Passive tunnel boring poor geological detection device and method

Abstract

The present invention discloses a passive tunneling poor geology detection device and method, belonging to the technical field of geological detection during tunnel construction. The passive tunneling poor geology detection device is characterized by comprising several detection mechanisms disposed within advance boreholes on the tunnel face; the detection mechanisms comprising a protection system, a signal acquisition system, a signal transmission system, and an intelligent terminal system; the signal acquisition system being disposed within the protection system and used to protect the signal acquisition system; and the signal acquisition system being connected to the intelligent terminal system via the signal transmission system and transmitting the collected signals to the intelligent terminal system for processing. The passive tunneling poor geology detection device and method described in the present invention can address the problems of existing devices, such as complex structures, inconvenient use, and low detection accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of geological detection in tunnel construction, and in particular to a passive tunnel excavation unfavorable geological detection device and method. Background Art

[0002] Due to various factors, including topography, geology, and climate, tunnel excavation often presents a series of geological risks and hidden dangers, including water inrush, mud inrush, fracture zones, rock bursts, and freeze-thaw and frost heave. Failure to promptly warn and address these risks can severely impact tunnel construction safety and progress. Water inrush is the most common risk.

[0003] Water inrush in tunnels is often related to the surrounding geological conditions and precipitation. When tunnel excavation reaches strata containing faults, fissures, and karst caves, water inrush channels are more likely to form. Drastic changes in precipitation conditions at the construction site can also trigger water inrush accidents. Water inrushes can have multiple impacts on the construction process: small water inrushes can worsen the on-site construction environment and reduce the efficiency of support work; large water inrushes can flood equipment and construction personnel, delaying construction progress, increasing construction costs, and in severe cases, causing casualties. Water inrushes can also cause fluctuations in groundwater levels, impacting the surrounding ecological environment. Furthermore, sediment and wastewater carried along by water inrushes can contaminate surrounding water bodies and soil. Therefore, timely and effective monitoring of water bodies ahead of tunnels under construction is crucial to ensuring safe and stable construction.

[0004] Advanced geological prediction can obtain information about the surrounding rock in front of the tunnel face in advance to prevent disasters. Existing earthquake detection and advanced geological prediction technologies are mostly based on the full-space seismic wave field propagation model, and observation systems are arranged on the tunnel wall to obtain information ahead. However, the actual tunnel space is disturbed by free interfaces such as the tunnel face and tunnel wall and does not completely comply with the full-space wave field propagation law. The detection method based on the full-space model is prone to false detection and missed detection. The arrangement of observation systems on the tunnel wall is time-consuming, costly, and has poor repeatability, which is not conducive to multiple detections. At present, manual methods are mostly used to achieve anomaly imaging and interpretation. When the amount of data is too large, the imaging cycle is long, the cost is high, it is greatly affected by human influence, and it has strong multi-solution.

[0005] Existing devices and methods for detecting adverse geological conditions still face problems such as cumbersome equipment installation and operation, severe attenuation and diffusion of reflected wave signals, and poor signal reception during the detection process, which affect detection efficiency and accuracy. Summary of the Invention

[0006] The purpose of the present invention is to provide a passive tunnel boring bad geological detection device and method to solve the problems of complex structure, inconvenient use and low detection accuracy of existing devices.

[0007] To achieve the above-mentioned objectives, the present invention provides a passive tunnel excavation unfavorable geological detection device, comprising a plurality of detection mechanisms, which are arranged in the advance borehole of the tunnel face; the detection mechanisms include a protection system, a signal acquisition system, a signal transmission system and an intelligent terminal system, the signal acquisition system is arranged inside the protection system, the protection system is used to protect the signal acquisition system, and the signal acquisition system is connected to the intelligent terminal system via the signal transmission system, and transmits the collected signals to the intelligent terminal system for processing.

[0008] Preferably, the protection system includes several detection sleeves connected end to end and a magnetic sleeve for sending the detection sleeve into the advance drilling hole. The detection sleeve is provided with several mounting holes for allowing the signal acquisition system to pass through the detection sleeve. The mounting holes are provided with covers for sealing the mounting holes. The interior of the detection sleeve is provided with a power element for driving the cover to open or close the mounting hole, and the power element is connected to the intelligent terminal system.

[0009] Preferably, a buckle is provided at the head end of the detection sleeve, and a slot adapted to the buckle is provided at the tail end of the detection sleeve, and adjacent detection sleeves are connected via the buckle and the slot.

[0010] Preferably, a connector is provided at one end of the magnetic sleeve, and the magnetic sleeve is connected to the detection sleeve via the connector. A switch structure for controlling the connection or disconnection of the connector and the detection sleeve is provided on the magnetic sleeve.

[0011] Preferably, the switch structure includes a coil, which is wound on the outer surface of the magnetic sleeve. A handle is provided at the other end of the magnetic sleeve, a battery connected to the coil is provided in the handle, and a switch for controlling the connection or disconnection of the battery and the coil is provided on the handle; the connector and the detection sleeve are both made of ferromagnetic materials, and the handle is made of insulating material.

[0012] Preferably, the signal acquisition system includes a detector, a base for mounting the detector is provided inside the detection sleeve, the base corresponds to the mounting hole one-to-one, the detector is electrically connected to the base, a lifting element for driving the base to rise and fall is provided inside the detection sleeve, the lifting element is connected to the intelligent terminal system, a battery pack is provided inside the detection sleeve, the battery pack is connected to the base through a wire, and the battery pack is connected to the intelligent terminal system; the detector is connected to the signal transmission system.

[0013] Preferably, the detector includes a probe, an insulating protective shell is provided on the outside of the probe, a metal interface connected to the probe is provided on the protective shell, the probe is connected to a conductive mounting slot on the base through the metal interface, and the mounting slot is connected to the wire.

[0014] Preferably, a rubber convex ring is provided on the outer surface of the protective shell, a groove adapted to the convex ring is provided in the installation groove, and the detector is clamped with the base through the convex ring and the groove.

[0015] Preferably, the signal transmission system includes a storage unit and an antenna, the storage unit is connected to the probe through a signal transmission line, the storage unit is connected to the antenna through a signal transmission line, the antenna is connected to the signal transmission line through a quick connector, and the signal transmission line is located inside the detection sleeve.

[0016] The detection method based on the above-mentioned passive tunnel boring poor geological detection device includes the following steps:

[0017] S1. Determine the inspection requirements based on the tunnel size and safety level, and determine the total length of the inspection sleeve;

[0018] S2. Assemble the detection sleeve and install the detector in the detection sleeve. Check the detector to ensure that it is working properly. Insert the detection sleeve into the advance drill hole.

[0019] S3. Insert the connector of the magnetic sleeve into the tail end of the terminal detection sleeve, turn on the switch, and when the coil is energized, the connector generates magnetic force, fixing the connector and the magnetic sleeve. The detection sleeve is sent to a specific position in front of the tunnel face through the magnetic sleeve. Turn off the switch and remove the magnetic sleeve from the advance drill hole.

[0020] S4. The intelligent terminal system is used to control the extension of the lifting element. The lifting element extends the probe of the detector from the mounting hole through the base, and the probe contacts the wall of the advance drilled hole.

[0021] S5. Hammer the tunnel face to calibrate the wave velocity of the geophone.

[0022] S6. Tunnel blasting: The detector receives the incident wave signal and the reflected wave signal. The detector stores the incident wave signal and the reflected wave signal in a storage unit through a signal transmission line and sends the signal to the intelligent terminal system through an antenna.

[0023] S7. The intelligent terminal system pre-processes the received signal, identifies the rock mass quality, and predicts the coordinates and size of the unfavorable geological conditions ahead;

[0024] S8. After completing a tunnel inspection, the intelligent terminal system controls the lifting element to descend and the probe to be retracted into the inspection sleeve; the inspection sleeve is removed from the advance borehole through the magnetic suction sleeve; the inspection sleeve and detector are removed to prepare for the inspection of the next construction face.

[0025] The advantages and positive effects of the passive tunneling unfavorable geological detection device and method described in the present invention are:

[0026] 1. The present invention utilizes the existing advance boreholes left by advance drilling for layout, without adding additional drilling workload on site, thereby improving detection efficiency and reducing labor.

[0027] 2. The detection sleeve of the present invention can be spliced ​​to meet the detection needs of different lengths and is easy to transport and carry.

[0028] 3. The present invention can adjust the number of installed detectors and the installation spacing according to the tunnel size and construction safety level to achieve different detection accuracy, and there are no unnecessary parts or wires exposed outside, and the appearance is clean and tidy.

[0029] 4. The device of the present invention has a simple structure and is easy to use. It is arranged in front of the tunnel face, is closer to the unfavorable geological body, has a shorter reflected wave propagation path, and has less effective signal loss, and has high recognition accuracy and precision for unfavorable geological bodies.

[0030] 5. The present invention can simultaneously perform two functions: rock mass quality identification and poor geological body prediction. The present invention uses seismic waves generated by drilling and blasting to identify rock mass quality and predict poor geological bodies, without the need for additional seismic sources, thus saving detection costs.

[0031] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the structure of the passive tunnel boring adverse geological detection device of the present invention in application state;

[0033] Figure 2 Schematic diagram of the protection system structure of the present invention;

[0034] Figure 3 This is a schematic diagram of the detection sleeve end structure of the present invention;

[0035] Figure 4 This is a schematic diagram of the cross-sectional structure of a detection sleeve of the present invention;

[0036] Figure 5 This is a schematic diagram of the structure of the magnetic sleeve of the present invention;

[0037] Figure 6 Flow chart of the detection method of the present invention;

[0038] Figure 7 Schematic diagram of the HSP method;

[0039] Figure 8 This is the XOY slice diagram of the reflection wave analysis result;

[0040] Figure 9 Schematic diagram for rock mass quality identification.

[0041] Reference numerals

[0042] 1. Tunnel; 2. Detection device; 3. Reflected wave signal; 4. Face; 5. Advance drilling; 6. Seismic wave signal; 7. Adverse geology; 21. Protection system; 211. Detection sleeve; 212. Mounting hole; 213. Cover; 214. Buckle; 215. Slot; 216. Magnetic sleeve; 217. Handle; 218. Switch; 219. Connector; 2110. Coil; 22. Signal acquisition system; 221. Probe; 222. Protective shell; 223. Convex ring; 224. Groove; 225. Base; 226. Mounting slot; 227. Battery pack; 228. Lifting element; 229. Wire; 23. Signal transmission system; 231. Signal transmission line; 232. Quick connector. DETAILED DESCRIPTION

[0043] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the inventive product is usually placed when in use. These are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. In the description of the present invention, it should also be noted that, unless otherwise expressly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. In the event of any inconsistency, the meaning described in this specification or the meaning derived from the contents recorded in this specification shall prevail. In addition, the terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0045] In order to accurately describe the technical content of this application and to accurately understand the present invention, the following explanations or definitions of the terms used in this specification are given before describing the specific embodiments:

[0046] Drilling and blasting: Drilling and blasting refers to the excavation of rock by drilling, charging, and blasting. Drilling and blasting has long been the primary method for excavating rock for underground structures.

[0047] Water gushing: also known as sudden water inrush, is the phenomenon of sudden large-scale water gushing that occurs during the construction of underground caves and tunnels when passing through areas with developed caves, especially when encountering underground river systems, thick layers of water-bearing gravel layers, and large fault zones connected to surface water.

[0048] Detector: A detector is a device that detects useful information from a fluctuating signal. It is used to identify the presence or change of waves, oscillations, or signals.

[0049] Tunnel face: Tunnel face refers to the top rock surface exposed during tunnel excavation. It is a professional term in tunnel engineering.

[0050] Seismic waves: Seismic waves are the wave phenomenon in which energy generated when underground rocks break or vibrate propagates within the earth. This wave can transmit energy and cause vibration.

[0051] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0052] like Figure 1 As shown. A passive tunnel excavation poor geological detection device includes several detection mechanisms, which are arranged in the advance borehole 5 of the tunnel face 4. The detection mechanism is arranged in the existing advance borehole 5 left by the advance drilling, without adding additional drilling work on site, improving detection efficiency and reducing labor. The detection mechanism includes a protection system 21, a signal acquisition system 22, a signal transmission system 23 and an intelligent terminal system. The signal acquisition system 22 is arranged inside the protection system 21. The protection system 21 is used to protect the signal acquisition system 22 to ensure that the signal acquisition system 22 can collect information at a designated position in front of the tunnel face 4. The signal acquisition system 22 forms a three-dimensional detection array on the tunnel face 4 for collecting seismic wave signals 6. The signal acquisition system 22 is connected to the intelligent terminal system through the signal transmission system 23, and the collected signals are transmitted to the intelligent terminal system for processing. The intelligent terminal system is composed of existing parallel computing units, high-efficiency storage units, professional software and other equipment to achieve noise reduction and display of seismic wave signals 6.

[0053] like Figure 2As shown. The protection system 21 includes a number of detection sleeves 211 connected end to end and a magnetic sleeve 216 for sending the detection sleeve 211 into the advance drilling hole 5. The detection sleeve 211 is provided with a number of mounting holes 212 for allowing the signal acquisition system 22 to pass through the detection sleeve 211, and a cover 213 is provided at the mounting hole 212 to block the mounting hole 212. The interior of the detection sleeve 211 is provided with a power element that drives the cover 213 to open or close the mounting hole 212, and the power element is connected to the intelligent terminal system. The power element can adopt an existing micro-electric cylinder as needed, and the micro-electric cylinder drives the cover 213 to slide in the detection sleeve 211, thereby blocking the mounting hole 212 and reducing the damage or influence of the external environment on the detector.

[0054] The front end of the detection sleeve 211 is provided with a buckle 214, and the rear end of the detection sleeve 211 is provided with a slot 215 that matches the buckle 214. Adjacent detection sleeves 211 are connected by the buckle 214 and the slot 215. The buckle 214 and the slot 215 facilitate the assembly of the detection sleeves 211. The number of detection sleeves 211 assembled according to the required length can meet the needs of testing at different depths.

[0055] like Figure 5 As shown. A connector 219 is provided at one end of the magnetic sleeve 216, and the magnetic sleeve 216 is connected to the detection sleeve 211 through the connector 219. A switch 218 structure is provided on the magnetic sleeve 216 to control the connection or disconnection of the connector 219 and the detection sleeve 211. The switch 218 structure includes a coil 2110, and the coil 2110 is wound on the outer surface of the magnetic sleeve 216. A handle 217 is provided at the other end of the magnetic sleeve 216, and a battery connected to the coil 2110 is provided in the handle 217, and a switch 218 is provided on the handle 217 to control the connection or disconnection of the battery and the coil 2110. The connector 219 and the detection sleeve 211 are both made of ferromagnetic materials, and the handle 217 is made of insulating material.

[0056] After the coil 2110 is energized, the connector 219 generates magnetic force, and the connector 219 magnetically attracts the detection sleeve 211 , thereby sending the detection sleeve 211 into the required depth of the advance borehole 5 through the magnetic sleeve 216 , or taking the detection sleeve 211 out of the advance borehole 5 .

[0057] like Figure 4As shown, the signal acquisition system 22 includes a detector. A base 225 for mounting the detector is located within the detection sleeve 211, corresponding one-to-one with the mounting hole 212. The detector is electrically connected to the base 225, which provides power to the detector. A lifting element 228 is located within the detection sleeve 211 to drive the base 225 up and down. The lifting element 228 is connected to the intelligent terminal system to control the lifting of the lifting element 228. The lifting element 228 can be a conventional micro-electric cylinder and micro-extensor. The lifting element 228 drives the detector to extend from the detection sleeve 211, contact the wall of the advance borehole 5, and thus receive the seismic wave signal 6. A battery pack 227 is located within the detection sleeve 211, connected to the base 225 via a wire 229. The battery pack 227 is connected to the intelligent terminal system to control the switch 218 of the battery pack 227. The detector is connected to the signal transmission system 23.

[0058] According to different construction scales of the tunnel 1 and geological detection requirements, different numbers and spacings of detectors may be arranged in the detection sleeve 211 to achieve optimal detection results.

[0059] The detector includes a probe 221, which is enclosed by an insulating protective housing 222. Protective housing 222 is provided with a metal interface for connecting to probe 221. Probe 221 is connected to a conductive mounting slot 226 on base 225 via the metal interface. Mounting slot 226 is connected to a wire 229. Mounting slot 226 is a copper slot used to transmit seismic wave signals 6 collected by probe 221 to signal transmission system 23.

[0060] A rubber raised ring 223 is provided on the outer surface of the protective housing 222. A groove 224 is provided within the mounting groove 226, which mates with the raised ring 223. The detector is engaged with the base 225 via the raised ring 223 and the groove 224. Pressing the detector forces the raised ring 223 into the groove 224, completing the installation of the detector on the base 225. The detector is easy to install and remove.

[0061] Probe 221 is an existing geophysical probe 221, which is mainly composed of a shell, a mass block (magnet), a coil 2110, a spring and a damper. Among them, the shell protects the internal components and is usually made of strong metal or plastic to prevent the influence of the external environment. The mass block is a high-quality magnet suspended on a spring and moves relative to the coil 2110 when the seismic wave passes. The coil 2110 is wound around the magnet, and when the magnet moves, an induced current is generated in the coil 2110. The spring is used to suspend and stabilize the magnet so that it can move freely and quickly return to the equilibrium position. The specifications of probe 221 are set to a frequency response range of 1Hz to 1000Hz and a sensitivity between 20V / m / s and 100V / m / s.

[0062] like Figure 3 The signal transmission system 23 includes a storage unit and an antenna. The storage unit is connected to the probe 221 via a signal transmission line 231. The storage unit is connected to the antenna via a signal transmission line 231. The antenna is connected to the signal transmission line 231 via a quick connector 232. The signal transmission line 231 is located inside the detection sleeve 211.

[0063] The intelligent terminal system is composed of existing computer system equipment, including a high-efficiency central processing unit, storage units, and specialized platforms. The intelligent terminal system utilizes existing technologies to share a platform with handheld tablets and mobile phones, enabling remote operation of the device, real-time viewing of detector operating status information, and receiving packaged files of sampled seismic waves. The intelligent terminal system utilizes existing technologies to generate adaptive imaging frequencies and resolutions for each inspection location within Tunnel 1 based on the initial refined sampling information from Tunnel 1, balancing the storage and collection of effective data. The intelligent terminal system utilizes existing deep learning technologies to efficiently and accurately identify the visualized seismic wave images, determining the type, distance, and risk level of potential adverse geological conditions 7 ahead of the tunnel face 4. Using existing technologies and a 3D visualization platform, the intelligent terminal system integrates information collected from single or multiple boreholes to create a 3D image of the defect. As Tunnel 1 progresses, the 3D database is updated and improved, forming a 3D geological information database for the region, providing a reference for future engineering construction in similar areas.

[0064] like Figure 6 The detection method based on the above-mentioned passive tunnel boring poor geological detection device includes the following steps:

[0065] S1. Determine the detection requirements according to the size and safety level of the tunnel 1 and determine the total length of the detection sleeve 211.

[0066] S2. Assemble the detection sleeve 211 and install a detector in the detection sleeve 211. Check the detector to ensure that it works normally, and insert the detection sleeve 211 into the advance borehole 5.

[0067] S3. Insert the connector 219 of the magnetic sleeve 216 into the tail end of the terminal detection sleeve 211, turn on the switch 218, and after the coil 2110 is energized, the connector 219 generates magnetic force, the connector 219 is fixed to the magnetic sleeve 216, and the detection sleeve 211 is sent to a specific position in front of the tunnel face 4 through the magnetic sleeve 216; turn off the switch 218, and remove the magnetic sleeve 216 from the advance drilling hole 5.

[0068] S4. The lifting element 228 is controlled to extend through the intelligent terminal system. The lifting element 228 extends the probe 221 of the detector from the mounting hole 212 through the base 225 , and the probe 221 contacts the hole wall of the advance drill hole 5 .

[0069] S5. Hammer the tunnel face 4 to calibrate the wave velocity of the detector.

[0070] S6. Tunnel 1 is blasted, and the detector receives the incident wave signal and the reflected wave signal 3. The detector stores the incident wave signal and the reflected wave signal 3 in the storage unit through the signal transmission line 231 and sends the signal to the intelligent terminal system through the antenna.

[0071] S7. The intelligent terminal system pre-processes the received signal, determines the rock mass quality, and predicts the coordinates and size of the unfavorable geological conditions ahead.

[0072] S8. After completing one inspection of tunnel 1, the intelligent terminal system controls the lifting element 228 to descend, and the probe 221 is retracted into the inspection sleeve 211; the inspection sleeve 211 is removed from the advance borehole 5 via the magnetic sleeve 216; the inspection sleeve 211 and the detector are removed, and preparations are made for the inspection of the next construction face 4.

[0073] The device described in the present invention can realize two functions: prediction of unfavorable geological conditions and identification of rock quality.

[0074] Adverse geological prediction:

[0075] The seismic wave reflection method used is the HSP method. Figure 7 As shown. This method is based on the theory of elastic waves, and the propagation process follows the Huygens-Fresnel principle and the Fermat principle. The prerequisite for implementing this method is that there is a difference in wave impedance in the medium. The wave field propagation speed, particle vibration amplitude, etc. are closely related to the composition, density, structural characteristics, etc. of the medium. By utilizing the characteristics of geological bodies such as fault fracture zones, karst, groundwater, etc. and the background strata, the prediction of unfavorable geological bodies 7 is achieved. During the implementation of HSP, according to the characteristics of tunnel 1 construction, the seismic wave signal 6 generated by the blasting during the construction of tunnel 1 is used as the prediction excitation signal of the HSP method, and the data is received by spatially arranged detectors to realize data acquisition, and the inversion analysis is performed through the deep domain diffraction scanning offset superposition imaging technology. The prediction theoretical formula of the method is as follows:

[0076]

[0077] Where: R 12 Represents the reflection coefficient; ρ1, ρ2 represent the medium density, the unit is kg / m 3 ,υ1,υ2 represent the longitudinal wave velocity in the medium, the unit is m / s.

[0078] Before blasting, the positions of each geophone are first determined based on the position of detection sleeve 211. After determining the positions, wave velocity calibration is performed to determine the propagation velocity of seismic waves in normal strata. After the drilling and blasting method is initiated, the incident seismic wave generated by the blasting propagates toward the front of Tunnel 1. When it encounters geological bodies such as water and cavities, whose wave impedance differs significantly from that of normal strata, it reflects and produces reflected waves. These reflected waves are sequentially received by multiple geophones in a three-dimensional spatial field. The received waveform data is processed through operations such as spectrum analysis, correlation interferometry, and inversion imaging. The time difference between the incident and reflected waves arriving at each geophone is calculated. Using the principle of triangulation, the azimuth coordinates and size of the seven unfavorable geological bodies ahead are calculated, completing the geological forecast and guiding the construction of Tunnel 1.

[0079] The schematic formula of positioning principle is as follows:

[0080]

[0081] Where S represents the earthquake source location, T represents the location of the adverse geological body, G i represents the detector position, v represents the wave velocity, t i Indicates the propagation time.

[0082] For each detector G i , given S and G i In the case of coordinates and v, the t of each detector i The inversion algorithm is used to calculate the position of the reflection source based on the data. The inversion model will iteratively adjust the position of the bad geological body until the error between the calculated propagation time and the arrival time actually recorded by the detector is minimized, and the position T of the bad geological body can be solved.

[0083] The reflection wave analysis results are as follows Figure 8 shown.

[0084] Rock mass quality judgment:

[0085] Regarding the rock mass quality identification function, since the detection device 2 is placed in front of the tunnel face 4, by calculating the time difference between the seismic waves generated by the earthquake source reaching each detector, the quality of the rock mass within a certain distance in front of the tunnel face 4 can be identified. The theoretical prediction formula of this method is as follows:

[0086]

[0087] Where: V P represents the propagation velocity of longitudinal waves; K represents the bulk modulus of the material, G represents the shear modulus of the material, and ρ represents the density of the material.

[0088] like Figure 9As shown in the figure, broken rock is composed of multiple irregular blocks. The contact between particles is less tight than in intact rock, and there are more voids and contact interfaces within the rock. Compared to intact rock, the bulk modulus K is lower, so the propagation speed of seismic waves in broken rock areas is slower than that in intact rock areas. This is reflected in signal collection as different time differences between equally spaced detectors detecting seismic waves. When there is a broken rock area between two detectors, the time it takes for the second detector to detect seismic waves is longer than when there is intact rock between the two detectors. In principle, the more broken the rock, the longer it takes for the second detector to detect seismic waves.

[0089] Therefore, the passive tunnel boring poor geological detection device and method described in the present invention can solve the problems of complex structure, inconvenient use and low detection accuracy of existing devices.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A passive tunnel boring unfavorable geological detection device, characterized by: The system includes several detection mechanisms, which are arranged in the advance borehole of the tunnel face; the detection mechanism includes a protection system, a signal acquisition system, a signal transmission system and an intelligent terminal system. The signal acquisition system is arranged inside the protection system and is used to protect the signal acquisition system. The signal acquisition system is connected to the intelligent terminal system through the signal transmission system and transmits the collected signals to the intelligent terminal system for processing; The protection system includes a plurality of detection sleeves connected end to end and a magnetic sleeve for inserting the detection sleeve into the advance drill hole. The detection sleeve is provided with a plurality of mounting holes for allowing the signal acquisition system to pass through the detection sleeve. The mounting holes are provided with a cover for blocking the mounting holes. The interior of the detection sleeve is provided with a power element for driving the cover to open or close the mounting hole. The power element is connected to the intelligent terminal system. One end of the magnetic sleeve is provided with a connector, the magnetic sleeve is connected to the detection sleeve via the connector, and a switch structure for controlling the connection or disconnection of the connector and the detection sleeve is provided on the magnetic sleeve.

2. A passive tunnel boring unfavorable geological detection device according to claim 1, characterized in that: The head end of the detection sleeve is provided with a buckle, and the tail end of the detection sleeve is provided with a slot adapted to the buckle, and adjacent detection sleeves are connected by the buckle and the slot.

3. The passive tunnel boring unfavorable geological detection device according to claim 1, characterized in that: The switch structure includes a coil, which is wound on the outer surface of a magnetic sleeve. A handle is provided at the other end of the magnetic sleeve. A battery connected to the coil is provided in the handle. A switch for controlling the connection or disconnection of the battery and the coil is provided on the handle. The connector and the detection sleeve are both made of ferromagnetic materials, and the handle is made of insulating material.

4. The passive tunnel boring unfavorable geological detection device according to claim 1, characterized in that: The signal acquisition system includes a detector. A base for mounting the detector is provided inside the detection sleeve. The base corresponds to the mounting hole one-to-one. The detector is electrically connected to the base. A lifting element for driving the base to rise and fall is provided inside the detection sleeve. The lifting element is connected to the intelligent terminal system. A battery pack is provided inside the detection sleeve. The battery pack is connected to the base via a wire, and the battery pack is connected to the intelligent terminal system. The detector is connected to the signal transmission system.

5. The passive tunnel boring unfavorable geological detection device according to claim 4, characterized in that: The detector includes a probe, an insulating protective shell is provided on the outside of the probe, a metal interface connected to the probe is provided on the protective shell, the probe is connected to the conductive mounting groove on the base through the metal interface, and the mounting groove is connected to the wire.

6. A passive tunnel boring unfavorable geological detection device according to claim 5, characterized in that: A rubber convex ring is provided on the outer surface of the protective shell, a groove matched with the convex ring is provided in the installation groove, and the detector is clamped with the base through the convex ring and the groove.

7. The passive tunnel boring unfavorable geological detection device according to claim 1, characterized in that: The signal transmission system includes a storage unit and an antenna. The storage unit is connected to the probe through a signal transmission line. The storage unit is connected to the antenna through a signal transmission line. The antenna is connected to the signal transmission line through a quick connector. The signal transmission line is located inside the detection sleeve.

8. A detection method based on a passive tunnel boring unfavorable geological detection device according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Determine the inspection requirements based on the tunnel size and safety level, and determine the total length of the inspection sleeve; S2. Assemble the detection sleeve and install the detector in the detection sleeve. Check the detector to ensure that it is working properly. Insert the detection sleeve into the advance drill hole. S3. Insert the connector of the magnetic sleeve into the tail end of the terminal detection sleeve, turn on the switch, and when the coil is energized, the connector generates magnetic force, fixing the connector and the magnetic sleeve. The detection sleeve is sent to a specific position in front of the tunnel face through the magnetic sleeve. Turn off the switch and remove the magnetic sleeve from the advance drill hole. S4. The intelligent terminal system is used to control the extension of the lifting element. The lifting element extends the probe of the detector from the mounting hole through the base, and the probe contacts the wall of the advance drilled hole. S5. Hammer the tunnel face to calibrate the wave velocity of the geophone. S6. Tunnel blasting: The detector receives the incident wave signal and the reflected wave signal. The detector stores the incident wave signal and the reflected wave signal in a storage unit through a signal transmission line and sends the signal to the intelligent terminal system through an antenna. S7. The intelligent terminal system pre-processes the received signal, identifies the rock mass quality, and predicts the coordinates and size of the unfavorable geological conditions ahead; S8. After completing a tunnel inspection, the intelligent terminal system controls the lifting element to descend and the probe to be retracted into the inspection sleeve; the inspection sleeve is removed from the advance borehole through the magnetic suction sleeve; the inspection sleeve and detector are removed to prepare for the inspection of the next construction face.

Images