| Close coal seams are distributed in our country,and the interaction is large,which is the best difficult problem we try our best to solve.Based on the 29204working face of Dongqu coal mine,this paper studies the surrounding rock deformation law and supporting parameters of the roadway under the goaf of close distance coal seam by using the methods of theoretical analysis,numerical simulation and field practice.(1)The mechanical analysis formula of roof damage in close distance coal seam is established.The damage depth h_σof upper coal seam is 3.49m.The floor between two coal seams has been damaged,but not completely damaged,The roof of No.9coal seam has many kinds of media properties,such as broken roof in goaf,broken block fracture roof between coal seams and intact roof.(2)Based on the analysis of the damage degree of the strata between the two coal seams,the stress distribution and the yield failure state of the surrounding rock under the close mined out area are analyzed by using the numerical simulation calculation.We can conclude the outcome is the most small deformation when the stagger distance is 10-20m.(3)It is determined that the row spacing of anchor bolts at the top of the gateway is 800×800mm,that of the side bolts is 750×800mm,the length of the bolt is?22?(16)(23)(15)(15)mm,and the length of anchor cable is?21.6?(18)(20)(15)(15)mm.(4)The field observation scheme design and field measurement are carried out.We can see that the deformation in the surrounding rock of roadway is small,so the design of support is safe.There are 24 pictures,9 tables and 72 references. |
PDF Full Text Request