试件形状对冻结粉土抗压强度影响的试验研究  

An Experimental Study of the Effect of Specimen Shape on Compressive Strength of Frozen Silt

作　　者：李海鹏[1] 杨维好[1] 黄家会[1] 宋雷[1] 朱元林[2] 

机构地区：[1]中国矿业大学建筑工程学院岩土工程研究所,江苏徐州221008 [2]中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,甘肃兰州730000

出　　处：《冰川冻土》2005年第6期920-925,共6页Journal of Glaciology and Geocryology

基　　金：中国矿业大学青年科研基金及引进人才资助项目;中国科学院冻土工程国家重点实验室开放基金项目;国家自然科学基金项目(40171021)资助

摘　　要：在不同温度和应变率条件下,分别对圆柱体和正方体冻结粉土进行了单轴抗压强度试验,分析比较了二者的应力-应变关系、抗压强度及破坏应变.结果发现:单轴压缩下正方体与圆柱体冻结粉土的力学性质存在差异.正方体冻结粉土的应力-应变曲线有明显的弹性屈服点,屈服点后曲线呈线性硬化,而圆柱体冻结粉土的应力-应变曲线无明显弹性屈服,全应力-应变曲线呈抛物线型.相同温度和应变率条件下,圆柱体试样的应变软化程度比正方体试样大.相同试验条件下正方体冻结粉土的抗压强度及破坏应变大于圆柱体的抗压强度和破坏应变,二者抗压强度及破坏应变的差异程度与温度和应变率无关.研究结果可为冻结壁的设计提供重要依据和参考.To explore specimen shape effects on the compressive strength of frozen silt, a series of uniaxial compressive strength tests was respectively performed on frozen silt in cylindrical and cubic shapes at the same experimental conditions. The obtained data included the relationships of stressstrain, compressive strength and failure strain. It is found that the mechanical behaviors are different between cylindrical and cubic samples under uniaxial compression. For the cubic sample, an elastic yield occurs distinctly in the initial section of the stress-strain curve, and the sample behaves linearly strain hardening after initial yield. For the cylindrical sample, the whole stress-strain curves show approximately a parabola shape and have no distinct elastic yield in the initial section. The degree of strain softening for cylinder specimens is higher than that of cubic specimens at the same temperature and strain rate. The compressive strength and failure strain of cubic specimen are higher than that of cylindrical specimen at the same testing conditions. The difference of compressive strength and failure strain between cubic and cylindrical specimens is independent of temperature and strain rates. In the ranges of tested temperature and strain rate for frozen silt, the compressive strength of cubic specimen is 0.8 times higher than that of cylindrical specimen. The failure strain of cubic specimen is 1.4 times higher than that of cylindrical specimen. This study provides an important basis for designing frozen wall in artificial freezing shaft.

关 键 词：冻结粉土 形状效应 抗压强度 破坏应变 

分 类 号：P642.14[天文地球—工程地质学]