Study On The Drilling Pressure Relief Support Technology Of High Stress Soft Rock Coal Roadway

With the increase of mining scale and intensity, mining operation turns to the deep constantly, and supporting and maintenance of the soft rock roadways,especially the high stress soft rock roadways, is becoming more and more prominent.Difficult supporting roadway of this kind often needs to repair for many times to control the stability, and not only increases the cost of production, but also seriously affects the mine safety production.It is a severe challenge to roadway support of deep mining.Therefore, studying on the reasonable supporting technology of the deep high stress soft roadway has very important practical significance.Taken 2609 rail gateway in the Chen Silou coal mine as engineering background, the paper adopted methods of field investigation, laboratory test,theoretical analysis and numerical simulation to study the supporting problem of the high stress soft rock roadway. The research contents and results are as follows:1)The paper measured the physical and mechanical properties of surrounding rock of 2609 rail gateway in Chen Silou coal mine.The results show that surrounding rock is loosed and broken, the intensity is low, the RQD index is poor, the argillaceous components is more,the cementation is low, and easy to weathering disintegration and plastic flow.Then,we concluded that it is the typical soft rock.2)According to the surrounding rock loose circle theory, the paper analyzed the mechanism of drilling pressure relief.Based on the elastic-plastic theory, established drill mathematical model to calculate the stress and displacement components of the elastic and plastic zone surrounding the drill hole, then obtained that plastic radius of the drill hole is a positive correlation with in-situ stress and a negative correlation with coal cohesion. FLAC3 Dis used to establish the three-dimensional borehole pressure relief model to study the different length, aperture and distance on the effect of pressure relief, and concluded that increasing the length of drilling, appropriate increase aperture and reduce drilling borehole spacing, can obtain better pressure relief effect.3)On the basis of damage form of 2609 rail gateway, the paper analyzed the main failure characteristics,and revealed the failure mechanism. Therefore,put forward the control idea of "transfer"- "release"- "resistant",and used FLAC3 D to simulate three kings of solutions to verify the feasibility.4)The paper designed the concrete supporting parameters of 2609 rail gatewayand applied to the field. Mine pressure observation showed that the deformation of surrounding rock was small during the tunneling.