Application of horizontal directional drilling technology in grouting and water blocking of deep buried tunnels in water conservancy and hydropower

Abstract

When excavating deep buried tunnels in complex and fractured formations, how to quickly and effectively solve common problems such as leakage and water inrush has become the focus of ensuring tunnel safety and effective excavation. The construction of a certain water conservancy tunnel was taken as the engineering background, measures the water inflow, water inflow points and other data, combined with long-distance directional drilling technology. Four grouting holes are arranged on a hole layout circle with the tunnel axis as the center and a radius of 7.02 meters. The horizontal section is parallel to the tunnel axis and the minimum distance from the tunnel contour line is 2.5 meters. Advance pre grouting is carried out through bidirectional directional long drilling on the ground. The result show that the permeability rate is not more than 3 Lu, and the water output of the tunnel excavation treatment section is not more than 147 m³/h. The treatment effect is obvious. From this, it can be concluded that compared with traditional ground vertical hole curtain grouting and palm face cyclic grouting processes, this grouting technology reduces the number of boreholes, improves grouting efficiency, controls grouting range, saves grouting materials and construction period, creates favorable conditions for safe tunnel excavation, and has certain reference significance for similar tunnel water blocking treatment.

Keywords

water conservancy and hydropower / tunnel / directional drilling / ultra long drilling / grouting