Study On The Working Mechanism Of Pipe Umbrella Reinforcement In Weak Surrounding Rock Mass Tunnel

Along with the China west develop carrying in a deep-going way, the construction pace of infrastructures is accelerated. But the mountainous and lack of wolds make the complex of the geology character. The railway and the road tunnel through this zone must have the main parts in the weak and broken area. Barrel vault advanced support technology with its remarkable advantage, which was proved in the mountain tunnel, will be to apply broadly more.At present, the barrel vault advanced support technology is widely applied and developed in the tunnel and underground project. The underground engineering technician is also familiar with this technology. But the two advanced support technology of the Pipe-roof protection is not accurate in their mechanics behavior, the most suitable surrounding rock condition and the rationality design and construction, which make worthy to do thorough research.The barrel vault advanced support technology's effort was mainly studies by 2-D finite element method (FEM) at home. 3-D FEM analysis paper is seldom found in this area. The only 3-D analysis is an equivalent simulation to the function of the Pipe-roof protection, but it can't research on the mechanics behavior being under construction. It is not only composite support structures' full simulations are required but also the completely process of the construction is needed to 3-D analysis to fulfill the behavior and to test and verify the design parameter's reliability. But these works are rarely done.This paper did a thorough research on the pipe-roof advance support by study on the barrel vault advanced support technology, mechanics behavior being under construction and construction method, especially when do the mechanical simulation of the pipe-roof advance support, combining the composite support structures, which means anchorage, shotcrete and pipe-roof and the construction process. The mechanical behaviors of the pipe-roof advance support during the construction process were obtained which have provided a new thought to the barrel vault advanced support technology in design and research.