| Under the influence of underground mining,the landslide caused by the deformation and failure of overlying rock mass is called mining landslide,and the slope that produces deformation is called mining slope.In recent years,with the rapid development of social economy in Guizhou province,the exploitation of coal resources has been greatly increased,and the resulting geological disasters in mines are increasingly frequent,especially in Liupanshui,Guizhou.In Liupanshui area,many slopes have been deformed for many years under the influence of coal seam mining,but no overall damage has occurred so far,which has brought a severe test to the prevention and control of geological disasters:What is the stability?Project management is difficult,high cost of relocation,relocation or management?If governance,how to govern? The key to solve this problem is to correctly evaluate the stability of mining-induced slope on the basis of understanding the law of deformation evolution of mining-induced slope.Therefore,it is of great significance to analyze the influence on the formation mechanism of slopes under such complex mining conditions.Based on this,this article Faer mining area in Liupanshui city,Guizhou province Jianshanying deformation body as the typical case,through field investigation,geophysical prospecting and mining data collection methods,find out the deformation of slope structure characteristics,the characteristics of mined-out area distribution,deformation and failure characteristics,on the basis of the particle flow numerical simulation and analysis of the forming mechanism of deformation.On this basis,the effects of deformation and damage on slopes under single-layer mining and multi-layer mining conditions are compared,which provides some reference for coal mining and prevention of mine disasters.Mainly achieved the following research results:(1)The basic characteristics of Jianshanying deformation body were identified.Jianshanying deformation body takes ridge line as the dividing line and presents a large Angle "V" shape.It presents a gently counter-inclined layer structure in the slope of the NE side and a transverse slope in the SW side,which has the characteristics of soft and hard interbedding structure.There are 6 minable coal seams in the lower part of the slope,which has a long mining history and formed a large area of goaf.Under the influence of mining action,the overall deformation of the slope is relatively obvious,the internal cracks of the slope are developed.The Mudstone crushing and extrusion phenomenon at the foot of the slope is obvious,and 35 fractures of different sizes are developed at the top of the slope.(2)The micromechanical parameters and joint mesh models of the rock are obtained.The microscopic mechanical parameters of the rock in the study area were obtained by comparing the laboratory test data with the rock numerical simulation test and the engineering analogy method.The similar joint rock mass model was constructed by using the equivalent rock mass technology in the particle flow simulation.(3)The numerical simulation basically simulates the deformation of the slope of the Jianshanying deformation body and the expansion process of the crack.After the deformation of the Jianshanying deformation in the M1 coal seam,a large number of fissures have been formed inside the slope.Some cracks have extended to the slope table,and the trailing edge of the slope has also been dumped to some extent.The mudstone at the slope is squeezed and broken.As the mining progresses,there are many long cracks in the slope after mining the M5-3 coal seam.The trailing edge is also more obvious,and the mudstone at the foot is more broken.When the mining of M10 coal seam is completed,the number of cracks on the slope has not increased further,but with the adjustment of the internal stress of the slope,some cracks have been dumping,and the settlement has increased greatly,which makes the caving belt compact and the rock layer is wrong.Paragraph,the foot of the slope has been more inflated at this time.When the mining is completed,it is speculated that with the later rainfall,the large cracks on the slope will be further filled with water.Under the action of water,the slope will form a “ladder shaped” potential slip surface.With the accumulation of rainwater inside the slope,the landslide The rear edge of the body produces a large thrust,and the "locking section" may be sheared,causing the slope to slide as a whole.(4)Through the comparative analysis of slope deformation under the action of single layer mining,the influence of goaf location,depth and length on slope deformation and failure is discussed.The results show that in single coal seam mining,the relative slope position of the goaf has a great influence on the slope.When the slope goaf is located outside the projection line of the slope shoulder,the slope deformation is obvious.When the goaf is located in the interior of the slope shoulder projection line,the deformation of the slope is less affected.At the same time,the mining depth and length have little influence on the slope deformation within a certain range.When the difference is large,the slope deformation will have a more obvious impact.(5)Through the comparative analysis of slope deformation under multi-layer mining,the influence of mining thickness and repeated mining on slope deformation and failure is discussed.The results show that in the mining of multiple coal seams,the influence of mining thickness on the horizontal displacement of the slope is complicated,and there is no obvious law.In addition to being closely related to the thickness of the mining,it is also affected by the degree of crack development inside the slope,while the vertical displacement and the displacement are Both decrease with the decrease of mining thickness.At the same time,in the multi-coal mining,the maximum settlement of the slope is greater than or equal to the mining thickness,and the maximum settlement often occurs where the coal seam goaf overlaps the most,and The degree of overlap increases,and the maximum settlement exceeds the thickness of the mining,indicating that it is greatly affected by repeated mining during multi-coal mining. |
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