Study On Suitability Of Flat Ratio And Support Parameter Of Large Section Highway Tunnel

In recent years,with the rapid development of China's economy,the "urban disease" phenomenon in the process of urbanization has been puzzling the people's daily life.In order to solve the congestion problem,the number of the newly-built municipal roads is increasing.Thus,large section highway tunnels with lower high-span ratio,larger span emerge as the times require and showing a trend of rapid increase.Since the choose of the high-span ratio and the support parameter is frequently study from similar engineering experience at home and abroad at present,there is no set of mature technology for reference.The utilization,rationality and reliability of the high-span ratio and the support system,whether it is applicable to the project,are worth researching.Therefore,it is necessary to carry out the research on the suitability of the high-span ratio and the support parameter of municipal roads with large sections.This paper based on the Maluan mountain tunnel,according to the methods of statistical analysis,numerical simulation,laboratory experiment and field monitoring,systematically study the suitability of the high-span ratio and the support parameter of municipal roads with large sections.The main results are as follows:(1)The present high-span ratio and the support parameter situation at home and abroad are investigated.According to the survey data,the design characteristics of large section tunnels with small high-span ratio are analyzed and summarized.Based on the design data of the support project,the rationality of the high-span ratio and the support parameter of the support project are preliminary evaluated.(2)Based on comprehensive investigation of large section tunnels with small high-span ratio and specific project,according to the research methods of numerical simulation,laboratory experiment and others,the research on the stability of the surrounding rock-support system of the large section highway tunnels under different high-span ratios and support parameters was carried out.This paper focuses on the stress of the surrounding rock-support system,the evolution characteristics of the displacement field,the stress characteristics of the support system,etc.The mechanical behavior characteristics of surrounding rock-support system of the large section highway tunnels under different high-span ratios and support parameters are revealed.The rationality of the high-span ratio and the support parameter of the large section municipal roads are studied.(3)Based on the numerical simulation,laboratory experiment,coupled with present characteristics of high-span ratio and support parameter of large section municipal roads,the reasonable high-span ratio and support parameter ranges for large section municipal roads under different surrounding rock grades are put forward.Thus,the original design of the support project can be optimized.