Study On The Treatment Method Of The Inclined Slope With Weak Interlayers Based On Electrochemical Modification Of Mudstone

Mudstone is a common lithology in the sedimentary strata of open-pit coal mine,which has an obvious characteristic of softening by water.So the existence of mudstone interlayer usually has a bad impact on the slope stability and production safety.Therefore,solving the problem of the slope stability with soft interlayer is important for the safe and efficient production of the open pit coal mine.However,mudstone's property of easily being softened makes traditional reinforcement methods unable to play a better role in strengthening.So in this thesis,changing the hydro-physical properties of mudstone is the research direction.And the method of enhancing the strength and changing the characteristic of easily being softened by water is electrochemical modification.In order to obtain the best modification effect,the electrochemical modification experiment conditions were explored by the standard of shear strength.As a result,the best electrolyte and electrode material were determined.Compared with the original mudstone,it was found that the water sensitivity indexes of the modified mudstone,such as liquid limit and plastic limit,water absorption characteristics and water softening properties,have been improved obviously.Combined with the modification effect,the mechanism of electrochemistry technology to modify the mudstone was analyzed from the micro point of view with theoretical analysis.The reinforcement effect is achieved by electro-osmotic drainage and electrochemical cementation.In addition,the mechanism of electrochemical modification to strengthen the macro mechanical strength parameters was studied from the micro perspective of mudstone particles.Firstly,the particle size composition before and after the modification of mudstone was tested by particle analysis experiment,and it was found that the electrochemical modification can effectively discharge the clay content and reduce the water sensitivity of mudstone.In order to study the micro parameters of the bonding model in PFC,the unconfined compressive strength of specimens made by consolidation was tested,and the final parameters which are consistent with the physical experimental phenomena and strength were obtained continuous adjustment in PFC.The bond cohesion and bond tension strength of the main related parameters increased significantly.At the same time,it was found that the drainage effect of electro osmotic drainage can exceed the limit of pressure consolidation drainage.Based on the analysis of the seepage law and stress state of the slope with a relatively impervious layer,the formula of FOS in the state of two-dimensional limit equilibrium of the layered slope with soft interlayer under water pressure.Through numerical simulation,the change rule of the plastic zone of the simplified slope model gradually expands with the degradation of the shear strength parameters of the weak layer is analyzed.And the gradual evolution process of the slope failure from quantitative change to qualitative change is verified.According to the development law of the failure of the weak front,the reinforcement position is proposed and the stress state and the formula of FOS after reinforcement are deduced.And three kinds of electrode arrangement forms are put forward for the slopes with soft interlayer in different occurrence states as a preliminary simple reinforcement scheme.In FLAC3 D,a three-dimensional fluid structure interaction model of slope is built to analyze the stability of slope under water pressure.At the same time,five different lengths of the weak interlayer are reinforced by combining the strength parameters obtained from electrochemical experiments.The reasonable reinforcement length is determined by analyzing the maximum displacement and shear strain of weak layer.There are 68 figures,8 tables,109 references in this thesis.