Strength behaviors and meso-structural characters of loess after freeze-thaw

Xu, Jian; Ren, Juanjuan; Wang, Zhangquan; Wang, Songhe; Yuan, Jian

doi:10.1016/j.coldregions.2018.01.011

Cited by 98 publications

(55 citation statements)

References 19 publications

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“…Figures 13 and 14, respectively. As can be observed from Figure 13, the cohesion of soils in closed and open systems both decrease gradually with the increase of freeze-thaw cycles and then gradually stabilize, which is in agreement with the results of remolded soils from Xu et al [12]. Similar to the failure strength of soil, the cohesion decreases most after the rst freeze-thaw cycle.…”

Section: Elastic Modulussupporting

confidence: 88%

“…e one is the freeze-thaw cycles test in the closed system where no outer water is available during the freezing process, and the other is in the open system where outer water is supplied from the bottom of the sample during the freezing process [8]. Referring to the viewpoint of Wong and Haug [8] that the development rate of frost depth is greater than that of moisture migration in soil, numerous authors have studied the influence of freeze-thaw cycles on the mechanical properties of soil under the closed system [9][10][11][12]. e existing investigations have been carried out focusing on the strength properties of the soil after freezethaw cycles, such as the unconfined compressive strength [3], failure strength [11], shear strength [12,13], and modulus of elasticity [14,15].…”

Section: Introductionmentioning

confidence: 99%

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Comparative Study on Mechanical Properties of Compacted Clay under Freeze-Thaw Cycles with Closed and Open Systems

Xian

Lü

Yao

et al. 2019

Advances in Materials Science and Engineering

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The frost heave and thaw settlement caused by freeze-thaw cycles will seriously affect the engineering properties of soil. This paper attempts to comparatively investigate the deterioration effect of freeze-thaw cycles on the mechanical properties of compacted clay in closed and open systems. The specimens were frozen and thawed from the top to bottom in two systems. The moisture contents and deformations after freeze-thaw cycles were measured. Mechanical parameters of soil were examined through triaxial compression tests. Results show that the moisture content and deformation of soil change evidently with the increase of freeze-thaw cycles in the open system, while these parameters in the closed system change little. In the open system, the attenuation rate of failure strength, elastic modulus, and angle of internal friction of soil subjected to 7 freeze-thaw cycles are all about 2 times as large as that in the closed system and the attenuation rate of cohesion is even 4 times of that in the closed system. These differences reveal that the deterioration effect of freeze-thaw cycles on soil strength is aggravated after water supply. These findings indicate that soil structure damage and moisture content increase is the dominant factor affecting engineering properties of the soil in the open system.

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Section: Elastic Modulussupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Comparative Study on Mechanical Properties of Compacted Clay under Freeze-Thaw Cycles with Closed and Open Systems

Xian

Lü

Yao

et al. 2019

Advances in Materials Science and Engineering

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“…According to Figure 19, the relationship between the volume of the preconsolidation pressure and the volume after the release of the sample pressure is as follows: Figure 19 and Tables 1 and 3 show that e 0 � 0.92, p c � 1035.18 kPa, and e c � 0.834. Substituting these data into equation (42) yields ΔV d � 5.375 cm 3 . erefore, the sample of a ring knife can be reduced to the volume under the prior pressure as follows:…”

Section: Loess Microscopic Statistical Damage Variablementioning

confidence: 99%

“…Similarly, Lu et al [40] studied the effects of freeze-thaw cycles on the cracking of cohesive soils. Zhou et al [41] and Xu et al [42,43] studied the effects of freeze-thaw cycles on mesostructural characteristics and mechanical behaviors using scanning electron microscopy (SEM) and soil mechanics tests.…”

Section: Introductionmentioning

confidence: 99%

Structural Strength Deterioration Characteristics and a Model of Undisturbed Loess under the Action of Wetting and Freeze‐Thaw Cycles

She

et al. 2019

Mathematical Problems in Engineering

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Undisturbed loess is affected by external environmental disturbances, such as wetting and freeze-thaw cycles, which cause microstructural changes that have an important impact on the structural strength of the loess. These changes in turn affect the stability of structures such as embankments, slopes, and guards. This article takes the Q3 undisturbed loess in Lintong District, Xi’an, as an example. The effects of wetting and freeze-thaw cycles on the loess expansion ratio and pore structure were studied by wetting tests, freeze-thaw cycle tests, and scanning electron microscopy (SEM). The changes in the compression index and compression modulus were studied by a confined compression test. The loess e-lgp compression curve was obtained according to the confined compression test, and the newly defined concepts of the loess structural strength, residual structural strength, and structural strength damage variable, in addition to the e-lgp compression curve, were combined with the experimental data to calculate the damage value generated by the disturbance during the sampling and preparation of loess. The deterioration of the structural strength and damage variable of loess was analyzed. Based on the microscopic statistical damage theory and Weibull distribution, the model used the volume expansion ratio as a variable to establish a statistical damage model under wetting and freeze-thaw cycles. Finally, on the basis of the test, the model parameters were determined. The models were verified by taking loess from a foundation pit in the northern suburbs of Xi’an and were in good agreement with the results of the test. Ultimately, the models have good practicability and can provide guidance for engineering design and construction.

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“…This phenomenon affects some engineering features of fine-grained soils, such as water content, bearing capacity, and permeability adversely. It is mentioned in the following references that freeze-thawing causes structural and volumetric changes in clayey soils (Wang et al, 2017;Wang et al, 2018;Xu et al, 2018;Lu et al, 2018). Andersland and Ladanyi (2004) indicated that freezing, thawing, and redistribution of water in the ground during seasonal temperature changes are responsible for variations in soil properties and the behavior of foundation materials.…”

Section: Introductionmentioning

confidence: 99%

Effect of Aspect Ratio on the Freezing-Thawing of a Ch Clay

Akbulut¹,

Zaimoğlu²

2019

Scitech

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The geotechnical properties of fine grained soils which depends on the variation of aspect ratio (ξ=length/diameter) exposed to freezing-thawing is not known clearly. The effect of aspect ratio on unconfined compression strength and freezing-thawing resistance of fine grained soils after 0, 5, 10, and 20 freezing-thawing cycles have been investigated in this study. The freezing-thawing test was conducted in an automatic freezing-thawing cabinet, the freezing and thawing temperatures of which were selected as-20°C and +25°C, respectively. The unconfined compression test was conducted in an unconfined compression testing apparatus, the loading ratio of which was 0.8 mm/min. These values were held constant throughout the test. Tests were conducted on cylindrical samples with different ξ (length/diameter) ratios prepared at standard Proctor energy. The test results indicated that, as ξ ratio decrease and the number of freezing-thawing cycles increase, unconfined compression strength decrease and freezing-thawing grain loss increase.

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Strength behaviors and meso-structural characters of loess after freeze-thaw

Cited by 98 publications

References 19 publications

Comparative Study on Mechanical Properties of Compacted Clay under Freeze-Thaw Cycles with Closed and Open Systems

Comparative Study on Mechanical Properties of Compacted Clay under Freeze-Thaw Cycles with Closed and Open Systems

Structural Strength Deterioration Characteristics and a Model of Undisturbed Loess under the Action of Wetting and Freeze‐Thaw Cycles

Effect of Aspect Ratio on the Freezing-Thawing of a Ch Clay

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