| The rock slope of soft and hard interlayer(including weak structural surface)will cause damage to its structural stability to different degrees,which is a major geological disaster affecting the safe operation of the project and people's life.It has the characteristics of wide distribution,frequent activities,complex production conditions and many factors.Along with our country's engineering scale expands unceasingly,the variety and the complexity of the prevention and the movement mechanism,making prediction difficult,has caused casualties and economic property of the huge losses,and people also realize the slope stability analysis and treatment measures of the research is of great significance,in the world is always one of the main research of geological disasters.To correctly understand the damage of shale formation to slope structural stability and engineering construction safety,it is necessary to take a reasonable research method to conduct in-depth research on this kind of problem,and put forward reasonable technical treatment measures,many major accidents occur because of slope engineering treatment measures.Taking caocun reservoir,xin 'an county,luoyang city,as the simulation background,the stratigraphic lithology of the study area is mainly composed of quartz sandstone with thin layer shale,which is a monoclinic structure with a tendency of 170 ° ~ 185 ° and a dip Angle of 11 ° ~ 15 °.The shale is purple-red,mainly composed of clay,highly weathered and 4-9m thick.The occurrence is NW85° Angle 14°.The whole rock stratum slopes gently towards the downstream of the spillway.The shale layer is developed below the normal water level,the strongly weathered shale is affected by the seepage of the reservoir water,and its strength is greatly reduced,which greatly affects the stability of the right abutment slope and the safety of the dam.Based on the field investigation of engineering geological conditions and rock mass mechanics test of dam site area,the deformation characteristics of soft and hard interbedded rock slope were analyzed by FLAC3 D numerical analysis and traditional limit equilibrium method.Using limit equilibrium method for slope safety factor of slope was a typical profile,through numerical analysis of reservoir right abutment before and after the reinforcement measures of the displacement field,stress field distribution and the maximum principal stress distribution analysis of the reliability analysis safety stability of the spillway slope is studied in a variety of working conditions,carried out the research of spillway slope reinforcement scheme.The main research results of shale slope stability in dam site area of caocun reservoir are as follows:(1)field survey of the engineering geological conditions of the dam site,based on the detailed description method of joint and fracture analysis,the site selected 12 Windows for joint description,the statistics of the sketch window of the joints of the rose,and investigation of rock mass fault zone and shale distribution type,rock mass mineral analysis.(2)using the limit equilibrium method of slope on the premise of not excavation of right dam abutment slope according to the calculation and analysis of natural condition and seismic conditions,and after taking anchor cable reinforcement schemes are analyzed,and the right dam shoulder slope in natural condition and seismic conditions overall anti-sliding stability increased,compared with natural condition of slope safety factor has a significant improvement.(3)through finite difference software FLAC3 D to shale under natural state and submerged saturation state,the calculation results show that shale natural state,the right abutment overall deformation is small,small impact on the overall security: right abutment curtain upstream side shale flooding saturated state,the overall deformation are mainly concentrated in the downstream area of the region near the maximum displacement is located in the downstream of the dam axis downstream,due to the parameters of the shale weaker,right dam shoulder slope has a tendency to downstream integral sliding,reinforcement is required.Two types of reinforcement schemes are considered,namely prestressed anchor cable and anti-slide pile.After adopting the reinforcement scheme,the displacement at the bottom of the right abutment is relatively reduced,while the displacement at the top of the slope is minimal.Under the condition of full excavation of the right abutment of the dam,if the flood reaches the normal water level,the maximum principal stress of the slope body is compressive stress,and the maximum position is distributed in the downstream rear part of the dam axis,both sides of the spillway facing the water surface,the fissure facing the water surface and the rear part of the right abutment.(4)the calculation model and engineering geological section of the reliability analysis of the right abapment slope are exactly the same as the limit equilibrium method,and the number of simulation times is 8000.The safety coefficient of the right abapment slope under natural working conditions and seismic engineering after the reinforcement of prestressed anchor cable is analyzed.The safety coefficient of the slope under natural working conditions is 1.48,and the safety coefficient of the right abutment slope under treatment measures is 1.61.Compared with the natural slope,the safety after reinforcement is significantly improved,which can meet the needs of construction safety.(5)according to cao village reservoir dam site area of shale slope could cause the engineering problems,the scene of the comprehensive consideration,engineering cost under the influence of factors such as the construction difficulty,choose the reasonable supporting scheme,engineering measures from the governance effect and optimal economy and ease of construction several perspective,it is recommended to use prestressed anchor cable,namely in the right abutment curtain upstream and downstream side of the main sliding direction set spacing 5 m prestressed anchor cable. |
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