Practical application of water pressure test in deep shaft construction of tunnel

Owing to the number of water-bearing layers is more and thicker, and the fracture zone is more and the geological structure is extremely complicated in Gaoligongshan Tunnel deep shaft, there have a risk of water inrush during excavation process.After pre-grouting to the deep shaft surface with hydraulic pressure test inspection of surface pre-grouting technological achievements, the hydraulic pressure test is conducted through seal the water by stopping the slurry plug, pressure the water in stages, by adopting the variable speed regulating pump that meets the requirements of pressure water flow test parameters to adjust the pressure water flow to realize multi-stage pressure water test, besides, combined with the hydraulic pressure test method of vertical shaft surface pre-grouting effect, this method is applied to the surface pre-grouting construction of Gaoligongshan Tunnel deep shaft.The results show that the hydraulic can also calculate the permeability coefficient of aquifer and residual water inflow of wellbore accurately and can effectively inspect the surface pre-grouting during the construction of the ground pre-grouting of tunnel deep shaft with unusually complicated hydrogeological conditions.The results prove that the hydraulic pressure test is a scientific and effective method to test the effect of surface pre-grouting in deep tunnel shaft which could also be applied in the non-coal field with more and thicker aquifers, unusually complex geological structures and broken zones.