风化片岩残积土剪切特性研究

为考察片岩残积土的剪切特性，结合鄂西北山区某边坡工程，开展了风化岩残积土大型原位直剪试验，研究了风化岩残积土的结构组成、剪切面破损特性、剪切强度特性及其含石率、起伏度等相关关系。结果表明：该风化岩残积土应力-应变曲线多呈应变硬化特征，无明显峰值；束状孤石和束状石组多为翻滚和啃断破坏，起伏度随含石率的增大而增大，近似呈线性关系；爬坡效应会引起剪胀，造成剪应力和垂直应力的增大；随着垂直应力的增大，剪切破坏机制逐渐由滑移破坏变为啃断破坏，剪压应力比（剪应力与垂直应力的比值）逐渐减小。研究成果可为边坡工程变形及稳定性分析提供参考。

Study of shear properties of weathered schist residual soil

To study the shear property of weathered schist residual soil, in-situ direct shear tests was carried out at a slope project in northwest mountain area of Hubei province; and the structural composition, fracture characteristics, relationship of stone ratio and waviness and so on were analyzed. The results show that: The stress and strain curves show strain hardening features, and no obvious peak. The lonely stone and cluster stones are rolling and gnawing fracture in shear surface. There is an approximate linear relationship between waviness of shear surface and stone ratio; and the value of waviness increases with the increase of stone ratio. The climbing effect may cause shear dilation and increase of shear stress and normal stress. With increase of normal stress, the failure mechanism in shear surface turns sliding into gnawing fracture; and the ratio of shear-normal stress is in decrease. The results can be referenced for deformation and stability analysis of slope projects.