Researches On The Condition Of Cavitation Of Unlined Diversion Type Pressure Tunnel And The Stability Of Surrounding Rock

In the hydraulic engineering,the circulate appearance of diversion type pressure tunnel to directly influence normal usage and economic benefit of the whole engineering. The diversion type pressure tunnel belongs to long line structure, it will through different sector in the process of excavation and various geologic environment condition will be have. It requests that we combine the environment which diversion type pressure tunnel place to analysis the surrounding rock, to investigate it's appearance and take it to the reference for whether or what kind of lining we will applied to.It's different between diversion type pressure tunnel and traffic tunnel. In regard to its usage function among the circulate period of tunnel, any is good in the property and inside the simple environment of rock mass for tunnel, also the coupling effect will not break the surrounding rock and the permeation unlikely influences to generate electricity usage, then we can choose unlined for the tunnel's cross section. Under the premise satisfied to normally use, this kind of performance output performance is considerable. Currently, domestic and international still not mature to the researches of this aspect,it's seldom to see the researches of whether we will set lining to the tunnel. This paper from commence to a few aspects which had already pressed the diversion type pressure tunnel surrounding rock stability to result in to influence more and greatly, investigate their influence effect produce, use this as the tunnel's cross section lining or not of reference. Concrete device and related conclusion are as follows:â‘ T emporary take no account of the action of groundwater, solve the tangential stress values of key points in the diversion type pressure tunnel's surrounding rock. Carry on a comparison with rock mass strength and initial certain the work condition of the software simulation sphere. Imitate tunnel's excavation later on, then computing the displacement value and carry on contrast with the biggest allowable strain value, therefore,we can make sure the stability of the surrounding rock which is under the different work conditions.â‘¡In the second step, we can check the surrounding rock which have been influenced by the internal water pressure when temporary take no account of the action of groundwater. Seeing the stream in the surrounding rock as a laminar flow, solve the Laplace equation under this condition, and we can beg the distributions of head pressure in the surrounding rock during the process of the internal water leak through by combine to the condition of boundary. Certain the tunnel's minimum cover up deeply then simulation to the tunnel which under the maximum internal water pressure by combine to the boundary condition. Analysis the result of simulation, we can see that the shallow of depth of burial isn't suitable for adoption unlined form of the diversion type pressure tunnel.â‘¢Investigating the stability of the surrounding rock which is influenced by groundwater before the tunnel operate. It is the same that to solve the distribution of groundwater's head pressure and when the tunnel was influenced by internal water. Then simulate the condition of the tunnel by software which named FLAC . For further, we can get the work condition sphere of adoption unlined form of the diversion type pressure tunnel based the condition which certain above.â‘£Analysis the stability of surrounding rock which influenced by the ground- water,internal water and the afresh distributed stress during the period of usage. And proposes the condition of unlined of the diversion type pressure tunnel which is suitable to the paper's background engineering.Based on the theoretical analysis and numerical simulations , this paper systematically conducts the research on the utilization of the unlined cross section under pressure of diversion type pressure tunnel. According to their different work conditions and different operational period of stability, thus this paper proposes the condition of unlined of the diversion type pressure tunnel which is suitable to the paper's background engineering. The results are typical, therefore, can provide certain information for the specific practical engineer activities.