Model for Resilient Modulus and Permanent Strain of Subgrade Soils

1998 ◽  
Vol 1619 (1) ◽  
pp. 85-93 ◽  
Author(s):  
A.S. Muhanna ◽  
M.S. Rahman ◽  
P.C. Lambe
Keyword(s):  
Simple Model ◽  
Plastic Strain ◽  
Confidence Intervals ◽  
Empirical Model ◽  
Resilient Modulus ◽  
Cohesive Soil ◽  
Repeated Loading ◽  
Subgrade Soils ◽  
Permanent Strain ◽  
Proposed Model

The resilient modulus and cumulative permanent strain of subgrade soils under anticipated repeated loading are important considerations for the design of a pavement against fatigue and rutting failures. A simple model was developed to evaluate the resilient modulus and accumulated permanent strain of cohesive subgrade soils under repeated loads. The empirical model was derived from the observed behavior of an A-6 cohesive soil. The model was tested against an A-5 soil. The proposed model was found to predict adequately the resilient modulus and the accumulated plastic strain for all A-6 and A-5 specimens with 90 percent confidence intervals of 0.61 and 1.4, and 0.66 and 1.39, respectively.

Correlation between Resilient Modulus and Plastic Deformation for Cohesive Subgrade Soil under Repeated Loading

2008 ◽  
Vol 2053 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Shu-Rong Yang ◽  
Wei-Hsing Huang ◽  
Chi-Chou Liao
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Hardening ◽  
Resilient Modulus ◽  
Cohesive Soil ◽  
Repeated Loading ◽  
Hardening Behavior ◽  
Subgrade Soil ◽  
Stress Levels ◽  
Strain Hardening Behavior

Pavement performance is related to resilient modulus and plastic deformation of pavement materials, which in turn are affected by environmental conditions and traffic loading. A series of triaxial tests was conducted on a residual lateritic soil for 10,000 load repetitions, with some specimens subjected to 100,000 load repetitions, to characterize the behavior of cohesive subgrades under repeated loading, including resilient modulus and plastic deformation. The shakedown concept was used to describe the accumulated plastic deformation and the strain-hardening and softening behavior. Experimental results show that the resilient modulus of cohesive subgrades exhibits strain-hardening behavior under low stress levels. In the meantime, the rate of plastic strain accumulation becomes diminutive. Soil under this condition is in a stable state. Conversely, under high stress levels, cohesive soil tends to soften after a specific number of load applications and accumulates excessive plastic strain and leads to an unstable state. To predict the plastic strain of subgrade soil under repetitive loading, regression models incorporating the strain-hardening behavior for a cohesive soil were used.

Model for predicting resilient modulus of unsaturated subgrade soil using soil-water characteristic curve

2015 ◽  
Vol 52 (10) ◽  
pp. 1605-1619 ◽  
Author(s):  
Zhong Han ◽  
Sai K. Vanapalli
Keyword(s):  
Moisture Content ◽  
Soil Water ◽  
Resilient Modulus ◽  
Characteristic Curve ◽  
Optimum Moisture Content ◽  
Model Parameters ◽  
Soil Water Characteristic Curve ◽  
Subgrade Soils ◽  
Fine Grained ◽  
Proposed Model

Soil suction (ψ) is one of the key factors that influence the resilient modulus (MR) of pavement subgrade soils. There are several models available in the literature for predicting the MR–ψ correlations. However, the various model parameters required in the existing models are generally determined by performing regression analysis on extensive experimental data of the MR–ψ relationships, which are cumbersome, expensive, and time-consuming to obtain. In this paper, a model is proposed to predict the variation of the MR with respect to the ψ for compacted fine-grained subgrade soils. The information of (i) the MR values at optimum moisture content condition (MROPT) and saturation condition (MRSAT), which are typically determined for use in pavement design practice; (ii) the ψ values at optimum moisture content condition (ψOPT); and (iii) the soil-water characteristic curve (SWCC) is required for using this model. The proposed model is validated by providing comparisons between the measured and predicted MR–ψ relationships for 11 different compacted fine-grained subgrade soils that were tested following various protocols (a total of 16 sets of data, including 210 testing results). The proposed model was found to be suitable for predicting the variation of the MR with respect to the ψ for all the subgrade soils using a single-valued model parameter ξ, which was found to be equal to 2.0. The proposed model is promising for use in practice, as it only requires conventional soil properties and alleviates the need for experimental determination of the MR–ψ relationships.

scholarly journals Studies on resilient modulus value from cyclic loading tests for cohesive soil

2017 ◽  
Vol 49 (2) ◽  
pp. 117-127 ◽  
Author(s):  
Wojciech Sas ◽  
Andrzej Głuchowski ◽  
Maciej Miturski
Keyword(s):  
Cyclic Loading ◽  
Triaxial Test ◽  
Resilient Modulus ◽  
Cohesive Soil ◽  
Cyclic Test ◽  
Repeated Loading ◽  
Silty Clay ◽  
Cbr Test ◽  
Loading Tests ◽  
Cyclic Loading Tests

Abstract In this article the cyclic CBR test as a reference method in determination of resilient modulus (Mr) is confronted with results of cyclic triaxial and unconfined uniaxial cyclic test. The main idea of conducted experiments is establish relationship between cyclic loading tests in testing of natural subsoil and road materials. The article shows results of investigation on cohesive soil, namely sandy silty clay, commonly problematic soil in Poland. The results of repeated loading triaxial test resilient modulus were displayed in order to compare them with cyclic CBR test results by using the Mr–Ө model. Some empirical correlation between factors obtained from triaxial test or uniaxial unconfined cyclic test and cyclic CBR test was introduced here. The behavior of resilient modulus was also examined in this paper.

scholarly journals Studies on Cyclic and Dynamic Loading on Cohesive Soil in Road Engineering

2016 ◽  
Author(s):  
Wojciech Sas ◽  
Andrzej Głuchowski ◽  
Katarzyna Gabryś ◽  
Emil Soból ◽  
Alojzy Szymański
Keyword(s):  
Dynamic Loading ◽  
Resilient Modulus ◽  
Poisson Ratio ◽  
Cohesive Soil ◽  
Repeated Loading ◽  
Cohesive Soils ◽  
Laboratory Equipment ◽  
Road Design ◽  
Triaxial Apparatus ◽  
Soil Behaviour

Soil investigations concerning cyclic and dynamic loading differ from static analysis. The Problem with the abovementioned loads becomes more important, when cohesive soils are taken into consideration. There are plenty of scientific reports containing the analyses of non-cohesive soil behaviour, yet there is still a lack of similar studies on cohesive soils. Repeated loading and dynamic excitations differ between themselves and parameters which are used to describe those phenomena are not congruent. Road constructors seek new approaches to design methods, which would take into account more types dynamic and cyclic excitations. For a successful utilisation of these occurrences in designing codes, mechanical parameters, such as resilient modulus Mr, shear modulus G and Poisson ratio υ or dumping ratio D, need to be determined. The laboratory tests were conducted on sandy clays, which are a common soil in Poland, using specialized laboratory equipment, such as a resonant column and cyclic triaxial apparatus. The aim of the work presented in this paper was to measureand analyse the abovementioned mechanical characteristics. The paper ends with conclusions regarding the application of cyclic and dynamic loading characteristics in road design.

scholarly journals Determination of the Resilient modulus MR for the lime stabilized clay obtained from the repeated loading CBR tests

2012 ◽  
Vol 44 (2) ◽  
pp. 143-153 ◽  
Author(s):  
Wojciech Sas ◽  
Andrzej Głuchowski ◽  
Alojzy Szymański
Keyword(s):  
Resilient Modulus ◽  
Back Analysis ◽  
Road Construction ◽  
Repeated Loading ◽  
Recoverable Strain ◽  
Subgrade Soils ◽  
Test Parameters ◽  
Local Soil ◽  
Repeated Test

Abstract Determination of the Resilient modulusMR for the lime stabilized clay obtained from therepeated loading CBR tests. The main aim of this paper is to prove that CBR repeated test is useful to give an adequate like unconfi ned cyclic triaxial test parameters for design the pavement and subgrade soils. That parameter is the Resilient modulus (MR) which is the elastic modulus based on the recoverable strain under repeated load. Resilient modulus (MR), is an important parameter which characterizes the subgrade’s ability to withstand repetitive stresses under traffic loadings. The 1993 AASHTO guide for design of flexible pavements recommends the use of MR. The additional aim is connected with the concept of sustainable development. For many countries, where resources are at premium, it is very important that stabilized local soil can be used for road construction. For ensuring that stabilized clay can be used for pavement material standard compaction, CBR and repeated CBR tests were performed. In that paper parameter MRof the subgrade lime stabilized clay soil by laboratory CBR repeated test were determined using for calculation formulas from triaxial cyclic test. Based on AASHTO empirical equation the static CBR values using back analysis was also calculated. Finally both values of CBR determined and calculated were compared.

Subgrade resilient modulus prediction using light-weight deflectometer data

2017 ◽  
Vol 54 (3) ◽  
pp. 304-312 ◽  
Author(s):  
S. Hamed Mousavi ◽  
Mohammed A. Gabr ◽  
Roy H. Borden
Keyword(s):  
Resilient Modulus ◽  
Soil Layer ◽  
Constitutive Models ◽  
Structure Design ◽  
Light Weight ◽  
Confining Stress ◽  
Subgrade Soils ◽  
Novel Approach ◽  
Proposed Model ◽  
Light Weight Deflectometer

Resilient modulus has been used for decades as an important parameter in pavement structure design. Resilient modulus, like other elasticity moduli, increases with increasing confining stress and decreases with increasing deviatoric stress. Several constitutive models have been proposed in the literature to calculate resilient modulus as a function of stress state. The most recent model, recommended by the Mechanistic–empirical pavement design guide (MEPDG) and used in this paper, calculates resilient modulus as a function of bulk stress, octahedral shear stress, and three fitting coefficients: k1, k2, and k3. Work in this paper presents a novel approach for predicting resilient modulus of subgrade soils at various stress levels based on light-weight deflectometer (LWD) data. The proposed model predicts the MEPDG resilient modulus model coefficients (k1, k2, and k3) directly from the ratio of applied stress to surface deflection measured during LWD testing. The proposed model eliminates uncertainties associated with needed input parameters for surface modulus (ELWD) calculation, such as the selection of an appropriate value of Poisson’s ratio for the soil layer and shape factor. The proposed model was validated with independent data from other studies reported in the literature.

Resilient Modulus and Plastic Strain of Unsaturated Cohesive Subgrade Soils

2006 ◽  
Author(s):  
Johnson H. S. Kung ◽  
H. D. Lin ◽  
Shu-Jung Yang ◽  
Wei-Hsing Huang
Keyword(s):  
Plastic Strain ◽  
Resilient Modulus ◽  
Subgrade Soils

scholarly journals Repeated Loading of Cohesive Soil – Shakedown Theory in Undrained Conditions

2015 ◽  
Vol 37 (2) ◽  
pp. 11-16 ◽  
Author(s):  
Andrzej Głuchowski ◽  
Alojzy Szymański ◽  
Wojciech Sas
Keyword(s):  
Cyclic Loading ◽  
Soil Mechanics ◽  
Cohesive Soil ◽  
Small Strain ◽  
Repeated Loading ◽  
New Production ◽  
Permanent Strain ◽  
Shakedown Theory ◽  
Resilient Response ◽  
Cyclic Loading Tests

Abstract The development of industry and application of new production techniques could bring about extraordinary problems that have been neglected. One of these challenges in terms of soil mechanics is high frequency cyclic loading. Well constructed foundation may reduce this troublesome phenomenon but excluding it is usually uneconomic. In this paper, shakedown theory assumptions were studied. Cyclically loaded soils behave in various ways depending on the applied stress rate. Common cohesive soils in Poland, i.e., sandy-silty clays are problematic and understanding of their behaviour in various conditions is desired. In order to study repeated loading of this material, cyclic triaxial test were carried out. Cyclic loading tests were conducted also in one way compression. These methods in small strain regime allow permanent strain increment analysis with resilient response after numerous cycles. This behaviour was subsequently exploited in the study of shakedown theory. This paper contains some conclusions concerning the above-mentioned theory.

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