A method for monitoring the jamming of a tunnel boring machine

Abstract

The present invention discloses a method for monitoring the jamming of a tunnel boring machine, which relates to the technical field of full-face hard rock tunnel boring machines. The key points of its technical solution are as follows: vibration sensors are respectively installed on the inner surface of the shield and the outer surface of the main beam, and an industrial control computer is installed in the TBM control room. Then, according to the vibration signal data collected at the shield and the main beam, by analyzing the time-domain and frequency-domain characteristics of the data and the correlation between the Pearson coefficient and the spectrum coefficient to illustrate the similarity of the vibration signals at the two parts, the tunneling state and the jamming position of the TBM are judged accordingly, so as to achieve the goal of reducing the risk of TBM jamming.

Description

Technical Field

[0001] The present invention relates to the technical field of full-face hard rock tunnel boring machines, and more specifically, to a method for monitoring the jamming of a tunnel boring machine. Background Art

[0002] Tunnel Boring Machines (TBMs) have received increasing attention due to their advantages such as fast construction speed, safety and high efficiency, and low requirements for the density of operating personnel. With the continuous improvement of China's capabilities in TBM design, R & D, and production, the number of tunnels excavated using full-face rock tunnel boring machines has been increasing year by year. In recent years, tunnel construction in China has gradually developed towards longer and deeper-buried directions, which has enabled the TBM method to play an important role in such tunnel excavations. However, when TBMs are used to penetrate deep-buried, high in-situ stress, and soft and fractured strata, due to construction factors such as excavation disturbance, the surrounding rock may undergo significant deformation, resulting in the jamming of the TBM. This situation not only threatens the safety of on-site personnel but may also cause damage to mechanical equipment, thus seriously affecting the construction progress.

[0003] During the shielded tunneling process of a Tunnel Boring Machine (TBM), shield jamming accidents are the main problem leading to TBM jamming. The frequent occurrence of such accidents is due to the fact that when the TBM tunnels, it disturbs the surrounding rock, resulting in radial deformations such as local large deformations, creep, and overall convergence of the surrounding rock. If the deformation amount of the surrounding rock exceeds the over-excavation space reserved during the construction process, the shield of the TBM will be squeezed by the surrounding rock. This squeezing will increase the frictional resistance of the shield, and when the frictional resistance reaches a certain level, it may cause the TBM to jam.

[0004] To solve the above problems, Chinese Patent (Patent Publication No.: CN113008157A) discloses a method for monitoring the deformation of the inner surface of the shield of a tunnel boring machine, including: ① Marking monitoring points on the inner surface of the shield, which are distributed in multiple groups in the middle and rear parts of the shield. Each group of monitoring points is arranged circumferentially along the cross-section of the shield, and the distribution density of the monitoring points at the top of the shield is greater than that on both sides of the shield. ② Installing a set of optical strain gauges at each monitoring point. Each set of optical strain gauges includes a first strain gauge arranged along the axial direction of the shield and a second strain gauge arranged along the circumferential direction of the shield. ③ Installing a strain data acquisition instrument and a host computer inside the shield. ④ Installing a data processor in the construction site monitoring room. ⑤ Conducting data analysis to estimate the magnitude of the force between the surrounding rock and the shield, and based on this, predicting the tunneling state and jamming position of the tunnel boring machine to reduce the risk of jamming.

[0005] The above solution monitors the deformation of the inner surface of the shield through optical strain gauges, so as to achieve the purpose of predicting the tunneling state of the TBM and the position of the stuck machine and reducing the risk of machine jamming. However, there are still some defects in the method for monitoring the deformation of the inner surface of the tunnel boring machine shield: First, the above solution mainly relies on optical strain gauges to monitor the deformation of the inner surface of the shield, and judges the tunneling state by calculating the force between the surrounding rock and the shield. This method mainly monitors the deformation of the shield, and the relationship between the deformation and the stuck machine is not always direct, and there may be a risk of misjudgment. Second, the above solution needs to calculate the force through data analysis and indirectly judge the stuck machine situation based on the force. This process may have a certain delay, and requires a more complex calculation and analysis process, with a low degree of automation. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for monitoring the stuck machine of a tunnel boring machine to solve the problems of limitations in monitoring means, low real-time performance and low degree of automation in the prior art.

[0007] The above technical purpose of the present invention is achieved through the following technical solutions: A method for monitoring the stuck machine of a tunnel boring machine includes the following steps:

[0008] S1: Select appropriate monitoring points on the inner surface of the TBM shield and the outer surface of the main beam and mark them;

[0009] S2: Install vibration sensors at the monitoring points described in step S1, and the vibration sensors include data acquisition and transmission devices;

[0010] S3: Transmit the vibration signal data collected in step S2 to the industrial control computer in the TBM control room, and automatically collect and store the vibration signal data during the tunneling process in real time;

[0011] S4: Analyze the time domain, frequency domain characteristics and correlation of the vibration signal data obtained in step S3, judge the tunneling state and the position of the stuck machine of the TBM, so as to reduce the risk of machine jamming.

[0012] The present invention is further configured as: The layout method of the monitoring points on the shield surface in step S1 is specifically: The monitoring points are arranged circumferentially along the cross section of the shield, and the number of monitoring points arranged on the top of the shield is more than the number of monitoring points on both sides and the bottom of the shield.

[0013] The present invention is further configured as: The layout method of the monitoring points on the outer surface of the main beam in step S1 is specifically: The monitoring points are arranged longitudinally at certain intervals along the outer surface of the TBM main beam.

[0014] The present invention is further configured as: The vibration sensor in step S2 uses an acceleration vibration sensor.

[0015] By adopting the above technical solutions, the present invention can accurately monitor the vibration of key parts of the tunnel boring machine (TBM) by selecting and marking appropriate monitoring points on the inner surface of the TBM shield and the outer surface of the main beam, and installing acceleration vibration sensors at these points. The optimized layout of the monitoring points, especially the increase in the number of points at the top of the shield and the longitudinal layout strategy on the outer surface of the main beam, enables the entire monitoring system to capture the vibration changes of the TBM more comprehensively and sensitively, providing high-quality data support for subsequent data analysis and ensuring the comprehensiveness and representativeness of the data. The present invention also collects the vibration signal data during the tunneling process in real time through the vibration sensors and transmits it to the industrial control computer in the TBM control room by wired or wireless means, ensuring the timeliness and accuracy of the data. The real-time automated data acquisition and storage system reduces the need for human intervention and improves the reliability of the data;

[0016] In the analysis stage, the present invention can accurately judge the tunneling state and the position of the jammed machine of the TBM by comprehensively analyzing the time-domain and frequency-domain characteristics of the vibration signal data, as well as the correlation between the Pearson coefficient and the spectral coefficient, which helps to improve the accuracy of the judgment. And by accurately judging the tunneling state and the position of the jammed machine, measures can be taken in a timely manner to reduce the risk of the TBM getting jammed during the tunnel boring process, thereby improving the engineering efficiency and reducing the delays and losses caused by the jammed machine.

[0017] The present invention is further configured as follows: The specific method for judging the position of the jammed machine in step S4 is to analyze the vibration signal data obtained in step S3, and obtain the vibration signals of the main beam and the shield through time-domain signal analysis of the mean value, standard deviation, root mean square amplitude, and root mean square, and frequency-domain signal analysis of the spectral mean value, spectral variance, spectral centroid, and frequency standard deviation after Fourier transform, and compare the similarity between the two. And based on the correlation results of the Pearson coefficient and the spectral coefficient, combined with the on-site construction situation, judge the tunneling state of the TBM, evaluate whether the jammed machine occurs, and determine the position of the jammed machine.

[0018] The present invention is further configured as follows: The specific method of the Fourier transform is as follows: Sampling the continuous time-domain signal to obtain the discrete time-domain signal x(n), and then using the discrete Fourier transform to convert the discrete time-domain signal x(n) into the frequency-domain signal f(k). The specific formula is as follows:

[0019]

[0020] The i in the above formula is the imaginary unit,

[0021] The present invention is further configured as follows: The Pearson coefficient evaluates the correlation of the vibration signals of the main beam and the shield. The specific formula is as follows:

[0022]

[0023] Cov(X,Y) in the above formula is the covariance of the vibration signals at the monitoring points on the main beam and the shield, and σ X , σ Y are the standard deviations of the vibration signals of the main beam and the shield respectively. The value range of the Pearson correlation coefficient r pcc is [-1, 1].

[0024] The present invention is further configured as: the spectral coefficient evaluates the correlation of the vibration signals of the main beam and the shield, and the specific formula is as follows:

[0025]

[0026] In the above formula, are the spectral values of the vibration signals at the main beam and the shield respectively, is the conjugate complex number of the spectral value of the vibration signal at the shield, and the spectral correlation coefficient r scc The value range of is [-1, 1].

[0027] The present invention is further configured as: in step S4, the risk of TBM jamming is judged according to the correlation between the Pearson correlation coefficient r pcc and the spectral correlation coefficient r scc , and the specific judgment method is as follows:

[0028] TBM is tunneling normally:

[0029] TBM has a risk of jamming:

[0030] TBM has a serious jamming:

[0031] By adopting the above technical solutions, the present invention provides a multi-dimensional analysis of vibration signal data through the comprehensive analysis of the mean value, standard deviation, root mean square amplitude, root mean square time domain characteristics of the vibration signal, and the spectral mean value, spectral variance, spectral centroid, and frequency standard deviation after Fourier transform. Such a method can not only capture the overall change trend of the vibration signal, but also deeply understand the change of the frequency components of the signal, and can more accurately identify the vibration signal characteristics of the main beam and the shield; the present invention uses the discrete Fourier transform to convert the sampled discrete time domain signal into a frequency domain signal, providing an efficient signal conversion and analysis method. The use of the Fourier transform makes the analysis of the frequency components of the vibration signal more intuitive and accurate, so as to better identify possible abnormal situations during tunneling;

[0032] The present invention evaluates the correlation between the vibration signals of the main beam and the shield through the Pearson correlation coefficient and the spectral correlation coefficient, which can effectively quantify the similarity of the vibration signals of the two. The value ranges of these correlation indexes are clear ([-1, 1]), which can intuitively reflect the linear relationship and spectral relationship between the vibration signals, and help to more reliably judge the tunneling state of the TBM and the risk of jamming; the present invention can accurately judge the tunneling state, evaluate the jamming risk and determine the jamming position by comparing the similarity of time-domain characteristics and spectral characteristics and combining the correlation of the Pearson coefficient and the spectral coefficient; according to the specific value ranges of the Pearson correlation coefficient and the spectral correlation coefficient, the present invention sets three different risk judgment criteria of normal tunneling, jamming risk, and serious jamming, providing clear judgment basis and operation guidelines for on-site construction personnel. The division of such risk levels makes on-site monitoring and emergency decision-making faster and more accurate, reduces human judgment errors, and improves construction safety and efficiency.

[0033] In summary, the present invention has the following beneficial effects:

[0034] The jamming monitoring method for a tunnel boring machine provided by the present invention installs vibration sensors on the inner surface of the shield and the outer surface of the main beam respectively, installs an industrial control computer in the TBM control room, and then, according to the vibration signal data collected at the shield and the main beam, analyzes the time-domain and frequency-domain characteristics of the data and the correlation of the Pearson coefficient and the spectral coefficient to illustrate the similarity of the vibration signals at the two parts, and accordingly judges the tunneling state and the jamming position of the TBM, achieving the goal of reducing the jamming risk of the TBM. Description of the Drawings

[0035] Figure 1 It is an analysis diagram of the vibration signals and correlation coefficients of the top shield and the side shield of the TBM in the embodiment of the present invention;

[0036] Figure 2 It is a schematic diagram of the layout of the vibration signal monitoring points of the main beam and the shield of the TBM in the embodiment of the present invention;

[0037] Figure 3 It is a flow chart of the jamming risk determination of the TBM in the embodiment of the present invention. Detailed Embodiment

[0038] The following further describes the present invention in detail with reference to the attached Figures 1-3 drawings.

[0039] Embodiment: A jamming monitoring method for a tunnel boring machine includes the following steps:

[0040] Step S1: Select appropriate vibration monitoring points on the outer surface of the TBM main beam and the inner surface of the shield, and mark them.

[0041] The selection of the monitoring points is carried out according to the following principles:

[0042] ①The monitoring points shall be arranged at positions that do not affect the normal operation and tunneling of the TBM, and ensure that the monitoring points are relatively concealed and not damaged by construction.

[0043] ②To accurately collect the vibration signals of each group of monitoring points, it is required that there are no other interference sources on the outer surface of the main beam and the inner surface of the shield near the monitoring points, and ensure that the vibration sensors are not affected by factors such as temperature, humidity, and electromagnetic interference.

[0044] ③Since the shield jamming at the crown and shoulders occurs relatively frequently during the TBM tunneling process, the monitoring points should be arranged as many as possible at the crown, left and right shoulders of the upper half of the shield. At the same time, a certain number of monitoring points also need to be arranged at the lower half of the shield, and the arrangement of each group of monitoring points should ensure symmetry about the central axis of the TBM shield cross-section.

[0045] Specifically, in the present invention, each group of monitoring points is longitudinally arranged along the main beam cross-section and circumferentially arranged along the shield cross-section. The schematic layout of the main beam monitoring points and the shield monitoring points is as Figure 2 shown. One group of monitoring points on the shield cross-section altogether includes 7 vibration monitoring points. Each group of monitoring points is symmetrically arranged about the central axis of the TBM shield cross-section, and each group of monitoring points is coaxially arranged with the monitoring points in front of or behind it. Monitoring points No. ① - ⑦ are evenly arranged at an interval of 30° on the upper semi-circle of the shield. For the TBM shield with an extra-large diameter, the number of monitoring points on the shield circumference can be increased according to the actual situation and requirements. Each group of monitoring points is coaxially arranged with the monitoring points in front of or behind it.

[0046] Step S2: Arrange a group of vibration sensors at each monitoring point selected in Step 1. Each group of vibration sensors is arranged longitudinally along the main beam and circumferentially along the shield.

[0047] The present invention selects and uses acceleration vibration sensors. The acceleration sensor obtains its vibration characteristics by measuring the acceleration of an object in different directions, and is particularly suitable for the vibration monitoring of large-scale mechanical equipment such as TBMs. Compared with velocity sensors and displacement sensors, the acceleration sensor can more sensitively capture the minute changes in vibration, and has higher accuracy for identifying the working state of the TBM and judging the risk of jamming.

[0048] Specifically, before installing the vibration sensor, it is necessary to thoroughly clean the surfaces of the TBM main beam and the shield to ensure close contact between the sensor and the measured surface and avoid interference sources that may affect signal accuracy. Before installation, the sensor needs to be carefully inspected to ensure that its appearance is intact, the interfaces and connection wires are in good condition, and the sensitivity and accuracy meet the requirements. During the installation process, the sensor should be firmly fixed at the selected position, and the direction and angle should meet the design requirements to ensure the accuracy and representativeness of signal acquisition. After installation, the wiring should be correctly connected to avoid interference and friction. Finally, hardware debugging is carried out to confirm normal data output, no signal interference or loss, and all installation and debugging situations are recorded and confirmed to ensure the normal operation of the system.

[0049] Step 3: Install and fix vibration sensors and supporting data transmission devices on the outer surface of the TBM main beam and the inner surface of the shield, and install an industrial control computer in the TBM general control room.

[0050] After arranging vibration sensors on the main beam and the shield of the TBM, the collected vibration signals are transmitted to the industrial control computer by wired or wireless means to achieve real-time monitoring without human intervention. In this way, the vibration signals of the main beam and the shield can be automatically and continuously collected, and then the operating state of the TBM can be monitored in real time, and it can be predicted whether the TBM is jammed.

[0051] Specifically, the data transmission devices should be installed in a proper position that does not affect the normal construction of the TBM and is convenient for maintenance, and the lighting power supply of the TBM itself is used to supply power to the data transmission devices to ensure stable power supply for these devices in the harsh construction environment; the signals collected by the vibration sensors are connected to the corresponding data transmission devices through data transmission lines, and each connection line needs to be clearly marked to ensure that the vibration signals at the monitoring points correspond one by one with the data acquisition channels and avoid signal confusion or misreading; the signal data collected by the data transmission devices is transmitted to the industrial control computer through the transmission lines. During the connection process, it is necessary to ensure that each line is firmly and correctly connected to avoid reverse connection or poor contact; the laying of the data transmission lines should avoid the mechanical moving parts during the operation of the TBM to prevent line damage or signal interruption caused by friction, extrusion, etc.; the layout of the lines should be as concealed as possible to prevent being accidentally touched or damaged during the construction process;

[0052] Install an industrial control computer in the TBM general control room so that the operator can centrally monitor the vibration signal acquisition and transmission during the construction process; the industrial control computer should be installed in a convenient operation position and keep an appropriate distance from other equipment at the construction site to reduce electromagnetic interference. The industrial control computer realizes remote control and data reception of vibration sensors and data transmission devices by connecting to the internal network of the construction site. The internal network connection should ensure the stability and security of data transmission to avoid data loss or external interference.

[0053] Step 4: The acquisition and monitoring system composed of vibration sensors, data transmission devices, and industrial computers can collect and store the vibration signal data of the main beam and shield in real time and automatically.

[0054] After the industrial computer is connected to the construction site intranet, researchers can view the working status of the acquisition and monitoring system through remote operation software.

[0055] Step 5: Researchers can remotely view, download, and analyze the collected vibration signal data. Through time-domain signal analysis of mean value, standard deviation, root mean square amplitude, and root mean square, and frequency-domain signal analysis of spectral mean value, spectral variance, spectral centroid, and frequency standard deviation after Fourier transform, the vibration signals of the main beam and shield can be obtained, and the similarity between the two can be compared. Finally, based on the correlation results of Pearson coefficient and spectral coefficient, combined with the on-site construction situation, the tunneling state of the TBM can be judged, whether a machine jam occurs can be evaluated, and the location of the machine jam can be determined.

[0056] Specifically, after the acceleration vibration signals on the TBM main beam and shield are collected by the installed vibration sensors in the X-axis, Y-axis, and Z-axis directions, in order to simplify data processing and facilitate later analysis, the following formula is used to calculate the synthesized acceleration vibration signal in the X-axis and Y-axis directions. The specific formula is as follows:

[0057]

[0058] Then, the synthesized acceleration vibration signal is transmitted to the industrial computer in the TBM master control room through the data transmission device. Combining with the vibration signal analysis software equipped on the industrial computer, the time-domain characteristic indexes are calculated. The specific formula is as follows:

[0059] Maximum value:

[0060] Standard deviation:

[0061] Root mean square amplitude:

[0062] Root mean square:

[0063] Then, the continuous time-domain signal is sampled first to obtain the discrete time-domain signal x(n), and then the discrete Fourier transform (DFT) is used to convert the discrete time-domain signal x(n) to the frequency-domain signal f(k). The specific formula is as follows:

[0064]

[0065] In the above formula, i is the imaginary unit, After the frequency-domain signal is obtained through conversion, combining with the vibration signal analysis software equipped on the industrial computer, the frequency-domain characteristic indexes are calculated. The specific formula is as follows:

[0066] Spectrum mean value:

[0067] Spectrum variance:

[0068] Spectrum centroid:

[0069] Frequency standard deviation:

[0070] Based on the above-mentioned time-domain characteristic indexes calculated, next, the Pearson correlation coefficient is used to evaluate the correlation of the vibration signals of the main beam and the shield. The specific formula is as follows:

[0071]

[0072] Cov(X,Y) in the above formula is the covariance of the vibration signals at the monitoring points of the main beam and the shield, σ X , σ Y are the standard deviations of the vibration signals of the main beam and the shield respectively. The value range of the Pearson correlation coefficient r pcc is [-1,1].

[0073] Based on the above-mentioned frequency-domain characteristic indexes calculated, next, the spectrum correlation coefficient is used to evaluate the correlation of the vibration signals of the main beam and the shield. The specific formula is as follows:

[0074]

[0075] In the above formula, are the spectrum values of the vibration signals at the main beam and the shield respectively, is the conjugate complex number of the spectrum value of the vibration signal at the shield. The value range of the spectrum correlation coefficient r scc is [-1,1].

[0076] Based on the Pearson correlation coefficient r pcc and the spectrum correlation coefficient r scc to judge the risk of TBM jamming. As shown in Appendix Figure 3 , the specific judgment method is as follows:

[0077] TBM is tunneling normally:

[0078] TBM has the risk of jamming:

[0079] TBM has a serious jamming:

[0080] Technicians use MATLAB software to extract and process 1000 consecutive vibration signals collected from the top shield and side shield of the TBM respectively. Then, according to the standard deviation calculation formula of vibration signals and the Pearson correlation coefficient formula, they program in MATLAB to calculate the Pearson correlation coefficient of the 1000 consecutive vibration signals, and finally obtain the correlation change trend of the vibration signals of the TBM top shield and side shield, thereby judging whether the TBM is stuck and predicting its stuck risk. The Pearson correlation coefficient of the vertical line identification section is in the interval (0, 0.7], as shown in the appendix Figure 1 As shown, it indicates that this interval is the high-risk area for TBM jamming.

[0081] This specific embodiment is only an interpretation of the present invention and is not a limitation thereof. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A method for monitoring the jamming of a tunnel boring machine, characterized in that: It includes the following steps: S1: Select appropriate monitoring points on the inner surface of the TBM shield and the outer surface of the main beam and mark them; The specific layout method of the monitoring points described in step S1 on the shield surface is as follows: The monitoring points are arranged circumferentially along the cross-section of the shield, and the number of monitoring points arranged at the top of the shield is more than that at the two sides and the bottom of the shield; S2: Install vibration sensors at the monitoring points described in step S1. The vibration sensors include data acquisition and transmission devices; S3: Transmit the vibration signal data collected in step S2 to the industrial control computer in the TBM control room, and automatically collect and store the vibration signal data during tunneling in real time; S4: Analyze the time-domain, frequency-domain characteristics and correlations of the vibration signal data obtained in step S3 to judge the tunneling state and the jamming position of the TBM, so as to reduce the risk of jamming; The specific method for judging the jamming position in step S4 is to analyze the vibration signal data obtained in step S3, and obtain the vibration signals of the main beam and the shield through time-domain signal analysis of mean value, standard deviation, root mean square amplitude, root mean square, and frequency-domain signal analysis of spectral mean value, spectral variance, spectral centroid, and frequency standard deviation after Fourier transform, and compare the similarities between the two, and based on the correlation results of the Pearson coefficient and the spectral coefficient, combined with the on-site construction situation, judge the tunneling state of the TBM, evaluate whether jamming occurs, and determine the jamming position; The specific method of the Fourier transform is as follows: sampling the continuous time-domain signal to obtain a discrete time-domain signal , and then using the discrete Fourier transform to transform the discrete time-domain signal into a frequency-domain signal . The specific formula is as follows: ； In the above formula, is the imaginary unit, ; The Pearson coefficient evaluates the correlation of the vibration signals of the main beam and the shield. The specific formula is as follows: ； In the above formula, is the covariance of the vibration signals at the monitoring points on the main beam and the shield, , are the standard deviations of the vibration signals of the main beam and the shield respectively, and the Pearson correlation coefficient ranges from [-1, 1]; The spectral coefficient evaluates the correlation of the vibration signals of the main beam and the shield. The specific formula is as follows: ； In the above formula, , are the spectral values of the vibration signals at the main beam and the shield respectively, is the conjugate complex number of the spectral value of the vibration signal at the shield, and the spectral correlation coefficient ranges from [-1, 1]; In step S4, based on the Pearson correlation coefficient and the spectral correlation coefficient to judge the risk of TBM jamming, the specific judgment method is as follows: Normal tunneling of TBM: ; The TBM has the risk of being stuck: ; Serious jamming of the TBM occurred: .

2. The tunneling machine jamming monitoring method according to claim 1, wherein: The specific layout method of the monitoring points described in step S1 on the outer surface of the main beam is as follows: The monitoring points are arranged longitudinally at regular intervals along the outer surface of the TBM main beam.

3. A tunneling machine jamming monitoring method according to claim 1, characterized in that: The acceleration vibration sensor is used as the vibration sensor in step S2.

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