Study On The Support Structures' Reliability Of Deep Buried Tunnel In Soft-weak Surrounding Rocks

With the development of China's national economy, road passenger and freight transport increase rapidly, and highway is becoming the mainstream of transport industry in China. for its special advantages, tunnels are widely used in engineering now, which is producing more and more good benefits to society and economy. However, the environmental conditions about the support structure of tunnel are so complex, that it is hard to figure out the physical and mechanical performances clearly. Therefore, the design of support structures of tunnel becomes technologically difficult. That is why probability theory and mathematical statistics become increasingly important in the study of reliability of the support structures at its limit state.In this paper, we based on the support structures'working mechanism of deep buried tunnel in soft-weak rock, and combined with the monitoring data of Luo Ping Tunnel, according the literature of reliability theory results to select load effect and structural resistance for random variable, and established the function of tunnel support structure, using the principles of structural reliability analysis to study on support structures'reliability of deep buried tunnel in soft-weak surrounding rock. The main works can be drawn as follows:â‘ Compared with the advantages and disadvantages of current methods in structural reliability analysis of the first order second moment method, higher order moment method, stochastic finite element method, Response Surface Method and of the Monte Carlo Method, combined with the reliable analysis'characteristics and choused the appropriate method to analyze the support structures'reliability of deep buried tunnel in soft-weak surrounding rock.â‘¡According to the data of convergence and vault settlement by site monitoring at typical cross section of deep buried tunnel in soft-weak surrounding rocks. Analyze the uncertainties under similar surrounding rock conditions and using the same support parameters which led to deformation of the initial support very different.â‘¢Modeling and analysis by ANSYS software, based on the code for design of road tunnel and site monitoring results, to set aside as a deformation displacement control conditions, established a initial supports'structure function of deep buried tunnel in soft-weak surrounding rocks; Besides, based on the calculation of eccentric compression resistance compressive strength and tensile strength, established the structure function of secondary lining too.â‘£Based on the technology of PDS in ANSYS software, compile the process of initial support secondary linings'reliability analysis by APDL, and consider the relevance of some random variables. Analyze the effect, reliability and sensitivity of supporting structure by Latin hypercube sampling of Monte Carlo method, and calculating failure probability and reliability index of tunnel support structure, and find out the major factor which caused failure of tunnel support structure.