Effect of moisture content on mechanical and damage behavior of frozen loess under triaxial condition along with different confining pressures

Xu, Xingkai; Li, Qionglin; Lai, Yeong‐Lin; Wen-tai, Pang; Zhang, Ruiping

doi:10.1016/j.coldregions.2018.10.004

Cited by 86 publications

(18 citation statements)

References 14 publications

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“…Some interesting research has been carried out on F-T damage and mechanical performance of intact rocks or loess in cold regions (Walder and Hallet, 1985;Krautblatter et al, 2010Krautblatter et al, , 2013Tan et al, 2011;Pudasaini and Krautblatter, 2014;Shen et al, 2019;Xu et al, 2019). However, few reports exist on the damage mechanism and fracturing process of fractured rocks in cold regions.…”

Section: Introductionmentioning

confidence: 99%

Fatigue Deformation and Energy Change of Single-Joint Sandstone After Freeze-Thaw Cycles and Cyclic Loadings

et al. 2019

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In cold regions, saturated fractured rock is prone to crack initiation, extension, and branching along the original fracture end under the effect of freeze-thaw (F-T) cycles and cyclic fatigue loadings. The resulting strength deterioration is accompanied by large amounts of pore growth, which results in localized damage and fracturing along the crack end and even causes overall failure. To study the fatigue damage behaviors of fractured rocks under F-T cycles and cyclic loadings, single-joint quasi-sandstone specimens with joint angles of 45 • and 90 • were prepared. Subsequently, F-T damage tests with 0, 10, and 20 cycles and cyclic loading tests with different stress levels were performed. The F-T damage features are discussed based on the binarization image of localized damage along the joint ends and their wave velocity variations. It is found that the frost damage of single-joint quasi-sandstone tends toward a strip with localized fatigue characteristics. Moreover, the changes of strain compliance and dissipated energy are studied under the effect of loading-unloading fatigue. Some of the interesting phenomena observed are as follows: (i) during the early stage of cyclic loading, the joint can be compacted; nevertheless, it tends to expand along the fracture direction once it passes the elastic stage, and the irreversible plastic deformation is stable at this stage. (ii) The cracks caused by F-T damage in the 45 • single-joint samples deflect along the fracture direction, in contrast to the 90 • single-joint specimens. Moreover, the samples with a 45 • single joint are more susceptible to original fracture at the early stage of the failure process, which results in a different failure mode from that of the 90 • single-joint samples. (iii) The F-T cycles and cyclic loadings have a coupling effect on the single-joint sandstone. The strain compliance and hysteresis energy keep increasing uniformly after the F-T cycles and cyclic loadings.

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Section: Introductionmentioning

confidence: 99%

Fatigue Deformation and Energy Change of Single-Joint Sandstone After Freeze-Thaw Cycles and Cyclic Loadings

et al. 2019

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“…As a soil layer freezes, its pore water migrates from unfrozen areas toward subzero areas, where the pore water crystallizes into pore ice (and sometimes ice lenses appear), resulting in severe frost heave and performance deterioration in soil engineering applications (Kozlowski & Nartowska, 2013; Simonsen & Isacsson, 2001; Xu, Li, Lai, Pang, & Zhang, 2019; Zhou, Ma, Zhang, Mu, & Li, 2018). Although freeze–thaw cycles lead to the deterioration of soil mechanical properties, the strength of soil can be significantly improved when frozen.…”

Section: Discussionmentioning

confidence: 99%

An evaluation of the effects of microstructural characteristics and frost heave on the remediation of saline‐alkali soils in the Yellow River Delta, China

Geng

et al. 2020

Land Degrad Dev

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In the Yellow River Delta of China, soil salinization is of serious concern from both agricultural and environmental perspectives. In this study we investigated the microstructural characteristics of saline‐alkali soils in this region and explored the influence of frost heave on soil microstructure. Soil mineral composition, pore distribution, particle arrangement, and pore characteristics were measured using X‐ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM). Soil pore characteristics, overall porosity, and unconfined compressive strength (UCS) were measured at water content of 10, 15, 20, 25% (w/w) before and after freezing at −10°C. The results showed that deterioration of soil physical properties was largely caused by dense particle arrangement, high proportion of ultra‐micropore‐specific surface area, and poor pore distribution, rather than mineral content or particle size distribution. The microstructure of saline‐alkali soil was greatly improved by frost heave with the overall porosity and UCS of frost heave‐treated soil samples significantly higher than for the control. Moreover, particle cementation decreased with increasing soil water content. This study demonstrated that a combination of XRD, SEM, and MIP offers accurate evaluation of the microstructural characteristics of saline‐alkali soils, and frost heave may serve as an economically sustainable and technically feasible method for saline‐alkali soil amelioration in the Yellow River Delta.

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“…ey used a medium triaxial shear apparatus to test the resilience modulus and analyzed the deformation characteristics of the materials under the unloading and reloading process; furthermore, they revealed the variation law of the deformation modulus. Xu et al [19] explored the mechanical behavior and damage characteristics of frozen soil under different moisture contents by completing triaxial loadingunloading cycle tests. Xiao et al [20] performed loading and unloading triaxial tests to study the failure strength and the failure modes of a rock-like material containing a preexisting fissure.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Mechanical Behavior of Lean Cemented Sand and Gravel Material in Unloading and Reloading Paths

Yang

Shan

et al. 2021

Advances in Materials Science and Engineering

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Lean cemented sand and gravel (LCSG) materials are subjected to unloading-loading when an LCSG dam is opened for water drainage and then refilled or a roadbed base is subjected to repeated wheel loads. To investigate the behavior of the LCSG materials under loading-unloading, previous studies utilized the complete loading triaxial test. In contrast, in this study, the consolidated drained triaxial tests in the unloading and reloading paths for materials with cementing agent contents of 60 and 100 kg/m3 under different confining pressures, for which each curve generates three loading-unloading cycles, were applied to investigate the unloading and reloading mechanical behavior. Experimental results indicated that the unloading and reloading behavior of the LCSG materials produced stress-strain curves exhibiting a crescent-shaped hysteresis loop, which differs from that exhibited by coarse-grained soil. Although the shape of the crescent-like hysteresis loop was preserved as stress levels increasing, it gradually expanded. Compared with that of the typical triaxial test, the cohesive force and the increasing internal friction angle increased. Further, as the confining pressure increased, the crescent-like hysteresis loops tapered, shear strength increased linearly, and the modulus of resilience increased nonlinearly; the latter’s rate of change, however, decreased. The change in volumetric strain was small during unloading as the stress level changed.

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Effect of moisture content on mechanical and damage behavior of frozen loess under triaxial condition along with different confining pressures

Cited by 86 publications

References 14 publications

Fatigue Deformation and Energy Change of Single-Joint Sandstone After Freeze-Thaw Cycles and Cyclic Loadings

Fatigue Deformation and Energy Change of Single-Joint Sandstone After Freeze-Thaw Cycles and Cyclic Loadings

An evaluation of the effects of microstructural characteristics and frost heave on the remediation of saline‐alkali soils in the Yellow River Delta, China

Experimental Study on Mechanical Behavior of Lean Cemented Sand and Gravel Material in Unloading and Reloading Paths

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