为了研究滑坡中滑体粒径级配及滑动面粗糙程度对滑坡运动的影响，利用干燥松散砂的流动性，采用干燥松散砂体进行室内直剪和滑坡模拟斜板试验，探讨不同粗砂含量砂体与不同粗糙度滑面对试验结果的影响。首先进行直剪试验，通过界面剪切试验探究剪切中粗糙面材料与砂体间的力学特征及行为机制。再使用3D扫描仪对滑坡模拟斜板试验进行全程记录，对滑体运动过程及停积状态进行分析，总结不同试验条件下滑体运动特征参数的变化规律。最后从力学角度分析滑体力学特征与滑面粗糙度对滑体堆积形态的影响，最终建立基于滑体粗颗粒含量及滑面相对粗糙度作用下的滑体中粗颗粒最远散落距离的计算模型及视摩擦系数关系曲线。主要得到以下结论：

（1）直剪试验中随着法向应力的增大，抗剪强度随之增大，且其所在的应变随之增大，并且法向应力对砂体的剪胀有一定的抑制作用。砂体中粗砂含量对剪切力学性质也有一定的影响，分析认为少量的粗砂颗粒对中细砂体整体强度表现出削弱的作用。

（2）采用3D扫描仪对斜板试验过程进行记录，并观察堆积体表面形态，分析认为在下滑过程中由于砂体颗粒与接触面材料间的碰撞及颗粒间的相互作用导致了颗粒分选。

（3）通过对堆积体形态特征值与砂体粗颗粒含量（w）及滑面材料相对粗糙度（摩擦系数Rr）的变化规律进行分析，发现堆积体主体堆积长度、宽度、粗颗粒最远滑动距离等均随粗砂颗粒含量及滑面相对粗糙度的变化表现出一定的变化规律。

（4）根据能量守恒定律及试验数据，建立了适用于本试验中混合砂体最远运动距离L与粗砂含量和接触面相对粗糙度Rr的关系式；通过公式推导得到的视摩擦系数μ_s关系曲线与试验结果较吻合，且可以较好的适用于实际的滑坡中。

In order to study the influence of particle size grading of sliding body and roughness of sliding plane on landslide movement. This paper uses the fluidity of dry and loose sand to conduct indoor direct shear test and slope simulation plate test of dry sand body, and discusses the influence of sand body with different coarse sand content and roughness on the test results. Firstly, direct shear test was carried out to explore the mechanical behavior mechanism between the rough surface material and sand body in shear by interface shear test. Then, a 3D scanner was used to record the whole process of the landslide simulation inclined plate test, record and analyze the movement process of the sliding body and the stagnation state, and study the change rule of the sliding body motion characteristic parameters under different test conditions. Finally, from the perspective of mechanics, the effects of the properties of the sliding body and the roughness of the sliding surface on the movement process of the sliding body and the packing morphology of the sliding body were analyzed. Finally, a calculation model of the farthest dispersion distance of coarse particles in the slide based on the coarse particle content of the slide and the relative roughness of the slide surface and the relationship curve of the coefficient of apparent friction is established. This paper mainly draws the following conclusions:

(1) With the increase of normal stress in the direct shear test, the shear strength increases along with the increase of the strain of it, and the normal stress has a certain inhibitory effect on the dilatancy of sand body. The content of coarse sand in the sand body also has a certain influence on the shear mechanical properties. The analysis shows that a small amount of coarse sand particles weaken the overall strength of the medium and fine sand body.

(2) 3D scanner was used to record the test process of inclined plate, and it was analyzed that particle sorting was caused by the collision between sand particles and contact surface materials and the interaction between particles in the sliding process.

(3) Based on eigenvalue deposit form and sand body of coarse particle content (w) and relative sliding surface material roughness (Rr) friction coefficient is analyzed. It was found that the accumulation length, width and farthest sliding distance of coarse particles in the main body of the pile showed a certain variation pattern with the change of coarse sand content and relative roughness.

(4) According to the law of conservation of energy and the test data, the relation formula of the maximum movement distance L suitable for the test mixed sand body and the content of coarse sand and the relative roughness of contact surface Rr was established. The relationship curve of apparent friction coefficient μ_s obtained by the derivation of equation is in better agreement with the experimental results and is better applicable to the actual landslide.

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