The Experimental Study On The Failure Characteristics And Supporting Of Different Shapes Of Roadways In High Ground Stress

The depth of coal mining in our country is increasing year by year,and some mines in the mid-east have began to mine the deep coal. The deep mines are facing more and more complex environment,particularly the problem of roadway supporting is more and more serious. The important reason why the deformation and failure of deep roadways is serious is high ground stress,which makes the safe production and high efficiency of the mines affected. The problem of controlling the surrounding rock in high ground stress roadways needs to be solved at once. So the study on the failure characteristics and controlling roadways in high ground stress is of great guiding significance.On the basis of researching the existing circumstances of the deformation and failure of the surrounding rock in high ground stress roadways,the paper made theoretical study and similar material simulation united to analyze the factors making the roadways failed,failure characteristics and mechanism in high ground stress roadways,to introduce the current supporting theory. Besides,the deformation and failure characteristics of surrounding rock of circular and rectangular roadways under high ground stress were be studied,and the effect were contrasted by using the common supporting ways of deep roadways,and some suggestions about supporting were provided. The conclusions include:(1)The deformation and failure characteristics of circular roadway under high vertical stress were studied. After the roadway was mined,the shear failure on both sides occurred because the concentrated stress exceeded it’s intensity,and the upper and lower shear crack intersected and cut the surrounding rock which became the shape of wedge. The rock whose shape is crescent dropped from the roof because the shear crack had extended to the roof and intersected. The shear crack extended to the floor and developed along the bedding,which made the floor be the shape of basin bottom.(2)The supporting method of the circular roadway combined anchors,cables,shotcrete with metal mesh to contrast the failure scope and deformation. The roof subsidence was reduced 13.3mm,and the upheaval of floor was reduced 3.8mm,meanwhile the scope of failure on two sides was reduced 30 mm. It showed that the supporting made the deformation and failure controlled effectively,whose effect was good.(3)The deformation and failure characteristics of rectangular roadway under high vertical stress were studied. After the roadway was mined,the shear failure in the top corner occurred because the concentrated stress exceeded it’s intensity,afterwards both sides dropped whose shape is arc. The sinking deflection of the roof increased,and the tensile failure and abscission layer turned up. Because of the function of horizontal extrusion stress, the shear rupture and abscission layer of the floor occurred.(4)The supporting method of the rectangular roadway combined anchors,cables,beams with metal mesh to contrast the failure scope and deformation. The roof subsidence was reduced 27.7mm,and the upheaval of floor was reduced 3.9mm,meanwhile the scope of failure on two sides was reduced 70 mm. It showed that the supporting made the deformation and failure controlled effectively,whose effect was good.