Sample ID:#5
Lab ID:2005325-005 Collection Date:5/25/2020
Matrix:Soil
Analyses Result Qual Units Date AnalyzedDFRL
Cation Exchange Capacity by EPA 9081 Analyst:COBatch ID: R59659
Cation Exchange Capacity 6/5/2020 9:31:18 PM1.00 meq/100g 117.0
Organic Matter of Organic Soils by ASTM D2974 Analyst:SSBatch ID: R59699
Organic Matter 6/4/2020 12:00:00 PM0.500 %11.44
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