祝艳波, 韩宇涛, 兰恒星, 等. 2021. 接触角度对黄土-三趾马红土界面剪切力学特性影响研究[J]. 工程地质学报, 29(3): 879-890. doi: 10.13544/j.cnki.jeg.2021-0041.
    引用本文: 祝艳波, 韩宇涛, 兰恒星, 等. 2021. 接触角度对黄土-三趾马红土界面剪切力学特性影响研究[J]. 工程地质学报, 29(3): 879-890. doi: 10.13544/j.cnki.jeg.2021-0041.
    Zhu Yanbo, Han Yutao, Lan Hengxing, et al. 2021. Experimental study on influence of contact angle on shear strength of interfaces between loess and Hipparion red clay[J]. Journal of Engineering Geology, 29(3): 879-890. doi: 10.13544/j.cnki.jeg.2021-0041.
    Citation: Zhu Yanbo, Han Yutao, Lan Hengxing, et al. 2021. Experimental study on influence of contact angle on shear strength of interfaces between loess and Hipparion red clay[J]. Journal of Engineering Geology, 29(3): 879-890. doi: 10.13544/j.cnki.jeg.2021-0041.

    接触角度对黄土-三趾马红土界面剪切力学特性影响研究

    EXPERIMENTAL STUDY ON INFLUENCE OF CONTACT ANGLE ON SHEAR STRENGTH OF INTERFACES BETWEEN LOESS AND HIPPARION RED CLAY

    • 摘要: 西北黄土高原第四系黄土广泛沉积于新近系三趾马红土之上形成粗糙接触的异质土界面,为典型的易滑层面。为探讨接触界面粗糙度对黄土-三趾马红土界面剪切力学特性影响,研制界面制样装置及剪切仪,开展简化黄土-三趾马红土界面直剪试验研究。结果表明:界面剪切破坏模式有齿间滑动、齿间滑动-齿面剪断、齿面剪断3种,界面接触角度越大,破坏模式越趋于齿面剪断,接触角度越小,破坏模式越趋于齿间滑动;界面剪切应力-剪切位移曲线演化规律表明界面脆性剪切破坏特征明显,且界面接触角度越大,峰值前剪切刚度与剪切破坏位移越大,峰值后剪切位移“跳跃”跌落现象越明显,界面脆性剪断破坏特征越显著;界面剪切过程产生明显剪胀效应,随界面接触角度增大,峰值剪胀角呈先减小而后增大趋势,反映了界面不同剪切破坏模式变化;受界面间初始黏聚强度与剪切破坏模式影响,界面抗剪强度随法向应力呈非线性变化,并受界面接触角度影响,峰值强度随界面角度增大呈先增大而后减小趋势,残余强度随界面角度增大呈增大趋势。

       

      Abstract: Loess is widely deposited on the Hipparion red clay and forms weak interfaces,which is a typical slippery layer in northwest China. To investigate the influences of interface contact angle on shear strength characteristics of interfaces between loess and Hipparion red clay,we performed a series of direct shear experiments using a home-developed shear equipment. The results indicate that the failure modes of interfaces between loess and Hipparion red clay can be divided into sliding,sliding and shear-off,and cutoff. The interface contact angle affects the failure mode of interfaces. When the interface contact angle of interface is larger,the failure mode tends to be cutoff. When the interface contact angle of interface is smaller,the failure mode tends to be sliding. The shear stress-displacement curves of interfaces show that the shear failure characteristics of interfaces are brittle obviously. As the interface contact angle of interface increases,the shear stiffness and shear failure displacement of interfaces increase,and the "dropping" phenomenon of shear stress-shear displacement curves becomes more obvious. The dilatancy effect of interfaces is obvious in the shear process. The peak dilatancy angle of interfaces decreases first and then increases with the increasing interface contact angles,which reflects the different shear failure modes of interfaces. The shear strength of interfaces varies nonlinearly with the normal stresses and interface contact angles. The peak strength of interfaces increases first and then decreases with the increasing interface contact angles,and the variation range of peak strength increases with the increasing normal stresses. The residual strength of interfaces increases with the increasing interface contact angles,and the variation range of peak strength increases with the increasing normal stresses.

       

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