Study On The Stress Distribution Characteristics Of Continuous “Double Shell” In Soft Rock Of Deep Roadway

In recent decades in our country coal demand increases unceasingly,shallow coal resources drying up.More and more shallow to the deep mine,a new mine mostly for deep mines.Excavation and supporting of roadway is the top priority of the coal mine production,roadway influenced by ground stress and tectonic stress,characterized by hard rock,in shallow for soft rock engineering in deep is characteristics of roadway deformation damage quantity increase,the traditional support method is difficult to achieve the supporting effect,the late of the high cost of maintenance,need a new supporting theory and supporting technology.In this paper,we study mainly based on the continuous "double hull" supporting theory,in view of the supporting problems of deep soft rock tunnel excavation,targeted support scheme is put forward.At the beginning of the clutch to write reading a large number of references,this paper mainly adopts theoretical analysis,field research,analog simulation,numerical simulation and industrial test of a variety of research methods,the continuous "double hull in deep soft rock tunnel excavation surrounding rock stress distribution characteristics of the study.In this paper,the research contents and conclusions are as follows:(1)The definition system comprehensive description of the soft rock,soft rock properties and mechanical properties,analysis of roadway deformation and failure mechanism of the ceramic two coal deformation and failure characteristics of return air lane and the factors influencing the deformation and failure has made a comprehensive analysis.(2)Using the numerical simulation software to simulate the deformation law of surrounding rock of roadway under different buried depth,stress state and plastic zone distribution,summarizes the conclusion of roadway surrounding rock with the increase of buried depth as far as possible big,broken is wide and the decrease of strength of surrounding rock,roadway concentrated stress area is more obvious,according to the simulation result,increase of confining pressure and broken zone is beneficial to reduce the stress of surrounding rock,high intensity,make transfer to deep stress.(3)Similar simulation experiment simulation different lateral pressure coefficients(?=1,1.5,2)the roadway deformation and stress distribution characteristics,and prove that stress in the process of deformation of surrounding rock of roadway surrounding rock stress transfer to the deep,deep in the shell,under the support of shallow shell stress release,as the main load bearing area of deep surrounding rock.Lateral pressure coefficient to 1 "double hull" continuous support and the single shell bolting roadway effects were similar,but with the increase of pressure coefficient,supporting effect difference.(4)The concept and the continuous "double hull" supporting mechanism,using the mechanics formula of "single shell",the continuous "double hull" and the continuous "double shell" support for elastic-plastic analysis.Mechanics model is set up,and deduces the plastic zone and elastic zone of roadway surrounding rock stress and displacement;Damage range of the plastic zone is deduced,thus supporting radius are put forward.(5)The continuous "double shell" on the basis of deep soft rock tunnel excavation supporting theory and technology of second coal mine tao xin nan total return air roadway control scheme and parameter,and implement industrial test.Through the field application shows that roadway mine pressure appear violent before repair,roof,side and bottom destroyed;After repair,the surrounding rock of roadway intact,can work normally.