摘要
针对青藏铁路北麓河粉质黏土,利用电阻率-应力-应变试验设备,获取了不同温度单轴压缩条件下的电阻率-应力-应变全过程曲线,探讨了冻土导电性能及其机敏性。试验结果表明,在含水率w=17.8%、干密度ρd=1.71g/cm3、加载应变率为1mm/min试验条件下,初始电阻率ρ0、最大电阻率ρm、最大切线模量对应的电阻率ρtm随温度降低而同步增大;冻土在压缩过程中具有较强的压敏性,随着压应力增大,电阻率变化可分为电阻率减小区、平衡区和剧增区;冻土单轴最大切线模量与温度之间呈线性关系,最大切线模量对应的应力及应变σtm、εtm、峰值应力对应应变εm表现出温度敏感性,当T=-15℃时,σtm、εtm、εm值最小;当T>-15℃时,σtm、εtm、εm值随T降低而增大,冻土随温度降低延性增强脆性减弱;当T<-15℃时σtm、εtm、εm值随T降低而增大,冻土随温度降低,脆性增强,延性减弱。
Using the frozen soil uniaxial compressive apparatus combined with electrical resistivity observation for whole process, a series of uniaxial compressive tests under different environmental temperatures are performed for the clay in Beilu River with an initial water content of 17.8 % and dry density of 1.71g/cm^3 under a loading strain rate of 1 mm/min, in which the complete testing data for the stress -strain curve and the associated electrical resistivity-strain curve are obtained. The experimental results indicate that ρ0, ρm, ρtm are increased with decrement of the temperature T and they are changed synchronically. The frozen soil performs highly pressure-sensitivity, with the increasing of stress, the procedure of electrical resistivity includes three stages： decreasing stage, balance stage and sharply increasing stage. There is the linear relationship between the largest tangent modulus and temperature. σtm,εtm,εm show sensitivity to temperature, the value of σtm,εtm,εm is minimum when the temperature is -15℃. The ductibility of frozen soil is enhanced and its brittleness is reduced; at the same time σtm,εtm,εm are increased with the decreasing of the temperature, when T 〉 -15 ℃.The frozen soil has opposite characters when T 〈 -15 ℃.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2009年第7期1974-1980,共7页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.40672193)
中国科学院冻土工程国家重点实验室开放课题(No.SKLFSE200605)资助
关键词
冻土
单轴压缩
切线模量
应力-应变-电阻率
机敏性
温度
青藏铁路
frozen soil
uniaxial compressive strength
tangent modulus
stress-strain- electrical resistivity
alert performance
temperature
Qinghai-Tibet Railway
