人工冻结软黏土力学特性试验研究  

Experimental Study on Mechanical Properties of Artificially Frozen Soft Clay

作　　者：曾宇 白瑶[1] 孙鹏 韩天宇 ZENG Yu;BAI Yao;SUN Peng;HAN Tianyu(School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)力学与建筑工程学院,北京100083

出　　处：《工业建筑》2023年第10期105-111,共7页Industrial Construction

基　　金：中央高校基本科研业务费专项资金资助项目(2022XJLJ01)。

摘　　要：为研究不同因素对天津地铁7号线冻结软黏土力学特性的影响,对人工冻结软黏土进行了不同温度、不同围压以及不同加载速率条件下的三轴压缩试验。结果表明:不同冻结温度、不同围压下冻结软黏土的应力-应变曲线均为应变硬化型;在试验条件下,冻结软黏土的抗压强度与围压、加载速率呈正相关,与冻结负温呈负相关;随着冻结负温的降低,试样破坏模式由鼓胀变形变为局部剪切破坏,围压水平对抗压强度的影响逐渐减小;在试验冻结负温范围内,黏聚力随冻结负温降低而增大,变化范围为0.897~3.281 MPa,内摩擦角随冻结负温降低而减小,变化范围为7.7°~20.6°,两者与冻结负温均有良好的线性关系;采用四种冻土应力-应变关系对实测数据进行拟合,验证了改进Duncan-Chang模型对冻结软黏土的适用性。To study the influence of different factors on mechanical properties of frozen soft clay of Tianjin Metro Line 7,triaxial compression tests were conducted on artificially frozen soft clay at different temperatures,confining pressures,and loading rates.The results indicated that the stress-strain curves of frozen soft clay at different temperatures and confining pressures were all strain hardening.In experimental conditions,the peak compressive strength of frozen soft clay was positively correlated with confining pressures and loading rates and negatively correlated with temperatures.With the decrease of frozen negative temperature,the failure mode of specimens changed from bulging deformation to local shear failure,and the influence of confining pressure levels on compressive strength gradually decreased.In the frozen negative temperature range of tests,with the decrease of frozen negative temperatures,the cohesive strength increased range of 0.897 to 3.281 MPa,the internal frictional angle decreased varying in the range of 7.7°to 20.6°.Both of them had good linear relations with frozen negative temperature.Four kinds of frozen soil relations between stress and strain were used to fit the measured data,and the applicability of the improved Duncan-Chang’s model to frozen soft clay was verified.

关 键 词：冻土强度 温度 围压 加载速率 本构模型 

分 类 号：TU41[建筑科学—岩土工程]