同忻井田地应力测量与回采巷道稳定性研究

In-situ stress measurement and the stability of the mining roadway in Tongxin mine field

为保证同忻煤矿安全、高效开采,采用应力解除法对大同矿区同忻井田3-5#煤层的地应力场进行了测量,结合理论分析、数值模拟与现场监测,分析了在该类型应力场中不同巷道布置方向与巷道围岩稳定性之间的关系。测得同忻井田最大主应力为20.42 MPa,方位角为245.18°,确定了同忻井田地应力场属于σHv型。理论计算和数值模拟的结果表明,有利于回采巷道稳定性的布置方向为与最大水平主应力方向成30°,并采用巷道顶板离层监测仪对其进行了验证。

The purpose of the paper is to identify and determine the safety status in-situ for the efficient mining in Tongxin coal mine area.To achieve the purpose,the paper has managed to make exploration of the in-situ stress field of 3-5 # coal seam of Tongxin mine field in Datong mining group with the stress relief method.In our study,we have done a theoretical analysis in combination with a numerical simulation as well as the monitoring on-spot.At the same time,we have also analyzed the relation between the different roadway layout directions and the stability of the surrounding rocks in this type under the in-situ stress.We have also measured the maximum principal stress of Tongxin coal mine,which turns out to be 20.42 MPa,whereas the middle stress has been found equal to 14.07 MPa and the minimum stress accounts for 11.75 MPa.What is more,we have also measured the maximum principal stress azimuth which is about245.18°,with the middle stress being 335.20° and the minimum stress-153.00°.Morever,in terms of the stress dip angle,the maximum principal stress dip angle is equal to 2.27°,while the middle stress is-69.96° and the minimum one is 3.54°.Thus,it can be concluded that the ground stress field of Tongxin coal mine should be attributed to the type of σHv.The theoretical calculation and numerical simulation further prove that,suppose the arrangement direction is in a 30° horizontal angle with the maximum horizontal principal stress,the stress should be in favor of the stability of mining roadway.Therefore,if it is necessary to make the calculation results well credible,it would be of great need to examine and measure it with the instruments for testing the roof separation kinetics.The results of our measurement and simulation have thus demonstrated that the roof convergence of No.2100 roadway has been detected ranging from 7 mm to 14 mm with the roof convergence of No.2103 roadway being from 4 mm to 7 mm.Thus,what we have found is well in agreement with the results of the theoretical calculation and numerical simulations,hence,being able to provid a theoretical basis and practical means for promoting the safety production of the aforementioned coal mine.