The Study On Realation Between Bearing Stratum And Basic Suppoting System Of Tunnel

Along with the extension of mining depth, under the action of the surrounding rock which is in deep high stress, the softing characters of surrounding rock begin to appear, larger range of crushing zone appeared around surround rock, this make the stability of surrounding rock become difficult to matain, what’s more, though we adopt greatly heavy support with basic support, under influence of mining and other factors, there is also a large deformation of roadway. In order to seek new support method and solve the large deformation and the difficulty of support, we put forward a method which control the surrounding rock’s stability by rebuilding the bearing stratum and make bearing stratum and basic support system bear the presser of surrounding rock simultaneously, so as to maintain the stability of surrounding rock.This paper is based on intact rock and circular tunnel, and then combining with the mechanical parameters of rock, through the numerical simulation and similarity simulation, besides, utilizing the theorical analysis, then to study the realationship between bearing stratum and basic support. The main content of this paper involves the influences of stability of surrounding rock which bring about from single bearing stratum and single basic support, the influences of stability of surrounding rock which produces by the revelent parameters of bearing stratum, what’s more, the influences of stability of surrounding rock under the corporate action of bearing stratum and basic support, numerical simulation of the relationship between bearing stratum and fundmental support, of course, the theorical analysis of the relationship between bearing stratum and fundmental support. The results of the study shows that the proper position of bearing stratum lies in the middle of tunnel, its proper length is 6m which exceeds its radius of plastic zone slightly, and its thickness is 600 mm which is 3/10, contrasted the radius of tunnel, besides that, also seeking that the existence of bearing stratum is good for the stability of surrounding rock while it is not the higher the better with the increasing of support strength, assess the coordinative relationship between bearing stratum and basic supporting system by different plans under the action of bearing stratum with fundermental support; in addition, get the formula of radius of plastic zone which has been modified and can be used as the relation between the bearing stratum and basic support, according to the former hypothesis. By the study of relationship between bearing stratum and basic support, understanding the coordinative relations between basic supports and bearing stratum, being good for controlling the deformation of surrounding rock through bearing layer with basic support simultaneously, in other words, it provides conditions for mataining the stability of surrounding rock in tunnels.