Study Of The Grouting Technique Of Jiaozhou Gulf Sub-Sea Tunnel In Qingdao

The experiences of other subsea tunnels built, high pressure water outburst is fatal accident. The groundwater inrush is high pressure , and the source is infinite. Drain , pumping and heighten the inner air pressure of tunnel are all inefficacious. Therefore, the basic method of groundwater control is grouting.This paper is based on the project of the QingDao subsea tunnel. Through synthetized the theory of strata grouting, and summarized the former experience, the author studied the advance grouting technique of the subsea tunnel. The following studies are included:1. The grouting technique of the hazardous zone, where the high pressure water can outburst, were studied. Emphases of studies were the strengthening range of grouting , choosing of grouting pressure, concreting time of grout, installing of the check system of grouting ,and construction technique of grouting.2.Through research of the erosion mechanisms of seawater to the grouting material, author studied the endurance of it, and then got the commonly principle of choosing grouting material. For the need of strengthening surrounding rock and preventing groundwater discharge, the author analysed with the performance of several grouting materials in laboratory and determined the pure cement slurry, MC slurry, water-glass slurry and HSC slurry as main grouting material in construction.3. Connected to the conclusion of the theory studies of steady-state seepage flow, and based on the numerical simulation analysis of different schemes of groundwater preventing and discharge, the conclusion is that the curtain grouting can be taken for minishing water percolating capacity of the tunnels. Adopting "Stop firstly, drain slightly" as the principle to design subsea tunnel is appropriate.