KEY TECHNOLOGIES FOR TUNNEL CONSTRUCTION IN WATER RICH SAND IN GROUND OF SOIL AND ROCK STRATA

Qingdao has a water rich sand in the ground comprising soil and rock strata. This paper analyses the advanced deep hole grouting and curtain grouting reinforcement technique in the soft hard formation under tunnel construction. It uses field monitoring and excavation sampling analysis for their applicability in formation combining soil and rock strata. The results show that when the advanced deep hole grouting is used in water rich sand layer in the tunnel vault, the grouting effect is difficult to control, the vaults, the nearer the sand grouting effect is more difficult to master, the more serious the tunnel leakage. Construction is easy to bulge on the formation and the tunnel seepage more. When the sand layer in the vault above by curtain grouting, monitoring results show that hole deformation and surface subsidence can be controlled within the effective range. Grouting effect and workers' technology demand are higher. For rock combined with rich water sand, soil excavation can use the loose blasting technique, which makes reinforcement strata to form part of the leaking channels.