桩—垃圾土界面力学特性的试验研究  

Research on Mechanical Characteristics of Pile-garbage Soil Interface

作　　者：郭凤伟 肖昭然[1] 陈鹏 杨清晨 赵云[1,2] GUO Feng-wei;XIAO Zhao-ran;CEHN Peng;YANG Qing-chen;ZHAO Yun(College of Civil Engineering and Architecture,Henan University of Technology,Zhengzhou 450001,China;MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]河南工业大学土木工程学院,郑州市450001 [2]软弱土与环境土工教育部重点实验室(浙江大学),杭州市310058

出　　处：《公路》2023年第1期285-293,共9页Highway

基　　金：河南省科技厅自然科学项目,项目编号152107000008;软弱土与环境土工教育部重点实验室(浙江大学)开放基金资助项目,项目编号2019P03;河南工业大学高层次人才科研启动基金资助项目,项目编号31401175。

摘　　要：桩基础是垃圾填埋场地再利用的主要地基处理方式,桩-垃圾土的界面力学特性是分析桩-垃圾土相互作用的关键。为了研究桩-垃圾土接触面剪切特性,利用大型直剪仪开展桩-垃圾土大型界面剪切试验,系统研究了界面粗糙度、纤维含量、含水率等因素对桩-垃圾土界面力学特性的影响。结果表明:桩-垃圾土界面剪切应力随着剪切位移增大而增大,增长速率为先增大后趋于稳定,两者关系符合双曲线模型。不同法向应力作用下,随粗糙度的增大,抗剪强度呈先增大而后基本稳定的状态,桩侧粗糙度适当增加可以提高桩侧摩阻力以增加桩基的承载力。接触面剪切破坏符合摩尔-库仑剪切破坏准则,接触面黏聚力先增大后趋于稳定,内摩擦角逐渐增大,并在土体自身剪切强度附近变化。含水率对桩-垃圾土的抗剪强度影响较小。随着垃圾土纤维含量的增加,内摩擦角减小,黏聚力增大;在一定的法向应力下,随着纤维含量的增加,剪切强度减小。Pile foundation is the main foundation treatment method for the reuse of garbage landfill sites. The mechanical properties of the pile-garbage soil interface are the key to analyzing the pile-garbage soil interaction. In order to study the shear characteristics of the pile-garbage soil interface, a large-scale direct shear instrument is used to carry out a large-scale pile-garbage soil interface shear test, and the effects of interface roughness, fiber content, moisture content and other factors on the mechanical properties of the pile-garbage soil interface are systematically studied. The results show that the shear stress of the pile-garbage soil interface increases with the increase of the shear displacement, and the growth rate first increases and then gradually becomes stabilized. The relationship between the two is in line with the hyperbolic model. Under different normal stresses, with the increase of roughness, the shear strength first increases and then is basically stable. Appropriate increase in pile side roughness can increase the pile side friction resistance and increase the bearing capacity of the pile foundation.The shear failure of the contact surface conforms to the Mohr-Coulomb shear failure criterion. The cohesive force of the contact surface increases first and then stabilizes. The internal friction angle gradually increases and changes near the shear strength of the soil itself. The moisture content has minor impact on the shear strength of pile-garbage soil. With the increase of fiber content, the internal friction angle decreases and the cohesive force increases, and under a certain normal stress, with the increase of fiber content, the shear strength decreases.

关 键 词：桩-垃圾土 界面剪切 粗糙度 纤维含量 含水率 大型直剪试验 

分 类 号：U416.1[交通运输工程—道路与铁道工程]