Study On Stability Control Of Roadway Surrounding Rock Affected By Excavation DisturbanceAnd High Stress

Longquan coal mine belt roadway and return air roadway are two adjacent and parallel roadways.The roadway props have the characteristics of large cross-section,large buried depth and through complex geological structure and fault zone,especially under the influence of driving disturbance of return air roadway,the belt roadway appears serious damage phenomenon.In this paper,based on the engineering background of these two roadways,theoretical analysis,field in-situ measurement,numerical simulation and engineering application and monitoring methods are used to study the disturbance influence law between these two roadways,and the corresponding optimization and engineering application verification of the original support scheme of the belt roadways are carried out.The main conclusions are as follows:(1)The buried depth of the belt roadway reaches 750 m,and the horizontal structural stress appears under the influence of the nearby faults.The roadway is in a high stress environment as a whole.At the same time,the roof of the belt roadway is a composite roof.The test results of the rock mechanical parameters of each rock stratum show that the surrounding rock fracture is developed within7 m from the roof surface,and the overall strength is low.(2)The distance between the belt roadway and the return air roadway is 25 m.The field measurement and engineering monitoring results show that the belt roadway is obviously affected by the disturbance of the return air roadway.Under the influence of the disturbance,the surrounding rock cracks increase and the displacement increases within 7 m of the roof and 4 m of the side of the belt roadway.The significant period of the disturbance is 5 days,and the surrounding rock above 7 m from the roof is basically not affected by the disturbance The original support scheme has poor control effect on the surrounding rock stability of the belt roadway.(3)The distance between roadways is an important factor in the disturbance intensity of shadow driving.The numerical simulation results show that when the distance between roadways is 45 m,the belt roadways are basically not affected by the disturbance of return air roadways;when the distance betweenroadways is 35 m,the disturbance effect is small;when the distance between roadways is 25 m,the belt roadways are obviously affected by the disturbance,and the convergence of the middle roof and floor and the two sides are 24.3%and 31.7% higher than that of 45 m,respectively,and the left side is more close to the left side The deformation of the side is 25.6% higher than that of the right side,and the asymmetric deformation of the two sides is serious.When the roadway spacing is 15 m,the convergence of the roof and floor of the belt roadway and the displacement of the two sides are 46.6% and 72.1% higher than that of the 45 m,respectively.The belt roadway is severely affected by the disturbance and the surrounding rock is seriously damaged.(4)When the driving face of return air roadway is more than 8 m from the measuring station of belt roadway,the vertical stress of the two sides of the measuring station is obviously affected by the disturbance.When the roadway spacing is 45,35 and 25 m,the vertical stress of the left side of belt roadway is2.3%,18.9% and 10.2% higher than that of the right side,and the vertical stress of the left side is greater than that of the right side.However,when the roadway spacing is 15 m,the vertical stress distribution of the left and right sides changes,and the vertical stress of the left side is lower than that of the right side 7.6% in the right.(5)Due to the construction distance of the existing belt and return air roadways,it is difficult to change their relative positions.Therefore,combined with the causes of the damage of the belt roadways,the original support scheme is optimized by increasing the support strength of anchor bolts and anchor cables.The results of engineering application show that the roof subsidence of the roadway under the support of the optimized scheme is 82.6% lower than that of the original support scheme,while the displacement of the two sides is 81%lower,and the stability control effect of the surrounding rock of the roadway is obvious.The disturbance effect can also be effectively reduced by adjusting the roadway spacing.For the roadway layout in the next section,the roadway spacing can be appropriately enlarged to 35 m.