HomeMy WebLinkAbout1.18 Kumar Pavement StudyLake Springs Ranch
Subdivision Preliminary Plan/PUD Amendment December 2025
Exhibit 18 | Pavement Subsoil Study
H-P ~KUMAR
Geotechnical Engineering l Engineering Geology
Mate ri als Testing I Environmental
5020 County Road 154
Glenwood Springs, CO 81601
Phone: (970) 945-7988
Fax: (970) 945-8454
Email: hpkglenwood@kumarusa.com
Office Locations: Parker, Glenwood Springs, and Silverthorne, Colorado
December 16, 2016
Mike Berkeley
c!o TGMC, Inc
Attn: Tim Malloy
402 Park Drive
Glenwood Springs, Colorado 81601
tim@tgmalloy.com
Subject:
Gentlemen:
Project No.16-7-318
Subsoil Study for Pavement Section Design, Proposed Lake Springs Ranch
Development, County Roads 114 and 115, Garfield County, Colorado
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 1 ½ 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 piesented 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
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pavement materials, typically consist of sandy clay and silty sandy clay with gravel. The section
of about¼ 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. l 76xl 06), 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 sub base. The design section
assumes structural coefficients of0.44 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
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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-P~KUMAR
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 -Hveeni Stabilometer Test Results
Table 1 -Summary of Laboratory Test Results
cc: High Country Engineering-Dan Dennison (ddennison@hcen g.com)
H-P ~KUMAR Project No. 16-7-318
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i ~-----L ____ _
PROPOSED LAKE
SPRINGS RANCH
------400 0 400 800
APPROXIMATE SCALE-FEET
~!1-------.-----------""""T"-----------------"T-----1 :!/ it 16-7-318 H-P~KUMAR LOCATION OF EXPLORATORY BORINGS Fig. 1 ~t ....... ____ .....__ __________ ......_ _________________ ..._ ___ _,
BORING 1 BORING 2 BORING 3 BORING 4
12/6,50/5
WC=13.2
73/12 D0=84
0 12/12 (6) 10/12 m -200=53 0
WC=2.4 LL=41 1 WC=11.5 WC=14.2 +4=51 Pl=17 iDD=111 D0=108 -200=27
I A-7-6 (7)
I
I t-50/6 50/0 t-w w w w i.... i....
I 5 5 I :r: 15/12 42/12 :r: t-t-a. a. w w
0 13/12 20/12 0
WC=13.7 WC=11.9
-200=92 -200=94
LL=39 LL=38
Pl=21 Pl=22 10 A-6 (19) A-6 (21) 10
BORING 5 BORING 6 BORING 7 BORING 8
19/12
WC=9.1
0
~:l '7 15/6,50/0
(4) D0=109 (3) (3) 13/12 0
-200=77 (4)
LL=40 41/12 WC=7.0
WC=17.8
• • WC=11.1 Pl=12 D0=101
-200=38 A-6 (9) +4=17
t-36/1 2 -200=54 t-w w w w
i.... i....
I 5 5 I :r: 33/12 48/12 16/12 :r: t-t-a. a. w w
0 5/6, 18/6 16/12 0
WC=15.4 WC=13.7
D0=95 -200=96
-200=88 LL=46
Pl=27
10 A-7-6 (28) 10
BORING 9 BORING 10 BORING 11 BORING 12
28/12
WC=14.2
20/12 15/12 0 (3) D0=103 (4) (2) (1) 0
i (3) • -200=71 WC=11.1 (4) WC=14.0
a LL=48 jDD=111 20/12 D0=111
V Pl=22 1-200=94 -200=95 . I
0 A-7-6 (15) I
29/12 ' I m
t-154/12 t-~ WC=10.3 :;; w w
l w D0=114 w
i.... i....
I 5 5 I e :r: 36/12 ]63/12 60/12 35/12 :r: ~ t-t-a. WC=12.6 a. w w
~ 0 24/12 WC=17.5 36/12 -200=90 0
J WC=16.8 -200=84 WC=12.1 LL=37
l DD=94 LL=47 -200=79 Pl=21
-200=53 Pl=11 LL=39 A-6 (18)
~~ LL=46 A-7-5 (12) Pl=21
z~ 10 Pl=6 A-6 (16) 10
0 1 A-7-5 (2) ~ '' -~ ~!
.;~
a,:;
ii 16-7-318 H-P~KUMAR LOGS OF EXPLORATORY BORINGS Fig. 2 E f ...
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LEGEND
(5) I ASPHALT, THICKNESS IN INCHES SHOWN IN PARENTHESES TO LEFT OF THE LOG.
(5) I ~~~~COURSE, THICKNESS IN INCHES SHOWN IN PARENTHESES TO LEFT OF THE
[71 CLAY (CL); SLIGHTLY SANDY TO SANDY, SCATTERED GRAVEL, STIFF TO VERY L_j STIFF, SLIGHTLY MOIST TO MOIST, MIXED BROWN, MEDIUM TO HIGH PLASTICITY.
[71 SAND AND CLAY (SC-CL); SILTY, GRAVEL AND COBBLES , MEDIUM DENSE/VERY Lj STIFF, LIGHT BROWN, CALCAREOUS, LOW PLASTICITY.
~ GRAVEL (GM-GC); SILTY, CLAYEY, SANDY, COBBLES, PROBABLE BOULDERS, Ed MEDIUM DENSE, GRAY-BROWN, CALCAREOUS, BASALT ROCK.
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RELATIVELY UNDISTURBED DRIVE SAMPLE; 2-INCH 1.0. CALIFORNIA LINER SAMPLE.
DRIVE SAMPLE; STANDARD PENETRATION TEST (SPT), 1 3/8 INCH 1.0. SPLIT SPOON
SAMPLE, ASTM D-1586.
~] DISTURBED BULK SAMPLE.
/ DRIVE SAMPLE BLOW COUNT. INDICATES THAT 10 BLOWS OF A 140-POUND HAMMER 1 O 12 FALLING 30 INCHES WERE REQUIRED TO DRIVE THE CALIFORNIA OR SPT SAMPLER 12 INCHES.
t PRACTICAL AUGER REFUSAL.
NOTES
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);
Pl = PLASTICITY INDEX (ASTM D 4318);
A-6 {19) = AASHTO CLASSIFICATION (GROUP INDEX) (AASHTO M 145).
~~-----------------....... -----------------------ii 16-7-318 I H-P~KUMAR I LEGEND AND NOTES I Fig. 3 o>,__ _____ ...._ _________ _.,_ __________________ _.,_ ___ __,
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HYDROMETER ANALYSIS SIEVE ANALYSIS
TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS J 24 HRS 7 HRS
100 45 MIN 15 MIN 60MIN 19MIN .4MIN IMIN .:aa 1100 •so ,..,a 130 .,. ,10 ,a • 3/8'" 3 1 ,· 1 112" 3 " 5"6"
' ! ' i
a
' --i I I i ! 90
'
10
V I i I I I
ea '' 20 ! :-!
I I
70 I 30 : :
I I
I ! --+-60 f---,a
so I l so ! i I I I
•o
i -+-----r+ --60
I ! I I
I !
30 I 70
i
I
i I
20 f-80
I I
! I
10
; I i ! 90 i I
! l 0 I I I I I I I I I i I i 100
.001 .002 .005 .009 .019 .037 .075 ,150 .300 .600 ... 1.18 1 2.36 4.75 •. s 19 38.1 76.2 127 , 200
CLAY TO SILT
GRAVEL 3 "
LIQUID LIMIT 31
SAMPLE OF: Sandy Clay
HYDROMETER ANALYSIS
TIME READINCS
24 HRS 7 HRS
.425 2.0 152
DIAMETER OF PARTICLES IN MILLIMETERS
SAND GRAVEL
1-------.--------,.----t------,.--------1COBBLES
SAND
FINE MEDIUM COARSE FINE COARSE
12 %
PLASTICITY INDEX
U.S. STANDARD SERIES
SILT AND CLAY
16
85 %
FROM: Boring I O I' -4'
SIEVE ANALYSIS
CLEAR SQUARE OPENINGS
I
100 .... MIN , .. MIN 6OMIN 19MIN .tMIN 1MIN •~oo •100 •so •40 •30 •~5 •10 ~B
·--._I __ --+---+---+
1
, __ --,' ----<----+ l I ~~ l l
3• s1"s_" e" 0
i l ' -: i 1 ·:~_ ~ --==---,.----t·--+----r---r ·7·
---+-----+---+---+---------1---...-"'~'--4--..;-+-'--+--...;:_ t----+---+---+---+I----+! ---+!--ii
90
80
JO
20
I J i I I
! ! I .
I : V ,, ,,,
10 ---+-----~--1------+1---+---! 1 I 7--~+-30
____ L_ -, . --+----: +---+--+--+----+--~i_J___ ___ --~--~-__ l ____ l __ ~--40
BO j I I i ] ! j
i • ! t ; 1 i I
so 1---~---1---+----+.--~----· r·----r·--+--<---+--+---i'---+---"'-----+---· 1
j ! I j l l I
so
ea ,a ----r----------+---1------:------t----------+ ----t-··+--l----.---,:-r-----~,,-----~------~ -----+----r -
___ : -! ti_j !----: :_ -___ J __ _,_ ____ t---!-----H-70 30
i
i
20 1---,-----e---+----+---"-·
I
1 ! : l j I I I l I
l ' l 1 1 l ! [
~ , ---+---, ea
l i ; ; : I
10
I I ! l l I I I i I
•a -j-i -r-----r--;, !·---;-!--i 7 Jj
.0·~0'"1 --_-;;a-::-02:;--''-'-1 .""o~;::5;"' ... ''--':.'o"'o~~--:.0~11"•--'-:;·oca'37!:--''--'--:! 1 .0:':~'a-, 'w''---:. 1°"s""o ... ,_..,_3°'00,,-J'--''-,.•"'~0""1-''-'1-''1:-_,-;: e:;---,2,.,t . .:!l"'s'-1 -'',:-_!a~s;-'-'.J...J. ''-:!-~ :.,,, ,---,1-=~---'-,"'•="'. 1,-.1.....J 1 '--1:!:s"=.2='-'-1 -:-1 "'~1="'
1
'-::-!2001 00
CLAY TO SILT
GRAVEL 4 "
LIQUID LIMIT 43
.425 2.0 152
DIAMETER OF PARTICLES IN MILLIMETERS
GRAVEL SAND
t-------,-------.-----1r-----.-------tCOBBLES
FINE MEDIUM
SAND 24 %
PLASTICITY INDEX
COARSE FINE
SILT AND CLAY
13
COARSE
72 "
SAMPLE OF: Calcareous Sandy Silty Clay FROM: Boring 10 0 1'-4'
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It
These test results apply only to the
samples which were tested . The
testing report shall not be rtproduced,
except In full, without the written
approval of Kumar & A:1:sociotes, Inc.
Sieve analysis testing is performed in
occordance with ASTM 0422, ASTM C136
and/or ASTM 01140.
~"§" .gt---------.-------------------.------------------------------,.-------1 H 16-7-31a H-P~KUMAR GRADATION TEST RESULTS Fig. 4 !~._ ________ .._ __________________ .._ ____________________________ ...., ______ ..,
R-VALUE
TEST SPECIMEN 1 2 3 4 R-VALUE
(300 psi)
MOISTURE CONTENT(%) X
DENSITY (pct) X
EXPANSION PRESSURE (psi) X
EXUDATION PRESSURE (psi) X
R-VALUE X <5
100
90
80
70
60
C1>
:I ca 50 >,
~
40
30
20
10
0
0 100 200 300 400 500 600 700 800
EXUDATION PRESSURE (psi)
SOIL TYPE : Sandy Clay (CL) A-6 (12)
LOCATION : CR114 Garco, Boring 1@ 1-4'
DATE SAMPLED: DATE RECEIVED : DATE TESTED : 11/17/16
GRAVEL: 3 SAND: 12 SILT AND CLAY: 85 These test results apply lo the samples which were
tested. The testing report shall not be reproduced ,
except tn full. without the written approval of Kumar &
LIQUID LIMIT: 31 PLASTICITY INDEX : 16
Associates , Inc, R~value performed in accordance with
ASTM 02844. Atterberg limits performed in accordance
with ASTM 04318. Sieve analyses performed In
accordave wrth ASTM D422, 01140
16-7-3181 HP/KUMAR HVEEM STABILOMETER TEST RESULTS Fig 5
R-VALUE
TEST SPECIMEN 1 2 3 4 R-VALUE
(300 osil
MOISTURE CONTENT(%) 41.7 40.3 38.5
DENSITY (pct) 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 9
100
90
80
70
60
Cl)
::I
ni ~ 50
0:::
40
30
20
10 ✓r
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 were
tested. The tl!!sting report shall not be reproduced,
except in full . without the written approval of Kumar &
Associates, Inc. R-value performed in accordance with
LIQUID LIMIT: 43 PLASTICITY INDEX: 13 ASTM D2844. Atterberg limits performed in accordance
with ASTM 04318. Sieve analyses performed in
accordave with ASTM 0422, 01140
16-7-3181 HP/KUMAR HVEEM STABILOMETER TEST RESULTS Fig 6
H-P~l<UMAR
TABLE 1
SUMMARY OF LABORATORY TEST RESULTS
Project No. 16-7-318 .
Page 1 of 2
SAMPLE LOCATION NATURAL NATURAL GRADATION ATTERBERG LIMITS AASHTO PERCENT HVEEM"R" MOISTURE DRY GRAVEL SAND PASSING LIQUID PLASTIC VALUE CLASS-SOIL OR BORING DEPTH CONTENT DENSITY NO. 200 LIMIT INDEX IFICATION BEDROCK TYPE (%) (%)
SIEVE
(ft) (%) (pcf) (%) (%)
1 1 11.5 111 Sandy Clay
1-4 3 12 85 31 16 5 A-6 (12) Sandy Clay
3 13.7 92 39 21 A-6 (19) Slightly Sandy Clay
2 1 14.2 108 Sandy Clay
3 11.9 -
' 94 38 22 A-6 (21) Slightly Sandy Clay
3 1 2.4 51 22 27 Silty Clayey Sandy Gravel
4 1 13.2 84 53 41 17 A-7-6 (7) Calcareous Silty Clay and
Sand with Gravel
5 1 11.1 38 Silty Clayey Sandy Gravel
6 1 9.1 109 77 40 12 A-6 (9) Silty Sandy Clay with
Gravel
3 15.4 95 88 Silty Sandy Clay with
Gravel
7 1 and 3 7.0 17 29 54 Silty Sand and Clay with
(combined) Gravel
SAMPLE LOCATION NATURAL NATURAL
MOISTURE DRY
BORING DEPTH CONTENT DENSITY
(ft) (%) (pcf)
8 1 17.8 101
3 13.7
9 1 14.2 103
3 16.8 94
10 1 11.1 111
1-4
3 and 5 17.5 (combined)
11 3 12.1
-
12 1 14.0 111
3 10.3 114
5 12.6
H-P~l<UMAR
TABLE 1
SUMMARY OF LABORATORY TEST RESULTS
GRADATION ATTERBERG LIMITS
PERCENT HVEEM"R" GRAVEL SAND PASSING LIQUID PLASTIC VALUE
NO. 200 LIMIT INDEX (%) (%)
SIEVE
(%) (%)
96 46 27
71 48 22
53 46 6
94
4 24 72 43 13 9
84 47 11
79 39 21
95
90 37 21 .
AASHTO
CLASS-
IFICATION
A-7-6 (28)
A-7-6 (15)
A-7-5 (2)
A-7-5 (10)
A-7-5 (12)
A-6 (16)
A-6 (18)
Project No.16-7-318
Page 2 of 2 ,
SOIL OR
BEDROCK TYPE
Silty Sandy Clay
Slightly Sandy Clay
Sandy Clay
Clayey Silt and Sand
Slightly Sandy Clay
Calcareous Sandy Silty
Clay
Calcareous Sandy Silty
Clay
Sandy Clay with Gravel
Slightly Sandy Clay
Sandy Clay
Sandy Clay