Research on the zoning of homogeneous areas of tunnel surrounding rock based on horizontal directional drilling

Abstract:

This paper relies on the horizontal directional drilling project in the preliminary investigation stage of the expansion and reconstruction project of the Lion Rock Tunnel in Hong Kong. Based on the engineering geological data， borehole television images， acoustic wave data， and water pressure test data， a method combining qualitative and quantitative analysis is adopted to explore its application in the zoning of homogeneous areas. The optical imaging of borehole television makes up for the deficiency in obtaining the dip angles of the fracture orientations when the rock is fragmented. Acoustic logging and water pressure tests provide data on the integrity and permeability of the rock mass. The joint zoning of homogeneous areas using multiple methods helps to improve the accuracy and reliability of the classification of tunnel surrounding rock. The experimental results are highly consistent with the actual situation， demonstrating that the comprehensive geophysical exploration method can efficiently detect the development of stratum fractures， and the method for zoning homogeneous areas of the surrounding rock is accurate， providing technical support for engineering investigation.