| Aiming at the complex engineering problems affecting the stability of soft and hard interbedded slopes,this paper takes the soft and hard interbedded rock slopes of the east side of the Jiepailing open pit as the research object,and analyzes the structure of the east side soft and hard interbedded slopes.Investigate and classify the damage characteristics,and study the engineering characteristics of the slope rock mass.Using numerical simulation analysis methods,a total of 25 sets of orthogonal experiments were designed,and the slope stability sensitivity analysis was carried out on 6 influencing factors: soft rock thickness,hard rock thickness,cohesion,internal friction angle,rock inclination,and rock inclination.Judge their significant influence and relevance,analyze the deformation and failure modes of soft and hard interbedded slopes in the mining area,and provide support for the protection measures of the eastern slope.The main research contents and results are as follows:(1)Through on-site investigation of the mining area,the geological structure and hydrogeological conditions of the mining area were understood,and the soft and hard interbedded rock slopes of the east bank were investigated in detail.The investigation found that there were 5 soft and hard interbedded slopes in the east bank.Among them,there are 4 bedding slopes and 1 anti-dipping slope.The soft and hard rocks are silty shale and quartz sandstone.And through investigation and later analysis,it is known that the influencing factors affecting the stability of the soft and hard interbedded slopes of the east bank include the slope structure and rock inclination,the lithology and combination characteristics of the soft and hard layers,and rainfall.(2)Carry out mineral composition analysis,hydraulic property test and rock mechanics test on hard rock(quartz sandstone)and soft rock(silt shale)respectively.It is concluded that water will not affect the quartz sandstone too much,but It will greatly change the nature of silty shale.The soft rock layer of the soft and hard interbedded slope can be regarded as the aquifer and the hard rock layer as the water barrier.(3)Using 3DEC numerical simulation software,the 25 groups of orthogonal tests were analyzed in sequence,and it was found that the influencing factors: soft layer thickness,soft rock cohesion,and rock inclination have greater influence on the maximum slope displacement and the slope safety factor.Is a significant factor affecting slope stability.In addition,there is a significant correlation between the inclination angle of the rock formation and the safety factor of the slope.(4)Using rock saturation parameters to simulate and analyze the failure modes and stability of different slopes under extreme rainfall conditions,and study the laws of slope deformation failure modes and slope stability under different rock inclination angles and different soft layer thicknesses.According to the results of the research,specific treatment suggestions are made for the slope of the east bank.Studies have shown that the deformation and failure modes of different rock layers in different slope structures are significantly different;as the thickness of the soft layer increases,the stability of the slope gradually deteriorates.In the natural excavation state,the overall stability of the soft and hard interbedded slopes of the east bank is in order from high to low: Section 1-1,nearhorizontal soft and hard interbeded slopes> down-dip and same-direction gently-dip slopes>down Inclined steep slope in the same direction;section 2-2,steep slope near upright soft and hard interbedded slope>anti-dip soft and hard interbedded slope.The most prone to damage areas of the slope are the forward-dip,same-direction steep slope and the anti-dip soft-hard interbedded slope.The treatment suggestions for the soft-hard interbedded slope of the east bank are: control the water source,change the disaster-causing body,and focus on the area.Implement monitoring measures,etc. |
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