Advanced detection apparatus and method for tunnel boring machine based on seismic waves from controllable seismic source

An advanced detection method for a tunnel boring machine based on seismic waves from a controllable seismic source, comprising the following steps:

• synthesizing, by means of delayed excitation of each electromagnetic controllable seismic source assembly, a wavefront excited by each seismic source assembly in the form of spherical waves into a beam surface, and adjusting a propagation angle of the wavefront through different delay lengths;
• when a forward propagation angle is θ, an excitation delay between each electromagnetic controllable seismic source assembly is calculated as follows:
• t
• =
• x
• ⁢
• sin
• ⁢
• θ
• v
• ;
• wherein t represents a delayed excitation time of a current electromagnetic controllable seismic source assembly relative to a previous electromagnetic controllable seismic source assembly;
• x represents a spacing between the electromagnetic controllable seismic source assemblies;
• v represents a wave velocity in surrounding rock;
• θ represents the propagation angle of the wavefront;
• a delayed excitation time of a first electromagnetic controllable seismic source assembly t=0s;
• and a delayed excitation time of an nth electromagnetic controllable seismic source assembly
• t
• n
• =
• ∑
• i
• =
• 0
• n
• ⁢
• t
• i
• ;
• receiving seismic records by three-component geophones, performing interferometric processing on seismic data from the controllable seismic source assemblies by means of cross-correlation, obtaining a wave velocity of direct waves through analysis, and creating a homogeneous initial velocity model based on the wave velocity result;
• removing the direct waves in interferometric seismic records;
• exciting seismic records at a seismic source assembly position of the obtained initial velocity model to obtain a forward-propagating wavefield;
• applying the actually obtained interferometric seismic records with the direct waves removed in reverse time at positions of the three-component geophones to obtain a reverse-propagating wavefield;
• and
• performing correlation stacking on the two wavefields to obtain a reverse time migration imaging result based on beamforming;
• an advanced detection apparatus for a tunnel boring machine based on seismic waves from a controllable seismic source, comprising:
• the electromagnetic controllable seismic source assemblies arranged on both sides of a working platform of the tunnel boring machine and comprising a telescopic push rod, a counterweight housing, an airbag, a support, a first base, and a second base, wherein the telescopic push rod is fixed on a side of the counterweight housing facing a rock wall;
• and
• both the counterweight housing and the airbag are fixed to the first base, the airbag is located on a side of the counterweight housing distal from the telescopic push rod, and the first base is fixedly connected to the second base via the support.