A method for qualitatively judging the water filling of caves in front of tunnels based on diffracted shear waves

Abstract

The invention discloses a method for qualitatively judging the water filling condition of a karst cave in front of a tunnel based on diffracted shear waves. An excitation point is arranged on the face of a subway tunnel to excite seismic shear waves; Three-component geophones; excite seismic shear waves in front of the face at the excitation point, and then each three-component geophone receives the feedback seismic data in real time and transmits it to the seismic recorder; performs interference wave elimination processing on the seismic data received by the seismic recorder , so as to obtain the diffracted shear wave data and direct shear wave data reflected by the cave; the obtained diffracted shear wave data reflected by the cave are migrated and imaged, so as to obtain the position information of the cave; by analyzing the energy of the diffracted shear wave and the direct shear wave The energy ratio can be used to qualitatively judge the water filling situation of the cave. Not only can the position of the cave in front of the tunnel be determined, but also the water filling situation of the cave in front can be judged qualitatively, so as to provide data support for the subsequent safe excavation of the tunnel.

Description

technical field [0001] The invention relates to a method for detecting a karst cave in front of a subway tunnel, in particular to a method for qualitatively judging the water filling situation of a karst cave in front of a tunnel based on a diffraction shear wave. Background technique [0002] The excavation of hard rock subway tunnels usually adopts the mining method. During the construction of the tunnel, the karst cave is the key channel for serious geological disasters such as water gushing, water and mud inrush, and caving. Therefore, in order to ensure the safety of subway construction, it is particularly necessary to carry out corresponding advanced forecasting during the excavation process of subway construction. The existing research results and on-site practical experience show that there is a lack of a reliable, effective and easy-to-operate method and means in detecting the water filling of karst caves. For example, due to the influence of complex urban traffic r...

AI Technical Summary

Problems solved by technology

Existing data show that diffraction shear-wave imaging can detect and identify important subsurface structural information, such as broken zones, faults, pinch-out points, small-scale intrusions, and other discontinuous geological bodies, but diffraction shear-wave imaging cannot directly Used in tunnels, the reason is that due to the influence of interference waves, the diffracted shear waves reflected by the cave cannot be extracted from the received seismic data, and thus the water filling situation of the cave ahead cannot be accurately detected, which ultimately affects the subsequent safe excavation of the tunnel.

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