Method for measuring depth of loose ring of deeply-buried columnar jointed rock tunnel

Abstract

The invention provides a method for measuring the depth of a loose ring of a deeply-buried columnar jointed rock tunnel. The method comprises the steps that firstly, holes are formed in the rear portion of a tunnel face of the tunnel and used for installing Bragg fiber grating sensors; the interface of the loose ring of the deeply-buried columnar jointed rock tunnel is measured according to readings of the Bragg fiber grating sensors, and then the depth of the loose ring is obtained; fracture pressure and reopening pressure of cylindrical surfaces on the two sides of the interface of the loose ring are measured through a cyclic pressure water test method; by analyzing the difference value of the measured fracture pressure and the measured reopening pressure, the depth of the loose ring of the columnar jointed rock tunnel is further determined accurately. The method is combined with a testing method to conduct correction mutually, data measured by the grating sensors are monitored and analyzed by means of the optical principle, and measured data are accurate, intuitive and easy to distinguish; furthermore, the loose interface and depth are determined accurately according to data, measured by the grating sensors, of the loose interface and depth of the columnar jointed rock tunnel through pressure water testing.

Description

technical field [0001] The invention relates to a method for measuring the depth of the slack circle of a deep-buried columnar joint rock mass tunnel, which is mainly applicable to the columnar basalt surrounding rock cave sections of deep-buried traffic tunnels and hydraulic tunnels. Background technique [0002] Columnar jointed rock mass is a special type of rock mass. After volcanic eruption or surface overflow, basalt forms uniformly distributed irregular hexahedral columns in the process of condensation and contraction. The measurement of the relaxation depth of the surrounding rock in the section will be affected by the irregular cylinder, so the conventional wave velocity measurement structure faces the problem of insufficient applicability, and the relaxation depth is particularly important for the design of the bolt length, and it is necessary to measure the relaxation through a suitable measurement structure Depth, design a reasonable length of anchor. Contents ...

AI Technical Summary

Problems solved by technology

[0002] Columnar jointed rock mass is a special type of rock mass. After volcanic eruption or surface overflow, basalt forms uniformly distributed irregular hexahedral columns in the process of condensation and contraction. The measurement of the relaxation depth of the surrounding rock in the section will be affected by the irregular cylinder, so the conventional wave velocity measurement structure faces the problem of insufficient applicability, and the relaxation depth is particularly important for the design of the bolt length, and it is necessary to measure the relaxation through a suitable measurement structure Depth, design a reasonable length of bolt

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