The Deformation Laws Of Surrounding Rock Of Maanziliang Tunnel And The Structural Safety Study Of Initial Support

The study on surrounding rock deformation of highway tunnel and initial supportingstructure safety are valuable for the tunnel construction under complex condition.This papertakes researches on the Ma Anzi-liang highway tunnel project. The research. adopted themethod of combinning theoretical analysis, support design, numerical simulation and fieldmonitoring The main results are as follows:（1）The main factors analysis of surrounding rock deformation.in Ma Anzi-lianghighway tunnel have been completed The results show that the influence factors ofsurrounding rock deformation have three aspects such as classification of surrounding rock,crustal stress and construction factor aspects. The construction factors are influenced bymethods of excavation, support structure, adjacent to construction effect.and so on.（2）The initial support parameters design of IV surrounding rock in Ma Anzi-lianghighway tunnel are completed by engineering analogy and theoretical calculation. This paperhas studied rationality of initial support parameters of IV surrounding rock under differentexcavation methods and different depth.through FLAC^3Dnumerical simulation. The resultsshow that keeping the core subsoil are reasonable excavation methods for IV surroundingrock tunnel. And different depthes had large influence on initial support parameters.（3）This paper completed the on-site monitoring scheme design and study. Deformationcharacteristics of tunnel surrounding rock are studied by using the deformation curves,deformation velocity curve, and the deformation and acceleration curve. This paper hasstudied relationships among surrounding rock classification, stability time and value bystatistical methods The deformation law of surrounding rock in Ma Anzi-liang highwaytunnel is obtained. The tendency of actual value and FLAC^3Dpredicted value are.basicallyidentical by comparing the field measurement data and numerical simulation results.（4）The safety evaluation of initial support of steel concrete is finished through thetheoretical calculation and numerical simulation methods. The results show that, the initial support safety coefficient decreasesing as the steel arch frame spacing increasesing, during thesame burried depth. The reduce range is not too big. The initial support safety factor relativelyreducing. as burried depth increasesing during the same steel arch frame spacing. The initialsupport effect of steel reinforced concrete is very obvious, and the safety factor of initialsupport is not less than2, then it means the shotcrete is safety and the safety factor isconservative.