HomeMy WebLinkAbout3811; Flower Fields Mass Grading; Flower Fields Mass Grading; 1985-03-01FINAL REPORT OF TESTING AND OBSERVATION
SERVICES DURING MASS GRADING OPERATIONS
FOR
FLOWER FIELDS
CARLSBAD, CALIFORNIA
For
MR. JERRY ELDER
c/o James J. Werners Construction Company
San Diego, California
GEOCON, INCORPORATED
San Diego, California
March, 1985
GEOCON
INCORPORATED ENGINEERS AND GEOLOGISTS • CONSULTANTS IN THE APPLIED EARTH SCIENCES
File No. D-3014-J02
March 22, 1985
Mr. Jerry Elder
c/o James J. Wenuers Construction Company
2496 "E" Street, Suite B
San Diego, California 92102
Attention:
Subject:
Mr. James Wermers
FLOWER FIELDS
TRACT NO. 83-13
CARLSBAD, CALIFORNIA
FINAL REPORT OF TESTING AND OBSERVATION
SERVICES DURING MASS GRADING OPERATIONS
Gentlemen:
In accordance with your request and our proposal
have provided testing and observation services during the mass grading of
the subject subdivision. Our services were performed during the period of
February 13, 1985 through March 19, 1985. The scope of our services
included the following:
• Observing the grading operation, including the Installation
of subdrains and the removal and/or processing of loose
topsoil, existing uncontrolled fill soils and alluvial soil.
Preparing an As-Graded Geologic Map.
Preparing this final report of grading.
9530 DOWDY DRIVE » SAN DIEGO, CALIFORNIA 92126 » PHONE (619) 695-2880
File No. D-3014-J02
March 25, 1985
General
The grading contractor for the project was Devenco. The project plans were
prepared by Deardorff and Deardorff and are entitled "Grading Plans for
Flower Fields, City of Carlsbad Tract No. 83-13.
The project soils report is entitled "Geotechnical Investigation for
Assessors Parcel No. 167-030-54, Carlsbad, California," prepared by Geocon,
Incorporated dated August 23, 1983.
References to elevations and locations herein were based on surveyor's or
grade checker's stakes in the field and/or interpolation from the
referenced Grading Plans.
Grading
Grading began with the removal of brush and vegetation from the area to be
graded and the material was then exported from the site. Loose topsoils,
existing uncontrolled fill soils and loose alluvial soils in areas to
receive fill were removed to firm natural ground.
Prior to placing fill, the exposed natural ground surface was scarified,
moisture conditioned and compacted. Fill soils derived from onsite cutting
operations were then placed and compacted in layers until the design
elevations were attained.
Slopes
Cut slopes have inclinations of 1.5 to 1.0 (horizontal to vertical) with
maximum heights on the order of 10 feet. Slopes beneath the buildings
separating the levels have inclinations of 1.3 to 1.0. Fill slopes have
inclinations of 2.0 to 1.0 (horizontal to vertical) with maximum heights on
the order of 35 feet. The fill slopes were periodically backrolled with a
sheepsfoot compactor during construction and were track-walked with a
bulldozer upon completion. All exposed slopes should be planted, drained
and maintained to reduce erosion. Slope planting should consist of a
drought-tolerant mixture of native plants and trees having a variable root
depth. Iceplant should not be used on slopes. Slope watering should be
kept to a minimum to just support the vegetative cover.
Finish Grade Soil Conditions
During the grading operation, building pads which encountered clayey soils
at grade were undercut at least 3 feet and capped with granular soils.
Similarly, our observations and test results indicate that granular soils
were placed within at least the upper 3 feet of finish grade on fill lots.
The laboratory test results indicate that the prevailing soil conditions
-2-
File No. D-3014-J02
March 25, 1985
as defined by UBC Standard Table 29-C. Table III
presents a summary of the indicated Expansion Index of the prevailing soil
condition of each lot.
In addition to capping building pads as described above, the cut portion of
those pads which contained a cut-fill transition within the building area
(or contained hardrock at subgrade) was undercut at least 3 feet and
replaced with compacted fill soil.
Subdrains
Subdrains were installed at the general locations shown on the approved
Grading Plans. The subdrains were "as-built" for location and elevation by
the project Civil Engineer.
Soil and Geologic Conditions
The soil and geologic conditions encountered during grading were found to
be similar to those described in the project geotechnical report. The
enclosed reductions of the approved Grading Plans depict the as-graded
geologic conditions observed. The approximate locations of subdrains are
also indicated. No soil or geologic conditions were observed during the
grading which, in our opinion, would preclude the continued development of
the property as planned.
CONCLUSIONS AND RECOMMENDATIONS
Based upon laboratory test results and field observations, it is our
opinion that the prevailing soil conditions within 3 feet of finish pad
grade consist of "low" to "medium" expansive soils as classified by UBC
Standard Table 29C.
We recommend the following foundation and slab design criteria for the
proposed one- and/or two-story condominium structures.
Foundations
Lve loads;
Footings should have a minimum width of 12 inches. This bearing pressure
may be increased by up to one-third for transient loads such as wind or
seismic forces.
File No. D-3014-J02
March 25, 1985
Continuous footings for Building Nos. 1, 3, 4 and the Pool and
JTenniT Court structures, should be reinforced with four No. 4 bars, two
placed near the top and two near the bottom.
Slabs for Building Nos. 1, 3 and 4 should be reinforced
with 6x6-6/6 welded wire mesh or No. 3 reinforcing bars placed at 3-foot
centers both ways. The slabs should be underlain with 4 inches of clean
sand and, where moisture sensitive floor coverings are planned, a visqueen
moisture barrier protected by 1 inch of the sand cushion should be
provided. Great care should be taken during the placement and curing of
concrete flatwork to reduce the potential for shrinkage cracking.
4. The laboratory tests indicate that "medium" expansive soil is present
within the pool area. A structural engineer should be consulted for proper
structural design.
5. Footings should not be placed within 5 feet of the top of slopes.
Footings that must be located in this zone should be extended in depth such
that the outer bottom edge of the footing is at least 5 feet horizontally
from the face of the slope.
6. No special subgrade presaturation is deemed necessary prior to placing
concrete, however, the exposed foundation and slab subgrade soils should be
sprinkled as necessary to maintain a moist condition as would be expected
in any such concrete placement.
Lateral Loads
This design value
~as~sume~stfiat footings or shear keys are poured neat against properly
compacted granular fill soils or undisturbed formational soils and that the
soil mass extends at least 10 feet horizontally from the face of the
footing or three times the height of the surface generating passive
pressure, whichever is greater. The upper 12 inches of material not
protected by floor slabs or pavement should not be included in design for
passive resistance.
-4-
File No. D-3014-J02
March 25, 1985
Retaining Walls
9. Unrestrained retaining walls should be designed to resist the pressure
exerted by an equivalent fluid weight of 35 pcf. This value assumes that
granular onsite material will be used for backfill, that the backfill
surface will be level, and that no surcharge loads will be acting on the
wall. For walls with backfill surfaces inclined at no steeper than 2.0 to
1.0,
10. For walls restrained from movement at the top, such as basement walls,
an additional uniform horizontal pressure of 8H psf (H equals the height of
the wall in feet) should be applied in addition to the active lateral
pressures given above.
11. All retaining walls should be provided with a backfill drainage system
adequate to prevent the buildup of hydrostatic forces.
12. All foundation excavations should be observed by a representative of
Geocon, Incorporated to evaluate actual soil conditions.
Any additional grading performed at the site should be done under our
observation and testing. All trench backfill material in excess of 12
inches in depth should be compacted to at least 90 percent relative compac-
tion. This office should be notified at least 48 hours prior to commencing
additional grading or backfill testing.
LIMITATIONS
The conclusions and recommendations contained herein apply only to our work
with respect to grading, and represent conditions at the date of our final
inspection, March 19, 1985. Any subsequent grading should be done under
our observation and testing. As used herein, the term "observation" implies
only that we observed the progress of the work with which we agreed to be
involved. Our conclusions and opinions as to whether the work essentially
complies with the job specifications are based on our observations,
experience and testing. Subsurface conditions, and the accuracy of tests
used to measure such conditions, can vary greatly at any time. We make no
warranty, expressed or implied, except that our services were performed in
accordance with engineering principles generally accepted at this time and
location.
We will accept no responsibility for any subsequent changes made to the
site by others, by the uncontrolled action of water, or by the failure of
others to properly repair damages caused by the uncontrolled action of
water.
-5-
File No. D-30U-J02
March 25, 1985
If there are any questions regarding our recommendations or if we may be of
further service, please contact the undersigned.
Very truly yours,
ON, INCORPORATED
aes E. Likins
17030
MRR:JEL:ltn
(6) addressee
Michael W. Hart
CEG 706
Michael R. Rahilly
RCE 28188
File No. D-3014-J02
March 25, 1985
TABLE IA
Summary of Laboratory Compaction Test Results
ASTM D1557-70
Sample
No.
1
2
3
4
5
6
7
8
9
10
Description
Brown, Clayey SAND
Dark brown, Clayey SAND
Green-brown, Silty SAND
Dark brown, Sandy CLAY
Light tan, Silty SAND
Olive brown, Silty SAND
Dark brown, Sandy CLAY
Brown, Clayey SAND
Tan, Silty SAND
Brown, Silty SAND
Maximum Dry
Density
pcf
122.6
124.9
1112.6
117.8
118.9
127.0
125.5
126.0
124.2
118.5
Optimum
Moisture
% Dry Wt.
8.9
9.2
14.8
12.9
12.9
11.3
10.8
9.7
12.2
12.8
File No. D-3014-J02
March 25, 1985
TABLE IB
Summary of Laboratory Expansion Index Test Results
Sample
No.
1
2
3
4
5
6
7
8
9
10
Moisture
Before
Test
%
9.7
10.6
14.4
13.4
12.1
11.0
10.6
10.4
10.7
11.9
Content
After
Test
%
19.0
20.1
33.6
30.2
25.7
21.5
23.2
22.1
24.7
25.3
Dry
Density
pcf
110.5
109.5
94.4
96.8
101.8
16.3
113.4
107.2
106.6
101.8
Expansion
Index
21
22
101
79
41
32
84
42
53
58
TABLE 1C
Summary of In-Place Moisture-Density and Direct Shear Test Results
try Moisture
Sample Density Content
No. pcf %
*6 113.9 11.4 350 25
*Sample remolded to approximately 90 percent of maximum dry density
at near optimum moisture content.
TABLE II
Summary of Field Density Test Results
Date
1985
2/19
2/20
2/21
H
3
^
Test
No. Location
1 Lot 8
2 '
3
4
9
9
10
5 Retest of #3
6 Retest of #4
7 Lot 8
8
9
10 N
^ 9
10
f 11
11 Retest of #10
12 /
13
14
15
\ 10
9
8
11
16 ' 10
17
18
19
20
10
9
8
' 9
Elevation
feet
68
70
70
69
70
69
68
72
76
77
77
78
79
72
82
80
82
74
76
77
Dry Dens.
pcf
103.8
104.9
106.1
100.7
102.6
108.4
109.4
107.6
108.3
100.0
107.4
109.3
108.4
108.8
115.4
112.7
113.6
113.1
108.0
.108.2
Moisture
% dry wt
20.7
16.3
13.0
13.4
13.0
14.5
12.8
13.5
16.0
14.9
13.7
14.0
16.1
13.0
12.5
13.4
13.2
14.6
15.7
15.2
Rel Comp
% of max
92
93
89
89
91
91
92
91
91
89
90
92
91
92
92
90
91
9Q
91
91
Soil Type
& Remarks
3
3
4 Ck.
3 Ck.
3
4
4
4
4
3 Ck.
4
4
4
4
2
2
2
2
5
5
#5
#6
#11
TABLE II CONTINUED
Summary of Field Density Test Results
Date Test
1985 No. Location
2/21 21 Lot 10
22 v
23
24 -I
11
11
' 11
2/22 25 Access Road
26 . Lot 9
27 >
28
29
30
31
32
33
34
2/25 35
36
•N 37
d 38
. 10
11
11
11
11
10
10
8
9
8
8
f 11
^ 39 Access Road
S 40 Lot 9
Elevation
feet
84
83
84
88
90
81
84
90
90
92
91
86
87
80
86
82
82
92
94
90
Dry Dens. Moisture
pcf % dry wt
109.9
107.8
110.9
109.8
112.7
112.5
114.4
112.5
114.5
113.1
107.6
108.4
107.3
109.1
107.9
108.8
110.2
109.6
108.8
109.3
13.6
14.7
14.3
13.9
12.6
12.0
10.0
13.9
12.8
13.0
15.8
15.3
15.2
16.3
14.9
14.8
15.4
15.1
14.7
14.7
Rel Comp
7, of max
92
90
93
92
90
90
91
90
91
90
90
91
90
92
90
92
93
92
91
92
Soil Type
& Remarks
5
5
5
5
2
2
2
2
2
2
5
5
5
5
5
5
5
5
5
5
TABLE II CONTINUED
Summary of Field Density Test Results
Date Test
198.5 No. Location
2/25 41 Lot 8
A
42
43
44
8
9
10
45 V 11
46 Access Road
47 Lot 8
48 t
49
2/26 50
" 9
10
f 11
51 Fill Adj. Avenida De Anita
52
53
54
^
/
55 Lot 16
56 Between Lot #15 & #16
•\ 57 Entrance Drive
rf 58 Retest of #57
5 59 Lot 15
V 60 Entrance Drive
Elevation
feet
92
90
94
95
98
98 -
95
96
98
99
79
81
84
85
86
88
90
92
94
96
Dry Dens.
pcf
109.0
111.9
109.7
109.1
108.9
109.1
108.4
107.6
109.4
109.0
107.1
106.8
107.4
108.1
113.3
113.6
111.3
112.9
113.9
. 115.1
Moisture
% dry wt
12.8
14.2
14.9
14.6
15.6
13.8
16.4
16.1
15.9
16.7
16.3
14.3
14.5
14.6
14.0
13.2
14.6
14.2
15.0
13.1
Rel Comp
% of max
91
94
92
91
92
92
91
90
92
91
90
90
91
91
90
92
89
90
91
92
Soil Type
& Remarks
5
5
5
5
5
5
5
5
5
5
4
4
4
4
2
1
2 Ck. #58
2
2
2
TABLE II CONTINUED
Summary of Field Density Test Results
Date Test
1985 No. Location
2/27 61 Fill Adj. Avenida De Anita
62 Lot 16
63 '
64
65
66
67
68
69
70
2/27 71
72
73
74
75 N
17
15
16
8
9
11
10
9
11
9, Parking Lot
10, Parking
11, Parking
( 10
2/28 76 Access Road
_ 77 Lot 17
^^V 1
K 78 "N 15
< 79 ]/• 15
S 80 Between #14 & #15
Elevation
feet
98
100
102
103
103
98
100
102
105
107
109
111
112
114
115
101
104
1 • 105
107
114
Dry Dens. Moisture
pcf % drv wt
114.4
115.0
113.6
112.4
111.4
109.9
107.2
109.4
110.9
109.7
112.4
113.8
115.3
113.8
115.9
115.6
113.9
116.0
113.8
113.8
12.6
13.8
14.3
14.1
13.8
13.1
13.9
12.4
13.8
12.0
12.8
12.7
12.9
13.2
13.6
11.8
12.0
11.1
11.6
11.4
Rel Comp
% of max
91
92
92
91
90
92
90
92
93
92
90
91
92
91
93
92
90
92
90
90
Soil Type
& Remnrks
2
2
1
1
1
5
5
5
5
5
2
2
2
2
2
6
6
6
6
6
Date
1985
2/28
3/1
Test
No. LQ
81 Lot 15
82 Area below Lot 17
83 Lot 16
84 £ 16
85 15, Parking Lot
86 Area below Lot 16
87 Lot 17, Parking
88 ^ 689
90
91
92
93
94
95
96
97
98
99
100 s
6
5
5
6
6
7
7
1
1
1
1, Parking
1, Parking
TABLE II CONTINUED
Elevation
feet
106
100
104
104
116
108
106
98
100
102
104
106
107
106
108
95
97
99
105
102
Dry Dens,
pcf
112.9
116.1
114.2
113.0
113.3
112.5
114.7
114.2
116.7
113.8
117.0
116.8
115.3
114.1
117.8
117.0
117.3
118.9
114.2
116.7
Moisture
7' dry wt
13.0
12.7
13.0
13.4
11.1
12.3
11.0
13.1
12.8
13.2
14.2
13.1
12.6
12.0
12.8
11.9
12.4
13.4
14.2
13.7
Rel Comp
% of mnx
90
92
91
90
90
90
91
90
92
90
92
92
90
90
92
92
92
93
90
92
Soil Type
&D n 1Kemnrks
7
7
7
7
7
7
7
6
6
6
6
6
6
6
6
6
6
6
6
6
Date Test
3/4
3/5
101 Lot 5
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
^ 6
7
8
9
10
11
6
7
9
10
11
15
14
13
12
15
14
13
16
TABLE II CONTINUED
^^^-P^asUiL^e^^Jesults
Elevation
feet
113
114
114
113
114
114
114
115
117
116
116
117
105
116
118
118
108
116
120
112
Dry Dens.
Pcf
116.4
115.8
117.6
116.4
116.7
119.2
120.3
117.5
115.5
115.9
115.7
115.7
117.1
114.1
115.9
116.1
116.4
115.4
118.5
116.1
Moisture
'/„ dry wt
12.2
11.6
12.8
11.7
10.3
11.9
13.8
11.5
13.0
12.4
11.4
12.0
11.9
12.1
12.3
11.3
10.7
12.5
12.7
13.2
Rel Comp soil Type
-° 0[ S5a« & Remarks
92 6
91 6
92 6
91 6
91 6
93 6
94 6
92 &V
91 6
91 6
91 6
91 6
92 6
90 6
91 6
91 6\J
92 6V
90 6U
93 6\J
91 6
TABLE II CONTINUED
Date Test
1985 No- Location
3/5 121 Lot 16
122 ;
123
3/6 124
125
126
127
128
129
130
131
132
133
3/7 134
135
136
137
cj 138
4 139
S 140 N
12
12
1 , Upper Pad
3 A
4
5
6
7
8 v
8 Slope
9 Slope
10, Slope
10, Slope
11, Slope
8, Slope
8, Corner pad
9, Corner pad
10, Corner pad
1 11, Corner pad
Elevation
_ __ feet
114
120
121
FG 114.4
FG 115.5
FG 116.5
FG 115.5
FG 115.7
FG 116.7
FG 116.2
FG 100.0
FG 92.0
FG 82.0
FG 104.0
FG 102.0
FG 76.0
FG 107.7
FG 107.8
FG 107.9
FG 108.5
Dry Dens,
pcf
114.8
117.1
117.9
117.1
116.5
113.6
115.2
117.7
118.5
116.8
109.3
111.7
109.2
110.9
110.7
107.5
109.9
110.4
108.5
107.6
Moisture
% dry wt
11.8
10.7
12.6
11.5
13.1
L3.5
12.2
12.7
13.0
11.9
12.9
13.6
11.8
12.5
13.6
13.4
14.8
15.1
14.7
14.3
Rel Comp
vi rto o L m ti x
90
92
93
92
93
90
90
92
93
92
91
94
92
93
93
90
92
93
91
90
Soil Type
& Remarks
6
6
6
6
7
7
6
6
6
6
5
5
5
5
5
5
5
5
5
5
TABLE II CONTINUED
Summary of Field Density Test Results
Date
1985
3/7
3/8
3/11
.2'4s
Test
No.
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
Location
Lot 14
/
>,
^ 15
16
17
17
' 17
Slope Repair Property Adj. S. Place
• /
^
^
/r t
Lower Lot 2
Lower Lot 5
Lower Lot 6
Lower Lot 7
Upper Lot 9
Upper Lot 10
Upper Lot 11
Upper Lot 17
Lower Lot 2
Lot 15
Elevation
feet
116
112
116
104
107
110
107
110
113
115
104
FG 107.0
FG 107.2
FG 108.2
FG 116.3
FG 116.4
FG 117.0
FG 111.5
FG 105.9
118
Dry Dens,
pcf
114.6
114.0
114.4
115.2
116.8
115.3
115.1
117.7
116.6
116.3
114.2
114.9
116.9
115.3
114.9
116.0
116.4
116.2
116.1
117.6
Moisture
% dry wt
11.0
11.3
11.9
12.0
12.3
11.7
12.4
13.1
12.0
12.5
13.1
11.1
12.1
13.0
12.2
12.7
13.9
11.8
13.2
13.6
Rel Comp
°/ f\f m "> VfO \J L 1 1 1 Li ^
91
90
91
91
93
91
91
93
92
92
91
91
93
92
91
92
92
92
92
93
Soil Type
a Remarks
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
TABLE II CONTINUED
Summary of Field Density Test Results
Date Test
1985 No.Elevation
Location feet
3/11 161 Upper Lot 16 FG 120.7
162 Upper Lot 15 FG 121.5
163 Lower Lot 16 FG 112.2
164 Lower Lot 15 FG 113.0
165 Lower Lot 14 11.0
166 Lower Lot 14 FG 113.5
167 Upper Lot 14 118
3/12 168 ' Upper Lot 14 120
169 Lot 12 111
170 Upper Lot 14 FG 122.0
171 Lot 2,
172 Lot 7,
A
173 ^ 9,
174 12,
175 \ 15,
interior slope 110
interior slope 113
A 109
111
N/ 118
176 Slope below Access Road 96
3/13 177 Lot 12,
2 178 Lot 12,
3 179 Lot 13,
"^ 180 Lot 13,
Lower FG 115.0
Upper ' FG 122.0
Upper FG 122.5
Lower FG 114.0
Dry Dens,
pcf
116.8
115.1
116.3
116.0
115.5
115.3
114,5
114.5
115.1
116.4
113.2
114.8
115.7
114.9
115.2
108.2
112.9
113.5
116.9
119.2
Moisture
/» dry wt
12.2
12.3
12.4
13.1
12.2
13.5
12,4
12.8
14.0
13.9
12.4
12.6
13.6
11.4
12.8
14.5
10.5
11.1
13.0
14.2
Rel Comp
% of max
93
91
92
92
92
92
91
91
91
92
90
91
92
91
92
91
90
90
93
94
Soil Type
& Rsmorks
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
5
8
8
8
8
TABLE II CONTINUED
Summary of Field Density Test Results
Date
1985
3/13
3/14
3/15
3/18
^K.
Test
No.
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
Location
Lot 16, Parking
Tennis Court
Lot 12, Parking
4;6> t
West Slope Tennis Court
Slope west of pad 17
Pool Area
Retest of #188
Lot 1, Parking
t 15- t•Y
1, Upper\y
Parking Area West of Tennis Court
X Retest of #182
N of Tennis Court, Retaining Wall
Lot 1 , Upper
Retest of #195
Elevation
feet
116.5
FG 109.6
FG 115.0
FG 119.0
105
110
109
FG 114.1
114
107
110
111
112
FG 109.4
114.0
FG 113.3
114
Dry Dens.
pcf
114.4
101.9
113.3
113.3
113.8
96.3
112.3
93.9
107.2
109.8
114.1
113.1
108.8
107.2
108.5
107.8
112.6
Moisture
% dry wt
13.0
11.1
9.6
10.5
9.3
5.3
9.3
12.0
12.0
12.4
10.2
9.9
11.1
11.1
11.7
13.0
12.4
Rcl Comp
% of max
91
86 -
90
90
90
81 .
92
88
90
93
91
90
92 '
90 *
87
91
91
Soil Type
& Remarks
8
10 Ck.
8
8
8
5
1
10 Ck.
10
10
8
8
10
10
9 Ck.
10
9
#194
#189
#197
File No. D-3014-J02
March 25, 1985
TABLE III
Summary of Expansion Potential
Building No.Expansion Index Classification
1
2
3, 4
5, 6, 7
8-11
12 - 18
Pool,
58
42
84
42
41
42
58
medium
low
medium
low
low
low
medium
Tennis Court