Research on rock mass structure classification of adit based on 3D block index

Abstract

This article takes the long exploratory tunnel CPD1 of the water transmission and power generation system of Qingtian Pumped Storage Power Station in Zhejiang Province as the research object, and conducts a study on the classification of flat tunnel rock mass structure based on three-dimensional joint network simulation. Based on the grouping distribution of joints, statistical homogeneous zone segmentation is conducted, and a three-dimensional joint network model is generated based on statistics and probability, with each segment as a unit. On the front, side, and top surfaces of the 3D joint network model, virtual survey lines are arranged along the centroid and other angles to represent drilling holes. The RBI values of 108 virtual survey lines on three orthogonal planes are calculated, and the 3D block index of the rock mass is used to refine the classification of the rock mass structure in the adit. The results indicate that the rock mass structure type of CPD1 in the long exploration tunnel is from overall to block structure, with integrity ranging from complete to relatively complete.