麦秸秆加筋盐渍土的筋土界面综合抗剪强度试验  

Direct shear tests on interface shear strength of saline soil reinforced with wheat straw

作　　者：郑娇娇[1] 柴寿喜[1] 魏丽[1] 姜宇波[1] 

机构地区：[1]天津城建大学地质与测绘学院,天津300384

出　　处：《工程勘察》2015年第10期11-19,共9页Geotechnical Investigation & Surveying

基　　金：国家自然科学基金(41272335);天津市自然科学基金(12JCYBJC14500)

摘　　要：盐胀、溶陷和吸湿软化等不良特性,易引起滨海盐渍土的低强度和大变形问题。以麦秸秆作加筋材料,可以实现提高盐渍土的抗剪强度和抗变形性能的目的。为测试麦秸秆加筋土的抗剪强度,完成了麦秸秆与盐渍土的界面直剪摩擦试验。水平铺设麦秸秆,以含水率、干密度、加筋间距、麦秸秆有无茎节为条件,分析四种制样条件对筋土界面抗剪强度的影响。鉴于整个剪切界面上存在筋/土和土/土的两种摩擦作用形式,因此将其称为界面综合抗剪强度。试验结果显示:界面综合粘聚力和界面综合内摩擦角均随含水率和加筋间距的增大而逐渐减小,随着干密度的增大逐渐增大,且有茎节的大于无茎节的。研究证实了剪切界面上存在着筋/土和土/土两种摩擦作用,两者共同发挥作用,提高了麦秸秆加筋土的抗剪强度,两者对强度增长的贡献率取决于筋土面积比(加筋间距)。Coastal saline soil has the low strength and large deformation because of its bad properties such as the salt expansion, the dissolving depression and the serious water absorbing. Taking the wheat straw bars as the reinforcing material, the shear strength and the deformation behaviors of saline soil could be improved. In order to measure the shear strength of the reinforcement soil, the direct shear tests are carried out. The samples are made in the conditions with the wheat straw bars horizontally placed, different water content, dry density, bar spacing and wheat straw joints, and the interface shear strengths of the reinforcing soil are analyzed. There are two kinds of friction functions in its interface （ saline soil/wheat straw bar and saline soil/saline soil）, so the shear strength is the comprehensive value. The test results show that the cohesion and the angle of internal friction decrease with the increase of water content and wheat straw bar spacing, and increase with the increase of dry density, and the value with one bar joint is bigger than that with none. It is confirmed that the two kinds of friction functions （ soil/bar and soil/soil） improve jointly the shear strength of the reinforcement soil. The increase rate on the shear strength is based on the area ration of the bars and the soil （bar spacing）.

关 键 词：界面综合抗剪强度 加筋间距 加筋土 盐渍土 麦秸秆 

分 类 号：TU411[建筑科学—岩土工程]