Method for measuring wave speed of rock mass in front of tunnel face in tunnel

Abstract

The invention discloses the technology to explore palm surface frontage geology and measure frontage rock rolling velocity using reflection in the tunnel and underground engineering. It sets up two intersecting measuring lines in the palm surface, and sets up a measuring point at each certain distance on the line, and each measuring point makes the small shock - distance measuring or the excitation and reception of the small transmitter-receiver distance, and then, by unitary method, the time curves of each measuring point converge to a time profile. With the time profile, when the reflection of each reflector surface corresponding reflecting the axis and each measuring point, it determines each reflector surface, and if the rock rolling velocity known, it calculates the position of each reflector surface according to the reflection time of the measuring points. In the rear sidewall of the palm surface, sets up the measuring lines, and many measuring points on it, to measure the reflection time of each point from the reflector surface. Assuming the rock rolling velocity, according to the measuring point reflection time measured in the palm surface, calculates the invented reflector surface space position, and calculates the reflection time of sidewall measuring points to invented reflector surface under the rolling velocity assumption, and compared with the practical measuring reflection, then to adjust the assumed rolling velocity value, and gradually approaching, to obtain the closest actual rolling velocity value.

Description

technical field [0001] A method for measuring the wave velocity of the rock mass in front of the tunnel face in a tunnel. The invention relates to a method for measuring the wave velocity of the rock mass in front of the face of tunnels and other underground projects when exploring the geology ahead. Specifically, it uses the reflection method A technical method for measuring the wave velocity of the rock mass in front of the tunnel face. Background technique [0002] Among the geological prediction methods in front of the tunnel face currently in use, the reflection methods include the seismic reflection negative apparent velocity method (tunnel VSP), TSP, HSP, land sonar and other elastic wave reflection methods, and ground penetrating radar. and other electromagnetic methods. They all calculate the spatial position of the reflector by measuring the reflection time t of the reflector and the wave velocity V of the rock mass: [0003] Distance d=Vt / ...

AI Technical Summary

Problems solved by technology

But when the reflective surface is not parallel to the tunnel surface (the reflective surface is not perpendicular to the measuring line), because the occurrence of the reflective surface is not known, it is a result to be obtained according to the wave velocity and other parameters, so the accurate measurement of the wave velocity of the rock mass is not yet possible. value

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