Efectos de nivel freático alto y capilaridad

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Paper No. 023184

CD-ROM PAPERDuplication for publication or sale is strictly prohibited

without prior written permissionof the Transportation Research Board

TITLE: EFFECTS OF HIGH GROUNDWATER TABLE AND

CAPILLARY RISE ON PAVEMENT BASECLEARANCE OF GRANULAR SUBGRADES

Author(s): W. Virgil Ping, Haitao Liu,

Chaohan Zhang, and Zenghai Yang

Department of Civil and Environmental Engineering

Florida A&M University - Florida State University

College of EngineeringTallahassee, Florida 32310-6046

(850) 410-6129 (PH) (850) 410-6142 (FAX)

e-mail: [email protected]

and

David Horhota

Florida Department of Transportation

Gainesville, Florida 32609

Transportation Research Board

81st

Annual Meeting

January 13-17, 2002

Washington, D.C.


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Ping, Liu, Zhang, Yang, and Horhota

EFFECTS OF HIGH GROUNDWATER TABLE AND CAPILLARY

RISE ON PAVEMENT BASE CLEARANCE OF GRANULAR

SUBGRADES

ABSTRACT

High groundwater table exerts detrimental effects on the roadway base and the whole pavement.Base clearance guidelines have been developed to prevent water from entering the pavement

system in order to reduce its detrimental effects. This paper presents an experimental study to

evaluate the effects of high groundwater table and the moisture and capillary rise on determiningpavement base clearance for granular subgrades. A full-scale in-lab test-pit test was conducted to

simulate pavement profile and vehicle dynamic impact on the pavement. Three types of granular

subgrades were tested for this study.

The results showed that a 24-inch base clearance was considered adequate for the baseprotection of the A-3 subgrade against high groundwater tables. The A-2-4 soil with relativelyhigh suction value was more susceptible to the change of groundwater table than the A-3 soils.

The percent of fines of subgrade soil can significantly influence its moisture effect on the

resilient modulus.

Key Words: High groundwater table, capillary rise, base clearance, resilient modulus, granularsubgrade


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Ping, Liu, Zhang, Yang & Horhota 1

INTRODUCTION

Roadway pavements must be designed in such a way that water is prevented from entering the

places where it can cause damage. High groundwater table exerts detrimental effects on the

roadway base and the whole pavement. Base clearance guidelines have been developed toprevent water from entering the pavement system in order to reduce its detrimental effects (1). In

these guidelines a minimum height, the clearance, between a groundwater level and a particular

elevation within the pavement system is specified. The guidelines are intended to satisfy twoconcerns: 1) to prevent potential damages to the roadway base due to groundwater saturation or

high moisture content from capillary suction; 2) to achieve the required compaction and stability

during construction operations.

But the prevailing guideline neglects the fact that each roadway is built with a different

type of subgrade material. There can be different geotechnical properties related with different

subgrade soils such as permeability and suction in unsaturated state, which are critical for

capillary behavior (2,3). To assist in evaluating the effects of high groundwater table and the

moisture and capillary rise on determining pavement base clearance for granular subgrades, afull-scale in-lab test-pit test was conducted to simulate pavement profile and vehicle dynamic

impact on the pavement. Three types of granular subgrades were tested for this study. Parameterssuch as soil suction and coefficient of permeability were also measured in the laboratory. The

experimental program is described as follows.

EXPERIMENTAL PROGRAM

A full-scale laboratory evaluation of the three granular subgrade soils was conducted in a test-pit

facility. The stabilized subgrade and base component of a full-scale flexible pavement systemwas simulated in the test-pit facility. Moisture condition was manipulated by raising andlowering the water level in the test-pit. The subgrade materials were tested in different moisture

conditions that simulated different field conditions. Time Domain Reflectometry (TDR) probes

were deployed for measuring the moisture content within each layer of subgrade material in thetest-pit (4,5). The effect of capillary rise was also monitored in the experimental program. The

effect of the dynamic loadings was evaluated using the repeated plate load in the test-pit test.

Subgrade Materials

The soils under investigation in this study were three typical A-3, A-2-4 subgrade materials in

use in Florida representing the percent of fines passing No.200 sieve, which ranged from 4% to

14%. The three soils included Levy County A-3 (4% passing No.200), SR-70 A-3 (8% passingNo.200) and A-2-4 (14% passing No.200). The compaction characteristics were determined in

the laboratory using the modified Proctor (AASHTO T-180) method. The pertinent

characteristics of those subgrade soils are presented in Table 1. The soil suction measurementswere conducted in accordance with the AASHTO T273-86 procedure, except that the soil

samples were remolded. This test method covers the procedure for determining total suction


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force by using thermocouple psychrometers of the Spanner type (2,6). The soil suction versus

moisture content curves are presented in Figure 1 for the three soils.

Test-pit Experimental program

The test-pit facility re-constructs and simulates the subgrade and base components of a flexible

pavement system on a full-scale basis. The major concerns of test-pit test program are thedeformation and equivalent resilient modulus of a layered system under the static loading and

cyclic dynamic loading, which is used in modeling the impact of moving vehicle on the

pavement (7). The cyclic loading of a circular plate was activated with a one-second intervalwithin which the loading and resting periods would be 0.1 and 0.9 second respectively. For the

evaluation of moisture influence on the performance of pavement material, the water table was

kept adjusted within the pit while conducting a plate load test. The TDR probes were deployedwithin the test-pit for the monitor of moisture profile of pavement material.

The capillary action and resilient deformation of the materials under investigation were

evaluated with four levels of groundwater elevation: drained, flooded, intermediate levelsbetween the embankment-subgrade interface, and 12 inches above the embankment. To offsetthe loss due to capillary rise and evaporation, extra water had to be added within the pit to keep

the water table constant at each designated elevation prior to the moisture equilibrium and plate

load test.

The complete setup of test-pit experiment is mainly comprised of two parts full-scale

test-pit and loading system. A schematic view of the test-pit and the loading system andcompaction equipment is illustrated in Figure 2.

Test Arrangement

Levy County A-3 subgrade (4% passing No. 200) had been compacted and experimented withinhalf of the test-pit (8 feet by 6 feet). SR-70 A-3 (8% passing No. 200) and A-2-4 (14% passing

No. 200) subgrades had been compacted and experimented within one test-pit (8 feet by 12 feet).

Separated by wooden partitions, each of these subgrades accounted for half of the test-pit area.

During the test, three feet of subgrade material was compacted within the test-pit under

its optimum moisture condition. The subgrade materials were compacted into seven layers. With

the exception of the first and last lifts three inches thick, each lift was six inches in thickness.

The TDR probe was embedded on each of these layers respectively staggering one another. Thecircular rigid loading plate was positioned on the mid-point between two columns of vertically

arranged TDR probes. The TDR probe installation and test layout for the SR-70 A-3 and A-2-4

subgrades is shown in Figure 3.


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Phase I: Levy County A-3 Soil

A series of plate load tests were conducted at each time when the moisture equilibrium was

achieved for Levy County A-3 soil after adjusting the water table level. The designated testnumbers and their corresponding loading conditions for Phase I are summarized in Table 2.

Phase II: SR-70 A-3 and A-2-4 Soils

A total of fifteen plate load tests were conducted for both SR-70 A-3 and A-2-4 soils in the phase

II test-pit test after the establishment of moisture equilibrium for the soils. The designated test

numbers and their corresponding loading conditions for phase II are also summarized in Table 2.

Method of Analysis

The resilient modulus obtained from the plate load tests on subgrade is based on Boussinesqs

theory of deflections at the center of a circular plate. Burmister has extended this theory to a two-layer elastic system (8). The layers are assumed to be homogeneous, isotropic, and elastic solid

with a continuous interface with the bottom layer being infinite in depth. Under thesecircumstances, the equivalent single-layer resilient modulus under the cyclic loading on a two-layer system (base and subgrade layers) can be derived from the theory of elasticity:

)1(2

=

R

eR

paE (1)

where: EeR = equivalent resilient modulus of a two-layer

system

R = resilient deflection of the two-layer

system at N (number of cyclic load)

p = surcharge pressure from the circular plate

a = radius of the circular plate= Poissons ratio

If=0.35 and 0.50, Equation 1 will be as follow:

R

eR

paE

=

38.1(=0.35) (2)

R

eR

paE

=

18.1(=0.50) (3)

For this study, =0.35 was used for the granular subgrades. The equivalent modulus is

an excellent criterion for the evaluation of the strength of pavement materials (7).

EXPERIMENTAL RESULTS

The experimental results are summarized and presented in this section. A typical figure showing

the plate load test results is presented in Figure 4 for Levy County A-3 soil. The equivalent

modulus values under different loading and water table conditions are presented in Figures5,6,7,8,9, and 10 for the Levy County A-3, SR-70 A-3, and SR-70 A-2-4 soils, respectively. For


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each plate load test conducted, two figures are grouped together to represent a specific set of

plate load test results. The presented equivalent modulus value for each test was taken as theaverage modulus value of over 10,000 load cycles.

In the capillary rise study, the height of the capillary rise was the vertical distance

between the water table and the highest elevation where the moisture increase existed. The

capillary rise results for the three soils are summarized in Table 3.

ANALYSIS OF EXPERIMENTAL RESULTS

The contribution of a rise in capillary moisture to the decrease of the equivalent modulus was

quite different for different soils (see Figure 11). For Levy County and SR-70 A-3 soils, the

extensive accumulation of capillary moisture within capillary fringe after the adjustment of thegroundwater tables seemed to have little influence on the equivalent modulus. For the SR-70 A-

2-4 soil with a relatively higher capillary potential, a minor moisture increase in the capillary

zone would result in a 20% decrease in equivalent modulus. This is probably because the

increase of moisture content may have caused a more drastic suction decrease for a high suctionsoil, thus resulting in a more obvious decrease of resilient modulus value under the plate load. If

this assumption is true, then the design highwater clearance is more critical for high suction soilsthan for low suction soils.

Discussion

The fluctuation of resilient modulus as a result of the change in the groundwater table, illustrated

that mere soil structure itself was not the controlling factor for the elastic deformation (9,10). But

the mere presence of water did not guarantee a decreased resilient modulus. No significantdifference occurred for the resilient modulus of extremely coarse gravel whether it was flooded

or completely drained.

In the literature, the suggestion has been raised that correlating the resilient behavior ofsoil with the suction value it assumed, may be more appropriate than using moisture content or

degree of saturation as indicators for the analysis of subgrade resilient behavior (3). For aspecific subgrade soil, the resilient modulus is more or less dependent on the capillary moisture

developed from the groundwater table. However, for different subgrade materials, the resilient

modulus is more dependent on the capillary potential of each individual soil (suction value)rather than capillary moisture accumulated within a capillary zone.

Case Studies

The practical significance of designing base clearances is to optimize the thickness of the

pavement layers above the groundwater level including a structural asphalt concrete layer

satisfying both the economic and safety designs. A case study utilizing the measured resilientmodulus data to design the required thickness of flexible pavement layer with respect to different

groundwater levels would help to gain an insight into the economic aspect of importance for

such base clearances.


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The AASHTO Guide for Design of Pavement Structures (1986 and 1993) was adopted

for this case study relative to the change of groundwater table at SR-70 (11). In this designapproach, the effective roadbed soil resilient modulus (MR) to be used in the AASHTO design

equation was taken from the equivalent modulus of composite pavement profile in test-pit tests,

which is presented in Figures 5,7, and 9. The two schemes were studied in the following ways:

1. 50 psi plate loading with the equivalent modulus of the composite section for 5-inch limerockbase, 36-inch stabilized subgrade layer, and embankment

2. 20 psi plate loading with the equivalent modulus of the composite section for 36-inch

stabilized subgrade plus embankment

Table 4 summarizes the results of the required structural number and design thickness for

the asphalt concrete layer under different groundwater level variations.

The required thickness of the asphalt concrete layer was more sensitive to the

groundwater table variation for the SR-70 A-2-4 subgrade than for the SR-70 A-3 subgrade

under the same thickness (5 in.) of limerock base. This was especially obvious when the

groundwater table was raised from 12 in. to 36 in. above the embankment (i.e., 0 in. below the

limerock base). For the case of the 50-psi plate loading with 5-in. limerock base, the relationshipbetween the required asphalt concrete thickness and the groundwater table level was nearly

linear for the SR-70 A-3 subgrade. While for the SR-70 A-2-4 soil, the required thickness ofstructural asphalt layer was accelerated by the increase of the groundwater level.

Summary

The results of this case study for State Road 70 indicated that for the A-2-4 subgrade, a slightincrease of the groundwater table (12 in. or higher above the embankment) would demand an

exponential increase for the thickness of asphalt concrete layer in order to have the same quality

pavement performance. Thus, the most safe and economic way for the design of pavement is still

to maintain an adequate base clearance between the groundwater table and the bottom of the baselayer, which is essential for fine-grained subgrade materials (12).

CONCLUSIONS

Based upon the analysis and findings of this experimental study, the conclusions are summarized

below:1. Both Levy County A-3 soil and SR-70 A-3 soil were good subgrade materials to be used for

roadway pavements. A 24-inch base clearance was adequate for the base protection against

high groundwater tables.2. The percentage of fines passing through No. 200 sieve of a subgrade soil can significantly

influence its moisture effect on the resilient modulus. The SR-70 A-2-4 soil with relatively

high suction value was more susceptible to the change of groundwater table than the A-3soils. The resilient modulus deteriorated drastically when the groundwater table reached to the

top of the stabilized subgrade layer.

3. The A-3 soils with a higher permeability had a faster accumulation of capillary moisturewithin the capillary fringe than the A-2-4 soil with a lower unsaturated permeability. The

amount of capillary moisture incurred by a high water table was more dependent on the


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permeability than the capillary potential (soil suction) during a short period of time. For the

SR-70 A-2-4 soil having the highest suction, both the height of capillary rise and the amountof moisture developed over a short term were the lowest among the soils investigated.

4. For different subgrade materials, the resilient modulus was more influenced by the capillary

potential (suction) of a soil than the capillary moisture accumulated within the capillary fringe

above the water table.5. Case studies for the SR-70 project showed that the required thickness of the asphalt concrete

layer increased with an increase in the groundwater level above the embankment. The increaseof asphalt concrete thickness was more pronounced for the A-2-4 soil when the water table

was raised from 12 in. to 36 in. (i.e., 24 in. to 0.0 in. base clearance) above the embankment.

ACKNOWLEEDMENTS

Funding for this research was provided by Florida Department of Transportation (FDOT) andFederal Highway Administration (FHWA). Rick Renna, David Chiu, and Morteza Alian were

the FDOT project managers. The FDOT Research Center, through the assistance of Richard

Long and his stuff, provided financial and contractual support. Rick Venick and Ron Lewis ofthe FDOT State Materials Office provided technical support for the test-pit study.

REFERENCES

1. Elfino, M. K, An Evaluation of Design highwater Clearances for Pavements, Ph. D.

Dissertation, Dept. Of Civil Engineering, University of Florida, Gainesville, FL 1986.2. Fredlund, D. G., and H. Rahardjo, Soil Mechanics for Unsaturated Soils, John Wiley & Sons,

New York, 1993.

3. Edil, T. B., and Sabri E. Motan, Soil Water Potential and Resilient Behavior of Subgrade

Soils. In Transportation Research Record No. 705, TRB, National Research Council,Washington D.C., 1979, pp. 54-63.

4. Campbell Scientific Inc., CS615 Water Content Reflectometer, Logan, UT, 1998.

5. Klemunes, J., Determining Soil Volumetric Moisture Content Using Time Domain

Reflectometry, Office of Engineering Research & Development, Federal HighwayAdministration, Mclean, VA, 1998.

6. Klute, A.Method of Soil Analysis: Part I-Physical and Mineralogical Methods. 2nd ed. Soil

Science Society of American, Madison, Wis., 1986.7. Ping, W. V., and Z. Yang, Experimental Verification of Resilient Deformation for Granular

Subgrades. In Transportation Research Record 1639, TRB, National Research Council,

Washington D.C. 1998.

8. Burmister, D.M. The Theory of Stresses and Displacements in Layered Systems andApplication to the Design of Airport Runways. Proc., of the Highway Research Board, 1943.

9. Hicks, R. G. and C. L. Monismith, Factors Influencing the Resilient Response of GranularMaterials. In Highway Research Record No.345, Highway Research Board, Washington

D.C., 1971.

10. Lekarp, F., U. Isacsson, and A. Dawson, State of the Art. I: Resilient Response of UnboundAggregates,Journal of Transportation Engineering, Vol. 126, Reston, VA, 2000, pp. 66-83.


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11.AASHTO guide for Design of Pavement Structures. Joint Task Force on Pavements, Highway

Sub-committee on Design, American Association of State Highway and TransportationOfficials, Vols. I & II, 1986 and 1993.

12. Huang, Y. H., Pavement Analysis and Design, Prentice-Hall, Inc., Upper Saddle River, NJ,

1993.


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List of Tables

Table 1 Characteristics of Tested Subgrade Materials

Table 2 Test Sequence for Test-pit Experimental Program

Table 3 Summary of Capillary Rise for Subgrade Materials in Test-pit Test

Table 4 Results of Case Study for SR-70 -- Required Thickness of Asphalt Concrete under

Different Groundwater Tables

List of Figures

Figure 1 Summary of Suction vs. Water Content for Tested Soils

Figure 2 Test Pit Loading System and Compaction Equipment

Figure 3 Test-pit Setup for SR-70 A-3 & A-2-4 Subgrades

Figure 4 Levy County A-3 Soil EQ Modulus vs. Number of Cycles under Different Water Tables

(20 psi with Limerock)

Figure 5 Levy County A-3 Soil EQ Modulus

Figure 6 Levy County A-3 Soil Moisture Profile under Plate Load Test

Figure 7 SR-70 A-3 Soil EQ Modulus

Figure 8 SR-70 A-3 Soil Moisture Profile under Plate Load Test

Figure 9 SR-70 A-2-4 Soil EQ Modulus

Figure 10 SR-70 A-2-4 Soil Moisture Profile under Plate Load Test

Figure 11 Equivalent Modulus vs. Water Table


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Table 1 Pertinent Characteristics of Tested Subgrade Materials

+ LBR: Limerock Bearing Ratio, LBR=1.25CBR

Table 2 Test Sequence for Test-pit Experimental ProgramPhase I Levy County A-3 soil

Water Table

(inch)Test Number Plate Load (psi)

5-inch Base Layer

(Limerock)

Test Date

Mo./Day/Year

-20 1-L1 20 No 12/30/98

0 1-L2 20 No 2/5/99

+12 1-L3 20 No 2/26/99

+12 1-L4 20 Yes 3/23/99

+12 1-L5 50 Yes 3/24/99

+36 1-L6 50 Yes 3/31/99

+36 1-L7 20 Yes 4/1/99

Phase II SR-70 A-3 and A-2-4 soils

Water Table

(inch)Test Number Plate Load (psi)

5-inch Base Layer

(Limerock)

Test Date

Mo./Day/Year

0 2-N1(A-3) 20 No 7/19/99

0 2-S1(A-2-4) 20 No 7/20/99

+12 2-S2(A-2-4) 20 No 8/24/99

+12 2-N2(A-3) 20 No 8/25/99+12 2-S3(A-2-4) 50 Yes 9/2/99

+12 2-N3(A-3) 50 Yes 9/3/99

+36 2-N4A(A-3) 50 Yes 9/29/99

+36 2-S4(A-2-4) 50 Yes 9/30/99

+36 2-N4B(A-3) 50 Yes 10/5/99

-24 2-S5(A-2-4) 50 Yes 12/28/99

-24 2-N5(A-3) 50 Yes 12/29/99

-24 2-N6(A-3) 50 Yes 1/4/00

-24 2-S6(A-2-4) 50 Yes 1/5/00

+36 2-S7(A-2-4) 50 Yes 2/1/00

+36 2-N7(A-3) 50 Yes 2/2/00

MaterialNo.200 Passing

(%)Dry Density

(kN/M3)

OptimumMoisture (%)

LBR+

Permeability(cm/second)

Levy Co. A-3 4 16.7 9.5 22 5.52*10-3

SR-70 A-3 8 17.6 11.5 45 2.06*10-3

SR-70 A-2-4 14 19.2 10.6 124 1.97*10-5


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Table 3 Summary of Capillary Rise for Subgrade Materials in Test-pit Test

* Capillary rise passes through 12 in. standard A-3 sand within embankment

** Capillary rise passes through 12 in. standard A-3 sand within embankment

Soil TypeWater Table

(inches)

Time

Period

(days)

-20 to 0.0 29

0.0 to +12 19

-24 to -12 14

-12 to 0.0 17

0.0 to +12 28

-24 to -12 24

-12 to 0.0 42

0.0 to +12 40

15+12 **

>33

15

SR-70 A-2-4

Soil (14%)

Yes 5/17 to 6/10

No 6/10 to 7/22

Capillary

Rise

(inches)

Moisture

Stabilized

at each

Level

Moisture Data

recorded from

(Date: 1999)

21

13+12 *

21

Levy County

A-3 Soil

(4%)

Yes 1/5 to 2/3

Yes 2/5 to 2/23

26

>24

No 7/22 to 9/1

SR-70 A-3

Soil (8%)

Yes 5/17 to 5/31

Yes 6/10 to 6/27

Yes 7/22 to 8/20


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Table 4 Results of Case Study for SR-70 -- Required Thickness of Asphalt Concrete under

Different Groundwater Tables

-20 in.(Drained)

0.0 in. +12 in.

Structural Number N/A 1.54 1.74

Thickness of Asphalt

Concrete (in.)N/A 3.50 3.96










-24 in.

(Drained)+12 in. +36 in.

Structural Number 2.45 2.88 3.25


Concrete (in.)5.58 6.54 7.38

Structural Number 2.85 3.21 4.63


Concrete (in.)6.47 7.29 10.53

Plate Load Test (20 psi w/o Limerock)

Water Table (above Embankment)

SR-70

A-3

(Assumed

Limerock

10 inch)

SR-70

A-2-4

(Assumed

Limerock

10 inch)

Water Table (above Embankment)

SR-70 A-3

SR-70 A-2-4

SR-70

A-3

(Assumed

Limerock

5 inch)

SR-70

A-2-4

(Assumed

Limerock

5 inch)

Plate Load Test (50 psi with 5-inch Limerock)


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Figure 1 Summary of Suction vs. Water Content for Tested Soils

Soil Suction vs Water Content

0

50

100

150

200

250

300

350

400

450

4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0

Moisture Content, %

SoilSuction,

kPa

Levy Co. A-3

SR-70 A-3

SR-70 A-2-4


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Figure 2 Test-pit Loading System and Compaction Equipment

SAND 305mm

GRAVEL05mm

LOADING DEVICE

RIVERGRAVEL

24 WFBEAM

WATERSOURCE

Schematic View of Test-pit


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Figure 3 Test-pit Setup for SR-70 A-3 & A-2-4 Subgrades

(* Sequence of Water Table Adjustment)


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Figure 4 Levy County A-3 Soil EQ Modulus vs. Number of Cycles under Different Water Tables


Levy Count y A-3 Soil, EQ Modulus vs. Number o f Cycles

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

1 10 100 1000 10000 100000

Number of Cycles

EquivalentModulus,M

p

W . T. at +12 in. 1-L4

W . T. at +36 in. 1-L7Subgrade

Embankment

20psi

Limerock


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Equivalent Modulus of Levy County A-3 Soil

178.0

144.7

131.6

226.4

264.2

196.4

170.1

0

50

100

150

200

250

300

1-L1 1-L2 1-L3 1-L4 1-L5 1-L6 1-L7

Test Number

EquivalentModulus,

MPa

Levy County A-3 Soil Moisture Profile under Plate Load Test

0

3

6

9

12

15

18

21

24

27

30

33

36

0 5 10 15 20

Moisture Content, %

Elevation,

in.

1-L1, -20 in. W.T.

1-L2, 0 in. W.T.

1-L3, +12 in. W.T.

1-L4, +12 in. W.T.

1-L5, +12 in. W.T.

1-L6, +36 in. W.T.

1-L7, +36 in. W.T.

Figure 5 Levy County A-3 Soil EQ Modulus

Figure 6 Levy County A-3 Soil Moisture Profile under Plate Load Test

Limerock layer: 1-L4, 1-L5, 1-L6, and 1-L7


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Equivalent Modulus of SR-70 A-3 Soil

499.1

408.2

203.7

174.5

299.7

229.6208.0

0

100

200

300

400

500

600

2-N5 2-N6 2-N1 2-N2 2-N3 2-N4 2-N7

Test Number

EquivalentModulus,

MPa

SR-70 A-3 Soil Moisture Profile under Plate Load Test

0

3

6

9

12

15

18

21

24

27

30

33

36

0 5 10 15 20 25

Moisture Content, %

Elevation,

in.

2-N5, -24 in. W.T.

2-N6, -24 in. W.T.

2-N1, 0 in. W.T.

2-N2, +12 in. W.T.

2-N3, +12 in. W.T.

2-N4, +36 in. W.T.

2-N7, +36 in. W.T.

Figure 7 SR-70 A-3 Soil EQ Modulus

Figure 8 SR-70 A-3 Soil Moisture Profile under Plate Load Test

Limerock layer: 2-N3, 2-N4, 2-N5, 2-N6, and 2-N7


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Equivalent Modulus of SR-70 A-2-4 Soil

233.0

383.4

183.0

153.6

226.6

105.7

60.7

0

50

100

150

200

250

300

350

400

450

2-S5 2-S6 2-S1 2-S2 2-S3 2-S4 2-S7

Test Number

EquivalentModulus,

MPa

SR-70 A-2-4 Soil Mosture Profile under Plate Load Test

0

3

6

9

12

15

18

21

24

27

30

33

36

0 5 10 15 20 25 30 35

Moisture Content, %

Elevation,

in.

2-S5, -24 in. W.T.

2-S6, -24 in. W.T.

2-S1, 0 in. W.T.

2-S2, +12 in. W.T.

2-S3, +12 in. W.T.

2-S4, +36 in. W.T.2-S7, +36 in. W.T.

Figure 9 SR-70 A-2-4 Soil EQ Modulus

Figure 10 SR-70 A-2-4 Soil Moisture Profile under Plate Load Test

Limerock layer: 2-S3, 2-S4, 2-S5, 2-S6, and 2-S7


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Figure 11 Equivalent Modulus vs. Water Table

Average Equivalent Modulus vs Water Table

(20 psi without Lim erock)

0

50

100

150

200

250

300

350

400

450

500

-24 -18 -12 -6 0 6 12 18

Ground Water Table, in.

AverageEQ

Modulus,

Mpa

Levy Co. A-3

SR-70 A-3

SR-70 A-2-4

Ave rage Equivalent Modulus vs Water Table


0

50

100

150

200

250

300

350

400

450

500

-36 -24 -12 0 12 24 36 48

Ground Water Table, in.

AverageEQ

Mod

ulus,

Mpa

Levy Co. A-3

SR-70 A-3

SR-70 A-2-4

Efectos de nivel freático alto y capilaridad

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