HomeMy WebLinkAboutEx 17 - Kumar Report (16-7-318)Exhibit 17 I Subsoil Study Report for CR 114-115 (H-P/Kumar)
Lake Springs Ranch
Filing 2 Final Plat Application
April 2018
H-P-KUMAR
Geotechnical Engineering i Engineering Geology
Materials Testing ( Environmental
5020 County Road 154
Glenwood Springs, CO 81601
Phone: (970) 945-7988
Fax: (970) 945-8454
Email: hpkglenwood@kumarusa.com
December 16, 2016
Mike Berkeley
c/o TGMC, Inc
Attn: Tim Malloy
402 Park Drive
Glenwood Springs, Colorado 81601
tim@tgmalloy.com
Office Locations: Parker, Glenwood Springs, and Silverthorne, Colorado
Project No.16-7-318
Subject: Subsoil Study for Pavement Section Design, Proposed Lake Springs Ranch
Development, County Roads 114 and 115, Garfield County, Colorado
Gentlemen:
As requested, H-P/Kumar performed a subsoil study for pavement section design at the subject
site. The study was conducted in accordance with our proposal for geotechnical engineering
services to Mike Berkeley dated June 3, 2016. The data obtained and our recommendations
based on the proposed construction and subsurface conditions encountered are presented in this
report.
Proposed Construction: County Road 114 and a short distance of County Road 115 totaling
about 11/2 miles are proposed to be asphalt paved as part of the Lake Springs Ranch development.
The roadway alignment and grades will mostly not change significantly from the existing
roadway shown on Figure 1. Traffic loadings have not been provided except for current and
projected traffic volumes for buildout of the proposed Lake Springs Ranch development. The
traffic loading will need to consider temporary construction vehicles including heavy trucks.
If proposed conditions or traffic loadings are significantly different from those described above,
we should be notified to re-evaluate the recommendations presented in this report.
Site Conditions: County Roads 114 and 115 are asphalt and chip surface paved, 2 lane
roadways. The grades are gentle to moderate and typically shallow cuts and fills were used to
construct the roadways. A small pond is located near the middle of the project alignment near
Boring 6 shown on Figure 1. Vegetation along the roadway mainly consists of native grass,
weeds and sage brush. Basalt rocks are locally exposed on the ground and in road cuts.
Subsurface Conditions: The subsurface conditions along the roadway alignment were
evaluated by drilling 12 exploratory borings located approximately as shown on Figure 1. The
logs of the borings are presented on Figure 2. The subsoils encountered, below existing
-2 -
pavement materials, typically consist of sandy clay and silty sandy clay with gravel. The section
of about 1/4 mile at Borings 3, 4 and 5 mainly encountered basalt rocks in a silty clayey sand
matrix. The soils have low to medium plasticity and Hveem stabilometer testing performed on
samples of the clay, presented on Figures 4 and 5, resulted in "R" values of 5 and 9. No free
water was encountered in the borings at the time of drilling and the soils were slightly moist to
moist. The boreholes were backfilled with cuttings and patched following drilling completion.
Subgrade and Traffic Conditions: The subgrade conditions encountered in the exploratory
borings were somewhat variable but typically consist of low to medium plastic clay soils with
Hveem "R" values of 5 and 9 on the samples tested. An "R" value of 7 was used for design
purposes which correlated to a resilient modulus (Mr) value of 3200 psi. Design traffic loading
for flexible (asphalt) pavement was estimated using a current average daily traffic (ADT) of
about 200 and a future ADT of about 900 each way with 3% of the traffic single unit trucks and
2% of the traffic combination trucks. This results in an average 20 year design equivalent single
axel load (ESAL) of about 176,000. The truck traffic loading would include temporary
construction vehicles but these numbers should be reviewed by the project designers.
Pavement Section Design: Using the above subgrade condition (Mr=3200 psi) and assumed
design traffic information (20 year ESAL=0.176x106), an initial serviceability of 4.5, a terminal
serviceability of 2.5, and a reliability of 95%, we recommend the pavement section consist of 4
inches of asphalt on 6 inches of base course on 10 inches of subbase. The design section
assumes structural coefficients of 0.44 for asphalt, 0.14 for base course and 0.10 for subbase.
Pavement Material Properties: The asphalt should be a batched hot mix approved by the
design engineer and placed and compacted to between 92% and 96% of the theoretical maximum
density. The base course should meet CDOT Class 6 and the subbase should meet CDOT Class
2 aggregate base course specifications. The base course, subbase and required subgrade fill
should be compacted to at least 95% of standard Proctor density within 2% of optimum moisture
content. The placement and compaction of base and asphalt materials should be monitored and
tested on a regular basis by a representative of the geotechnical engineer.
Subgrade Preparation: Required fill to establish design subgrade elevation can consist of the
onsite soils or suitable imported soils meeting the project specifications. Prior to fill or pavement
placement, the subgrade should be stripped of unsuitable materials, scarified a depth of 8 inches,
adjusted to within 2% of optimum moisture content and compacted to at least 95% of standard
Proctor density. In soft or wet areas, the subgrade may require drying or stabilization prior to fill
placement. A geogrid such as Tensar TX 140 and sub -excavation and replacement with
aggregate base soils may be needed for the stabilization. The subgrade should be proof rolled.
Areas that deflect excessively should be corrected before placing pavement materials. The
subgrade improvements should be monitored and tested on a regular basis by a representative of
the geotechnical engineer.
Limitations: This study has been conducted in accordance with generally accepted geotechnical
engineering principles and practices in this area at the time of this study. We make no warranty
either express or implied. The findings and recommendations submitted in this report are based
upon the data obtained from the exploratory borings drilled at the locations indicated on Figure 1
H -P KUMAR
Project No. 16-7-318
-3 -
and to the depths shown on Figure 2, the proposed construction, and our experience in the area.
Our findings include interpolation and extrapolation of the subsurface conditions identified at the
exploratory borings and variations in the subsurface conditions may not become evident until
excavation is performed. If conditions encountered during construction appear different from
those described in this report, we should be notified at once so re-evaluation of the
recommendations may be made.
This report has been prepared for the exclusive use by our client for design purposes. We are not
responsible for technical interpretations by others of our information. As the project evolves, we
should provide continued consultation and field services during construction to review and
monitor the implementation of our recommendations, and to verify that the recommendations
have been appropriately interpreted. Significant design changes may require additional analysis
or modifications to the recommendations presented herein. We recommend on-site observation
of excavations and testing of structural fill and pavement materials by a representative of the
geotechnical engineer.
If you have any questions or if we may be of further assistance, please let us know.
Respectfully Submitted,
H-PKUMAR
Steven L. Pawlak, P.E
Rev. by: DAY
SLP/ksw
Attachments: Figure 1 — Location of Exploratory Borings
Figure 1 — Logs of Exploratory Borings
Figure 3 — Legend and Notes
Figure 4 — Gradation Test Results
Figures 5 and 6 — Hveem Stabilometer Test Results
Table 1 — Summary of Laboratory Test Results
cc: High Country Engineering — Dan Dennison (ddennison@hceng.com)
H -P ` KUMAR
Project No. 16-7-318
L__
L7
BORING 8
BORING 7
BORING 5
BORING 4 SPRINGS RANCH
BORING 11
ORING 12
c,,
PROPOSED LAKE
BORING 3
BORING 2
BORING 1
400 0 400 800
APPROXIMATE SCALE -FEET
16-7-318
H -P-" KUMAR
LOCATION OF EXPLORATORY BORINGS I Fig. 1
rpa Rneh Rd I1t\0ralling\167716-02
1-
w
w
0
w
w
0
1-
w
w
0_
w
w
D
0
5
10
BORING 1 BORING 2
12/12 (6)
WC=11.5
DD=111
1 16/12
13/12
WC= 3.7
-200=92
LL=39
PI=21
A-6 (19)
10/12
WC=14.2
DD=108
1 15/12
BORING 5 BORING
O (4)
(7)
5
10
rir
fes.
15/6,50/0
WC=1 1.1
-200=38
(4)
11
BORING 3
20/12
WC=1 1.9
-200=94
LL=38
PI=22
A-6 (21)
6
19/12
WC=9.1
DD=109
-200=77
LL=40
PI=12
A-6 (9)
33/12
BORING 9 BORING 10
28/12
WC=14.2
O (3) DD=103
(3) -200=71
/ LL=48
:./ PI=22
A-7-6 (15)
5
10
36/12
(4)
73/12
WC=2.4
+4=51
-200=27
50/6
42/12
BORING 4
(6)
(3)
BORING 7 BORING 8
(3)
5/6,18/6
WC=15.4
DD=95
-200=88
20/12
WC=11.1
'DD=111
1 -200=94
24/12
WC= 6.8
DD=94
-200=53
LL=46
PI=6
A-7-5 (2)
(3)
(4)
41/12 WC=7.0
+4=17
36/12 -200=54
48/12
BORING 11
(2)
12/6,50/5
WC=13.2
DD=84
-200=53
LL=41
PI=17
A-7-6 (7)
50/0
13/12
WC=17.8
DD=101
// 116/12
16/12
WC=13.7
-200=96
LL=46
PI=27
A-7-6 (28)
BORING 12
WC=17.5
-200=84
LL=47
PI=11
A-7-5 (12)
36/ 2
WC=12.1
-200=79
LL=39
PI=21
A-6 (16)
15/12
WC=14.0
DD=111
- 200=95
29/12
WC=10.3
DD=114
35/12
WC=12.6
- 200=90
LL=37
P1=21
A-6 (18)
0
5
10
0
5
10
0
5
10
a a
w
16-7-318
H-P%KUMAR
LOGS OF EXPLORATORY BORINGS
Fig. 2
LEGEND
(6) _ ASPHALT, THICKNESS IN INCHES SHOWN IN PARENTHESES TO LEFT OF THE LOG.
(6)
//
BASECOURSE, THICKNESS IN INCHES SHOWN IN PARENTHESES TO LEFT OF THE
LOG.
CLAY (CL); SLIGHTLY SANDY TO SANDY, SCATTERED GRAVEL, STIFF TO VERY
STIFF, SLIGHTLY MOIST TO MOIST, MIXED BROWN, MEDIUM TO HIGH PLASTICITY.
/-7 SAND AND CLAY (SC -CL); SILTY, GRAVEL AND COBBLES, MEDIUM DENSE/VERY
STIFF, LIGHT BROWN, CALCAREOUS, LOW PLASTICITY.
/-
GRAVEL (GM -GC); SILTY, CLAYEY, SANDY, COBBLES, PROBABLE BOULDERS,
MEDIUM DENSE, GRAY -BROWN, CALCAREOUS, BASALT ROCK.
RELATIVELY UNDISTURBED DRIVE SAMPLE; 2 -INCH I.D. CALIFORNIA LINER SAMPLE.
DRIVE SAMPLE; STANDARD PENETRATION TEST (SPT), 1 3/8 INCH I.D. SPLIT SPOON
SAMPLE, ASTM D-1586.
DISTURBED BULK SAMPLE.
NOTES
DRIVE SAMPLE BLOW COUNT. INDICATES THAT 10 BLOWS OF A 140 -POUND HAMMER
FALLING 30 INCHES WERE REQUIRED TO DRIVE THE CALIFORNIA OR SPT SAMPLER 12 INCHES.
PRACTICAL AUGER REFUSAL.
1. THE EXPLORATORY BORINGS WERE DRILLED ON OCTOBER 20, 2016 WITH A 4 -INCH DIAMETER
CONTINUOUS FLIGHT POWER AUGER.
2. THE LOCATIONS OF THE EXPLORATORY BORINGS WERE MEASURED APPROXIMATELY BY PACING
FROM FEATURES SHOWN ON THE SITE PLAN PROVIDED.
3. THE ELEVATIONS OF THE EXPLORATORY BORINGS WERE NOT MEASURED AND THE LOGS OF THE
EXPLORATORY BORINGS ARE PLOTTED TO DEPTH.
4. THE EXPLORATORY BORING LOCATIONS SHOULD BE CONSIDERED ACCURATE ONLY TO THE
DEGREE IMPLIED BY THE METHOD USED.
5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY BORING LOGS REPRESENT THE
APPROXIMATE BOUNDARIES BETWEEN MATERIAL TYPES AND THE TRANSITIONS MAY BE GRADUAL.
6. GROUNDWATER WAS NOT ENCOUNTERED IN THE BORINGS AT THE TIME OF DRILLING.
7. LABORATORY TEST RESULTS:
WC = WATER CONTENT (%) (ASTM D 2216);
DD = DRY DENSITY (pcf) (ASTM D 2216);
+4 = PERCENTAGE RETAINED ON NO. 4 SIEVE (ASTM D 422);
-200= PERCENTAGE PASSING NO. 200 SIEVE (ASTM D 1140);
LL = LIQUID LIMIT (ASTM D 4318);
PI = PLASTICITY INDEX (ASTM D 4318);
A-6 (19) = AASHTO CLASSIFICATION (GROUP INDEX) (AASHTO M 145).
16-7-318
H -P -KUMAR
LEGEND AND NOTES
Fig. 3
100
HYDROMETER ANALYSIS
SIEVE ANALYSIS
TIME READINGS
24 FIRS 7 685
45 MIN 15 MIN 60MIN 19MIN 414I6 1618 ./i.00
-1
#I00
U.S. STANDARD SERIES
#50 040 030 #16 /10 #8 04
CLEAR SQUARE OPENINGS
3/8" 3/4" 1 1 2" 3" 5"6" 8"O
I
90
80
1I
20
70
30
II
60
1
40
_
I
1
B
50
F
50
1
c
40
60
I
30
70
-1
20
80
1
I
10
1
I
1
1
0
I I III I I I 1 II1I11 I
I I III1
1 III IIIII
I I 11II111
100
.001
.002 .005 .009 .019 .037 .075 .150
.300 .600 1.18
2.36 4.75 9.5
19 38.1 76.2 127 200
DIAMETER OF
.425 2.0
PARTICLES IN MILLIMETERS
152
SAND
GRAVEL
CLAY TO SILT
COBBLES
FINE
I MEDIUM
'COARSE
FINE
I COARSE
GRAVEL 3 X SAND 12
X
SILT AND CLAY
85 X
LIQUID LIMIT 31
PLASTICITY INDEX
16
SAMPLE OF: Sandy Clay
FROM: Boring 1 0
1'-4'
HYDROMETER ANALYSIS
SIEVE ANALYSIS
TIME READINGS
U.S. STANDARD SERIES
CLEAR
SQUARE OPENINGS
24 MR5 7 MRS
100
45 MIN 15 MIN 601.119 191,11144618 1MIN
0 /100
050 040 /30 /16 010 A6 .4 3/8" 3/4"
1 1 2 3" 5"6" 8"0
90
IO
80
20
70
30
60
40
an
50
50
d
40
60
30
-
70
20
80
0
90
0
I1 1 1 I I I I I I I I
I II I
1I 1111
11111111
111111111
100
.001
.002 .005 .009 .019 .037 .075 .150
.300 .600 1.18
2.36 4.75 9.5
19 38.1 76.2 127 200
DIAMETER OF
.425 2.0
PARTICLES IN MILLIMETERS
152
SAND
GRAVEL
CLAY TO SILT
COBBLES
FINE
I MEDIUM
[COARSE
FINE
I COARSE
GRAVEL 4 X SAND 24
X
SILT AND CLAY
72 X
LIQUID LIMIT 43
PLASTICITY INDEX
13
SAMPLE OF: Calcareous Sandy Silty Clay
FROM: Boring 10 0
1'-4'
These test results apply only to the
samples which were tested. The
tasting report shall not be reproduced,
except In full, without the written
approval of Kumar & Associates, Inc.
Sieve analysis testing is performed in
accordance with ASTM 0422, ASTM C136
and/or ASTM 01140.
16-7-318
H-PtiKUMAR
GRADATION TEST RESULTS
Fig. 4
R -VALUE
TEST SPECIMEN
1
2
3
4
R -VALUE
(300 psi)
MOISTURE CONTENT (%)
x
DENSITY (pcf)
x
EXPANSION PRESSURE (psi)
x
EXUDATION PRESSURE (psi)
x
R -VALUE
x
<5
100
m
76
>
soILTYPE:
LOCATION:
DATE SAMPLED:
GRAVEL:
LIQUID LIMIT:
were
&
with
in
90
80
70
60
50
40
30
20
10
0
•,
„ , , ,
0 100 200 300 400
EXUDATION PRESSURE
Sandy Clay (CL) A-6 (12)
CR114 Garco, Boring 1 @ 1-4'
DATE RECEIVED:
3 SAND: 12 SILT AND CLAY:
31 PLASTICITY INDEX: 16
500
DATE TESTED:
„
(psi)
85
600
These
tested.
except
Associates,
ASTM
with
accordave
700
11/17/16
test results apply
The testing report
in full without the
Inc. R -value
D2844. Atterberg
ASTM D4318, Sieve
with ASTM D422,
800
to the samples which
shall not be reproduced,
written approval of Kumar
performed in accordance
limits performed in accordance
analyses performed
D1140
16-7-318
HP/KUMAR
HVEEM STABILOMETER TEST RESULTS
Fig 5
R -VALUE
TEST SPECIMEN
1
2
3
4
R -VALUE
(300 psi)
MOISTURE CONTENT (%)
41.7
40.3
38.5
9
DENSITY (pcf)
97.7
96.2
102.7
EXPANSION PRESSURE (psi)
0.000
0.000
0.000
EXUDATION PRESSURE (psi)
268
327
502
R -VALUE
6
10
12
100
90
80
70
60
w -
71 50
40
30
20
•
10
0
,,,,
0 100 200 300 400 500 600 700 800
EXUDATION PRESSURE (psi)
SOIL TYPE: Calcareous Sandy Silty Clay
LOCATION: CR114 Garco, Boring 10 @ 1-4'
DATE SAMPLED: DATE RECEIVED: DATE TESTED: 11/17/16
GRAVEL: 4 SAND: 24 SILT AND CLAY: 72 These test results apply to the samples which
tested. The testing report shall not be reproduced,
except in full. without the written approval of Kumar
Associates, Inc. R -value performed in accordance
LIQUID LIMIT. 43 PLASTICITY INDEX: 13 ASTM D2844. Atterberg limits performed in accordance
with ASTM 04318. Sieve analyses performed
accordave with ASTM D422, D1140
were
&
with
in
16-7-318
HP/KUMAR
HVEEM STABILOMETER TEST RESULTS
Fig 6
. VI U•.•• 'WI L
HVEEM"R" AASHTO
VALUE CLASS- SOIL OR
IFICATION BEDROCK TYPE
Sandy Clay II
Sandy Clay II
Slightly Sandy Clay II
Sandy Clay II
Slightly Sandy Clay II
Silty Clayey Sandy Graved'
Calcareous Silty Clay and II
Sand with Gravel
Silty Clayey Sandy Gravel II
Silty Sandy Clay with 11
Gravel
Silty Sandy Clay with il
Gravel
Silty Sand and Clay with II
Gravel
`/
`/
N
N
F
\J
I
In
.--I
'-
Nr
N
11
M
Cr
M
00
Cr)
7t
- PERCENT
PASSING
NO. 200
SIEVE
85
0\
0\
27
M
38
GRADATION
0
CO
-
22
N
N
GRAVEL
(%)
Cr)
IS
N
NATURAL
DRY
DENSITY
{pcf)
.--1
1 108
71-
00
Ch
O-
Q\
NATURAL
MOISTURE
CONTENT
(%)
,-1
r1
13.7
14.2
,_1
.--a
N
M
„_,
.-i
'--1
Cr;may
O
ISAMPLE LOCATION
DEPTH
(ft)
1-4
Cr)
-
Cr)
.--1
-
.--1
,_1
Cr)
1 and 3
(combined)
BORING
N
Cr)
In
VD
N
H -P KUMAR
SOIL OR
BEDROCK TYPE
Silty Sandy Clay
Slightly Sandy Clay 11
Sandy Clay
Clayey Silt and Sand II
Slightly Sandy Clay 11
Calcareous Sandy Silty II
Clay
Calcareous Sandy Silty II
Clay
Sandy Clay with Gravel II
Slightly Sandy Clay 11
Sandy Clay 11
Sandy Clay 11
N
Q
Qd
..
ON
r—
-i
Q
O
Q
00
ATTERBERG LIMITS
PLASTIC
INDEX
(%)
27
22
TZ
oi_
a- '.?-1
J
46
46
37
PERCENT
PASSING
NO. 200
SIEVE
TL
94
r-
GRADATION
a
a e
co
GRAVEL
(%)
NATURAL
DRY
DENSITY
(pcfl
101
M
—4
94
—4
—4
1 TTI
114
NATURAL
MOISTURE
CONTENT
(%)
00
c
13.7
16.8
.
l--
N
O
d
M
O
vp
N
11 SAMPLE LOCATION
DEPTH
(ft)
—
3 and 5
(combined)
BORING
00
p�
u 10
N