Study On Stability Property & Load Characteristics Of Tunnel In Jointed Rock Mass

In the process of designing tunnel structure and tunnel support, rock pressure ability must be defined firstly, which is applied to tunnel structure. Presently, rock pressure in complete rock mass and loosening rock mass has been researched profoundly and thoroughly; and the correlative theories being used to solve the tunnel-load problem have been formed. However, there is still a lack of research on rock pressure in fractured rock mass. Strictly speaking, it is rare to see the complete rock mass and loosening rock mass in nature, but fractured rock mass is much more common. And the nature as well as the character of structural plane in fractured rock mass is the major reasons determining the property of rock pressure and stability of tunnel.In this thesis, the theory and conception of rock mass structure have been introduced firstly in the respective of rock mass's structural mechanics. Afterwards, the character and classification of structure plane as well as structure body are presented. Fractured rock mass, especially layered rock mass formed by volume joint and breaking rock mass formed by multi-volume joints, is regarded as principal subject, which is then investigated by Distinct Element Method and its software UDEC, the tools adapted to research discrete mediator. As to this investigation, the steps are divided into several steps as follows: firstly, under the condition of excavating tunnel in fractured rock mass, the distribution characters of Second stress and stability of tunnel with no support are studied; Secondly, the distribution of rock pressure ceased by excavation in the uneven pressure rock mass formed by volume joint, has been analyzed. And parameter sensitivity analysis of structural plane which cease the distribution of rock pressure also has been studied as an emphasis. Based on those two analyses, the relationship between the parameter of structural plane and the stability and uneven pressure of tunnel are obtained, verified by an item as well. At last, the discussion is made about the relationship between the parameter of structural plane and the distribution characters of rock pressure in cracking rock mass formed by multi-volume joints. Based on the comparison between the numerical modeling results and rock pressure calculation, the proposals are made to point out the theoretical arithmetic methods of the tunnel rock pressure and stability in fractured rock mass.In this thesis, the exploratory research on distribution regularities of rock pressure and stability of tunnel in fractured rock mass has been done through numerical modeling. At the same time, some reference suggestions have been offered for analogous tunnel construction.