摘要
拟建川藏铁路穿越大量的高寒山区坡洪积粗颗粒土区域,目前对于这类季节性粗颗粒冻土的抗剪强度特性研究不多。通过川藏线季节性粗颗粒冻土在不同影响因素作用下进行的直剪正交试验,研究其抗剪强度参数的变化规律,其中重点讨论冻融作用、粗粒含量、温度、含水率及不同冻结状态下土体的抗剪强度变化规律。试验结果表明:经过6次冻融循环作用,粗颗粒冻土融化后的力学性质基本稳定。冻融作用对土体抗剪强度影响的变化规律与土体的最优含水率有关。当冻结温度为-15℃时,粗颗粒冻土的抗剪强度变化基本趋于稳定。在其他条件相同的情况下,冻土颗粒越粗,负温对土体的抗剪强度影响越小。在非冻结状态下,土体抗剪强度随含水率的增加而降低。在冻结状态下,随含水率的增加,土体的黏聚力增加,摩擦角减小。
The proposed Sichuan-Tibet railway will pass through the vast regions of eluvial and diluvial coarsegrained soil in high and cold mountainous area.However,little study has been done on the shear strength characteristics of seasonal coarse-grained frozen soil.Through the direct shear tests on coarse-grained frozen soil under different influence factors along the Sichuan-Tibet line,the variation law of shear strength parameters was studied,with a special focus on the variation law of shear strength under freeze-thaw action,coarse grain content,temperature,water content and different frozen states.The experimental results show that the mechanical property of coarse-grained frozen soil after melting is basically stable after 6 times of freeze-thaw cycle effect.The freeze-thaw effect on the variation law of shear strength is related to the optimum moisture content of the soil.At the freezing temperature of minus 15℃,the variation of shear strength of coarse-grained frozen soil tends to be stable.Under the same conditions,the minus temperature effect on the shear strength is smaller when the frozen soil particles are more coarse-grained.Under the non-frozen state,the shear strength of the soil decreases along with the increase of water content.Under the frozen state,with the increase of water content,the soil cohesion increases and the friction angle decreases.
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2018年第3期107-111,共5页
Journal of the China Railway Society
关键词
冻融
粗粒含量
季节性粗颗粒冻土
抗剪强度
freeze thawing
coarse grain content
seasonal coarse-grained frozen soil
shear strength
