Impact of hydraulic hysteresis on the small strain shear modulus of unsaturated sand

Khosravi, Arezoo; Shahbazan, Parisa; Pak, Ali

doi:10.1016/j.sandf.2018.02.018

Cited by 45 publications

(23 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, Khosravi et al (2018) proposed a semi-empirical equation to predict G max of unsaturated sand during hydraulic hysteresis. The model adopted the concepts of suction stress proposed by Lu and Likos (2006) to capture the effect of hydraulic hysteresis.…”

Section: Introductionmentioning

confidence: 99%

Impacts of Drying-Wetting and Loading-Unloading Cycles on Small Strain Shear Modulus of Unsaturated Soils

2019

View full text Add to dashboard Cite

The small strain shear modulus (G max) is an important parameter in geodynamic problems. In order to predict G max of unsaturated soils which are normally subjected to complex drying, wetting processes, effect of hydraulic hysteresis needs to be evaluated. Although several equations have been proposed in recent years, limitations still exist, requiring more research studies in this field. In this study, G max was investigated in a multi-stage test during several drying-wetting cycles and a loading-unloading cycle of net stress. The results revealed four key factors that directly influence the magnitude of G max : the void ratio, the net stress, matric suction and degree of saturation. While variations of the void ratio, net stress, and matric suction cause persistent responses of G max (i.e. if all other factors remain unchanged, G max would then be reversely proportional to the void ratio and directly proportional to the net stress and matric suction) , variations in the degree of saturation result in different responses. A decrease in the degree of saturation may induce a reduction or growth of G max since on the one hand it reduces the effect of matric suction, while on the other hand it increases the total effect of van der Waals attractions and electric double layer repulsions. At the same stress state, a reverse trend, induced by an increase in the degree of saturation, will occur with a growth in the effect of matric suction Void ratio Void ratio function Maximum small strain shear modulus k Material constant Propagation distance

show abstract

Section: Introductionmentioning

confidence: 99%

Impacts of Drying-Wetting and Loading-Unloading Cycles on Small Strain Shear Modulus of Unsaturated Soils

2019

View full text Add to dashboard Cite

show abstract

“…Small-strain shear modulus (G 0 ) is dependent on net stress, suction history, void ratio, over-consolidation ratio (OCR), strain rate, and plasticity index [24,36,[38][39][40][41]. Many empirical and semi-empirical expressions have been proposed for describing the relationship between suction and modulus.…”

Section: Suction-small-strain Shear Modulus Relationshipmentioning

confidence: 99%

Determining Shrinkage Cracks Based on the Small-Strain Shear Modulus–Suction Relationship

et al. 2019

View full text Add to dashboard Cite

This research aims to propose the use of spectral analysis of surface wave (SASW) tests along with in-situ suction measurements for non-destructive determination of shrinkage cracks. The underlying principle behind this proposed method is that, while suction and the small-strain shear modulus are positively correlated for intact samples, this is not the case for cracked ground. A series of SASW tests were performed on a clay embankment at different periods, during which the suction, modulus, and shrinkage crack depth varied seasonally. The soil water retention curve (SWRC) of the undisturbed sample collected from the cracked zone was determined, which related the suction-to-moisture content and void ratio of the soil. A free-free resonant frequency (FFR) test in the lab was conducted to determine the small-strain shear modulus (G0) at various moisture contents. The small-strain moduli from the SASW tests on the intact ground were generally higher than those from the FFR tests due to the effect of confining stress. A drop in the small-strain modulus determined using the SASW test was observed as an increase in suction-induced cracks and it relieved the horizontal stress. The crack depth measured in the field was then modelled using a semi-empirical procedure that can be used to predict crack depth relative to suction.

show abstract

“…However, the influences of inherent anisotropy on G0, an important property of sandy soil, are normally small matter. For unsaturated soils, several factors such as particle size, compacted water content, degree of saturation, matric suction, hydraulic hysteresis were found to be influential on the shear wave velocity and initial shear modulus G0 (Cho and Santamarina, 2001;Heitor et al, 2013;Oh et al, 2014;Khosravi et al, 2018). However, in those reports, the effects of inherent anisotropy on initial shear modulus of sand were less studied even for saturated sands.…”

Section: Introductionmentioning

confidence: 97%

Effects of inherent anisotropy on G0 of unsaturated sand

Toyota

Takada

2019

JGS Special Publication

View full text Add to dashboard Cite

Inherent anisotropy, resulted from sediment process, is an important aspect when considering the behavior of sandy soils. Also, accurate initial shear modulus G0 at very small strain is an essential parameter in many seismic designs and analyses of underground structures. In this research, the influences of inherent anisotropy on G0 were investigated by conducting a series of triaxial tests employed both local small strain (LSS) measurement technique and bender element (BE) method. Specimens were prepared using air pluviation method in an inclined container at different angles to create the inherent anisotropy induced by orientation of sand particles. The experimental results obtained on both saturated and unsaturated sands indicate that G0 was affected by depositional angle of the specimen. Moreover, those results showed greater G0 on unsaturated sand than that on saturated sand because of the application of matric suction.

show abstract

Impact of hydraulic hysteresis on the small strain shear modulus of unsaturated sand

Cited by 45 publications

References 23 publications

Impacts of Drying-Wetting and Loading-Unloading Cycles on Small Strain Shear Modulus of Unsaturated Soils

Impacts of Drying-Wetting and Loading-Unloading Cycles on Small Strain Shear Modulus of Unsaturated Soils

Determining Shrinkage Cracks Based on the Small-Strain Shear Modulus–Suction Relationship

Effects of inherent anisotropy on G0 of unsaturated sand

Contact Info

Product

Resources

About