Abstract:

Aeolian sand is a kind of unstable surrounding rock with low cohesion and poor self-stability, which brings great difficulties to tunnel design and construction. Hence, field measurement experiments are carried out on Wangjiawan Tunnel on Menghua Railway to explore the pressure and distribution law of surrounding rock in aeolian sand. The calculation model of the surrounding rock pressure of deep aeolian sand tunnel is obtained based on the distribution characteristics of surrounding rock pressure, and its rationality is verified by numerical analysis and field measurement data. The research results show that the distribution of surrounding rock pressure in deep aeolian sand is very uneven, but generally small at arch, and most of the primary support is under pressure. The calculation analysis results show that the Terzaghi theory is more rational in calculating tunnel surrounding rock pressure. The vertical surrounding rock of aeolian sand tunnel shows a double-peak shape, and the horizontal one shows a gradual increase shape. The calculation diagrams obtained are safer than the traditional mode of the railway tunnel design specification, which are more in line with the actual lining stress state.

Key words: deep aeolian sand tunnel, surrounding rock pressure, primary support, field monitoring, load distribution