Stability Of Surrounding Rocks And Dynamic Feedback Analysis For Heishan Tunnel Of Zhang-Zhuo Highway

Stability of surrounding rock during construction is the important factor considered by engineers. As the important and difficult project in the Project of Zhangjiakou-Zhouzhou highway, Heishan tunnel belongs to typical shallow-buried tunnel with soft surrounding rock, which is characterized by severe geological condition, long excaviation distance and great excavation section. During construction, loess, mixed soil with loess and crushed rocks always accompany along the tunnel. Contractor has to face such soil and rock with large deformation, low strength and collapsing.Generally, the main work contents of the paper are showed as follows:(1) Traditional triaxial tests are used to carry out study on mechanical properties of dolostone, and then the relationship between compressive strength and surrounding pressures will be determined. At the same time, the index of strength and deformation will be obtained based on the analysis of tests results.(2) Based on real time information measured of the typical monitoring section of tunnel, stability and deformation rate of surrounding rock are analyzed carefully. Furthemore, the optimal interval time between primary support and secondary support and two stages of construction can be given by measured values from field test.(3) Relationship between stability and mechanical parametes of surrounding rocks can be determined by systematical method. On the basis of Neural Network and Genetic Algorithms, the parameters of surrounding rocks can be given, and the important factors can be adjusted and analyzed in details. Then, the different supporting measures will be compared comperhenively.