Weak Rock Tunnel Bias Characteristics And Construction Control Technology

This paper is carried out on the study of soft surrounding rock in Huang-Qu-Nan Highway bias tunnel and tries to make some researches on the characteristics and control technology.On the basis of comprehensive research, summary and analysis, this article brings forward the construction technology of soft surrounding rock bias tunnel. The main research contents and results are as follows:At first, this paper tries to provide useful experience for similar projects by case investigation, analysis on the forming cause of bias tunnel and control measures and so on.Next, this paper offers the relatively theoretical foundation for the control measures of tunnel bias by applying numerical simulation and establishing calculation under different conditions calculated to study the surface inclination, depth, rock-level as, the affects of the tunnel excavation method on bias tunnel as well as the influential factors.Thirdly, this paper obtained the critical bias ply of different levels and slope surrounding, and the relations between critical bias ply and buried depth, surface Angle and the surrounding rock level according to the related standards and pullman's theory; then analyzed the relationship and the laws between surrounding rock stress, destroy numerical range and surface obliquity, buried depth and surrounding rock level which provides theoretical basis for the design and construction of the bias tunnel. Combined with these research and bias tunnel cases, the paper analyzed the mechanism and applicable condition of the bias tunnel control measures and summarized the construction procedures and construction principles of bias tunnel.In the end, this paper gives a demonstration of the feasibility of taking the bias control measures on the Soft Adjacent Rock of tunnel, and then points out the location of vital importance during construction, including some construction suggestions based on the practical engineering.This research result has been applied successfully to the construction of Soft Adjacent Rock in Huang-Qu-Nan Highway bias tunnel, safely guaranteed the tunnel construction and furthermore enriched the research achievements of soft surrounding rock highway bias tunnel.