Shield tunneling soft and hard stratum interface identification method and system based on change characteristics of slag

Abstract

The application provides a shield soft-hard stratum interface identification method and system based on slag change characteristics, which comprises the following steps: processing images at a slag outlet to obtain slag shape and volume, and obtaining the properties of hard rock stratum based on the slag shape and volume; performing real-time scanning on shield slag, determining the scanning surface of the surrounding environment through distance measurement values and angle values, forming a shield slag reconstruction model based on laser point cloud scanning, and obtaining the volume of the shield slag based on the shield slag reconstruction model; calculating the hard rock area proportion in the soft-hard interface according to the slag volume and the shield slag volume; obtaining the vibration signal of a shield cutter when the shield cutter enters a hard rock stratum from a soft stratum during the tunneling process of a shield tunneling machine in a composite stratum, and obtaining the change interface position of the soft-hard stratum according to the vibration signal; and drawing a shield excavation surface soft-hard stratum interface sketch based on the hard rock area proportion in the soft-hard interface and the change interface position of the soft-hard stratum, and identifying the shield excavation surface soft-hard stratum interface.

Description

Technical Field

[0001] This invention belongs to the field of shield tunneling face recognition technology, and particularly relates to a method and system for identifying the interface between soft and hard strata in shield tunneling based on the characteristics of soil and excavation changes. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With rapid economic development and the continuous expansion of urban scale, the construction of three-dimensional urban transportation has become the main trend in passenger transport development. Urban infrastructure transportation construction is evolving from ground-level construction to high-altitude and deep-ground construction. The shield tunneling method, with its advantages of high mechanization, safety, efficiency, environmental friendliness, and minimal ground disturbance, has become the mainstream construction method for underground engineering. However, given the complex and diverse geological features of various urban areas, the safe passage of shield tunnels faces significant challenges. Accurate perception of the geological conditions ahead of the tunnel excavation face is a crucial prerequisite for ensuring safe shield tunneling. Before shield construction, the mileage of adverse geological sections and the characteristics of adverse geological bodies should be clearly identified, risk analysis and early warning should be conducted, and targeted control measures should be formulated. Otherwise, serious safety accidents such as sudden water and sand inrush, ground collapse, and instability of the excavation face can easily occur.

[0004] However, in actual construction, the initial exploration often combines drilling and geophysical exploration. But drilling is mainly point-based exploration, making it difficult to obtain continuous and effective geological information. Furthermore, during the actual tunnel boring machine (TBM) construction, the excavation face in front of the TBM is under pressure, making it impossible to directly observe the condition of the excavation face. Therefore, how to quickly identify the excavation face ahead has become a key challenge for the safe tunneling of TBMs. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides a method and system for identifying the interface between soft and hard strata in tunnel boring machines based on the characteristics of soil and slag changes, which can quickly identify the excavation face ahead.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0007] Firstly, a method for identifying the interface between soft and hard strata in tunnel boring machines based on the characteristics of soil and slag variation is disclosed, including:

[0008] The image at the slag outlet is processed to obtain the shape and volume of the rock slag, and the properties of the hard rock layer are obtained based on the shape and volume of the rock slag.

[0009] The shield tunnel excavation soil is scanned in real time. The scanning surface of the surrounding environment is determined by distance measurement and angle value, forming a shield tunnel excavation soil reconstruction model based on laser point cloud scanning. The volume of the excavation soil is obtained based on the shield tunnel excavation soil reconstruction model.

[0010] The proportion of hard rock region in the soft-hard interface is calculated based on the volume of rock debris and soil.

[0011] The vibration signal of the shield cutterhead when it enters hard rock strata from soft strata during the tunneling process of the shield tunneling machine in composite strata is obtained, and the location of the interface between soft and hard strata is obtained accordingly.

[0012] Based on the proportion of hard rock areas in the hard-soft interface and the changing interface location of the hard-soft strata, a sketch of the hard-soft strata interface of the shield tunnel excavation face is drawn to identify the hard-soft strata interface of the shield tunnel excavation face.

[0013] As a further technical solution, before processing the image at the slag outlet, a high-definition image of the slag outlet is first obtained. Video frames are extracted at a frequency of one frame per set frame. Images taken with damaged lenses, as well as mosaic-like and redundant images caused by video stuttering, are removed to obtain effective images.

[0014] As a further technical solution, when extracting video frames at a frequency of one frame per set frame, the specific frame extraction frequency can be adjusted according to the tunnel boring machine's advancing speed.

[0015] As a further technical solution, the image at the slag outlet is processed, specifically including: binarizing the processed effective image, marking the rock slag area in the image using the watershed algorithm, calculating the rock slag volume and maximum radius using the equivalent elliptic algorithm, and determining the surrounding rock type based on the shape, volume, and gradation parameters of the rock slag generated during the tunneling process.

[0016] As a further technical solution, it also includes the step of constructing a relevant historical database: based on the fact that the shape, volume and gradation parameters of rock debris produced by different types of rocks under the action of the tunnel cutterhead all change, a relevant historical database is constructed using indoor tests, and the type of surrounding rock is determined based on the shape, volume and gradation parameters of the rock debris produced during the tunneling process.

[0017] As a further technical solution, when obtaining the volume of the excavated soil based on the shield excavation soil reconstruction model, a laser scanning radar is installed above the shield excavation conveyor belt to scan the shield excavated soil in real time.

[0018] As a further technical solution, when obtaining the location of the interface between soft and hard strata, the specific steps are as follows: when entering hard rock strata from soft strata, the strata properties change, and the shield cutterhead will vibrate under the same tunneling parameters. The vibration sensor arranged on the cutterhead receives and records the rotation orientation of the shield cutterhead at the time of data acquisition, thereby determining the spatial position of each signal acquisition system, and thus obtaining the location of the interface between soft and hard strata.

[0019] Secondly, a shield tunneling face soft and hard strata interface identification system based on the characteristics of soil and debris changes was disclosed, including:

[0020] The module for acquiring the properties of hard rock layers is configured to: process the image at the slag outlet to obtain the shape and volume of rock slag, and obtain the properties of hard rock layers based on the shape and volume of rock slag.

[0021] The slag volume acquisition module is configured to: perform real-time scanning of the shield tunnel slag, determine the scanning surface of the surrounding environment through distance measurement values ​​and angle values, form a shield tunnel slag reconstruction model based on laser point cloud scanning, and obtain the slag volume based on the shield tunnel slag reconstruction model;

[0022] The proportion of hard rock region in the soft-hard interface is calculated based on the volume of rock debris and soil.

[0023] The module for obtaining the change interface position is configured to obtain the change interface position of the soft and hard strata based on the vibration signal of the shield cutterhead when it enters the hard rock strata from the soft strata during the tunneling process of the shield tunneling machine in composite strata.

[0024] The module for identifying the interface between soft and hard strata at the excavation face is configured to: draw a sketch of the interface between soft and hard strata at the shield tunneling excavation face based on the proportion of hard rock areas in the interface and the changing interface position of soft and hard strata, and then identify the interface between soft and hard strata at the shield tunneling excavation face.

[0025] The above one or more technical solutions have the following beneficial effects:

[0026] The excavation face identification method proposed in this invention can continuously identify the excavation face in real time as the tunnel boring machine (TBM) advances, providing more continuous observation compared to drilling methods. Electromagnetic interference resistance: Unlike electromagnetic methods, the method proposed in this invention does not rely solely on electromagnetic waves, thus minimizing the impact of electromagnetic interference on the shield.

[0027] The method proposed in this invention integrates the identification of excavated soil and the vibration identification of the front roller cutter, combined with geological survey data, to more detailedly map the location and properties of the interface between soft and hard strata at the excavation face.

[0028] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0030] Figure 1 The implementation flow of the method proposed in the embodiments of the present invention;

[0031] Figure 2This is a schematic diagram showing the mounting position of the equipment mentioned in the embodiment of the present invention in the tunnel boring machine;

[0032] Figure 3 A schematic diagram of the composite strata at the shield tunnel excavation face is drawn for an embodiment of the present invention. Detailed Implementation

[0033] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0034] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0035] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0036] Example 1

[0037] This embodiment discloses a method for identifying the interface between soft and hard strata in tunnel boring machines based on the characteristics of soil and slag variation, including:

[0038] Step (1) Real-time scanning is performed using three-dimensional laser scanning, and a point cloud model is constructed, thereby calculating the particle size distribution ratio of the slag.

[0039] Step (2) Use the vibration sound of the cutter head as it moves from soft, moist strata into hard rock strata to determine the stratigraphic transition interface;

[0040] Step (3) integrates the aforementioned information to identify the geological strata distribution at the shield tunneling face.

[0041] The shield tunneling composite stratum excavation face identification method proposed in this invention has good identification continuity and strong anti-interference ability. Compared with traditional methods, it can achieve a more detailed exploration of the shield tunneling excavation face without directly observing the excavation face.

[0042] In one implementation example, step (1) involves identifying the properties of hard soil layers:

[0043] 1) Acquisition of slag and soil images:

[0044] A shield muck monitoring module 2 is installed above the shield muck conveyor belt 1 behind the shield. The shield muck monitoring module 2 includes a high-definition camera to capture high-speed images of the shield muck and obtain high-definition images at the muck outlet. Video frames are extracted at a frequency of one frame every 30 frames. The specific frame extraction frequency can be adjusted according to the muck discharge speed of the shield machine's screw conveyor. If the muck discharge speed is fast, the frame extraction speed is increased, and vice versa. Images captured by lenses with dirt, as well as mosaic and redundant images caused by video lag, are discarded.

[0045] 2) Identification of properties of hard strata

[0046] The aforementioned valid images are binarized, and the rock debris region in the image is marked using the watershed algorithm. The equivalent elliptic algorithm is used to perform equivalent calculations on the rock debris to obtain the volume and maximum radius of the rock debris, which can be used for the determination of the surrounding rock type in the following text.

[0047] It should be noted that the watershed algorithm is a common image calibration algorithm and is a commonly used image calibration algorithm in this field, so it will not be described in detail here.

[0048] Equivalent Ellipticity Algorithm: The rock debris is equivalent to an ellipticity, and the pixel values ​​of the principal and secondary axes are calibrated as a. p and b p The actual size is obtained by converting the formula (1), and the equivalent volume of rock slag is obtained by calculating the ellipsoid.

[0049]

[0050] Where: x is the actual size, x p Here, l is the pixel value of the size, and l is the actual size of the image. p The pixel size of the image

[0051] The shape, volume, and gradation parameters of rock debris produced by different types of rocks under the action of the tunnel boring machine cutter vary. Therefore, by using indoor tests, a historical database related to the above content can be constructed, and the type of surrounding rock can be determined based on the shape, volume, and gradation parameters of the rock debris produced during the tunneling process.

[0052] In one implementation example, step (2) involves identifying the volume of the excavated soil.

[0053] A laser scanning radar is installed above the shield muck conveyor belt 1 behind the shield tunnel to perform real-time scanning of the shield muck. The scanning surface of the surrounding environment is determined by distance and angle measurements, with a cross-sectional area of ​​S1, forming a shield muck reconstruction model based on laser point cloud scanning. This is combined with the shield conveyor belt design, specifically the scanning surface area S2 when the conveyor is unloaded, and the instantaneous velocity information v collected by the velocity sensor at that moment. i The volume of the slag at the current moment, V, can be obtained by calculating the volume as shown in equation (1). The total volume of the slag can be obtained by accumulating the volume. Combined with the volume of rock debris obtained in step 1 above, the proportion of hard rock area in the soft-hard interface can be calculated. The proportion of hard rock area = volume of rock debris ÷ total volume of slag. This provides a reference for the subsequent geological drawing of the soft-hard stratum interface, and serves as a correction data value to improve the accuracy of the sketch.

[0054] V = (S1 - S2) × v i ×(t i -t i-1(1)

[0055] Where: V refers to the volume of excavated soil at the current moment, S1 is the scanning area of ​​the excavated soil from the shield tunnel, S2 is the scanning area of ​​the conveyor belt when it is unloaded, v i For instantaneous velocity, (t) i -t i-1 ) represents the size of the selected time point.

[0056] A lidar is a two-dimensional photoelectric measurement system. One dimension is the laser ranging system, which uses lasers to measure the distance between the lidar and the surrounding environment. The other dimension is the angle control system, which controls the angle between the measuring laser and the surrounding environment by controlling the motor.

[0057] In one implementation example, step (3) involves identifying the interface between soft and hard strata at the shield excavation face.

[0058] During the tunneling process in complex strata, when the shield cutterhead enters hard rock strata from soft strata, the strata properties change, and the shield cutterhead will vibrate under the same tunneling parameters. The vibration sensor 3 arranged on the cutterhead receives and records the rotation position of the shield cutterhead at the time of data acquisition, thereby determining the spatial position of each signal acquisition system and obtaining the position of the interface between soft and hard strata.

[0059] In one implementation example, step (4) involves drawing a sketch of the interface between the soft and hard strata at the tunnel excavation face.

[0060] Based on the actual excavation dimensions of the tunnel boring machine and the project's geological survey data, combined with the information obtained in steps 1-3 above, such as the type of hard rock, the proportion of hard rock areas at the soft-hard interface, and the location of the interface between soft and hard strata, the following diagram is drawn: Figure 3 The diagram shows a sketch of the interface between soft and hard strata at the shield tunneling face, with the properties of the hard rock strata marked, providing a reference for setting shield tunneling parameters.

[0061] like Figure 2 As shown, the components involved in this embodiment of the invention are the shield tunnel muck conveyor belt 1, the shield tunnel muck monitoring module 2, which includes a laser scanning radar and a high-definition camera, and a cutterhead vibration detector 3.

[0062] like Figure 3 As shown, the parts are the shield excavation face software interface 4 and the hard rock part of the soft-hard interface 5.

[0063] Example 2

[0064] The purpose of this embodiment is to provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the above-described method.

[0065] Example 3

[0066] The purpose of this embodiment is to provide a computer-readable storage medium.

[0067] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the steps of the above method.

[0068] Example 4

[0069] The purpose of this embodiment is to provide a shield tunneling soft-hard stratum interface identification system based on the characteristics of soil variation, including:

[0070] The module for acquiring the properties of hard rock layers is configured to: process the image at the slag outlet to obtain the shape and volume of rock slag, and obtain the properties of hard rock layers based on the shape and volume of rock slag.

[0071] The slag volume acquisition module is configured to: perform real-time scanning of the shield tunnel slag, determine the scanning surface of the surrounding environment through distance measurement values ​​and angle values, form a shield tunnel slag reconstruction model based on laser point cloud scanning, and obtain the slag volume based on the shield tunnel slag reconstruction model;

[0072] The proportion of hard rock region in the soft-hard interface is calculated based on the volume of rock debris and soil.

[0073] The module for obtaining the change interface position is configured to obtain the change interface position of the soft and hard strata based on the vibration signal of the shield cutterhead when it enters the hard rock strata from the soft strata during the tunneling process of the shield tunneling machine in composite strata.

[0074] The module for identifying the interface between soft and hard strata at the excavation face is configured to: draw a sketch of the interface between soft and hard strata at the shield tunneling excavation face based on the proportion of hard rock areas in the interface and the changing interface position of soft and hard strata, and then identify the interface between soft and hard strata at the shield tunneling excavation face.

[0075] The steps and methods involved in the apparatuses of Embodiments 2, 3, and 4 above correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.

[0076] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0077] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for identifying the interface between soft and hard strata in shield tunneling based on the characteristics of spoil change, characterized by: include: The image at the slag outlet is processed to obtain the shape and volume of the rock slag, and the properties of the hard rock layer are obtained based on the shape and volume of the rock slag. Before processing the image at the slag outlet, a high-definition image of the slag outlet is obtained. Video frames are extracted at a frequency of one frame per set frame. Images taken with damaged lenses, as well as mosaic-like and redundant images caused by video stuttering, are removed to obtain effective images. The image at the slag outlet is processed, specifically including: binarizing the processed effective image, marking the rock slag area in the image using the watershed algorithm, calculating the volume and maximum radius of the rock slag using the equivalent elliptic algorithm, and determining the surrounding rock type based on the shape, volume, and gradation parameters of the rock slag generated during the tunneling process. Based on the fact that the shape, volume and gradation parameters of rock debris produced by different types of rocks under the action of shield cutterhead vary, a relevant historical database was constructed using indoor tests, and the type of surrounding rock was determined based on the shape, volume and gradation parameters of the rock debris produced during the tunneling process. A laser scanning radar is installed above the muck conveyor belt of the tunnel boring machine (TBM) to scan the muck in real time. The scanning surface of the surrounding environment is determined by distance and angle measurements, forming a reconstruction model of the muck based on laser point cloud scanning. The volume V of the muck is obtained from the reconstruction model, as shown in the following formula: V=(S1-S2)×v i ×(t i -t i-1 ); Where: V refers to the volume of excavated soil at the current moment, S1 is the scanning area of ​​the excavated soil from the shield tunnel, S2 is the scanning area of ​​the conveyor belt when it is unloaded, v i For instantaneous velocity, (t) i -t i-1 () represents the size of the selected time point; The proportion of hard rock area in the soft-hard interface is calculated based on the volume of rock debris and soil. The proportion of hard rock area = volume of rock debris ÷ total volume of soil. This provides a reference for subsequent geological mapping of the soft-hard strata interface and serves as a correction data value. The vibration signal of the shield cutterhead when it enters hard rock strata from soft strata during the tunneling process of the shield tunneling machine in composite strata is obtained, and the location of the interface between soft and hard strata is obtained accordingly. Based on the proportion of hard rock areas in the hard-soft interface and the changing interface location of the hard-soft strata, a sketch of the hard-soft strata interface of the shield tunnel excavation face is drawn to identify the hard-soft strata interface of the shield tunnel excavation face. When obtaining the location of the interface between soft and hard strata, specifically: when entering hard rock strata from soft strata, the strata properties change, and the shield cutterhead will vibrate under the same tunneling parameters. The vibration sensor arranged on the cutterhead receives and records the rotation orientation of the shield cutterhead at the time of data acquisition, thereby determining the spatial position of each signal acquisition system, and thus obtaining the location of the interface between soft and hard strata.

2. The shield tunneling soft-hard stratum interface identification method based on the characteristics of soil variation as described in claim 1, characterized in that, When extracting video frames at a frequency of one frame per set frame, the specific frame extraction frequency can be adjusted according to the tunnel boring machine's advancing speed.

3. A shield tunneling soft-hard stratum interface identification system based on the characteristics of spoil change, characterized by: include: The module for acquiring the properties of hard rock layers is configured to: process the image at the slag outlet to obtain the shape and volume of the rock slag, and obtain the properties of the hard rock layer based on the shape and volume of the rock slag; before processing the image at the slag outlet, a high-definition image at the slag outlet is first obtained, and video frames are extracted at a frequency of one frame per set frame to remove images taken under lens damage, as well as mosaic-like and redundant images caused by video lag, and obtain valid images; The image at the slag outlet is processed, specifically including: binarizing the processed effective image, marking the rock slag area in the image using the watershed algorithm, calculating the volume and maximum radius of the rock slag using the equivalent elliptic algorithm, and determining the surrounding rock type based on the shape, volume, and gradation parameters of the rock slag generated during the tunneling process. Based on the fact that the shape, volume and gradation parameters of rock debris produced by different types of rocks under the action of shield cutterhead vary, a relevant historical database was constructed using indoor tests, and the type of surrounding rock was determined based on the shape, volume and gradation parameters of the rock debris produced during the tunneling process. The muck volume acquisition module is configured to: install a laser scanning radar above the shield tunnel muck conveyor belt to scan the muck in real time; determine the scanning surface of the surrounding environment through distance and angle measurements; form a shield muck reconstruction model based on laser point cloud scanning; and obtain the muck volume V based on the shield muck reconstruction model, as shown in the following formula: V=(S1-S2)×v i ×(t i -t i-1 ); Where: V refers to the volume of excavated soil at the current moment, S1 is the scanning area of ​​the excavated soil from the shield tunnel, S2 is the scanning area of ​​the conveyor belt when it is unloaded, v i For instantaneous velocity, (t) i -t i-1 () represents the size of the selected time point; The proportion of hard rock area in the soft-hard interface is calculated based on the volume of rock debris and soil. The proportion of hard rock area = volume of rock debris ÷ total volume of soil. This provides a reference for subsequent geological mapping of the soft-hard strata interface and serves as a correction data value. The module for obtaining the change interface position is configured to obtain the change interface position of the soft and hard strata based on the vibration signal of the shield cutterhead when it enters the hard rock strata from the soft strata during the tunneling process of the shield tunneling machine in composite strata. The module for identifying the interface between soft and hard strata at the excavation face is configured to: draw a sketch of the interface between soft and hard strata at the shield tunneling excavation face based on the proportion of hard rock areas in the interface and the location of the interface where soft and hard strata change, and then identify the interface between soft and hard strata at the shield tunneling excavation face. When obtaining the location of the interface between soft and hard strata, specifically: when entering hard rock strata from soft strata, the strata properties change, and the shield cutterhead will vibrate under the same tunneling parameters. The vibration sensor arranged on the cutterhead receives and records the rotation orientation of the shield cutterhead at the time of data acquisition, thereby determining the spatial position of each signal acquisition system, and thus obtaining the location of the interface between soft and hard strata.

4. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method described in any one of claims 1-2.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it performs the steps of the method described in any of claims 1-2 above.

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