粉质黏土强度指标的水化学敏感性研究

发布时间：2018-04-23 20:35

本文选题：水-土化学作用 + 粉质黏土　；参考：《岩土力学》2016年12期

【摘要】：通过对重塑粉质黏土的液、塑限和固结慢速直剪试验,探讨了粉质黏土液限、塑性指数及抗剪强度与不同浓度Na Cl孔隙溶液的关系。试验结果表明,随着孔隙溶液浓度增加,液限随之减小,塑性指数表现出粉土的性质;不同竖向正应力下的强度随浓度变化表现出较大的差异,正应力较低时,强度不断减小,而正应力较高时,则强度不断增大,正应力介于二者之间强度则先降后升;内摩擦角随浓度增加而增大,最终趋于稳定;黏聚力先迅速减小后逐渐回升,且均为负值。其性质变化主要是因为扩散双电层、颗粒间作用力以及孔隙比发生了改变。基于Terzaghi的有效应力原理,对饱和粉质黏土固结慢速直剪试验测得的负值黏聚力进行了分析和讨论,认为渗透压力对黏聚力起了非常重要的作用,从而使黏聚力成为负值。
[Abstract]:The relationship between liquid limit, plastic limit and consolidation rate of silty clay, plastic index and shear strength of different concentrations of NaCl pore solution was studied by means of liquid, plastic limit and consolidation slow direct shear test of remolded silty clay. The experimental results show that with the increase of the concentration of pore solution, the liquid limit decreases and the plasticity index shows the properties of silt, and the strength of different vertical normal stress varies greatly with the change of concentration, and when the normal stress is low, the strength decreases continuously. When the normal stress is high, the strength increases continuously, the normal stress decreases first and then increases, the angle of internal friction increases with the increase of concentration, and the cohesion decreases rapidly and then increases gradually, all of which are negative. The change of properties is mainly due to the change of diffusion double layer, interparticle force and porosity ratio. Based on the effective stress principle of Terzaghi, the negative cohesive force of saturated silty clay is analyzed and discussed in the slow direct shear test. It is considered that the osmotic pressure plays a very important role in the cohesion and makes the cohesion become negative.
【作者单位】：桂林理工大学广西建筑新能源与节能重点实验室;中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室;
【基金】：国家自然科学基金(No.11372078,No.51309055) 广西自然科学基金创新研究团队项目(No.2012GXNSFGA060001);广西自然科学基金青年项目(No.2014GXNSFBA118236)~~
【分类号】：TU442

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