Study On Deformation Characteristics And Support Technology Of Shaft And Roadway With Soft Rock In Dahaize Coal Mine

Soft rock supporting problem of mine,has always been an important issue of coal production safety in our country,the mine shaft and support during the process of preliminary design need to be determined according to some existing similar experiences,but as a result of different engineering of mine,under the condition of different geological conditions,buried depth,will present a different mechanics phenomenon,so for the new mine,engineering of supporting design need according to actual situation.Daze Coal Mine's newly built mine is not only buried to a depth of nearly 700 m,but also most of the sections pass through soft rock,with large deformation and strong mobility of surrounding rock,which makes it difficult to maintain long-term stability of roadway support.Therefore,it is necessary to carry out research on surrounding rock support control technology of Daze newly-built soft rock roadway to improve the bearing capacity of surrounding rock of the roadway.The main research results are as follows:(1)According to the stress and deformation characteristics of surrounding rock of soft rock well and roadway,the load-bearing structure layer of surrounding rock of soft rock well and roadway is stratified,which is successively divided into "flow layer-plastic layer(plastic softening layer and plastic hardening layer)-elastic layer",and the layered mechanical model of load-bearing structure suitable for sea soft rock well and roadway is established.(2)Through the layered mechanical model of bearing structure,the wellbore surrounding rock of deep soft rock section is stratified,and the range of plastic bearing zone of wellbore surrounding rock of deep soft rock section is determined to be8.81?13.51 m,and the thickness is 4.7m.The calculation results show that the ultimate bearing strength of the deep soft rock section supported by Daze Coal Mine main shaft is 22.93 MPa,which is greater than the original rock stress of 16 MPa,which can meet the requirements of long-term stability.According to the division of its bearing area,the support design scheme is proposed: the first support adopts 600 mm reinforced concrete masonry crown,and the second support adopts 1700 mm reinforced concrete masonry crown.(3)By using the load-bearing structure layered mechanical model,the surrounding rock of the roadway at the bottom of the deep soft rock section is stratified,and the range of plastic load-bearing zone of the surrounding rock at the bottom of the roadway is determined to be 4.70?10.47 m,and the thickness is 5.77 m.It is calculated that the ultimate bearing strength of deep soft rock is 18.52 MPa after roadway support,which is greater than the original rock stress of surrounding rock 15.8MPa.This bearing structure can maintain the stability of roadway for a long time.And according to the bearing area of the division of its support design scheme: the first support using net shotcrete support,secondary support using bolt and anchor cable combined support design scheme.(4)The field monitoring data show that the stress and deformation of the surrounding rock tend to be stable after the secondary support.The maximum in-situ stress of the surrounding rock at 640 m is 23.6MPa,and the maximum radial deformation of the surrounding rock is 52 mm.The maximum stress of the roadway surrounding rock at the bottom of the shaft is 25.6MPa,the maximum displacement of the two sides is 52.7mm,and the maximum displacement of the roof and floor is44.5mm.The deformation conditions meet the requirements of the long-term stability of the roadway surrounding rock.