Vol15 No.7: 1597-1614
【Title】Effect of dry density on the liquefaction behaviour of Quaternary silt
【Author】ZHANG Chong-lei1,2,4; JIANG Guan-lu2; SU Li-jun1,3,4*; Liu Wei-ming1; ZHOU Gong-dan1,4
【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) Effect of dry density on the liquefaction behaviour of Quaternary silt. Journal of Mountain Science 15(7). https://doi.org/10.1007/s11629-018-4930-5
【Abstract】Quaternary silt is widely distributed in China and easily liquefies during earthquakes. To identify the influence of the dry density on the liquefaction behaviour of Quaternary silt, 40 cyclic triaxial liquefaction tests were performed on loose silt (dry density rd=1.460 g/cm3) and dense silt (rd=1.586 g/cm3) under different cyclic stress ratios (CSRs) to obtain liquefaction assessment criteria, determine the liquefaction resistance, improve the excess pore water pressure (EPWP) growth model and clarify the relationship between the shear modulus and damping ratio. The results indicate that the initial liquefaction assessmentcriteria for the loose and dense silts are a double-amplitude axial strain of 5% and an EPWP ratio of 1. The increase in the anti-liquefaction ability for the dense silt is more significant under lower confining pressures. The CSR of loose silt falls well within the results of the sandy silt and Fraser River silt, and the dense silt exhibits a higher liquefaction resistance than the sand-silt mixture. The relationships between the CSR and loading cycles were obtained at a failure strain of 1%. The EPWP development in the dense and loose silts complies with the “fast-stable” and “fast-gentle-sharp” growth modes, respectively. The power function model can effectively describe the EPWP growth characteristics of the dense silt. Finally, based on the liquefaction behaviour of silt, a suggestion for reinforcing silt slopes or foundations is proposed.
【Keywords】Liquefaction; Quaternary silt; Dry density; Earthquake magnitude; Liquefaction assessment; Cyclic stress ratio