Analysis Of Stability Characteristics Of Bedding Slopes In The Process Of Cladding Of Soft Black Shale Interlayers

Black shale due to this kind of material contain pyrite,in contact with air and water in the process of chemical reaction,release the hydrogen ions,the surrounding environment change for acidic environment,then inside and black shale mineral further reaction,internal structure and the change of black shale mineral composition,physical and mechanical performance and attenuation,which reduces the contains the slope stability of the black shale,in the end In this study,Xujiaping,Mianzhu,Deyang,was selected as the research object.The semi-soaking test of black shale was designed to simulate the continuous reaction process between black shale and water,and a series of test methods were combined to measure the chemical porosity of black shale in the semi-soaking process Physical and mechanical properties were studied,and the degradation process of mechanical properties was described based on the change of porosity.At the same time,the fluid-structure coupling equation considering chemical damage was derived:(1)XRD,IC,ICP,etc.were performed on black shale and black shale soaking solution for water-rock interaction.The results show that the minerals of feldspar,muscovite,calcite and pyrite in the soaking process of black shale are The content is decreasing,while the mineral content of quartz and illite is increasing.At the same time,combined with the change of ions in the solution,it is concluded that the minerals in the black shale are constantly changing under the action of water-rock,and some elements are dissolved in the mineral together with the transformation of minerals.in solution.(2)Triaxial tests were carried out for the physical and mechanical properties of black shale under water-rock interaction,and the change of porosity was calculated by the change of mass.The results show that:?the mass loss and porosity increase of black shale under water-rock action change slowly with the passage of time.?The mechanical properties of black shale,such as elastic modulus,compressive strength,cohesion and internal friction Angle,decrease with the increase of time,but the rate of decrease is slower and slower,and the best fitting is exponential function.?The chemical damage variable function was established based on porosity,and the mechanical properties were fitted with the function and time respectively.The comparison showed that the function fitted with chemical damage variable and mechanical properties could show the deterioration process of mechanical properties more scientifically(3)Based on the rock balance equation,combined with the effective stress principle and elastic constitutive model,the rock differential balance equation represented by the displacement is obtained,and then on the basis of the seepage continuity equation,combined with Darcy's law and mechanical knowledge,the fluid-solid Finally,the chemical damage variable is combined with the coupling equation through the change of porosity,and the fluid-structure coupling equation system considering chemical damage is obtained.(4)The test results of mechanical performance degradation function considering fluid-structure coupling theory of chemical injury,used in the COMSOL software,to Xu Jiaping slope as the background to carry on the numerical simulation,the typical slope under the action of the slope in the three games,coupling the displacement and deformation features of change over time and pore water pressure distribution,According to the deformation,the slope can be divided into three stages: stable stage,slow deformation stage and accelerated deformation stage.