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According to a previous geological investigation, high-speed and long-distance loess landslides in the South Jingyang platform in Shaanxi Province are closely related to the static liquefaction of loess. Considering the typical loess landslides in this area, isotropic consolidated undrained (ICU) triaxial tests and scanning electron microscopy analyses were conducted in this study. The main conclusions are as follows: (1) The stress-strain curves indicate strong strain softening under different confining pressures. The pore water pressure increases significantly and then remains at a high level; (2) The liquefaction potential index (LPI) shows an increasing trend followed by stabilization; the larger the LPI is, the smaller the state parameter (Ψ) is. The steady-state points of the loess are in the instability region; however, the steady-state strength is not zero; (3) Based on the ICU test results, the average pore diameter decreases; the shape ratio remains essentially unchanged; and the fractal dimension and roundness show different trends. The proportions of the macropore and mesopore decrease; that of the small pore increases slightly; and that of the micropore increases significantly; (4) The compression deformation of the highly spaced pores causes rapid strain hardening. A rapid strain softening results from the pore throat blockage at the beginning of particle rearrangement and reorganization. A stable strain softening is related to the agglomeration blocking of the reconstructed pore throat in the gradually stable stage of particle rearrangement and reorganization.
Rui-Xin Yan; Jian-Bing Peng; Jin-Yuan Zhang; Shao-Kai Wang. Static Liquefaction Capacity of Saturated Undisturbed Loess in South Jingyang Platform. Water 2020, 12, 2298 .
AMA StyleRui-Xin Yan, Jian-Bing Peng, Jin-Yuan Zhang, Shao-Kai Wang. Static Liquefaction Capacity of Saturated Undisturbed Loess in South Jingyang Platform. Water. 2020; 12 (8):2298.
Chicago/Turabian StyleRui-Xin Yan; Jian-Bing Peng; Jin-Yuan Zhang; Shao-Kai Wang. 2020. "Static Liquefaction Capacity of Saturated Undisturbed Loess in South Jingyang Platform." Water 12, no. 8: 2298.
Sufficient bonding at concrete–rock interfaces is an important prerequisite when designing supports using concrete or shotcrete. However, the bonding between concrete and rock is often affected by low temperatures in cold regions. This study focuses on the effects that freeze–thaw cycles have on meso-debonding at sandstone–concrete interfaces. The prepared sandstone-concretes composite materials were subjected to freeze–thaw cycles and nuclear magnetic resonance (NMR) test. The effects of the freeze–thaw cycles on sandstone–concrete composites and the interfacial pore changes are discussed in this paper. The extent of the interface-influencing zone (IIZ) and the process controlling interface debonding are described based on the results of those experiments. The three primary conclusions are as follows: (1) The volume of the micropores and macropores in sandstone increases with the freeze–thaw cycles; however, the volume of the mesopores decreases. (2) The IIZ lies in the sandstone, near the interface, and is accompanied by water enrichment. (3) From a mesoscopic point of view, the process of debonding in the sandstone-concrete is not initialized at the interface but occurs in the sandstone near the interface.
Yanjun Shen; Yongzhi Wang; Xin Wei; Hailiang Jia; Ruixin Yan. Investigation on meso-debonding process of the sandstone–concrete interface induced by freeze–thaw cycles using NMR technology. Construction and Building Materials 2020, 252, 118962 .
AMA StyleYanjun Shen, Yongzhi Wang, Xin Wei, Hailiang Jia, Ruixin Yan. Investigation on meso-debonding process of the sandstone–concrete interface induced by freeze–thaw cycles using NMR technology. Construction and Building Materials. 2020; 252 ():118962.
Chicago/Turabian StyleYanjun Shen; Yongzhi Wang; Xin Wei; Hailiang Jia; Ruixin Yan. 2020. "Investigation on meso-debonding process of the sandstone–concrete interface induced by freeze–thaw cycles using NMR technology." Construction and Building Materials 252, no. : 118962.
Since large-scale agricultural irrigation began in the 1980s, 92 landslides have occurred around the South Jingyang Plateau during the past 40 years. The geological disaster and soil erosion have caused numerous casualties and substantial property loss. In this work, several field investigations are carried out to explore the soil erosion and mechanical mechanism of these irrigated shallow loess landslides on the South Jingyang Plateau. (1) We investigated the spatial distributions, types and developmental characteristics of loess landslides. (2) We surveyed and monitored seasonal agricultural irrigation features and groundwater changes in the area since the 1980s and found that irrigation is a significant factor influencing groundwater changes, soil erosion and even causing landslides to occur. (3) Based on the field investigation, the occurrence of these irrigated shallow loess landslides was generalized, and it was found that the core process was due to the liquefaction of softening zone. We carried out a static liquefaction test and verified that the natural loess was prone to liquefaction. (4) The three main reasons for shallow loess landslides in the South Jingyang Plateau were discussed. This study provides a valuable reference for achieving an understanding of the relationship between seasonal agricultural irrigation and the occurrence of loess landslides in the area as well as similar irrigated agricultural areas.
Rui-Xin Yan; Jian-Bing Peng; Qiang-Bing Huang; Li-Jie Chen; Chen-Yun Kang; Yan-Jun Shen. Triggering Influence of Seasonal Agricultural Irrigation on Shallow Loess Landslides on the South Jingyang Plateau, China. Water 2019, 11, 1474 .
AMA StyleRui-Xin Yan, Jian-Bing Peng, Qiang-Bing Huang, Li-Jie Chen, Chen-Yun Kang, Yan-Jun Shen. Triggering Influence of Seasonal Agricultural Irrigation on Shallow Loess Landslides on the South Jingyang Plateau, China. Water. 2019; 11 (7):1474.
Chicago/Turabian StyleRui-Xin Yan; Jian-Bing Peng; Qiang-Bing Huang; Li-Jie Chen; Chen-Yun Kang; Yan-Jun Shen. 2019. "Triggering Influence of Seasonal Agricultural Irrigation on Shallow Loess Landslides on the South Jingyang Plateau, China." Water 11, no. 7: 1474.