Article
Engineering, Geological
Shenghua Cui, Xiangjun Pei, Yao Jiang, Gonghui Wang, Xuanmei Fan, Qingwen Yang, Runqiu Huang
Summary: The Daguangbao landslide, triggered by the 2008 Wenchuan earthquake, was a catastrophic mass movement with a volume of approximately 1.2 x 10(9) m(3). Laboratory tests revealed that the carbonate fault breccia on the sliding layer had a high liquefaction potential and low friction coefficient, which contributed to the initiation and movement of the landslide. Numerical calculations showed that the landslide occurred 36 seconds after the earthquake and collided with a riverbank in the 76th second, indicating that pore-water pressure during seismic shaking intensified the instability and mobility of the slope.
ENGINEERING GEOLOGY
(2021)
Article
Engineering, Environmental
Rongsen Zhu, Wan-li Xie, Qiqi Liu, Hui Yang, Qiyao Wang
Summary: Water diversion and irrigation projects have caused a significant number of loess collapses and landslides in the Loess Plateau of China since the 1970s. Accumulated ancient landslide deposits at the foot of the tableland are prone to sliding again with an increase in rainfall or irrigation. The weak characteristics of sliding zone soil play a key role in the revival of old landslides. Experimental results suggest that water content and shear rate have significant effects on the shear behavior of sliding zone soil, with the soil sample having the optimum moisture content exhibiting the highest shear strength. The increase in shear rate reduces soil strength, leading to high-speed and long-distance landslides. Scanning electron microscope observations confirm the changes in soil particles and pores, consistent with the macroscopic results. Therefore, the motion mechanism of reactivated landslides is associated with the interaction of water content and shear rate, significantly reducing the shear strength of the displaced materials.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Geosciences, Multidisciplinary
Kai Liu, Xingang Wang, Baoqin Lian, Zhaobo Zhu, Chen Xue
Summary: This study conducted a series of ring shear tests to investigate the mechanical characteristics of slip zone soils and their relationship with moisture content, dry density, shear rate, and shear method. The results showed that an increase in moisture content led to a significant reduction in residual strength, while an increase in dry density resulted in increased strength. Additionally, shear rate showed a negative relationship with shear strength within a certain range before a stepped shear band developed. The observed strain-softening phenomenon varied depending on the test conditions.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Engineering, Geological
Grytan Sarkar, Abouzar Sadrekarimi
Summary: The instability of coarse oil sands tailings (CST) was investigated in this study, and the effects of sample reconstitution method and tailings fabric on CST's instability behavior were explored. The results showed that the consolidation vertical stress and void ratio can affect the instability and post-liquefaction strength of the CST specimens.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2022)
Article
Engineering, Environmental
Di Wang, Dongqiang Xu, Eileen McCarthy, Romain Rodrigues de Amorim, Zili Li
Summary: This study investigates the undrained shear behavior of peat and reveals the degradation of shear stiffness. The undrained deviatoric shear resistance of peat continuously increases with increasing shear strain but does not show a distinct peak strength. The shear stiffness of peat specimens degrades significantly with increasing shear strain. A relationship model between the normalized shear stiffness and the normalized shear strain is proposed.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Geosciences, Multidisciplinary
Tengfei Wang, Kunlong Yin, Yuanyao Li, Zizheng Guo, Wei Wang
Summary: Many landslides in the Three Gorges Reservoir area in China have been reactivated, especially slow-moving landslides. The reactivation of these landslides is influenced by the hydraulic and mechanical properties of the sliding bodies and the sliding zone soil. Analysis of long-term monitoring data and laboratory testing of soil samples can provide insights into the mechanism of slow-moving landslide reactivation.
Article
Engineering, Geological
Zongxing Zou, Tao Luo, Shu Zhang, Haojie Duan, Shuwen Li, Jinge Wang, Yedan Deng, Jian Wang
Summary: This study proposed a new time-dependent stability evaluation method based on a temporal and spatial strength evolution model of the slip zone, with consideration of the combined effect of water level fluctuation and continuous deformation of reservoir landslide with time. This method was employed to evaluate the stability of the Outang landslide in the Three Gorges Reservoir area. The results indicate that the stability of the landslide decreases with time but at a gradually declining rate, and tends to be maintained at a critical state ultimately. Overall, this novel method establishes a direct connection between the shear strength of critical geomaterial and landslide evolution process, thus enabling a persuasive evaluation.
Article
Engineering, Marine
Shaoli Yang, Yubin Ren, Knut H. Andersen
Summary: The undrained shear properties of remoulded clay are crucial in offshore infrastructure design. The effects of thixotropy and reconsolidation were investigated in this study, demonstrating that they do not have an additive effect on the strength gain of remoulded clays. Additionally, the reconsolidated remoulded samples showed lower ratios compared to intact samples, indicating differences in shear strength and modulus.
Article
Environmental Sciences
Ersin Guler, Hasan Savas, Kamil Bekir Afacan
Summary: In stability problems, comparing collapse-inducing forces along potential surfaces and calculating resistance forces is essential. Ring shear tests can provide shear strength parameters for cohesive soils on large slipping surfaces, with relationships observed between parameters and friction angle.
FRESENIUS ENVIRONMENTAL BULLETIN
(2021)
Article
Chemistry, Multidisciplinary
Yinfeng Luo, Zongxing Zou, Changdong Li, Haojie Duan, Nang Mon Mon Thaw, Bocheng Zhang, Bingdong Ding, Junrong Zhang
Summary: This study investigates the shear constitutive model of slip zone soil and finds that the Gamma distribution function is the optimal model for describing the shear damage evolution process of slip zone soil.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Geological
W. Rong, J. S. McCartney
Summary: This study investigated the volumetric changes of unsaturated sand specimens during undrained cyclic shear tests, revealing a nonlinear relationship between volumetric contraction and degree of saturation. The largest contraction occurred at a saturation degree of 0.4, coinciding with the largest decrease in mean effective stress. The sand specimens followed a wetting-path scanning curve during shearing, with small changes in matric suction.
JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING
(2021)
Article
Engineering, Environmental
Qiang Xu, Weizao Wang, Litao Li, Yingdong Cao
Summary: The study found that under normal stresses lower than 100kPa, the peak shear strength and residual strength of the slip zone soils were larger than those of the slip zone soil-to-bedrock interface, leading to slope failure at a depth of 3-5m. Conversely, under normal stresses higher than 100kPa, the peak shear strength and residual strength of the slip zone soil-to-bedrock interface were larger than those of the slip zone soils, causing the slope to fail at a depth greater than 5m.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2021)
Article
Engineering, Multidisciplinary
Wengang Dang, Kang Tao, Linchong Huang, Xiang Li, Jianjun Ma, Tongtiegang Zhao
Summary: The DJZ-500 is a versatile servo-controlled dynamic shear test apparatus with both dynamic and static loading modules for force and displacement servo control experiments in various directions. It is capable of executing custom waveforms to study seismic response and frictional properties of geomaterials.
Article
Engineering, Marine
Jiayi Shen, Xinyi Wang, Qian Chen, Zhaoyi Ye, Qiaoling Gao, Jiawang Chen
Summary: The laboratory miniature vane shear test (MVST) is widely used to measure the undrained shear strength of marine sediments, but transferring soil samples from the seabed to the laboratory can reduce soil strength by releasing in situ confining stress. In this study, a Coupled Eulerian-Lagrangian (CEL) approach in ABAQUS is used to model the three-dimensional standard and miniature vane shear tests, and estimate the undrained shear strength of sensitive clay under different stress conditions. A linear strength model is proposed based on the numerical simulation results, which considers both the effects of confining stress and eliminates the size effects caused by vane blades of MVST. This model can be used to estimate the undrained shear strength of sensitive clay under shallow seabed surfaces.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Engineering, Geological
Malgorzata Wistuba, Elzbieta Gorczyca, Ireneusz Malik
Summary: This study conducted a statistical comparison between various precipitation parameters and dendrochronological reconstruction of landslide activity, revealing the long-term dependence of the landslide on precipitation conditions. The analysis led to the establishment of precipitation thresholds based on both direct causes and long-term preparatory precipitation necessary for the studied landslide to accelerate, providing valuable insights on the patterns of landslide-precipitation dependence.
ENGINEERING GEOLOGY
(2021)
Article
Engineering, Geological
Khang Dang, Kyoji Sassa, Hiroshi Fukuoka, Naoki Sakai, Yuji Sato, Kaoru Takara, Lam Huu Quang, Doan Huy Loi, Pham Van Tien, Nguyen Duc Ha
Article
Engineering, Geological
Kyoji Sassa, Khang Dang, Hideaki Yanagisawa, Bin He
Article
Engineering, Geological
Doan Huy Loi, Lam Huu Quang, Kyoji Sassa, Kaoru Takara, Khang Dang, Nguyen Kim Thanh, Pham Van Tien
Article
Engineering, Geological
Lam Huu Quang, Doan Huy Loi, Kyoji Sassa, Kaoru Takara, Hirotaka Ochiai, Khang Dang, Shinro Abe, Shiho Asano, Do Ngoc Ha
Article
Engineering, Geological
Pham Van Tien, Kyoji Sassa, Kaoru Takara, Hiroshi Fukuoka, Khang Dang, Tatsuya Shibasaki, Nguyen Duc Ha, Hendy Setiawan, Doan Huy Loi
Article
Engineering, Geological
Khang Dang, Kyoji Sassa, Kazuo Konagai, Asiri Karunawardena, R. M. S. Bandara, Kiyoharu Hirota, Qinwen Tan, Nguyen Duc Ha
Article
Engineering, Geological
Kiyoharu Hirota, Kazuo Konagai, Kyoji Sassa, Khang Dang, Yumika Yoshinaga, Emilio Kazuki Wakita
Proceedings Paper
Engineering, Civil
Pham Van Tien, Kyoji Sassa, Kaoru Takara, Khang Dang, Le Hong Luong, Nguyen Duc Ha
ADVANCING CULTURE OF LIVING WITH LANDSLIDES, VOL 5: LANDSLIDES IN DIFFERENT ENVIRONMENTS
(2017)