Time-Dependence of the Mechanical Behavior of Loess after Dry-Wet Cycles

Kai Liu,Tianfeng Gu,Xingang Wang,Jiading Wang

doi:10.3390/app12031212

Kai Liu, Tianfeng Gu + Show 2 more

Open Access

https://doi.org/10.3390/app12031212

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Abstract

The structure, time-dependent mechanical deformation, and strength characteristics of loess, which is loose and porous with well-developed vertical joints, are greatly affected by the dry-wet cycles, which are attributed to periodic artificial irrigation, rainfall, and water evaporation. To better understand the creep characteristics of loess under the effect of dry-wet cycles, Q2 loess samples obtained from the South Jingyang County, China, were subjected to different dry-wet cycles (0, 5, 10, 15, 20) and sheared in triaxial creep tests. The experimental results revealed that: firstly, the maximum value of the deviatoric stress corresponding to creep failure gradually decreases with an increase in the dry-wet cycles. Secondly, the long-term strength of the loess after dry-wet cycles were obtained through the Isochronous Curve Method. It is found that the long-term strength and the number of dry-wet cycles showed an exponential decreasing relationship. In addition, the creep damage mechanism of loess due to dry-wet cycles is proposed. This study may provide the basis for understanding the mechanical behavior of the loess under the effect of dry-wet cycles, as well as guidelines for the prevention and prediction of loess landslide stability.

Highlights

Loess is a weakly cemented loose sediment with a special material composition, which is widely distributed in the Loess Plateau of China (Figure 1) [1,2]
The loess samples were sheared under a saturated condition with a maximum value of 20 dry-wet cycles, whereas the triaxial creep tests were not conducted on unsaturated loess samples prediction of loess landslide stability
The loess samples were sheared under a saturated condition with a maximum value of 20 dry-wet cycles, whereas the triaxial creep tests were not conducted on unsaturated loess samples with a wide range of dry-wet cycles

Summary

Introduction

Loess is a weakly cemented loose sediment with a special material composition, which is widely distributed in the Loess Plateau of China (Figure 1) [1,2]. Sci. 2022, 12, 1212 been made on the physical and mechanical properties of loess after dry-wet cycle2sofb1y3 using the uniaxial tensile shear test [23], direct shear test [24,25], the uniaxial compressive test [26], conventional triaxial test [7,27], the soil-water characteristic curve (SWCC) of loess [28], etc. FFiigguurree 99.. ((aa)) TThhee wwhhoollee pprroocceessss ccuurrvvee ooff ccrreeeepp ffoorr llooeessss wwiitthh 2200 ddrryy--wweett ccyycclleess,, ((bb)) ccrreeeepp ccuurrvveess ooff llooeessss wwiitthh 2200 ddrryy--wweett ccyycclleess

The Long-Term Strength of Loess Samples with Different Dry-Wet Cycles

Creep Damage Mechanism of Loess Samples Due to the Dry-Wet Cycles

Conclusions