Mechanical properties and microscopic failure process of exemplary argillaceous interlayer from east China

华东典型泥化夹层力学性质及微观破坏过程

The landslide disaster caused by the argillaceous interlayer not only destroys buildings,cultivated land,and roads but also seriously endangers human life and safety.This study concerns the mineral composition of selected argillaceous interlayer and their strength characteristics.To study the mineral composition of argillaceous interlayers,8 kinds of samples in the southern Jiangsu region of China were analyzed utilizing X-ray diffraction(XRD).The repeated direct shear strength tests(RDST)were carried out on the undisturbed specimens of the argillaceous interlayer.The results show that the argillaceous interlayer with high content of kaolinite shows ductile failure mode,which means that there is no obvious residual strength in the shear process.The arrangement of mineral particles on the shear surface of the specimens after different shear displacements was observed under the scanning electron microscope(SEM).It was observed that mineral particles on the shear surface showed a more directional arrangement with the increase of shear displacement.Furthermore,the influence of shear direction on the argillaceous interlayer with completely oriented mineral particles was studied through numerical experiments with four shear strength mechanisms proposition proposed.The influence of the mineral arrangement on the action occasion and magnitude of dilatancy component of shear strength is clarified in the shear mechanism.

泥质夹层引发的滑坡灾害不仅破坏建筑物、耕地和道路,还严重危害人类的生命安全。为了研究泥化夹层微结构的特点和细观渐进破坏规律及泥化夹层强度,通过X射线衍射(XRD)分析了华东苏南地区4个边坡共8种试样的矿物成分,并通过反复直剪强度试验(RDST)研究了各组试样的强度特征。结果表明,高岭石含量较高的泥化夹层表现为延性破坏模式,剪切过程中没有明显的残余强度。用扫描电子显微镜(SEM)观察了不同剪切位移后试样剪切面上矿物颗粒的排列情况。结果表明,随着剪切位移的增大,剪切面上的矿物颗粒呈现出更具方向性的排列。在此基础上,通过数值试验研究了剪切方向对矿物颗粒全定向排列的泥化夹层数值模型的影响,并提出了四种剪切强度机理。根据数值试验的结果,在剪切机理中论述了矿物排列方向对抗剪强度中剪胀分量作用时机及其相对大小的影响。