Vol15 No.8: 1789-1806
【Title】Dynamic behaviour of weathered red mudstone in Sichuan (China) under triaxial cyclic loading
【Author】ZHANG Chong-lei1,2; JIANG Guan-lu2; SU Li-jun1,3,4*; LIU Wei-ming1
【Addresses】1 Key Laboratory of Mountain Hazards and Earth Surface Processes, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; 2 Ministry of Education, Key Laboratory of High-speed Railway Engineering, School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China; 3 CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China; 4 University of Chinese Academy of Sciences, Beijing 100049, China
【Corresponding author】SU Li-jun
【Citation】Zhang CL, Jiang GL, Su LJ, et al. (2018) Dynamic behaviour of weathered red mudstone in Sichuan (China) under triaxial cyclic loading. Journal of Mountain Science 15(8). https://doi.org/10.1007s11629-017-4756-6
【Abstract】The construction of a high-speed railway (HSR) in Southwest China is being hindered by a severe shortage of high-quality subgrade materials. However, red mudstone is widely distributed in the Sichuan Basin of China. The ability to use weathered red mudstone (WRM) to fill subgrade beds by controlling its critical stress and cumulative strain would enable substantial savings in project investments and mitigate damage to the ecological environment. To better understand the dynamic behaviour of WRM,both monotonic and cyclic triaxial tests were performed. The evolution of the cumulative strain vs. increased loading cycles was measured. The influences of confining pressure and loading cycles on the dynamic modulus, damping ratio, critical cyclic stress ratio (CSR), and dynamic stress level (DSL) were investigated. The relationship between the CSR and loading cycles under different failure strain criteria (0.1%-1.0%) was analysed. The prediction model of cumulative strain was also evaluated.The results indicated that the shear strength of WRM sufficiently meets the static strength requirements of subgrade. The critical dynamic stress of WRM can thus satisfy the dynamic stress-bearing requirement of the HSR subgrade. The critical CSR decreases and displays a power function with increasing confining pressure. As the confining pressure increases, the DSL remains relatively stable, ranging between 0.153 and 0.163.Furthermore, the relationship between the dynamic strength and loading cycles required to cause failure was established. Finally, a newly developed model for determining cumulative strain was established. A prediction exercise showed that the model is in good agreement with the experimental data.
【Keywords】Cyclic triaxial tests; Cyclic stress ratio; Red mudstone; Critical dynamic stress; Cumulative strain; Railway subgrade