青藏斜坡黏土冻融循环物理力学性质试验  

TEST ON PHYSICO-MECHANICAL PROPERTIES OF QINGHAI—TIBET SLOPE CLAY UNDER FREEZING-THAWING CYCLES

作　　者：苏谦[1] 唐第甲[1] 刘深[1] 

机构地区：[1]西南交通大学土木工程学院,四川成都610031

出　　处：《岩石力学与工程学报》2008年第S1期2990-2994,共5页Chinese Journal of Rock Mechanics and Engineering

基　　金：青藏铁路建设总指挥部科技攻关项目

摘　　要：冻融过程使土体的结构、物理力学性质等发生变化,导致其工程性质恶化,影响线路稳定和列车的正常运行。为考察青藏铁路多年冻土区斜坡路基土体的长期稳定性,针对典型斜坡黏土在冻融循环条件下的主要物理力学性质,进行试验研究。试验结果表明:试样经历10次冻融后,其含水量、密度、黏聚力、内摩擦角等物理力学性质趋于稳定。土体冻融最终平衡状态与初始状态相关,其中初始干密度的影响尤为重要。随冻融循环过程增加,低密度土体的黏聚力有所提高,而高密度土体的黏聚力下降,内摩擦角变化较小。进行冻土斜坡路基稳定性分析时,建议取土体冻融平衡状态时的参数。It has become a common understanding that the structure,physico-mechanical properties of soils could be considerably changed by freezing-thawing cycles. With the variation of engineering properties,the normal running train was disturbed by the decline of subgrade stabilization. In order to study the long-term stabilization of slope in frozen soil area of Qinghai—Tibet Railway,a test was conducted under repeatedly freezing-thawing cycles,aiming at the main physico-mechanical properties of the representative clay. The results show that the physico-mechanical characters of the investigated soils become stable after 10 freezing-thawing cycles,such as water content,density,cohesion,internal friction angle and so on. The stable state is dependent on the original state of the soil sample,and the influence of the original dry density is very important. With the repeatedly freezing-thawing cycles,the cohesion of low density clay increases,but the cohesion of high density clay decreases,and the internal friction angle of the clay changes little. It is suggested that the parameters of soil at stable state should be adopted to estimate the stabilization of slope in frozen soil area.

关 键 词：土力学 黏土 冻融循环 抗剪强度 

分 类 号：TU442[建筑科学—岩土工程]