STUDY OF EXCAVATION METHODS OF HIGH-SPEED RAILWAY TUNNEL IN THE WEAK SURROUNDING ROCK

摘要

With the development of mountain tunnels in high speed railway in China, the choice of tunnel excavation methods plays a more important role especially when tunnel passes throng the weak surrounding rock. In this paper, the finite difference analysis is used to study the deformation features of surrounding rock caused by tunneling excavation, and the deformations of CD method, CRD method, twin-side heading method and three-bench seven-step method are compared. In order to make further research, the twin-side heading method and the three-bench seven-step method are used simultaneously in the weak rock of Xikema 1# tunnel in high-speed railway of Beijing to Shanghai. The finite difference analysis and the measured data point out that the settlement of the three-bench seven-step method is less than 30mm, but this method is more efficiency than the twin-side heading method.From the research of the paper, we conclude that the three-bench seven-step excavation method is more efficient than other methods in the control of construction period. At the same time the three-bench seven-step excavation method can meet the need of the settlement control in weak surrounding rock of mountain tunnel of high speed railway. The threebench seven-step excavation method is worth using widely.