HomeMy WebLinkAboutTHE SLAB - FDP - FDP160022 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORT400 North Link Lane | Fort Collins, Colorado 80524
Telephone: 970-206-9455 Fax: 970-206-9441
March 9, 2016
Maxiiimo Development Group
706 South College Avenue
Fort Collins, Colorado 80524
Attn: Christian Bachelet
Subject: Subsurface Investigation and
Hydraulic Conductivity Testing
808 West Prospect Road
Fort Collins, Colorado
CTL|T Project Number: FC07161-125
CTL|Thompson, Inc. has conducted a subsurface investigation and hydraulic
conductivity testing at 808 West Prospect Road. The purpose of our investigation was to
determine relevant soil and infiltration characteristics at the project location to inform
possible construction of a dry well drain system. This letter presents the results of our
investigation.
Subsurface Investigation
Our investigation included drilling three exploratory borings and six hydraulic
conductivity test holes at the locations shown on Figure 1. Our exploratory borings were
drilled to a depth of approximately 20 feet. Hydraulic conductivity test holes were drilled
to depths between 7½ and 15 feet as needed to test different soil layers. The hydraulic
conductivity test holes were fitted with slotted PVC pipes to facilitate testing. A
representative from our firm observed drilling, logged the soils encountered and
collected samples. Samples were taken at 2½ to 5 foot intervals by driving a 2.5-inch
O.D. modified California sampler 12 inches. This method is similar to the standard
penetration test and is typical of local practice. Summary logs of the borings, including
results of field penetration testing, are shown on Figure 2.
Samples were return to our laboratory and examined by the geotechnical
engineer for this project. Laboratory tests were assigned, including moisture content, dry
density, gradation and Atterberg limits tests to classify the soils. Results of laboratory
tests are given on Figure 3 and summarized in Table 1.
Subsurface Conditions
Soils encountered in our borings consisted of 12 to 20 feet of sandy clay with
layers of clayey sand overlying cleaner sands with occasional gravel. The upper 1 to 2
feet of material in all three borings was identified as probable fill. Groundwater was
encountered in one boring during drilling at a depth of 19 feet, and was measured in two
borings several days after drilling at depths of 18½ and 19 feet.
0
5
10
15
20
25
30
35
40
0
5
10
15
20
25
30
35
40
17/12
19/12
17/12
14/12
16/12
17/12
WC=78.0
DD=114
LL=32 PI=15
-200=78
WC=5.6
-200=15
WC=78.0
DD=114
LL=32 PI=15
-200=78
WC=5.6
-200=15
TH-1
10/12
11/12
14/12
13/12
19/12
11/12
WC=18.3
DD=110
LL=32 PI=15
-200=69
WC=5.7
-200=15
WC=18.3
DD=110
LL=32 PI=15
-200=69
WC=5.7
-200=15
TH-2
14/12
19/12
14/12
16/12
Sample of SAND, CLAYEY (SC) GRAVEL 8 % SAND 77
%
From TH - 1 AT 14 FEET SILT & CLAY 15 % LIQUID LIMIT %
PLASTICITY INDEX %
Sample of SAND, CLAYEY, GRAVELLY (SC) GRAVEL 11 % SAND 74
%
From TH - 2 AT 14 FEET SILT & CLAY 15 % LIQUID LIMIT %
PLASTICITY INDEX %
MAXIIIMO DEVELOPMENT GROUP
808 WEST PROSPECT ROAD
CTL | T PROJECT NO. FC07161-125
FIGURE 3
Gradation
Test Results
0.002
15 MIN.
.005
60 MIN.
.009
19 MIN.
.019
4 MIN.
.037
1 MIN.
.074
*200
.149
*100
.297
*50
0.42
*40
.590
*30
1.19
*16
2.0
*10
2.38
*8
4.76
*4
9.52
3/8"
19.1
3/4"
36.1
1½"
76.2
3"
127
5"
152
6"
200
8"
.001
45 MIN.
0
10
PASSING
MOISTURE DRY LIQUID PLASTICITY NO. 200
DEPTH CONTENT DENSITY LIMIT INDEX SIEVE
BORING (FEET) (%) (PCF) (%) DESCRIPTION
TH-1 7 78.0 114 32 15 78 CLAY, SANDY (CL)
TH-1 14 5.6 15 SAND, CLAYEY (SC)
TH-2 7 18.3 110 32 15 69 CLAY, SANDY (CL)
TH-2 14 5.7 15 SAND, CLAYEY, GRAVELLY (SC)
TH-3 7 11.0 112 23 6 55 CLAY, SANDY (CL)
TH-3 14 16.1 113 27 11 53 CLAY, SANDY (CL)
TABLE I
SUMMARY OF LABORATORY TESTING
ATTERBERG LIMITS
Page 1 of 1
* NEGATIVE VALUE INDICATES COMPRESSION.
MAXIIIMO DEVELOPMENT GROUP
808 WEST PROSPECT ROAD
CTL|T PROJECT NO. FC07161-125
20
30
40
50
60
70
80
90
100
CLAY (PLASTIC) TO SILT (NON-PLASTIC)
SANDS
FINE MEDIUM COARSE
GRAVEL
FINE COARSE COBBLES
DIAMETER OF PARTICLE IN MILLIMETERS
25 HR. 7 HR.
HYDROMETER ANALYSIS SIEVE ANALYSIS
TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS
PERCENT PASSING
0
10
20
30
50
60
70
80
90
100
PERCENT RETAINED
40
0.002
15 MIN.
.005
60 MIN.
.009
19 MIN.
.019
4 MIN.
.037
1 MIN.
.074
*200
.149
*100
.297
*50
0.42
*40
.590
*30
1.19
*16
2.0
*10
2.38
*8
4.76
*4
9.52
3/8"
19.1
3/4"
36.1
1½"
76.2
3"
127
5"
152
6"
200
8"
.001
45 MIN.
0
10
20
30
40
50
60
70
80
90
100
CLAY (PLASTIC) TO SILT (NON-PLASTIC)
SANDS
FINE MEDIUM COARSE
GRAVEL
FINE COARSE COBBLES
DIAMETER OF PARTICLE IN MILLIMETERS
25 HR. 7 HR.
HYDROMETER ANALYSIS SIEVE ANALYSIS
TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS
PERCENT PASSING
PERCENT RETAINED
0
10
20
30
40
50
60
70
80
90
100
13/12
11/12
WC=11.0
DD=112
LL=23 PI=6
-200=55
WC=16.1
DD=113
LL=27 PI=11
-200=53
WC=11.0
DD=112
LL=23 PI=6
-200=55
WC=16.1
DD=113
LL=27 PI=11
-200=53
TH-3
DEPTH - FEET
2.
DRIVE SAMPLE. THE SYMBOL 17/12 INDICATES 17 BLOWS OF A 140-POUND HAMMER
FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 12 INCHES.
FILL; CLAY, SAND, GRAVEL, MOIST, DARK BROWN
1.
NOTES:
WATER LEVEL MEASURED SEVERAL DAYS AFTER DRILLING.
CLAY, SANDY WITH LAYERS OF CLAYEY SAND, MOIST, STIFF TO VERY STIFF, BROWN,
RED-BROWN (CL, SC)
3.
LEGEND:
SAND, RELATIVELY CLEAN TO CLAYEY WITH OCCASIONAL GRAVEL, MOIST TO WET,
MEDIUM DENSE, BROWN (SP, SC)
DEPTH - FEET
WATER LEVEL MEASURED AT TIME OF DRILLING.
THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN
THIS REPORT.
Summary Logs of
Exploratory Borings
THE BORINGS WERE DRILLED ON FEBRUARY 18, 2016, USING 4-INCH DIAMETER
CONTINUOUS-FLIGHT AUGERS AND A TRUCK-MOUNTED DRILL RIG.
FIGURE 2
WC
DD
SW
-200
LL
PI
UC
SS
-
-
-
-
-
-
-
-
INDICATES MOISTURE CONTENT (%).
INDICATES DRY DENSITY (PCF).
INDICATES SWELL WHEN WETTED UNDER OVERBURDEN PRESSURE (%).
INDICATES PASSING NO. 200 SIEVE (%).
INDICATES LIQUID LIMIT.
INDICATES PLASTICITY INDEX.
INDICATES UNCONFINED COMPRESSIVE STRENGTH (PSF).
INDICATES SOLUBLE SULFATE CONTENT (%).
MAXIIIMO DEVELOPMENT GROUP
808 WEST PROSPECT ROAD
CTL | T PROJECT NO. FC07161-125