初始含冰量对冻结粉质砂土变形与强度的影响

基于一系列同一温度、不同初始含冰量和应变率条件下的高含冰冻结粉质砂土的单轴压缩试验，开展了高含冰量对冻结粉质砂土变形行为和强度特性的初步研究。结果表明：随着试样中初始含冰量的增加，冻结粉质砂土的塑性增强，当初始含冰量超过210.1%后，应力-应变曲线趋近于冰的特性，可用修正的Duncan-Chang双曲线模型较好地描述其单轴压缩应力-应变关系；当应变率为0.083×10-3 s-1和0.467×10-3 s-1时，其初始切线模量呈非线性增大，但当应变率为0.667×10-3 s-1时，初始切线模量增大到一最大值之后转而减小，并且影响程度与应变率大小有关；当初始含冰量从32.9%增加到304.0%，冻结粉质砂土强度也是先非线性增大，然后逐渐趋于稳定，两者可用对数函数关系很好地描述。其研究结果可为开展高含冰冻土区路基的稳定性评价提供基础。

Experimental study of uniaxial compressive deformation and strength of frozen silty sand under different initial ice contents

On the basis of a series of uniaxial compressive tests on frozen silty sand under different initial ice contents and strain rates, the uniaxial compressive deformation and strength characteristics of frozen silty sand are discussed and analyzed. The results show that with the initial ice content increasing, the plasticity of frozen silty sand is enhanced and the stress-strain behavior gradually tends to the characteristic of remolded ice after the initial ice content increases above 210.1%, and the relationship between stress and strain can be described by using the revised Duncan-Chang model. With initial ice content increases, the initial tangent modulus of frozen silty sand nonlinearly rises when the strain rate is 0.083×10-3 s-1 or 0.467×10-3 s-1; but it originally increases to a maximum value and then begins to decrease when the strain rate is 0.667×10-3 s-1. A log function can be used to describe the relationship between the uniaxial compressive strength and initial ice content, that is, the strength first increases and then gradually tends to be stable as the ice content augments from 32.9% to 304.0%. This study can supply a basis for evaluating the stability of subgrade in permafrost region with ice-rich soil.