岩土力学2024，Vol.45Issue(1)：197-212,16.DOI:10.16285/j.rsm.2023.1013
正融冰川碎屑冰冻体剪切强度劣化机制研究
Mechanism of shear strength degradation of subglacial debris under thawing
摘要
Abstract
Affected by global warming,the subglacial debris on the Qinghai-Xizang Plateau in China is transforming from a frozen state into a thawing state,seriously affecting the glacier shear strength and glacier stability.In order to study the influence of thawing on the shear properties of subglacial debris,this paper introduced a new variable,the thawing rate,to quantitatively evaluate the amount of melted ice,and direct shear tests were carried out on thawing samples.Subsequently,a numerical model was established based on the finite-discrete element method to study the effects of thawing rate and gravel content on the shear behavior of subglacial debris.The results show that the thawing process significantly reduces the peak shear stress,cohesion,and inner friction angle.The relationship between shear strength parameters and thawing rate can be expressed using a linear relationship.The analysis of the factors affecting the shear strength parameters of thawing subglacial debris suggests that the reduction in the contribution of cementitious force can be responsible for strength degeneration.As the thawing rate increases from 2％to 4％,the deformation mode transitions from strain-softening to strain-hardening,and the failure mode shifts from rough serrated mode to smooth circular arc mode.Additionally,an increase in gravel content leads to a significant decrease in the shear strength of subglacial debris.However,the reduction range decreases as the thawing rate increases.This study provides valuable insights for evaluating the stability of glaciers by considering the effects of thawing on the shear properties of subglacial debris.关键词
碎屑冰冻体/融化/直剪试验/剪切力学行为/有限-离散元Key words
subglacial debris/thawing/direct shear test/shear behavior/finite-discrete element分类
建筑与水利引用本文复制引用
孟秋杰,宋宜祥,黄达,马文著,钟助,岑夺丰..正融冰川碎屑冰冻体剪切强度劣化机制研究[J].岩土力学,2024,45(1):197-212,16.基金项目
国家自然科学基金资助项目(No.42272331,No.U23A202579,No.42277187,No.41972297,No.42007276) （No.42272331,No.U23A202579,No.42277187,No.41972297,No.42007276）
河北省自然科学基金资助项目(No.D2021202001,No.D2020202002).This work is supported by the National Natural Science Foundation of China(42272331,U23A202579,42277187,41972297,42007276)and the Natural Science Foundation of Hebei Province(D2021202001,D2020202002). （No.D2021202001,No.D2020202002）
