Large-Scale Test Model of the Progressive Deformation and Failure of Cracked Soil Slopes
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ISSN 1674-487X
Large-Scale Test Model of the Progressive Deformation and Failure of Cracked Soil Slopes Zhi Zhou
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, Jiaming Zhang *1, Fulong Ning1, Yi Luo1, Lily Chong1, Kuangbiao Sun2
1. School of Engineering, China University of Geosciences, Wuhan 430074, China 2. Anhui Transportation Holding Group Co., Ltd., Hefei 230088, China Zhi Zhou: https://orcid.org/0000-0001-8064-3273; Jiaming Zhang: https://orcid.org/0000-0003-1309-0343 ABSTRACT: A large-scale test bed (LWH=6 m×3 m×2.8 m) instrumented with various sensors is used to examine the effects of rainfall infiltration and evaporation on the deformation and failure of cracked soil slopes, taking the Anhui area along the Yangtze River as a field example. The results indicate that (1) during rainfall, the soil around the shallow shrinkage fissures attains transient saturation, and the attendant decrease of matric suction is the primary cause of the shallow slope failure; (2) slope deformation continues during post-rainfall evaporation; (3) if a period of evaporation is followed by heavy rainfall, soil creep is concentrated near the deepest cracks, and two zones of steep gradients in pore pressure form at the crest and toe of the slope. Finally, a saturated zone forms near each crack base and gradually enlarges, eventually forming a continuous saturated layer that induces the slope instability or failure. KEY WORDS: slope failure, geological engineering, cracked soil slope, large-scale test, progressive deformation. 0
INTRODUCTION Many new highways have been recently constructed in steep areas along the Yangtze River in China (Iqbal et al., 2018; Cao et al., 2017; Li et al., 2016; Zhang et al., 2012; Jia et al., 2009). Gray-white cracked, and expansive soil is widely distributed in this area. The intermittent dry-wet cycle of the monsoonal climate causes the cyclical development of soil cracks, which increases the permeability and reduces the integrity of the soil. These conditions are conducive to slope failure during the rainy season (Schilirò et al., 2016; Sun et al., 2013; Zheng et al., 2009; Lim et al., 1996). The economic and social impact of cracked soil landslides has made it necessary to embark on research into the mechanism of instability and dominant triggering factors (Zhang M et al., 2015; Zhang G et al., 2012; Wang et al., 2010). Physical model tests are the most reliable method for studying the failure mode of rainfall-triggered landslides, in which the soil properties and boundary conditions can be controlled, and the pore-water pressures and stresses inside the slopes can be monitored (Wu et al., 2018, 2015; Fan et al., 2016; Lu et al., 2015; Huang et al., 2009; Lourenço et al., 2006). There have been some reports on the slope failure mechanism triggered by rainfall using model tests. For example, undisturbed expansive rock, remoulded expansive soil and silty clay were used in the slope model test (Fan et al., 2016; Wu et al., 2015; Zhang Y et al., 2015) *Corresponding author: [email protected] © China University of Geosciences (Wuhan) and Springer-
