Flexible-formwork driving roadway technology along goaf retaining wall in large mining height working face
The technology of retaining roadway along goaf with flexible formwork concrete has been used in China for many years.In the medium-thickness coal seam and thin coal seam mining it has a-chieved better support effect,but in the thick coal seam working face with large mining height,it is dif-ficult to support the roof effectively because of the high roadway,high pressure of the roadway side sup-port,and the low strength of the concrete in the early stage is easy to be damaged by the pressure.In addition,the mine pressure in the large mining height face is severe,and it is difficult to maintain the roadway,so a new technology of driving roadway along goaf with flexible form of concrete pre-cast wall is put forward.Before the mining of the last working face,the flexible formwork wall of concrete is poured in advance after brushing coal to expand the slope,so as to improve the overall supporting force of the coal side,and at the same time,to solve the problem that the flexible formwork concrete wall can not effectively bear the roof pressure in a short period of time.After mining a certain distance,then lag-ging along the wall is propased to dig the lower working face back to mining roadway,and the direction of digging and in the upper working face back remains the same,to alleviate the succession of tension and ultimately to achieve no coal pillar mining.This paper takes Wangzhuang Coal Industry 3503 work-ing face back mining leaving pre-cast wall as the engineering example.In this paper,the mechanical model of surrounding rock structure of roadway driving along goaf retaining wall is established,the wall mechanical support parameters are calculated theoretically,and the implementability of this technology is verified by field application.The results show that:the theoretical calculation and analysis determine the wall height and width ratio of 5 m × 1.5 m,and the concrete strength of C30 can meet the require-ments of retaining wall support.The overall deformation of the roadway driven along the wall is small,the maximum displacement of the roof and floor and the two sides is only 260 mm and 125 mm,and the maximum compression 18 MPa of the wall is less than the bearing capacity of the wall itself.The lower working face is stabilised after 115 m of tunneling near the roadway.The application of this technology has a good effect in the whole stage,possible to meet the requirements of roadway use,and effectively solves the major technical problems of retaining roadway along goaf in large mining height face.It can provide a technical reference for coal pillar mining without coal pillar in similar conditions.
driving roadway along goaf remaining wallflexible-formwork concretemechanical modellarge mining height working facemine pressure monitoring
万方数据
维普
