HomeMy WebLinkAboutSubsurface Geotechnical Assessment-2008 SUBSURFACE
GEOTECHNICAL ASSESSMENT
Carlson Family,Estate
460,500,520,550 Tonkana Road
Orono,Minnesota
Project 2008.053
PREPARED BY
SPC ENGINEERING,PA
1296 HUDSON ROAD
ST PAUL,MN 55106
June 17, 2008
SPC ENGINEERING & TESTING,INC.
4764 EUROPA TRAIL
HUGO,MN 55038
651.653.6349
June 17, 2008
Project 2008.053
Carlson Family Estate
460,500, 520, 550 Tonkana Road, Orono,Minnesota
OBJECTIVES AND SCOPE OF SERVICES
SPC Engineering&Testing,Inc.,4764 Europa Trail,Hugo,Minnesota,55038 was retained
by Construction Consulting & Inspections, Limited, herein after referred to as the "Client", to
perform a subsurface geotechnical assessment on a parcel of land located at the address in the above
title block.The purpose of this investigation is to identify and evaluate soil properties on the site with
respect to re-constructing the existing bituminous street and driveways,thereon.
June 12, 2008, five soil borings were performed to nominal depth of 11.5±feet within the
project area at locations directed by the client. From the resulting data recommendations are
presented regarding pavement design.
SCOPE OF SERVICES
The client authorized the following scope of services:
Perform five(5) standard penetration test boring to nominal depths of be 11.5±feet below
grade or refusal.
Sample soil using a 2"O.D.split-barrel sampler driven into the soil by a 140 lb weight falling
3 0".After an initial set of 6",the number of blows required to drive the sampler an additional
12"is known as the penetration resistance or N-value.The N-value is an index of the internal
friction of cohesionless soil, the consistency of cohesive soils, and the density of all soils.
Sampling will conform to the methods set forth in ASTM procedure D1586-84.
Classify recovered soil samples by the Visual-Manual method in accordance with ASTM D-
2488. Representative portions of the samples may be submitted to the laboratory for further
examination and for verification of the field classification in accordance with ASTM D2487-
85. Information indicating depth and identification of the various strata,the N-value,water
level information and pertinent information regarding the drilling method will be documented
on comprehensive soil boring logs.
Prepare an engineering report including a log of each boring along with our recommendations
for allowable soil bearing pressures and estimates of foundation settlement.
The purpose of this report is to present the results of our field and laboratory exploration assessment
and the associated engineering review.Please note that this report is for geotechnical purposes only
and is not intended to document the presence or absence of any environmental contaminants that
could be present at the site.
1
SITE OBSERVATIONS
The site is currently developed with homes, street and driveways.
BORING LOCATIONS AND ELEVATION
The number of borings and their locations were determined by the Client, as shown on the
enclosed Site Drawing. Please refer to the Site Drawing attached to this report for a sketch of the
boring locations.
FIELD INVESTIGATION
The borings were accomplished using the Standard Penetration Test (SPT) method of
investigation using a Split-Barrel Sampler(SBS). An attachment describes the soil classification
system used(Unified).
SOIL BORING RESULTS
Refer to the individual boring logs for a detailed description of soils and moisture conditions
encountered. Attached to the soil boring logs is a key explaining terms and entries. The depth of
individual layers of soils may vary somewhat from those indicated on the logs due to unsampled
intervals between split-barrel sampler tests and, most importantly, the occurrence of transition
between soil layers. Also,soil profiles not in the vicinity of the borings may vary. Refusal to auger
advancement was not encountered at the boring locations indicating lack of bedrock to depths tested.
Groundwater was not encountered as indicated in the soil boring logs. The water level checks
were performed at the completion of the boring and at varying times after the boring.The recordings
are depicted in the boring logs. Groundwater levels may occur and vary according to various
climatological and meteorological influences undetermined within the tie frame, scope and budget
allowed in this investigation. In addition,area development patterns can influence groundwater. The
indicated groundwater results are for conditions at the time of testing only.
CONCLUSIONS AND RECOMMENDATIONS
The following conclusions and recommendations are based upon interpreted results of boring
logs,their relation to the planned work,and other information. Because the borings represent a small
portion of the site in relation to the proposed area of work, ongoing review of construction should
be carried out. If excavations reveal subsurface soils of a different nature than those observed in the
boring,the Geotechnical Engineer should be contracted for possibly revised recommendations.
1. Pavement Subgrade Preparation
We refer to the attached sheet entitled "Bituminous Pavement Subgrade Preparation and
Design"for information on pavement design and subgrade preparation including items such as test
roll evaluation, subgrade drainage and compaction recommendations.
2
The subsoils in the upper 3 feet of the existing street and driveway as indicated in the soil
boring logs and as discussed below;
Borings 1,2,3,4,and 5 subsoils under the existing Bituminous, Class 5 Gravel and
silty sand fill (found in Borings 2 and 3) consist of sandy clay (Sandy Clay Loams
AASHTO A-4 or Clays AASHTO A6).
After removal of the existing bituminous pavement section the stability of the pavement
subgrade should be evaluated by means of a test roll prior to paving. All unstable areas of subgrade
should be removed and replaced with additional class 5 aggregate. The bottom of the subgrade
should be compacted prior to adding new aggregate base material.New fill should be compacted per
the Specified Density Method (MnDOT Specification 2105.3fl).
Streets and driveways should have clearance from maximum anticipated groundwater levels.
This groundwater clearance, as practical, should be three feet or more from known groundwater
level. Soil Boring ground water elevation measurements indicate that this guideline has been met.
Mottled soil as indicated in the Soil Boring Logs indicates seasonally saturated ground water levels
near the existing ground surface. Subsurface drains could be installed to increase pavement life if the
clients construction budget, existing topography and connections onto existing drainage structures
make it practicable.
2. Pavement Section Thickness Designs
The thickness of pavement section will depend on the type of material present within the
upper portion of the subgrade. It is assumed that this subgrade material will consist of the existing
clays or sand loams found on this site. In this report,we recommend the pavement design be based
on an assumed R-value of 20, AASHTO Soil Type A-4 or Clays AASHTO A6.
MATERIAL Section Thickness Section Thickness
Car Parking Areas Roadway Areas
Bituminous Wear (Type 41) 1 '/2" 1 ''/i"
Bituminous Base (Type 31) 1 '/2" 1 '/z"
Class 5 Aggregate Base (MnDOT 3138) 8" 8"
Geo-fabric reinforcement* None Yes
*Installed as per manufactures recommendation.
3. Limitations of Investigation
The Geotechnical Engineer has prepared this report using an ordinary level of care and in
accordance with generally accepted foundation and soil engineering practices. Because the
borings represent only a small portion of the total site and for other reasons, SPC Engineering&
Testing, Inc.,does not warrant that the borings are necessarily representative of the entire site but
3
only of the boring locations at the time of investigation. No warranty of the site is made or
implied. The boring logs should only be used in preliminary design and estimating work and in
conjunction with corrective procedures.
The scope of this report is limited strictly to geotechnical issues which include the
establishment of soil profile and only those conclusions expressly made. Please note that this
work is not intended to document the presence or absence of any environmental contaminants at
the site, nor for identifying applicable local, state or federal laws or regulations of a on-
geotechnical nature which may or may not be applicable to this site. Further, SPC Engineering &
Testing, Inc., will not be held responsible for facts not disclosed to the Geotechnical Engineer.
The bore hole voids were backfilled by Development Engineering using native cuttings or
sealed as per the Minnesota Department of Health Rules. Some continuing settlement may occur
if construction does not take place in the near future. If settlement does occur, the Client should
backfill with additional material.
This report and all supporting information is furnished only to the Client and his assigns
for the designated purpose. No representations to other parties or for other uses are made.
Soil samples retrieved during the investigation process will be retained in the office of SPC
Engineering&Testing, Inc. for a period of 30 days from the date of testing. After 30 days from
the date of testing. After 30 days,the samples may be discarded unless a request is received to
retain for a longer period.
ENGINEER'S CERTIFICATE
I hereby certify that this plan, specification or report was prepared by me or under my
direct supervision and that I am a duly registered Professional Engineer under the Laws of the
State of Minnesota.
SPC ENGINEERING& TESTING, INC.
Todd C. Wille,PE
Minnesota Registration No. 25058
4
SOIL BORING LOG DEVELOPMENT ENGINEERING , PA
1296 Hudson Road
St Paul,Mn 55106
PROJECT: Carlson Estate
LOG OF BORING NO: 1
DEPTH SURFACE ELEVATION: GEOLOGY N WB SAMPLE LAB&OTHER TESTS
IN FEET DESCRIPTION&CLASSIFICATION # TYPE R W DEN L.L./P.L.
1 (0'4')Ashalt Pavement Section
-
(4"-5') Dark Brown, Sandy Clay with a little
2- Gravel(CL). Moist. Medium Glacial Till
3- 7 N 1 SBS 12
4-
5-
(6-11.5') Brown, Silty Clay with a little
6- Gravel (CU. Moist. Stiff 10 N 2 SBS 11
7-
8- Medium and Mottled at 7.5 feet 8 N 3 SBS 14
9-
10- Stiff at 10 feet
11- 9 N 4 SBS 16
12- End of Boring at 11.5 feet. No Refusal.
13-
14-
15-
16-
17-
18-
19-
20— WEATHER: Sunny
21-1 1 TEMP: 80o
WATER LEVEL MEASUREMENTS DRILLING DATA
UKILLIPOW
SAMPLED CASING CAVE-IN MUD
DATE TIME(HRS) DEPTH DEPTH DEPTH LEVEL WATER LEVEL CREW CHIEF: BR
6/12/08 1:00 11.5' 10' N/A N/A DRY BCR METHOD: 3 1/4" HAS
6/12/08 11:45 9' DRY ACR 2"OD SBS
F-350/CME 45B
BORING COMPLETED: I 6/12/08
SOIL BORING LOG DEVELOPMENT ENGINEERING , PA
1296 Hudson Road
St.Paul,Mn 55106
PROJECT: Carlson Estate
LOG OF BORING NO: 2
DEPTH SURFACE ELEVATION: 819.97 GEOLOGY N WB SAMPLE LAB&OTHER TESTS
IN FEET DESCRIPTION&CLASSIFICATION # I TYPE R W DEN L.L./P.L.
-4" Ashalt 4"- Pavement Section
1- 10" Limestone Class 5 Gravel
(10"-2.5')Brown,Silty Sand with Class 5 Gravel
2- (SM),Moist FIII
3- (25-11.5)Brown,Sandy Clay with a little Gravel 8 N 1 SBS 12
(CL),and with fine grained sand laminations(SP),
4- Mottled,Moist,Medium Glacial Till
5- at 5 feet no sand laminations
6- 7 N 2 SBS 14
7-
8- 7 N 3 SBS 14
9-
10-
11- 8 N 4 SBS 16
12- End of Boring at 11.5 feet. No Refusal.
13-
14-
15-
16-
17-
18-
19-
20- WEATHER: Sunny
21- TEMP: 80o
WATER LEVEL MEASUREMENTS DRILLING DATA
UKILLINU
SAMPLED CASING CAVE-IN MUD
DATE TIME(HRS) DEPTH DEPTH DEPTH LEVEL WATER LEVEL CREW CHIEF: BR
6/12/08 12:00 11.5' 10' N/A N/A DRY BCR METHOD: 3 1/4" HAS
6/12/08 12:45 9' DRY ACR 2"OD SBS
F-350/CME 45B
BORING COMPLETED: 6/12/08
SOIL BORING LOG DEVELOPMENT ENGINEERING , PA
12%Hudson Road
St Paul,Mn 55106
PROJECT: Carlson Estate
LOG OF BORING NO: 3
DEPTH SURFACE ELEVATION: 819.97 GEOLOGY N WB SAMPLE LAB&OTHER TESTS
IN FEET DESCRIPTION &CLASSIFICATION # TYPE R W DEN L.L./P.L.
-6" AshaR 6"-1Pavement Section
1' I Class 5 Gravel
(1'-2.5') Dark Brown, Silty Sand, Gravelly
2- (SM). Moist Fill
3- (2.5'-11.5') Brown, Sandy Clay with a little Glacial Till 7 N 1 SBS 14
4-
Gravel(CL), Mottled, Moist, Medium
5-
6- 8 N 2 SBS 16
7-
8- 8 N 3 SBS 12
9-
10-
11- 8 N 4 SBS 15
12- End of Boring at 11.5 feet. No Refusal.
13-
14-
15-
16-
17-
18-
19-
20- WEATHER: Sunny
21- TEMP: 80o
WATER LEVEL MEASUREMENTS DRILLING DATA
WKILLINU
SAMPLED CASING CAVE-IN MUD
DATE TIME(HRS) DEPTH DEPTH DEPTH LEVEL WATER LEVEL CREW CHIEF: BR
6/12/08 11:00 11.5' 10' N/A N/A DRY BCR METHOD: 3 1/4" HAS
6/12/08 11:45 9' DRY ACR 2"OD SBS
F-350/CME 45B
BORING COMPLETED: 6/12/08
SOIL BORING LOG DEVELOPMENT ENGINEERING , PA
1296 Hudson Road
St.Paul,Mn 55106
PROJECT: Carlson Estate
LOG OF BORING NO: 4
DEPTH SURFACE ELEVATION: 819.97 GEOLOGY N WBSAMPLE LAB&OTHER TESTS
IN FEET DESCRIPTION&CLASSIFICATION # TYPE R W DEN L.L./P.L.
Ashalt s"-1' Pavement Section
1- Limestone Class 5 Gravel
(1'-7.5') Grey, Sandy Clay with a little
2- Gravel (CL), Moist, Medium Glacial Till
3- 7 N 1 SBS 12
4-
5-
6- 8 N 2 SBS 14
7-
8- (7.5'-10')Brown,Silty Clay(CL)with Gray,fine 7 N 3 SBS 14
grained Sand laminations(SP),Mottled,Moist,
9- Medium
10-
(10'-11.5')Brown,Sandy Clay with a little Gravel
11- (CL),Mottled,Moist,Stiff 10 N 4 SBS 14
12- End of Boring at 11.5 feet. No Refusal.
13-
14-
15-
16-
17-
18-
19-
20- WEATHER: Sunny
21- 1 TEMP: 80f
WATER LEVEL MEASUREMENTS DRILLING DATA
UKILLIN
SAMPLED CASING CAVE-IN MUD
DATE TIME(HRS) DEPTH DEPTH DEPTH LEVEL WATER LEVEL CREW CHIEF: BR
6/12/08 10:00 11.5' 10' N/A N/A DRY BCR METHOD: 3 1/4" HAS
6/12/08 10:45 9' DRY ACR 2" OD SBS
F-350/CME 45B
BORING COMPLETED: I 6/12/0$
SOIL BORING LOG DEVELOPMENT ENGINEERING , PA
1296 Hudson Road
St.Paul,Mn 55106
PROJECT: Carlson Estate
LOG OF BORING NO: 5
DEPTH SURFACE ELEVATION: 819.97 GEOLOGY N WB SAMPLE LAB&OTHER TESTS
IN FEET DESCRIPTION &CLASSIFICATION # I TYPE R W DEN L.L./P.L.
'-6" Ashalt 6"4Pavement Section
1' Class 5 Limestone Gravel
2- (1'-11.5') Brown, Sandy Clay with a little Glacial Till
Gravel (CL), Mottled, Moist, Medium
3- 6 N 1 SBS 12
4-
5- Stiff at 5 feet
6- 10 N 2 SBS 15
7-
8- 10 N 3 SBS 16
9-
10-
11- 10 N 4 SBS 16
12- End of Boring at 11.5 feet. No Refusal.
13-
14-
15-
16-
17-
18-
19-
20- WEATHER: Sunny
21-1 TEMP: 80f
WATER LEVEL MEASUREMENTS DRILLING DATA
UKILLINU
SAMPLED CASING CAVE-IN MUD
DATE TIME(HRS) DEPTH DEPTH DEPTH LEVEL WATER LEVEL CREW CHIEF: BR
6/12/08 9:00 11.5' 10' N/A N/A DRY BCR METHOD: 3 1/4" HAS
6/12/08 9:45 8' DRY ACR 2"OD SBS
F-350/CME 45B
BORING COMPLETED: 1 6/12/08
SOIL BORING LOG
PROJECT: BORING I:Oc-']=
LOG OF BORING NO:
DEPTH SURFACE ELEVATION: SAMPLE LAB i OTWER TESTS
IN GEOLOGY N WB
L_L_
FEET DESCRIPTIONAN0CLASSIFIGATION I TYPE R W DE p L
1
► 2I
t 3 � I �
4 �
t
6I 4 t
fi
7 I Soil Classificatibn, using Origin \ Other
t visual-manual and/or labora- of Soil \ Data as
8 tor;r'.methods� atc4rding to the necessary
t I Unified Soil Classification '
9 System, or to other system as _ Atterberg
t J appropriate Limits{
10 Penetration "N" I
Value - Number
of blows to drive Densitey* !
Split-Barrel Sam-
12-1 pler one foot pcf
l
13-' ater Bearing Moisture
Content
! ( Y = Yes
N = No
1 � �
15- Water
! Level
I Svmbol
16J Length of Sample '
Recovered
Sample Number
17' i -
Indicates Type
18 . of Sample: ;
SBS = Split-barrel
1 i FA = .Flight Auger * = Lab test on
20 HA - Hand Auger recovered sample
ST - Shelby Tube
21 (thinwall)
WATER LEVEL MEASUREMENTS T DRILLING DATA ,
SAMPLED CASING CAVE-0d Omit-LING WA"ER -
DATE TIME Or PVT" DEPTM of FT" r110 LEVEL LEVEL Cray.CAlet
Metmod.
I
UNIFIED SOEL CLASSIFICATION
Group
wjatr DFsi�om Typical taamet Laboratory ckassificatioa Qiteria
GV1, Weil-grades gravels gravel-sand Cu-D=greater than 6:Cc<(D'J� between I and 3
c
mixtures. little or no fines O.. D.atD—
` ' rPoorly graded gravels,gravel- „ c
c GP sand mixtures,:iuk or no fines Not meeting all gradation requirements for GW
_ V _O
= ` Z — Get d �.
.. — Silty gravels,gravel-sand elft = 3 Atterberg limits below
a� e _ — mixturts = line or P.I. less than a
A / u .: a Above •A' lire with P.J.
::�::? between 3 and 7 are bor-
t Z 3 = w deri— .zses requiring use
e C: a
Atererg limits abve"A"GC Clayey�gravels.gravel-sand-cby of dual symbols
t o n r mixtures =_ line with P.I.greater than 7
;L.2
G w
SW Well-graded sands. gtaselly — e Cu=D=grease than a:Ce.(D'-e bet-e-n 1 and 3
sands.little or no fines a D. D.tD_
: 3
Y "'= SP Poorly graded sands.gravelly :
sands little or no lines c 3 -Not meeting all gradation reauiremm%for SW
"J V
t Z O �` y
C Y
t = ? SM dc= Anerberg limits below "A'•
_ Q _ Silty sands.sand-sat c :,
matures a� - line or P.I.las than s Limits plating in hatched
u t o c zone with P.J. between s
3 = YC J L N and l am borderline cases
a;5 requiring use of dual sym-
SIC
Clayey sands.sand<lay aix- 4_ AtsQ�g limits above•A" boas
< lures X^'o line with P.I.gr Mur than 7
Inorganic silts and vm fine
HL sands.rock flour.silty or darn•
fine sands or ciavev silts with60 t t
slight plasticity For etusifi=ton of fax-grained
.�. wds and fine fraction of coarse-
I
C Inorganic clays of l(r-to me• s0 graifed;,ails.
z dium plauicity,gravelly days Atterberg Limns plotting in + t
�+ hatched area are bonle!ltne [lass•CL
M 1 1
sandy days.Silty'days.lean
ifieattorts requiring use of dual i
c
Y / .= days 40 tyntoots. I t
Ec aticn of A4ww: t
,�.. PI X0.'3 tLL-St t
e ' OL Organic sibs and organic silty
Z _ class of low plasticity 10 1
r
s s t
• Inorganic sills.mxauww or (nM"aa0 MM
l
a SIH diatomaceous free sandy or 4 20 t
Silty soils.elastic silts t l
i t CL t t
s,a _ t
e v CH Inorganic days of high pias- 10 t
may.fat days 7 s
7 = 4 ___ct►3i��1� MI.w etc
.
e S OH Organic days of medium to 0 10 70 70 40 50 60 70 10 90 100
_ j Nigh plasticity.orgartsc silts
S=_ Pi Peat and Other highly or ac Liquid Urut
o` g stotl: Ptastt•:uy Gert
GENERAL TERMINOLOGY NOTES FOR
SOIL IDENTIFICATION AND DESCRIPTION
GRAIN SIZE GRAVEL PERCENTAGES
Tenn ASTM Term Percent
Boulders Over 12" A little Gravel 3%to 15%
Cobbles 3"to 12" With Gravel 15%to 30%
Gravel #4 sieve to 3" Gravelly 30%to 50%
Sand #200 to 44 sieve
Fines(silt and clay) Pass#200 sieve
CONSISTENCY OF PLASTIC SOILS RELATIVE DENSITY
OF NON-PLASTIC SOILS
Term N-Value. BPF
Very Soft less than 2 Tenn N-Value,BPF
Soft 24 Ven Loose 0--4
Medium 5-8 Loose 5-10
Stiff 9-15 Medium Dense I 1-30
Very Stiff 16-30 Dense 31-50
Hard Greater than 30 Very Dense Greater than 50
MOISTURE/FROST CONDITION LAYERING NOTES.
D(Dry): Absence of moisture,dusty,dry to
touch. Laminations: Layers less than'/"thick of
M(Moist): Damp; although free water not differingmaterial or color.
visible. Soil may still have a high
water content(over`optimum"). Lenses: Pockets of layers greater than'/2"
W(Wet/ thick of differing material or color.
Waterbearing): Free water visible. Intended to
describe non-plastic soils.
F(Frozen): Soil frozen.
FIBER CONTENT OF PEAT ORGANIC DESCRIPTION
Tenn Fiber Content(Visual Estimate)
Fibric Greater than 67% Non-peat soils are.described as organic, if soil is
Hemic 33 to 67% judged to have sufficient organic content to influence
Sapric Less than 33% the soil properties.
BITUMINOUS PAVEMENT SUBGRADE PREPARATION AND DESIGN
GENERAL
Bituminous pavements are considered layered`flexible" systems. Dynamic wheel loads transmit high local
stresses through the bituminous/base onto the subgrade. Because of this,the upper portion of the subgrade requires
height strength/stability to reduce deflection and fatigue of the bituminous/base system. The wheel load intensity
dissipates through the subgrade such that the high level of soil stability is usually not needed below about 2'to 4'
(depending on the anticipated traffic and underlying soil conditions). This is the primary reason for specifying a
higher level of compaction within the upper subgrade zone versus the lower portion. Moderate compaction is
usually desired below the upper critical zone,primarily to avoid settlements/sags of the roadway. However,if the
soils present below the upper 3' subgrade zone are unstable,attempts to properly compact the upper 3'zone to the
100%level may be difficult or not possible. Therefore, control of moisture just below the 3'level may be needed to
provide a non-yielding base upon which to compact the upper subgrade soils.
Long-term pavement performance is dependent on the soil subgrade drainage and frost characteristic. Poor to
moderate draining soils tend to be susceptible to frost heave and subsequent weakening upon thaw. This condition
can result in irregular frost movements and"popouts," as well as an accelerated softening of the subgrade. Frost
problems become more pronounced when the subgrade is layered with soils of varying permeability. In this
situation.the free-draining soils provide a pathway and reservoir for water infiltration which exaggerates the
movements. The placement of a well drained sand subbase layer as the top of subgrade can minimize trapped
water. smooth frost movements and significantly reduce subgrade softening. In wet, layered and/or poor drainage
situations.the long-tenni performance gain should be significant. If a sand subbase is placed,we recommend it be
a"Select granular Borrow"which meets Mn/DOT specification 3149.2B.
PREPARATION
Subgrade preparation should include stripping surficial vegetation and organic soils. Where the exposed soils are
within the upper"critical" subgrade zone(generally 2 '/2 deep for"auto only" areas and 3'deep for"heavy duty"
areas).they should be evaluated for stability. Excavation equipment may make such areas obvious due to
deflection and rutting patterns. Final evaluation of soils within the critical subgrade zone should be conducted by
test rolling with heavy rubber-tired construction equipment,such as a loaded dump truck. Soils which rut or
deflect 1 or more under the test roll should be corrected by either subcutting and replacement; or by scarification,
drying. and recompaction. Reworked soils and new fill should be compacted per the"Specified Density Method"
outlined in Mn/DOT Specification 2105.3171.
Subgrade preparation scheduling can be an important consideration. Fall and Spring seasons usually have
unfavorable weather for soil drying. Stabilizing non-sand subgrades during these seasons may be difficult,and
attempts often result in compromising the pavement quality. Where construction scheduling requires subgrade
preparation during these times.the use of a sand subbase becomes even more beneficial for constructability
reasons.
SUBGRADE DRAINAGE
If a sand subbase layer is used, it should be provided with a means of subsurface drainage to prevent water build-
up. This can be in the form of draintile lines which tap into storm sewer systems,or outlets into ditches. Where
sand subbase layers include sufficient sloping, and water can migrate to lower areas,draintile lines can be limited
to finger drains at the catch basins. Even if a sand layer is not placed, strategically placed draintile lines can aid in
improving pavement performance. This would be most important in areas where adjacent non-paved areas slope
towards the pavement. Perimeter edge drains can aid in intercepting water which may infiltrate below the
pavement.
!"IN
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LAKE MINNETONKA ► / / f` i�- J %' %' , i i _ HOUSE
�_�r � ',, i- ' Ali ' � �_ �._ ��• f ' \� �' :
Aj
BRYANT REDROCK ' - •' �"=� `
SURFACE
NOTE
.PREFERRED CONFIGURATION FOR A b
PATH WOULD NOT REQUIRE
RETAINING WALLS.
IF GRADES6 HOUSE
TE
BECOME TOO SEP AND WALLS ARE
NECESSARY,"CONTRACTOR SHALL
PROVIDE PRECAST RETAINING` WALL �p i ' R% p 9 1 0 11 4
SYSTEM. CONTRACTOR SHALL
RECEIVE APPROVAL-FROM —
LANDSCAPE ARCHITECT*AND OWNER
FOR A PROPOSED GRADE AND
LOCATION PRIOR TO INSTALLATION. - -
NOTE ' 1� i ;O.\ \ -- t _ �3(room f !
CONTRACTOR SHALL STAKE THE LOCATIONS
OF TREES TO RECEIVE APPROVAL BY 1 1
LANDSCAPE ARCHITECT AND OWNER I - ) C !
j PRIOR TO INSTALLATION. Sugar Maple
HOUSE y , • �. Copper
Spruce
EIAT0&- i
LOCATION 0
Cal
10
POND'i
i
'o, ,
TONKAWA ROAD