Influence Investigation Of Tunneling Methods On Structure Stability Under Weak Rock-mass Condition

With the rapid development of national infrastructure construction,mountainous highway construction scale has been expanding,the construction technology level is also rising.As a key link in the construction of mountainous expressway,the quality of tunnel support has gradually become an important factor affecting the overall quality of mountainous expressway.The economy,rationality and safety of the supporting structure have gradually become the core of theoretical research and construction practice.content.In the construction of tunnel engineering,the project cost,the overall stability of the project will be affected by the stability of the surrounding rock and the stability of the support structure,which is the key to the construction of the tunnel.In this paper,the Zhangping tunnel of Chengxian to Wudu expressway is taken as the empirical object,and the numerical simulation of Midas NX tool is used to systematically study the construction scheme of tunnel supporting structure.The concrete research contents are as follows: Firstly,the construction scheme of the surrounding rock of the inlet section ? of Zhangping tunnel is analyzed and analyzed by numerical simulation tool.The advantages and disadvantages of the whole section method,the upper and lower ditch excavation method are compared and the latter The feasibility of the construction is used to improve the stability of the surrounding rock and the support of the tunnel.Then,the loosening of the tunnel is taken as the object of study,and the stress of the excavation,support and secondary lining are analyzed.The results show that,regardless of the construction scheme,the results of the displacement of the surrounding rock are manifested as the uplift of the surrounding rock in the arch area,the subsidence of the surrounding rock in the vault area,the surrounding rock of the side wall and the arch area.Compared with the upper and lower ditch excavation method,the front arch and the dome sinking are weaker than the latter,but the external wall of the former and the arch area are obviously stronger than the other the latter.For the convergence law of the vault,the measured data and the numerical simulation are consistent,but there are some deviations in the numerical value.This is because the numerical simulation can not be completely consistent with the actual situation,so it does not affect the final research conclusion.