非饱和粉土力学特性的大型直剪试验  

Mechanical properties of unsaturated silt with large scale shear test

作　　者：张海明[1] 姚爱军[1] 王兆辉[1] 雷刚[1] 杨晓[1] 刘晓晓[1] 

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124

出　　处：《辽宁工程技术大学学报（自然科学版）》2014年第10期1352-1356,共5页Journal of Liaoning Technical University (Natural Science)

基　　金：高等学校博士学科点专项科研基金资助项目(20121103110022)

摘　　要：以LG-8200M型室内大型直接剪切仪为基础,针对非饱和粉土的抗剪强度及变形特性问题展开实验研究.研究结果表明：（1）低含水质量分数的重塑非饱和粉土试样在高垂直压力下剪切峰值不明显,呈现明显的应变硬化特性,在低垂直压力（0.1 MPa）下剪应力-剪切位移关系存在剪切峰值,达到峰值后曲线趋于平缓.（2）相同含水质量分数的重塑非饱和粉土试样,其剪切面抗剪强度随法向应力的增大而提高,随剪切速率的增大而降低,剪切速率每增加0.4 mm/min,其抗剪强度减少约20%~30%.（3）不同含水质量分数的重塑非饱和粉土试样,其抗剪强度指标（c,φ）随含水质量分数的增大呈现先升高后减小的变化趋势,且含水量超过临界值后,粉土的抗剪强度会急剧衰减,内摩擦角比粘聚力衰减速度更为明显.The paper tested on shear strength and deformation properties of unsaturated silt with a LG-8200M direct shear apparatus. The results showed that （1） The low water content remodeling unsaturated silt samples under high vertical stress showed unconspicuous peak shear and presented significantly strain hardening property. Nevertheless, under the low vertical stress the curves tended to be gentle as well as reaching the peak shear existing in the shear stress-shear displacement curves. （2） The shear strength of the shear surface of remodeling unsaturated silt samples with the same water content increased with increase of the normal strength. The shear strength decreased with the increase of shearing rate （As shearing rate increased 0.4rnrn/min, the shear strength had a decreasing between 20% and 30%）. （3） With the rising of water content, the shear strength index（c, φ） of remodeling unsaturated silt samples of different water content firstly augmented, then minished, the attenuation rate of internal friction angle became much critical value. and under water the shear strength rapidly reduced and faster than cohesive when water content was over the critical value.

关 键 词：非饱和粉土 大直剪切实验 含水质量分数 剪切速率 力学特性 

分 类 号：TU411[建筑科学—岩土工程]