重复剪切作用下结构面起伏角度对其力学特性影响研究

A study of the influence of asperity inclination angle on the mechanical properties of a structural plane under repeated shear

在室内直剪试验的基础上,研究了重复剪切作用下起伏角对结构面变形和强度的影响。采用钢制模具和混凝土材料预制4种起伏角度结构面,分别在5级法向应力下进行6次直剪试验,记录每次剪切过程中的切向应力和法向位移随切向位移的变化。通过对切向应力和法向位移随切向位移变化曲线分析可知,首次剪切时,法向应力和起伏角度越大,结构面剪切破坏方式越容易从滑移破坏过渡为剪断破坏,对于同一种剪切破坏方式,法向应力越大,对结构面磨损或剪断的作用越强烈,峰值剪胀位移越小,起伏角度越大,锯齿被磨损或剪断的高度越大;第2次剪切开始,不论法向应力和起伏角度如何,结构面的剪切破坏方式基本上都转变为滑移破坏。

On the basis of direct shear tests, influence of asperity inclination angle on deformation and strength of a structural plane are examined. Structural planes of four asperity inclination angles are made using steel mould and concrete, and direct shear tests are conducted six times under five normal stresses. At the same time, shear stress and normal displacement are recorded. The analysis of shear stress-horizontal displacement and vertical displacement-horizontal displacement curve shows that the normal stress and asperity inclination angle become larger firstly and the structural plane is easier to be cut. For the same shear failure style, if the normal stress increases, the structural plane will be worn or cut more seriously, and the maximum vertical displacement is lower. If the asperity inclination angle increases, the zig-zag pattern will be worn or cut more seriously. From the second shear time, the structural plane is worn every time and is not affected by the normal stress and asperity inclination angle.