Research On Collapse Mechanism Of Slopes With Expansive Mudstone And Sandstone Interbedded Laminated Structure

With different lithologies, differential weathering occurs obviously between themudstone and sandstone. Coupled with the complex geological conditions and the specialengineering properties of the expansive, these factors caused the slopes with expansivemudstone and sandstone interbedded laminated structure failure modes of collapse complex.The domestic and foreign research on collapse mechanism of slopes with expansive mudstoneand sandstone interbedded laminated structure is not perfect. In this paper, through a practicalengineering example—renovation of national highway312slope collapse diseases studiedcollapse mechanism of slopes with expansive mudstone and sandstone interbedded laminatedstructure. Specific research contents and results are as follows:(1) Based on absorbing the domestic and abroad research results of slope collapse, thisthesis summarizes the classifications and failure modes of slope collapse and the influencefactors of slope collapse.(2) Based on the physical and mechanical experiment, this thesis analyzes the propertiesof expansive mudstone. Through a series of experiments on the mudstone, analyzes therelations among swelling force and moisture content, swelling ratio and upper load, swellingratio and time, swelling ratio and moisture content. By plotting curve of relationship betweeninfluencing and expansiveness, coupled with regression analysis of experimental data, theinfluences of various factors on the performance of mudstone were studied. This thesis getsthe physical and mechanical parameters of mudstone.(3) According to the geological investigations in the field and indoor experiments, fromstructural characteristics of slopes begins, order from the development characteristics andregularities of collapse, the formation condition of collapse, the typical slope collapse in thestudy area, qualitatively put forward collapse mechanism of slopes with expansive mudstoneand sandstone interbedded laminated structure—the tensile crack-type collapse.(4) By analyzing distributions of stress, displacement, plastic shear strain and celldamage under natural action, under rainfall action, under earthquake action for the CDEMnumerical calculation model, to research the failure mechanism of slope collapse undernatural action, under rainfall action, under earthquake action. Taking structural plane and jointinto account, using Continuum-based Discrete Element Method to reproduce and analyze thecollapse of slopes with expansive mudstone and sandstone interbedded laminated structure.(5) At last, the collapse mechanism of slopes with expansive mudstone and sandstoneinterbedded laminated structure was put forward by summarizing the geologicalinvestigations in the field and analysis on the results of laboratory tests and numericalsimulation. The failure process of slope collapse can be summed up as follow: mudstone spalling→fracture development in sandstone→local sandstone falling→collapsesoccurred.