不同含石量下土石混合体的剪切特性研究

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。

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

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 not more 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 not more 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.