深部冻结黏土结构性对变形特性影响试验研究

Experimental Study on the Influence of Deep Frozen Clay Structure on Deformation Characteristics

为了研究深度冻结黏土结构性对变形特性的影响,对淮北某矿不同温度下的原状土和重塑土进行无侧限单轴抗压试验研究,对比分析原状土和重塑土内部结构差异。研究结果表明:原状土在3种负温下均为软化型,重塑土在-5℃时为硬化型,-10℃、-15℃为软化型;随着温度的降低,原状土和重塑土峰值强度均在增大,原状土的峰值强度均大于重塑土,并且峰值强度在-15℃时较接近;峰值应变差异明显且重塑土的峰值应变大于原状土;引入切线模量比这一概念,并对其进行修正,在-5℃、-15℃时,原状土的弹性模量接近重塑土的1.5倍,-10℃时几乎接近。原状土和重塑土变形特性存在明显差异,主要取决于土体内部未冻结水的含量、开孔孔隙、闭孔孔隙和温度,研究分析结果具有一定的工程参考价值。

In order to study the influence of deep frozen clay structure on deformation characteristics,unconfined uniaxial compression tests were carried out on undisturbed soil and remolded soil at different temperatures in a mine of Huaibei,and the internal structure differences between undisturbed soil and remolded soil were compared and analyzed.The results show that the undisturbed soil is softening at three kinds of negative temperatures,remolded soil is hardening at-5℃,and softening at-10℃and-15℃.With the decrease of temperature,the peak strength of undisturbed soil and remolded soil increases,and the peak strength of undisturbed soil is greater than that of remolded soil.Their peak strength is almost close at-15℃.The peak strain difference is obvious,and the peak strain of remolded soil is greater than that of undisturbed soil.By introducing and modifying the concept of tangent modulus ratio,the elastic modulus of undisturbed soil is close to 1.5times of that of remolded soil at-5℃and-15℃,and almost close to that of remolded soil at-10℃.The deformation characteristics of undisturbed soil and remolded soil are obviously different,which mainly depends on the content of unfrozen water,open pore,closed pore and temperature.The research and analysis results have a certain engineering reference value.