A combined ground-hole-cavity fine detection method and system

Abstract

The present invention provides a combined ground-hole-cavity fine detection method and system, which arranges a detection and observation method for the rock-breaking seismic source of a tunnel boring machine in a combined ground-hole-cavity manner and performs time synchronization and spatial positioning; when the tunnel boring machine starts to work, the detection devices of the ground-hole-cavity synchronously collect and store signals; after the data collection is completed, the parameters during the tunneling process of the tunnel boring machine and the data collected by the receiving station array are processed to obtain the velocity model and seismic profile of the area in front of and around the tunnel; according to the obtained velocity model, seismic profile, and in combination with the spatial distribution of the excavation rock strength index and geological borehole data, the geological conditions of the rock mass in front of the working face of the tunneling machine and around the tunnel are known, realizing the early prediction of geological anomalies. The present invention can obtain the distribution of bad geological bodies in front of the tunnel boring face, can predict the quality grade of the rock mass in front of the drilling and timely detect the bad geological bodies in front of the tunneling face.

Description

Technical Field

[0001] The present invention belongs to the technical field of seismic wave method detection in advance geological prediction of tunnel construction, and particularly relates to a combined fine detection method and system for ground-hole-cavity. Background Technique

[0002] The statements in this part only provide background technical information related to the present invention, and do not necessarily constitute prior art.

[0003] The requirements for the construction quality, efficiency and safety of underground projects such as tunnels are getting higher and higher. Compared with the traditional drill and blast method, the construction of tunnel boring machines has the advantages of high mechanization degree and high construction efficiency, and the application of tunnel boring machines is becoming more and more extensive. However, the construction of urban underground projects faces complex and changeable geological conditions. If the geological conditions ahead are not explored in advance and disposed of in advance, disasters such as ground collapse, surface building overturning, and abnormal damage to tunnel boring machines are likely to occur under construction disturbances, resulting in construction delays, adverse environmental impacts and casualties, etc. Therefore, adopting advanced detection technology to timely detect the bad geological bodies in front of the tunneling face and formulate reasonable treatment plans and construction plans is an effective method to avoid disasters during the construction of tunnel boring machines.

[0004] In recent years, geophysical advanced prediction methods have been increasingly widely applied in tunnels constructed by tunnel boring machines. Among them, the seismic wave method has become one of the most widely used advanced prediction methods in tunnel boring machine construction tunnels due to its advantages such as high interface imaging accuracy and long detection distance. Applying the seismic wave method to the interior of tunnels requires improving the traditional seismic wave method to make it suitable for the special environment of tunnel construction. Swedish scholars such as B. Brodic proposed using ground and tunnel observation methods to conduct first-arrival tomography of transmitted waves and detect the location of fault zones. However, this method has the disadvantage that it can only obtain the formation information between the upper part of the tunnel and the ground surface and has a poor response to the information in front of the tunnel boring face. In the early 1970s, crosshole seismic technology was introduced into the oil and gas exploration and development field, that is, a seismic exploration method that is excited in one well and received in another well or multiple wells. This method has high computational efficiency in detecting formation geological structures, but has insufficient lateral resolution and poor ability to depict the boundaries of abnormal bodies. The monograph "Vertical Seismic Profile Technology" published by Academician Galperin (1973) laid the foundation for the development of VSP technology. This method can obtain rich azimuth and source-receiver offset information, effectively improve formation illumination, and has obvious advantages in vertical resolution. Shandong University proposed introducing the seismic-while-drilling technology in oil drilling into tunnel advanced prediction, using the rock-breaking signal of the tunneling machine as the seismic source and receiving simultaneously inside the tunnel and on the ground surface to form a ground-tunnel joint detection method, which can image the seismic wave velocity of rock masses in a large area in front of the tunneling face. However, this method can only obtain the reflection information of bad geology in front of the tunnel boring face and can only obtain and utilize the bad geology information at specific angles, which is not conducive to accurately imaging the bad geology in the target area in a full view and from multiple angles. Using the rock-breaking vibration of the tunneling machine as the seismic source can collect relatively rich surface wave information on the ground surface. Compared with obtaining surface wave signals using surface active sources, the seismic data collected by the tunneling source has a wider frequency band and more developed high-order modes, so more accurate underground structure information can be obtained.

[0005] In summary, the above several methods have their own advantages and disadvantages respectively. In this regard, by deeply combining the above several methods, using the surface, tunnel, and boreholes to collect multi-perspective and multi-wavefield seismic information, and depicting bad geology such as boulders and karsts underground from multiple angles, more accurate and high-quality geological conditions can be obtained. However, due to the special construction environment of urban underground tunnels, there are currently no relevant methods and technologies. At the current technical level, there are the following problems in fusing and utilizing the data of the three observation environments to achieve tunnel advanced prediction:

[0006] (1) Difficulty in time synchronization of multi-field seismic measurements: Precise time measurement is an important basis and condition for detection. To comprehensively utilize multi-wavefield seismic information on the surface, in the tunnel, and in boreholes, the acquisition times under the three conditions need to be precisely synchronized. Currently, there is no time synchronization system for relevant application conditions;

[0007] (2) Difficulties in observing the responses of poor geological conditions in the target area: Limited by the construction environment and observation space, the geophones inside the tunnel, on the ground surface, and in boreholes are mostly arranged in one dimension, and the acquisition of wavefield responses of poor geological conditions is incomplete. A specific observation system can only collect wavefield responses with specific characteristics.

[0008] (3) Difficulties in separating wavefields from multi - perspective wavefield data: The construction environment of urban underground tunnels is relatively complex, and a large amount of interference noise is coupled in the collected seismic records, suppressing the identification of effective information. It is difficult to extract effective signals from multi - perspective wavefield data.

[0009] (4) Difficulties in jointly imaging multi - perspective wavefield data: The spatial positions of data acquisition for multi - perspective wavefield data are different, and the wavefield characteristics of poor geological bodies reflected by the data also vary. Surface waves and body waves cannot be directly jointly utilized. Currently, there is little research on the joint application of multi - perspective wavefield data and various wavefields, and the method of jointly imaging multi - wavefield data is not yet mature. Summary of the Invention

[0010] To solve the above problems, the present invention proposes a ground - borehole - cavity joint fine detection method and system. The present invention can obtain the distribution of poor geological bodies in front of the tunnel boring machine, and can predict the quality grade of the rock mass in front of the tunneling and timely detect poor geological bodies in front of the tunneling face.

[0011] According to some embodiments, the present invention adopts the following technical solutions:

[0012] A ground - borehole - cavity joint fine detection method, comprising the following steps:

[0013] Arrange the detection and observation method of the rock - breaking seismic source of the tunnel boring machine with ground - borehole - cavity joint and perform time synchronization and spatial positioning.

[0014] When the tunnel boring machine starts to work, the detection devices of the ground - borehole - cavity synchronously collect and store signals.

[0015] After the data acquisition is completed, the parameters during the tunneling process of the tunnel boring machine and the data collected by the receiving station array are processed to obtain the velocity model and seismic profile of the area in front of and around the tunnel.

[0016] According to the obtained velocity model, seismic profile, and combined with the spatial distribution of the excavation rock strength index and geological borehole data, learn about the geological conditions of the rock mass in front of the tunneling machine working face and around the tunnel, and realize the early prediction of geological anomalies.

[0017] As an alternative implementation, the specific process of arranging the geophone source detection and observation method for the combined ground-hole-cavity tunnel boring machine includes: installing the pilot receiving station array of the rock-breaking source on the support plate behind the cutter head, arranging the tunnel receiving station array in the middle of the tunnel boring machine body or on the surrounding rock of the tunnel sidewall, arranging the surface receiving station array on the ground above the traveling route of the tunnel boring machine body, quickly arranging the surface receiving station array at a certain trace interval, and connecting the receiving station arrays of geological boreholes under far-hole conditions and near-hole conditions to an external power supply.

[0018] As an alternative implementation, the rapid arrangement of the observation method is carried out when the tunnel boring machine stops working, or the tunnel receiving station array, the surface receiving station array, the receiving station array of geological boreholes under far-hole conditions, and the receiving station array of geological boreholes under near-hole conditions are quickly arranged when the tunnel boring machine is working; the pilot receiving station array of the rock-breaking source is arranged when the tunnel boring machine stops working.

[0019] As an alternative implementation, the specific process of synchronous acquisition by the detection device of the ground-hole-cavity includes that when the cutter head of the tunnel boring machine rotates to cut the rock and generates vibrations, the vibrations of the cutter head breaking the rock are received by the pilot receiving station of the rock-breaking source installed behind the cutter head. The rock-breaking source simultaneously excites seismic waves to spread forward of the working face of the tunneling machine and around the tunnel. After the seismic waves encounter the wave impedance interface, they are reflected and received by the tunnel receiving stations, the surface receiving stations, and the receiving stations of the geological boreholes under near-hole conditions buried in the geological boreholes behind the wave impedance interface. At the same time, transmission occurs at the wave impedance interface and is received by the receiving stations of the geological boreholes under far-hole conditions buried in the geological boreholes in front of the wave impedance interface and the surface receiving stations. The pilot receiving station array of the rock-breaking source, the tunnel receiving stations, the surface receiving station array, the receiving stations of the geological boreholes under near-hole conditions, and the receiving station array of the geological boreholes under far-hole conditions automatically store the received seismic signals.

[0020] As an alternative implementation, the seismic record joint processing method includes:

[0021] Preprocessing the received signals;

[0022] Performing high-resolution extraction under near-hole conditions;

[0023] Performing wavefield optimization under far-hole conditions;

[0024] Separating body waves from the data collected by the surface receiving station array;

[0025] Performing cross-correlation and deconvolution processing on the source signal and the processed received signals;

[0026] Importing the coordinates of the observation system and performing automatic first arrival picking;

[0027] Performing spectral analysis and band-pass filtering;

[0028] Perform in - trace and inter - trace equalization;

[0029] Suppress ineffective reflected waves, retain effective reflected waves, and perform P - S wave separation;

[0030] Extract surface wave dispersion curves and dispersion energy diagrams;

[0031] For the data collected in the optimized long - offset borehole conditions and the dispersion curves of surface wave data, perform joint transmission - surface wave inversion, and use the joint inversion method to obtain the velocity model in front of the tunnel boring machine;

[0032] Using the velocity model obtained by joint inversion, adopt reverse - time migration imaging to obtain the seismic profile in front of the tunnel boring machine.

[0033] As a further limitation, the objective function of the joint transmission - surface wave inversion is:

[0034]

[0035] Among them, the first term on the right - hand side is the data fitting term, d obs is the collected transmission wave data and the extracted surface wave dispersion curves, G(m) is the transmission wave data and the forward - modeled dispersion curves obtained by forward - modeling the inversion model, the second term on the right - hand side is the model fitting term, m is the currently inverted model, m0 is the initial model, and the third term on the right - hand side is the cross - gradient term. m p represents the P - wave velocity, m s represents the S - wave velocity, W d ,W c ,λ,β are weights respectively.

[0036] As a further limitation, the velocity model used in the reverse - time migration imaging is:

[0037]

[0038] Among them, d Sur,obs ,d Hol,obs are the seismic data observed on the surface and in the long - offset borehole under geological borehole conditions respectively, d Sur,mod ,d Hol,mod are the seismic data observed on the surface and in the long - offset borehole under geological borehole conditions obtained by forward - modeling respectively, and a and b are the weights of the minimum errors of the seismic data observed on the surface and in the long - offset borehole under geological borehole conditions respectively.

[0039] A combined ground-hole-cavity fine detection system, comprising a rock-breaking seismic source leading receiving station array, a tunnel receiving station array, a surface receiving station array, a far-hole condition geological borehole receiving station array, a near-hole condition geological borehole receiving station array, a time synchronization system, and a seismic wave data processing instrument system, wherein:

[0040] The rock-breaking seismic source leading receiving station array is located behind the cutter head of the tunnel boring machine. The tunnel receiving station array is installed on the middle body of the tunnel boring machine or on the surrounding rock of the tunnel side wall. The surface receiving station array is located on the surface in front of the tunnel boring face. The near-hole condition and far-hole condition geological borehole receiving station arrays are located inside geological boreholes at different distances in front of the tunnel boring face;

[0041] The time synchronization system is used to precisely synchronize each station receiving array;

[0042] The seismic data processing instrument system is used to receive and store the observation data of each receiving station array and perform rapid processing.

[0043] The rock-breaking seismic source leading receiving station array is located behind the cutter head of the tunnel boring machine, records the vibration signals generated by the rotation and cutting of the cutter head of the tunnel boring machine on the rock, and the leading receiving station array has an automatic positioning system to automatically record its spatial position.

[0044] As an alternative implementation, the tunnel receiving station array is installed on the body of the tunnel boring machine or on the surrounding rock of the tunnel side wall, and is used to receive and store the seismic signals reflected from the tunnel side wall after the vibration of the cutter head breaking the rock encounters a bad geological body during propagation in the formation. The tunnel receiving station array is located on both sides of the tunnel and is arranged linearly.

[0045] As an alternative implementation, the surface receiving station array is located on the surface in front of the tunnel boring face, including multiple surface receiving stations, and each receiving station is a three-component receiving station, which is used to receive the reflected wave and transmitted wave signals generated after the seismic wave generated by the rock-breaking vibration of the tunnel boring machine as a seismic source passes through the wave impedance interface, and the surface wave signals generated after the seismic wave propagates to the surface.

[0046] As an alternative implementation, the near-hole condition geological borehole receiving station array is located in front of the tunnel boring face, and is used to receive and store the seismic signals reflected from the geological borehole after the vibration of the cutter head breaking the rock encounters a bad geological body during propagation in the formation. The near-hole condition geological borehole receiving stations are arranged linearly.

[0047] As an alternative implementation, the far-hole condition geological borehole receiving station array is located in front of the tunnel boring face, and is used to receive and store the seismic signals transmitted to the geological borehole after the vibration of the cutter head breaking the rock encounters a bad geological body during propagation in the formation. The far-hole condition geological borehole receiving stations are arranged linearly.

[0048] As an alternative embodiment, each receiving station array is configured with a time synchronization system, and the time synchronization system unifies the time of each receiving station array through GPS signals.

[0049] As an alternative embodiment, the data of each receiving station array are transmitted to a seismic wave data processing instrument system, and the seismic wave data processing instrument system is configured to jointly process the rock-breaking vibration and noise information collected from the tunnel and the surface to obtain seismic profiles of the area in front of and around the tunnel.

[0050] As an alternative embodiment, the rock-breaking vibration source pilot receiving station specifically includes a rock-breaking vibration source pilot receiving station and a support plate, and the rock-breaking vibration source pilot receiving station is fixed on the shield behind the cutter head through the support plate.

[0051] As an alternative embodiment, the tunnel receiving station array includes multiple tunnel receiving stations, which are sequentially fixed on the middle part of the tunneling machine body or on the surrounding rock of the tunnel side wall. Each tunnel receiving station includes a three-component receiving station and a fixing device, and the three-component receiving station is fixed on the tunneling machine or the surrounding rock of the tunnel through the fixing device.

[0052] As an alternative embodiment, the tunnel receiving station array includes two groups of tunnel receiving stations located on both sides of the tunneling machine respectively. Each group of tunnel receiving stations is at a certain distance from the tunneling face, and there is a certain spacing between the two groups of tunnel receiving stations.

[0053] As an alternative embodiment, the surface receiving station array includes multiple receiving stations, which are sequentially distributed on the traveling route of the tunneling machine body.

[0054] As an alternative embodiment, the time synchronization system includes multiple time synchronization hosts, which are respectively connected to the rock-breaking vibration source pilot receiving station array, the surface receiving station array, the tunnel receiving station array, the far-hole condition geological borehole receiving station array, and the near-hole condition geological borehole receiving station array.

[0055] As an alternative embodiment, each receiving station has an automatic positioning system.

[0056] As an alternative embodiment, the far-hole condition geological borehole receiving station array and the near-hole condition geological borehole receiving station array are pre-buried inside the geological borehole after the geological borehole is excavated, and the borehole is filled to make the geophone in close contact with the surrounding medium.

[0057] As an alternative implementation, built-in batteries are provided for each of the rock-breaking seismic source pilot receiving station arrays, surface receiving station arrays, and tunnel receiving station arrays. External power supplies are provided for the far-hole condition geological borehole receiving station arrays and near-hole condition geological borehole receiving station arrays to enable long-term acquisition.

[0058] When the tunnel boring machine stops working or is in operation, the present invention quickly arranges the observation system and conducts multi-angle observations through multi-spatial position combinations. During the tunneling process of the tunnel boring machine, the rock-breaking vibration of the cutter head is received by the rock-breaking seismic source pilot receiving station installed behind the cutter head. The rock-breaking seismic source simultaneously excites seismic waves to spread forward and around the tunnel in front of the tunneling machine. After the seismic waves encounter the wave impedance interface, they are reflected and received by the tunnel receiving stations, surface receiving stations, and near-hole condition geological borehole receiving stations buried in the geological boreholes behind the wave impedance interface. At the same time, transmission occurs at the wave impedance interface and is received by the far-hole condition geological borehole receiving stations and surface receiving stations buried in the geological boreholes in front of the wave impedance interface.

[0059] The above signals are transmitted in real time to the seismic wave data processing instrument system for real-time processing. For the special situation of tunnel prediction, different processing methods adapted to their wavelength characteristics are adopted for different receiving station arrays. Blind deconvolution based on time-varying wavelets is performed on the near-hole condition geological boreholes, wavefield optimization based on consistent deconvolution and amplitude compensation is performed on the far-hole condition geological boreholes, the surface data is separated into surface and body waves, and then signal interference is performed by combining the source signals collected by the rock-breaking seismic source pilot receiving stations with the signals collected by the other receiving stations after denoising to restore the wavefield signals. Then, cross-gradient-based "transmitted wave - surface wave" joint inversion is used to obtain the wave velocity inversion result, and on this basis, reverse time migration is performed to generate the seismic profile in front of the tunnel boring machine and make a more accurate assessment of the quality of the rock mass in front of the tunneling face.

[0060] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0061] (1) The present invention uses the rock-breaking vibration of the tunnel boring machine for advanced geological detection, which is safe and reliable and does not affect the normal construction of the tunnel. By using the multi-angle seismic observation method, the seismic wave receiving stations are seismic wave receiving sensors, arranged on the surface, the side of the tunnel, and geological boreholes, to realize the implementation and application of the tunnel seismic while drilling method. Through the joint use of transmitted waves, reflected waves, and surface waves for cross-gradient inversion and reverse time migration imaging, the entire space of the bad geological body in front of the tunneling face is detected in terms of breadth (detection range) and accuracy, and the quality of the entire space rock mass in front of the tunnel boring face is evaluated;

[0062] (2) It is particularly suitable for construction tunnels with "narrow observation space and tight detection time", solves the problem of one-sided view, and prevents the occurrence of false alarms and missed alarms.

[0063] (3) Adopt multiple observation systems to collect seismic waves from multiple perspectives, obtain rich and diverse wave field information, and use the characteristics of various wave fields for advanced detection;

[0064] (4) Conduct special data processing for different wave field characteristics, which can effectively improve the signal-to-noise ratio of the observed data and obtain more real and reliable advanced prediction results;

[0065] (5) Different wave fields have different sensitivities to formation information. The combined ground-borehole-cavity detection can collect various data. Among them, the reflected wave information collected by geological boreholes and the surface under near-borehole conditions is more sensitive to the interface information of bad geological bodies, and the travel time of transmitted waves collected by geological boreholes and the surface under far-borehole conditions is more sensitive to the formation velocity change. It can accurately locate the bad geological body in space, achieve precise detection in front of the tunneling face, and through surface data, macroscopic detection can be realized, and the geological conditions along the line can be known in advance to guide the tunneling construction;

[0066] (6) Using the rock-breaking vibration of the tunnel boring machine cutter head as the seismic source, surface wave data with a wider frequency band and more complete development of high-order dispersion curves can be obtained, and higher-precision inversion imaging can be achieved.

[0067] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, makes a detailed description as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0069] Figure 1 Schematic diagram of the combined ground-borehole-cavity fine detection system for tunnel construction;

[0070] Figure 2 Schematic diagram of the working state based on the combined ground-borehole-cavity fine detection for tunnel construction;

[0071] Figure 3 Data processing flow chart based on the combined ground-borehole-cavity fine detection for tunnel construction.

[0072] Among them, 1. Tunnel boring machine cutter head, 2. Three-component seismic station, 3. Rock-breaking seismic source pilot receiving station array, 4. Tunnel receiving station array, 5. Surface receiving station array, 6. Near-borehole condition geological borehole receiving station array, 7. Far-borehole condition geological borehole receiving station array, 8. Time synchronization system, 9. Seismic wave data processing instrument system. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0073] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0074] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0075] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0076] As Figure 1 shown in the schematic diagram of the tunnel construction site-hole-cavity joint fine detection system, Figure 2 is the schematic diagram of the working state based on the tunnel construction site-hole-cavity joint fine detection.

[0077] As Figure 1 shown, the tunnel construction site-hole-cavity joint fine detection system mainly includes a rock-breaking seismic source pilot receiving station array 3, a tunnel receiving station array 4, a surface receiving station array 5, a near-hole condition geological borehole receiving station array 6, a far-hole condition geological borehole receiving station array 7, a time synchronization system 8, and a seismic wave data processing instrument system 9.

[0078] As Figure 2As shown, as a typical implementation, the leading receiving station array 3 of the rock-breaking seismic source is arranged behind the cutter head 1 of the tunnel boring machine body, and is used to receive the vibrations generated by the rotation and cutting of the rock by the cutter head 1. The leading receiving station is equipped with an automatic positioning system and can store its spatial position. The tunnel receiving station array 4 is arranged in the middle of the boring machine body or on the surrounding rock of the tunnel sidewall, and receives and stores the seismic signals reflected from the tunnel wall after the rock-breaking vibration of the cutter head encounters a poor geological body during propagation in the formation. The surface receiving station array 5 is installed on the ground surface in front of the tunnel working face, and is used to receive and store the seismic signals reflected and transmitted to the ground surface after the rock-breaking vibration of the cutter head 1 encounters a poor geological body during propagation in the formation, and can receive and save the surface waves generated by the rock-breaking vibration of the cutter head and the environmental noise on the ground surface. The geological borehole receiving station array is arranged in the geological borehole in front of the tunnel boring machine. The near-borehole condition geological borehole receiving station array 6 and the far-borehole condition geological borehole receiving station array 7 are installed inside the geological boreholes at different distances in front of the tunneling face. The near-borehole condition geological borehole receiving station array 6 is used to receive and store the seismic signals reflected from the geological borehole after the rock-breaking vibration of the cutter head 1 encounters a poor geological body during propagation in the formation, and the far-borehole condition geological borehole receiving station array 7 is used to receive and store the seismic signals transmitted to the geological borehole after the rock-breaking vibration of the cutter head 1 encounters a poor geological body during propagation in the formation. After the layout of each receiving station array is completed, the time synchronization system 8 is turned on to synchronize the time of each station receiving array. The seismic wave data processing instrument system 9 imports the seismic data received and stored by the leading receiving station 3 of the rock-breaking seismic source, the tunnel receiving station array 4, the surface receiving station array 5, the near-borehole condition geological borehole station array 6 and the far-borehole condition geological borehole station array 7, and realizes fast and automatic processing to obtain the seismic profile of the area in front of and around the tunnel.

[0079] In different embodiments, the leading receiving station array of the rock-breaking seismic source is located behind the cutter head of the tunnel boring machine and records the vibration signals generated by the rotation and cutting of the rock by the cutter head of the boring machine. The leading receiving station array has an automatic positioning system and can automatically record its spatial position.

[0080] The tunnel receiving station array is installed on the tunnel boring machine body or on the surrounding rock of the tunnel sidewall, and is used to receive and store the seismic signals reflected from the tunnel sidewall after the rock-breaking vibration of the cutter head encounters a poor geological body during propagation in the formation. The tunnel receiving station array is located on both sides of the tunnel and is arranged linearly.

[0081] The surface receiving station array is located on the ground surface in front of the tunnel boring machine and includes multiple surface receiving stations. The surface receiving stations can be arranged in various forms such as linear, square, circular, etc. Each receiving station is a three-component receiving station and is used to receive the reflected wave and transmitted wave signals generated by the seismic waves generated by the rock-breaking vibration of the tunnel boring machine as the seismic source after passing through the wave impedance interface, as well as the surface wave signals generated after the seismic waves propagate to the ground surface.

[0082] The near-hole condition geological borehole receiving station array is located in front of the tunnel boring face, and is used to receive and store the seismic signals reflected into the geological boreholes after the cutter head rock-breaking vibration encounters bad geological bodies during propagation in the strata. The near-hole condition geological borehole receiving stations are linearly arranged.

[0083] The far-hole condition geological borehole receiving station array is located in front of the tunnel boring face, and is used to receive and store the seismic signals transmitted into the geological boreholes after the cutter head rock-breaking vibration encounters bad geological bodies during propagation in the strata. The far-hole condition geological borehole receiving stations are linearly arranged.

[0084] Each receiving station array is configured with a time synchronization system, and the time synchronization system unifies the time of each receiving station array through GPS signals.

[0085] The data of each receiving station array are transmitted to the seismic wave data processing instrument system, and the seismic wave data processing instrument system is configured to jointly process the rock-breaking vibration and noise information collected from the tunnel and the surface to obtain the seismic profile of the area in front of and around the tunnel.

[0086] It should be noted that in this field, each receiving station array includes several rows of receiving stations, including the case of only one row of receiving stations, and each receiving station is a three-component geophone.

[0087] The data processing process of the tunnel construction site-hole-cavity joint fine detection includes the extraction of effective signals from the tunnel construction site-hole-cavity joint detection data, the cross-gradient joint inversion of the signals to obtain the shear wave velocity model in front of the tunneling face, and the use of the velocity model obtained by the joint inversion to perform reverse time migration imaging. Through the cross-correlation imaging condition, the seismic profile in front of the tunnel boring machine working face is obtained.

[0088] First, before the detection, a rapid layout of the tunnel boring machine rock-breaking vibration source detection observation method for the site-hole-cavity joint is carried out. In this embodiment, the tunnel receiving station array 4 is arranged on the surrounding rock of the tunnel side wall. The tunnel receiving station array is composed of 6 receiving stations, and the channel spacing is 5 meters. The surface receiving station array 5 is arranged on the upper surface in front of the tunneling machine working face. The surface receiving station array is composed of 40 surface receiving stations. The surface receiving station array is rapidly arranged at a channel spacing of 2m, and the surface receiving stations are provided with an automatic positioning system to automatically store the positioning. The geological borehole receiving station arrays 6 and 7 are arranged in the geological boreholes under far-hole conditions and near-hole conditions in front of the tunneling face. 30 receiving stations in the geological boreholes are respectively buried in the near-hole condition and far-hole condition boreholes, so that the receiving stations are in close contact with the formation medium, and an automatic positioning system is set to automatically store the positioning. After the layout of each receiving station array is completed, the time synchronization system 8 is turned on for time synchronization.

[0089] When the tunnel boring machine starts to work, the cutter head 1 of the boring machine rotates to cut the rock, generating vibrations. The vibrations of the cutter head breaking the rock are received by the rock-breaking seismic source pilot receiving station 3 installed behind the cutter head 1. The rock-breaking seismic source simultaneously excites seismic waves that spread forward in front of the working face of the boring machine and around the tunnel. After the seismic waves encounter the wave impedance interface, they are reflected and received by the tunnel receiving station array 4, the surface receiving station 5, and the geological borehole receiving station 6 buried in the geological borehole under near-hole conditions behind the wave impedance interface. At the same time, the seismic waves are transmitted at the wave impedance interface, and the transmitted waves are received by the surface receiving station 5 and the geological borehole receiving station 7 buried in the geological borehole under far-hole conditions in front of the wave impedance interface. The surface receiving station array also receives the surface waves generated by the cutter head rock-breaking seismic source and the environmental noise on the surface. The information recorded by the above rock-breaking seismic source pilot receiving station array 3, tunnel receiving station array 4, surface receiving station array 5, near-hole condition geological borehole receiving station array 6, and far-hole condition geological borehole station receiving array 7 is transmitted to the seismic wave data processing instrument system 9 for automatic joint processing.

[0090] As Figure 3 shown, the seismic record joint processing process includes:

[0091] (1) Preprocessing of received signals:

[0092] By means of band-pass filtering, the instrument noise in the signals received by the rock-breaking seismic source pilot receiving station, geological borehole receiving station, surface receiving station, and tunnel receiving station is removed to ensure the quality of the collected seismic data.

[0093] (2) Fixed-point noise denoising of received signals:

[0094] Combined with the signals received by the rock-breaking seismic source pilot receiving station, using spectral subtraction, the strong interference noise in the seismic signals received by the tunnel receiving station and the surface receiving station is attenuated to separate the effective seismic signals.

[0095]

[0096] Among them, is the power spectrum of the pure seismic signal, E[|N(ω)|] is the mathematical expectation of the noise power spectrum, and |Y i (ω)| 2 is the power spectrum of the original noisy seismic signal;

[0097] (3) Extraction of body wave information under near-hole conditions:

[0098] Aiming at the problems that the recovery of the reflected wave field in boreholes under surface and near-borehole conditions is affected by the propagation distance, and the wavelet morphology changes greatly and is significantly different, a blind deconvolution method based on time-varying wavelets is carried out to achieve high-resolution data extraction. First, the signal received by the near-borehole geological borehole after denoising is subjected to the generalized S transform to obtain the time-frequency spectrum of the seismic record. Then, the amplitude spectrum of the time-frequency wavelet obtained by spectral simulation is subjected to inverse Fourier transform to obtain the time-varying wavelet and perform blind deconvolution to improve the data resolution;

[0099] (4) Optimization of the wave field under far-borehole conditions:

[0100] The quality of the observation data under far-borehole conditions is poor, the main frequency of the seismic record is low, the bandwidth is narrow, and the energy attenuation at long distances is serious. Considering factors such as shot points, geophone points, and offset distances, first, the signal received by the geological borehole under far-borehole conditions after denoising is frequency compensated through coherence deconvolution, and then amplitude compensation is performed through inverse Q filtering to improve the resolution of the observation data;

[0101] (5) Separation of surface waves and body waves:

[0102] The data collected by the surface receiving station array contain seismic waves, surface waves, and background noise generated by the cutterhead rock-breaking source, and surface waves and body waves need to be separated to make full use of the collected data;

[0103] (6) Interference of rock-breaking signals:

[0104] The source signal is subjected to cross-correlation and deconvolution processing with the received signal after denoising, which can further attenuate the incoherent noise and compress the rock-breaking vibration signal into an equivalent pulse signal to achieve the interference of unconventional rock-breaking sources and complete the conversion from the seismic record of unconventional rock-breaking sources to the seismic record of conventional sources;

[0105] (7) Import of the observation system and first arrival picking:

[0106] The relative coordinates of the rock-breaking source receiving station array, tunnel receiving station array, borehole receiving station array in the geological borehole, and surface receiving station array are imported, and the arrival times of the first arrival waves at the receiving stations in the geological borehole and on the surface in the seismic record are picked using the automatic first arrival picking method, and the wave velocity is calculated using their relative distances and the arrival times of the first arrival waves;

[0107] (8) Spectrum analysis and band-pass filtering:

[0108] The seismic record in the time domain is transformed to the frequency domain through Fourier transform, the noise signals in different frequency bands are removed through band-pass filtering, and the frequency band of the effective reflected wave is retained. Finally, the seismic record in the frequency domain is transformed back to the time domain through inverse Fourier transform to improve the signal-to-noise ratio of the seismic record;

[0109] (9) Trace gather equalization:

[0110] It includes in - trace equalization and cross - trace equalization steps. In - trace equalization is to compress the waves with stronger energy in the shallow layer of each trace and increase the waves with weaker energy in the deep layer, so that the amplitudes of the shallow - layer and deep - layer seismic waves are controlled within a certain dynamic range; cross - trace equalization is mainly to eliminate the differences in excitation energy of different source points, so that the amplitude of the reflected wave is not affected by the excitation conditions and only reflects the geological structure situation;

[0111] (10) Effective signal extraction and P - S wave separation:

[0112] The f - k and τ - p joint filtering is used to suppress the interference waves and the ineffective reflected waves behind the tunneling machine working face. At the same time, the direct wave is cut off, and only the effective reflected waves from the front and side of the tunneling machine working face are retained and automatically extracted. And in the f - k domain or τ - p domain, the P - wave, SH - wave and SV - wave in the three - component seismic record are separated, which is convenient for the next step of migration imaging and geological interpretation;

[0113] (11) Extraction of surface - wave dispersion curve:

[0114] The frequency - Bessel transform method is used to transform the seismic record after removing the body waves into the f - v domain to obtain the dispersion energy map, and the multi - mode dispersion curves are extracted from the dispersion energy map;

[0115] (12) Joint inversion of "transmitted wave - surface wave" based on cross - gradient:

[0116] The data collected from the geological borehole under far - hole conditions with optimized wave field and the dispersion curves of the surface - wave data are imported and subjected to the joint inversion of "transmitted wave - surface wave". The velocity model in front of the tunnel boring machine is obtained by using the joint inversion method;

[0117] The objective function of the "transmitted wave - surface wave" cross - gradient joint inversion is:

[0118] Φ=∑||W d [d obs -G(m)]|| 2 +λ||W c (m - m0)|| 2 +β||τ(m)||

[0119] Among them, the first term on the right - hand side is the data - fitting term, d obs is the collected transmitted - wave data and the extracted surface - wave dispersion curves, G(m) is the transmitted - wave data and the forward - modeled dispersion curves obtained by forward - modeling the inversion model. The second term on the right - hand side is the model - fitting term, m is the currently inverted model, m0 is the initial model, and the third term on the right - hand side is the cross - gradient term, m p represents the P - wave velocity, m s represents the S - wave velocity, Wd , W c , λ, and β are weights respectively.

[0120] (13) Reverse time migration imaging:

[0121] Using the velocity model obtained by joint inversion, reverse time migration imaging is adopted. Through the cross - correlation imaging condition, a seismic profile in front of the working face of the tunnel boring machine is obtained;

[0122] The velocity model used in reverse time migration is:

[0123]

[0124] where d Sur，obs , d Hol，obs are the seismic data observed in the geological boreholes under surface and far - hole conditions respectively, d Sur，mod , d Hol，mod are the seismic data observed on the surface and in the geological boreholes under far - hole conditions obtained from forward modeling respectively, and a and b are the weights of the minimum errors of the surface - observed data and the geological - borehole - observed data under far - hole conditions respectively.

[0125] The cross - correlation imaging condition is:

[0126]

[0127] where I(x, y, z) represents the imaging result, S(x, y, z, t) represents the source wave field, R(x, y, z, t) represents the geophone wave field, and T is the total migration duration.

[0128] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. that can be made by those skilled in the art without creative efforts within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A combined ground-hole-cavity fine detection method, characterized in that, It includes the following steps: Arrange the detection and observation method of the rock-breaking seismic source of the tunnel boring machine with combined ground-hole-cavity, and perform time synchronization and spatial positioning; Wait for the tunnel boring machine to start working, and the detection devices of the ground-hole-cavity synchronously collect and store signals; After the data collection is completed, collect the parameters during the tunneling process of the tunnel boring machine and the data collected by the receiving station array, and process them to obtain the velocity model and seismic profile of the area in front of and around the tunnel; According to the obtained velocity model and seismic profile, combined with the spatial distribution of the rock excavation strength index and geological borehole data, know the geological conditions of the rock mass in front of the working face of the tunneling machine and around the tunnel, and realize the advanced prediction of geological anomalies; The seismic record joint processing method includes: Preprocess the received signals; Perform high-resolution extraction under near-hole conditions; Optimize the wave field under far-hole conditions; Separate the body waves and surface waves from the data collected by the surface receiving station array; Perform cross-correlation and deconvolution processing on the seismic source signal and the processed received signal; Import the coordinates of the observation system and perform automatic first arrival picking; Perform spectral analysis and band-pass filtering; Perform in-trace and inter-trace equalization; Suppress the ineffective reflected waves, retain the effective reflected waves, and perform P-wave and S-wave separation; Extract the surface wave dispersion curve and the dispersion energy diagram; For the data collected in the geological borehole under optimized far-hole conditions and the surface wave data dispersion curve, perform joint inversion of transmitted waves and surface waves, and use the joint inversion method to obtain the velocity model in front of the working face of the tunnel boring machine; Using the velocity model obtained by joint inversion, perform reverse time migration imaging to obtain the seismic profile in front of the working face of the tunnel boring machine; The objective function of the joint inversion of transmitted waves and surface waves is: Φ = ∑||W d [d obs -G(m)]|| 2 + λ||W c (m - m0)|| 2 + β||τ(m)|| Among them, the first term on the right side is the data fitting term, d obs is the collected transmission wave data and the extracted surface wave dispersion curve, G(m) is the transmission wave data and the forward dispersion curve obtained by forward modeling of the inversion model, the second term on the right side is the model fitting term, m is the currently inverted model, m0 is the initial model, and the third term on the right side is the cross-gradient term, m p represents the P-wave velocity, m s represents the S-wave velocity, W d ,W c , λ, and β are the weights respectively.

2. A combined ground-hole-cavity fine detection method according to claim 1, characterized in that, The specific process of arranging the detection and observation method of the rock-breaking seismic source of the tunnel boring machine with combined ground-hole-cavity includes: installing the leading receiving station array of the rock-breaking seismic source on the support plate behind the cutter head, arranging the tunnel receiving station array in the middle of the tunnel boring machine body or on the surrounding rock of the tunnel side wall, arranging the surface receiving station array on the ground above the traveling route of the tunnel boring machine body, quickly arranging the surface receiving station array at a certain trace interval, and connecting the far-hole condition geological borehole receiving station array and the near-hole condition geological borehole receiving station array to the external power supply.

3. A combined ground-hole-cavity fine detection method according to claim 1, characterized in that, Quickly arrange the observation method when the tunnel boring machine stops working, or quickly arrange the tunnel receiving station array, surface receiving station array, far-hole condition geological borehole receiving station array, and near-hole condition geological borehole receiving station array when the tunnel boring machine is working; arrange the leading receiving station array of the rock-breaking seismic source when the tunnel boring machine stops working.

4. A combined ground-hole-cavity fine detection method according to claim 1, characterized in that, The specific process of synchronous acquisition by the ground-hole-cavity detection device includes that when the cutter head of the tunnel boring machine rotates to cut the rock and generates vibrations, the rock-breaking vibration of the cutter head is received by the rock-breaking seismic source pilot receiving station installed behind the cutter head. The rock-breaking seismic source simultaneously excites seismic waves to spread forward of the working face of the tunneling machine and around the tunnel. After the seismic waves encounter the wave impedance interface, they are reflected and received by the tunnel receiving stations, the surface receiving stations, and the near-hole condition geological borehole receiving stations buried in the geological boreholes behind the wave impedance interface. At the same time, transmission occurs at the wave impedance interface and is received by the far-hole condition geological borehole receiving stations buried in the geological boreholes in front of the wave impedance interface and the surface receiving stations. The rock-breaking seismic source pilot receiving station array, the tunnel receiving stations, the surface receiving station array, the near-hole condition geological borehole and far-hole condition geological borehole receiving station arrays automatically store the received seismic signals.

5. A combined ground-hole-cavity fine detection method according to claim 1, characterized in that, The velocity model used in the reverse time migration imaging is as follows: where d Sur,obs , d Hol,obs are the seismic data observed in geological boreholes under surface and far - hole conditions respectively, and d Sur,mod , d Hol,mod are the seismic data observed on the surface and in geological boreholes under far - hole conditions obtained from forward modeling respectively. a and b are the weights of the minimum errors of the surface - observed data and the far - hole - condition geological - borehole - observed data respectively.

6. A combined ground-hole-cavity fine detection system, characterized in that, It includes a rock-breaking seismic source pilot receiving station array, a tunnel receiving station array, a surface receiving station array, a far-hole condition geological borehole receiving station array, a near-hole condition geological borehole receiving station array, a time synchronization system, and a seismic wave data processing instrument system, where: The rock-breaking seismic source pilot receiving station array is located behind the cutter head of the tunnel boring machine. The tunnel receiving station array is installed on the middle body of the tunnel boring machine or on the surrounding rock of the tunnel side wall. The surface receiving station array is located on the surface in front of the tunnel working face. The near-hole condition and far-hole condition geological borehole receiving station arrays are located inside geological boreholes at different distances in front of the tunnel working face; The time synchronization system is used to precisely synchronize each station receiving array; The seismic data processing instrument system is used to receive and store the observation data of each receiving station array and perform rapid processing; The seismic record joint processing method includes: Preprocessing the received signals; Performing high-resolution extraction under near-hole conditions; Performing wavefield optimization under far-hole conditions; Separating body waves and surface waves from the data collected by the surface receiving station array; Performing cross-correlation and deconvolution processing on the source signal and the processed received signals; Importing the coordinates of the observation system and performing automatic first arrival picking; Performing spectral analysis and band-pass filtering; Performing in-trace equalization and inter-trace equalization; Suppressing ineffective reflected waves, retaining effective reflected waves, and performing longitudinal and transverse wave separation; Extracting surface wave dispersion curves and dispersion energy diagrams; For the data collected in the optimized far-hole condition geological boreholes and the surface wave data dispersion curves, perform transmission wave-surface wave joint inversion, and use the joint inversion method to obtain the velocity model in front of the working face of the tunnel boring machine; Using the velocity model obtained by joint inversion, perform reverse time migration imaging to obtain the seismic profile in front of the working face of the tunnel boring machine; The objective function of the transmission wave-surface wave joint inversion is: Φ = ∑||W d [d obs -G(m)]|| 2 + λ||W c (m - m0)|| 2 + β||τ(m)|| Among them, the first term on the right side is the data fitting term, d obs is the collected transmitted wave data and the extracted surface wave dispersion curve, G(m) is the transmitted wave data and the forward dispersion curve obtained by forward modeling of the inversion model, the second term on the right side is the model fitting term, m is the currently inverted model, m0 is the initial model, and the third term on the right side is the cross-gradient term, m p represents the P-wave velocity, m s represents the S-wave velocity, W d ,W c , λ, and β are the weights respectively.

7. The ground-hole-cavity combined fine detection system according to claim 6, characterized in that, The rock-breaking seismic source pilot receiving station array is located behind the cutter head of the tunnel boring machine, records the vibration signals generated by the rotation of the cutter head of the tunneling machine to cut the rock, and the pilot receiving station array has an automatic positioning system to automatically record its spatial position.

8. The ground-hole-cavity combined fine detection system according to claim 6, characterized in that, The tunnel receiving station array is installed on the tunneling machine body or the surrounding rock of the tunnel side wall, and is used to receive and store the seismic signals reflected from the tunnel side wall after the rock-breaking vibration of the cutter head encounters a bad geological body during its propagation in the stratum. The tunnel receiving station array is located on both sides of the tunnel and is arranged linearly.

9. The ground-hole-cavity combined fine detection system according to claim 6, characterized in that, The surface receiving station array is located on the surface in front of the tunneling face of the tunnel, and includes multiple surface receiving stations. Each receiving station is a three-component receiving station, and is used to receive the reflected wave and transmitted wave signals generated after the seismic wave generated by the rock-breaking vibration of the tunneling machine as the seismic source passes through the wave impedance interface, as well as the surface wave signal generated after the seismic wave propagates to the surface.

10. The ground-hole-cavity combined fine detection system according to claim 6, characterized in that, The near-hole condition geological borehole receiving station array is located in front of the tunneling face of the tunnel, and is used to receive and store the seismic signals reflected from the geological borehole after the rock-breaking vibration of the cutter head encounters a bad geological body during its propagation in the stratum. The near-hole condition geological borehole receiving stations are arranged linearly.

11. The ground-hole-cavity combined fine detection system according to claim 6, characterized in that, The far-hole condition geological borehole receiving station array is located in front of the tunneling face of the tunnel, and is used to receive and store the seismic signals transmitted to the geological borehole after the rock-breaking vibration of the cutter head encounters a bad geological body during its propagation in the stratum. The far-hole condition geological borehole receiving stations are arranged linearly.

12. The ground-hole-cavity combined fine detection system according to claim 6, characterized in that, Each receiving station array is configured with a time synchronization system, and the time synchronization system unifies the time of each receiving station array through GPS signals; The time synchronization system includes multiple time synchronization hosts, which are respectively connected to the rock-breaking vibration source pilot receiving station array, the surface receiving station array, the tunnel receiving station array, the far-hole condition geological borehole receiving station array, and the near-hole condition geological borehole receiving station array.

13. The ground-hole-cavity combined fine detection system according to claim 6, characterized in that, The data of each receiving station array are transmitted to the seismic wave data processing instrument system, and the seismic wave data processing instrument system is configured to jointly process the rock-breaking vibration and noise information collected from the tunnel and the surface to obtain the seismic profile of the area in front of and around the tunnel.

14. The ground-hole-cavity combined fine detection system according to claim 6, characterized in that, Each receiving station has an automatic positioning system.

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