重塑黄土抗剪强度的环剪试验研究  

Experimental Study on Shear Strength of Remolded Loess by Ring Shear Test

作　　者：王炜 骆亚生[2] 

机构地区：[1]山西农业大学城乡建设学院,山西太谷030801 [2]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《水土保持通报》2017年第5期110-113,122,共5页Bulletin of Soil and Water Conservation

基　　金：国家自然科学基金项目"基于土体结构性变化的黄土滑坡灾变机理研究"(51178392);山西农业大学青年科技创新基金(J141702131)

摘　　要：[目的]研究大应变条件下黄土强度的影响因素及规律,为黄土地区发生滑坡等大变形破坏提供理论依据。[方法]利用环剪仪对重塑黄土进行大剪切位移下的剪切试验,探究不同正应力及剪切方式对不同含水率的重塑黄土其残余强度的影响。[结果]正应力越大,残余强度越大,达到残余强度所需的剪切位移越小;随着含水率的增大,残余黏聚力浮动值不大,残余内摩擦角逐渐减小,并据此拟合出残余内摩擦角与含水率的参考公式;从脆性指数的角度得出所研究的重塑黄土的应变软化都不明显,且脆性指数随着正应力和含水率的增加而降低。[结论]重塑黄土的峰值强度和残余强度受含水率、正应力的影响规律相似,可通过含水率对残余强度进行估算。[Objective]To study the influencing factors and rules of loess strength under large strain condition in order to provide a theoretical basis for large deformation damages like landslide in loess area.[Methods]Large shear displacement test with ring shear apparatus were conducted to explore the influence of positive stress and shear modes on the residual strength of remolded loess at different water content levels.[Results]The results showed that the greater the effective normal stress,the greater residual strength was,and the smaller the required shear displacement would be.The residual cohesive force fluctuated slightly and the residual internal friction angle decreased with the increase of water content,and a reference formula between residual internal friction angle and water content was fitted.From the perspective of brittle index,strain softening of the remolded loess was not obvious,and the brittleness index decreased with the increase of effective normal stress and water content.[Conclusion]The responses of the peak strength and residual strength to water content and positive stress were similar.Thus the residual strength can be estimated by water content.

关 键 词：重塑黄土 环剪试验 残余强度 脆性指数 

分 类 号：TU411[建筑科学—岩土工程]