Analysis of the causes of large-scale loess landslides in Baoji, China

Shi, Jiansheng; Wu, L. Z.; Wu, Shuren; Li, B.; Wang, Tao; Peng, Xin

doi:10.1016/j.geomorph.2016.04.013

Cited by 69 publications

(23 citation statements)

References 23 publications

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“…Loess disintegration is closely related to soil erosion and geological disasters such as collapse, landslides, and debris flow in loess areas (Ryashchenko et al, 2008;Krajcarz et al, 2016;Shi et al, 2016;Zhang et al, 2017;Peng et al, 2018). China has the most widely distributed loess areas on earth (Figure 1), particularly in the Loess Plateau, which is subject to extensive soil erosions.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of loess disintegration characteristics

Wang

Zhang

et al. 2019

Earth Surf Processes Landf

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Loess structures with large joints and fissures often undergo natural disintegration when subjected to contact with water. The slaking of loess results in the formation of loess gullies, caves, and landslides. To study the disintegration properties and the factors influencing them, we carried out field and laboratory tests. First, we carried out an in situ disintegration test using different sample shapes obtained from Heifangtai and analysed the effect of soil sample shape on loess disintegration. We then developed an improved disintegrator and tested the effect of different factors on the disintegration of loess. The effects of water content, salinity, and composition on disintegration are discussed. The results show that the loess disintegration process can be divided into three broad stages – wetting, softening, and subsidence – the disintegration is mainly concentrated in the third stage, while the first two stages are short and show very weak disintegration. The main factors influencing the disintegration of loess samples are shape, size, and clay mineral content. During the in situ disintegration test, the edge angles of soil samples are disintegrated, to soften all their edges. Disintegration duration increases with increasing sample size, but the extent of disintegration was found to decrease. Disintegration duration is inversely proportional to the loess disintegration rate. The loess disintegration rate is positively correlated with water temperature within a certain range; however, the reverse is observed with soil sample size and initial water content, and salinity was found to have little effect on the disintegration rate. Higher clay content of cohesive soil and weaker permeability leads to a slower disintegration rate. Additionally, lower cementation may easily cause loess disintegration. © 2019 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Experimental study of loess disintegration characteristics

Wang

Zhang

et al. 2019

Earth Surf Processes Landf

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“…Many loess slope spallilng hazards happened at Loess Plateau area of China due to the influence of heavy rainfall in the past twenty years (Figure 1) [2][3][4]. According to the previous research, loess slope spalling hazards can be triggered when water enters into loess slope at a shallow depth, while the saturated zone simultaneously rises from depth [5][6][7][8]. The matric suction in unsaturated loess decreased due to the increase of water contents, which induces the decrease of loess shear strength [9][10][11].…”

Section: Introductionmentioning

confidence: 94%

Effect of Dry-wet Cycle on the Formation of Loess Slope Spalling Hazards

Zhang

2018

CivileJournal

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This paper investigates the effect of dry-wet cycle process on the formation of loess slope spalling hazards. Based on the CT scan tests and macroscopic fissures analysis, the fissure variation law of loess samples under different dry-wet cycle times were determined. Through the laboratory direct shear tests, the variation law of shear strength, cohesion and angle of internal friction of loess samples under different dry-wet cycle times and different dry-wet cycle water content variation ranges were discussed. The results show that the natural water contents of Luo-chuan loess were higher than Tong-chuan loess due to it’s higher contents of clay particles. With the increase of dry-wet cycle times, the internal fissure numbers of loess samples increased dramatically. The value of shear strength and cohesion of loess samples in two different areas decreased dramatically due to the increase of dry-wet cycle times. Higher water content variation ranges of dry-wet cycles leaded to lower shear strength of loess samples under the same dry-wet cycle times. Loess slope spalling hazards often happened due to the decrease of shear strength and the occurrence of internal fissures in loess induced by the dry-wet cycle process.

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“…e core of geotechnical engineering research in loess regions is the analysis of the deformation, strength, and stability of loess in a complex external environment under mechanical disturbances. e most common loess disasters, as shown in Figure 3, primarily include loess landslides [8][9][10][11], collapses [12], loess collapsing [13,14], ground collapse or subsidence [15,16], ground fissures, and unstable slopes [17]. ese disasters are of global concern because of their great cost to humans [8,[18][19][20][21].…”

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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Analysis of the causes of large-scale loess landslides in Baoji, China

Cited by 69 publications

References 23 publications

Experimental study of loess disintegration characteristics

Experimental study of loess disintegration characteristics

Effect of Dry-wet Cycle on the Formation of Loess Slope Spalling Hazards

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

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