FEASIBILITY ANALYSIS OF PREFABRICATED CONCRETE SEGMENT LINING IN TUNNEL UNDER HIGH INNER WATER PRESSURE

With the special characteristics of fast tunneling,the double-shield TBM is suitable for long tunnel construction.But for pressure tunnel in hydropower engineering,the loading capacity of segment lining for tunnel under high inner water pressure is one of the keys to determine whether the segment lining is feasible and the double-shield TBM can be used for the tunnelling construction.Combined with the long pressure tunnel of the Qingsong Hydropower Project,the characteristics of deformation and stress distribution of segment lining are evaluated by calculation with 3D FEM;the important influential factors are analyzed;the stress and strain distributions in different conditions are obtained;and the knowledge for segment lining characters is deepened.It is found that the segment lining has the character of flexibility,and under the present technology of joint water-seal,as far as the Qingsong Hydropower Project is concerned,the segment lining can sustain the high inner water pressure.The conclusion is helpful for application of segment lining and double-shield TBM in hydropower engineering in China.