不同含石量下土石混合体的剪切特性研究  

Study on Shearing Characteristics of Soil-rock Mixture in Different Percentage of Rock

作　　者：孙韬 潘春雷 余旭 武小菲[1] SUN Tao;PAN Chunlei;YU Xu;WU Xiaofei(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,成都610031

出　　处：《路基工程》2020年第3期61-65,共5页Subgrade Engineering

基　　金：四川省科技计划重点项目:含巨粒土土石混合填料的工程性质和路基填筑技术研究(18YYJC0044)。

摘　　要：土石混合体作为一种优良的填料被广泛应用于路基填筑。为研究含石量对土石混合体抗剪强度的影响,利用大型直剪试验,分析不同含石量下土石混合体剪应力-剪切位移曲线及抗剪强度的变化规律。结果表明:当含石量≤20%,试样为密实悬浮结构时,剪切过程呈应变硬化,抗剪强度随含石量增加变化不明显;当20%<含石量≤50%,试样为密实骨架结构时,剪切过程呈应变硬化-应变软化,粗粒土之间的咬合逐渐增强,内摩擦角和黏聚力增加较大,含石量在50%左右,抗剪强度达到最大;当含石量>50%,试样为骨架空隙结构时,剪切过程呈应变硬化-应变软化-应变硬化,内摩擦角和黏聚力均出现下降。Soil-rock mixture as an excellent filler is widely used in roadbed construction.In order to study the influence of percentage of rock on shearing characteristics of soil-rock mixture,large-scale direct shear test was conducted to analyze the variation law of both the shear stress-shear displacement curve and the shear strength of this mixture in different percentage of rock.The result shows that,when the percentage of rock is equal or less than 20%and the sample is of dense suspension structure,the shearing process presents strain hardening,and the increase of shear strength is not apparent;when the percentage of rock is more than 20% but equal or less than 50% and the sample is a dense skeleton structure,the shearing process presents strain hardening-strain softening,the occlusion of coarse-grained soil increases gradually,and the friction angle and cohesion increase greatly;when the percentage of rock is about 50%,the shear strength reaches the maximum;when the percentage of rock is more than 50% and the sample is a skeleton void structure,the shear process presents strain hardening-strain softening-strain hardening,and there will have a drop on both the friction angle and the cohesion.

关 键 词：土石混合体 大型直剪试验 含石量 抗剪强度 剪应力-剪切位移曲线 

分 类 号：TU411.7[建筑科学—岩土工程]