CN113639849B - Monitoring method and system for tunnel surrounding rock block collapse based on natural vibration frequency - Google Patents

Abstract

The present disclosure proposes a tunnel surrounding rock block collapse monitoring system based on the natural vibration frequency, including: a tunnel laser vibration measurement system, a wireless vibration monitoring system and a block collapse disaster prediction system; the laser vibration measurement system discloses a system for tunnel excavation. The dangerous block is collected, and the natural vibration frequency of the dangerous block is collected to quickly determine the stable state of the dangerous block; the wireless vibration monitoring system monitors the natural vibration frequency of the dangerous block in real time for the dangerous block after support, The monitoring data is transmitted to the block collapse disaster prediction system in real time; the block collapse disaster prediction system is used to predict the collapse risk of the surrounding rock blocks of the tunnel.

Description

Collapse monitoring method and system of tunnel surrounding rock block based on natural vibration frequency

technical field

The disclosure belongs to the technical field of geotechnical engineering disaster monitoring and early warning, and in particular relates to a method and system for monitoring the collapse of tunnel surrounding rock blocks based on natural vibration frequencies.

Background technique

The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

The tunnel surrounding rock block collapse disaster is the isolated or semi-isolated structure formed by the combination of the existing structural plane in the rock mass and the free surface formed by the excavation, and the rock mass that deviates from the original position due to the breaking of the original equilibrium state and causes engineering accidents. Local instability accident. For a long time, the collapse of surrounding rock blocks has seriously threatened the tunnel construction and personnel safety. The mild ones caused delays in the construction period due to equipment destruction, and the severe ones caused a large number of casualties and major economic losses. front row.

The collapse of surrounding rock blocks is localized and sudden, and the catastrophe occurs in a short time and the displacement precursor is not obvious. Traditional stress, strain and displacement monitoring methods are difficult to capture effective disaster information. The mechanical catastrophe of rocks and structural planes will produce a variety of physical effects, such as abnormal changes in physical quantities such as microseismic and natural frequencies, and these physical quantities are interrelated and orderly. Through the correlation and combined analysis of various physical information, the reliability of the identification of the precursors of the collapse of the surrounding rock blocks can be improved, and the problem that traditional monitoring methods cannot effectively identify or accurately identify the precursors of the collapse of the surrounding rock blocks can be solved.

The "point-domain" monitoring in the prior art is a monitoring mode for the collapse disaster of the entire block, and different simple monitoring modes are proposed for key blocks and collapse areas respectively. In the "point-domain" monitoring method, Only wireless sensor monitoring is used, which is time-consuming, labor-intensive and costly.

Contents of the invention

In order to overcome the above-mentioned deficiencies in the prior art, the present disclosure provides a method for monitoring the collapse of the tunnel surrounding rock block based on the natural vibration frequency, which can effectively identify the precursor information of the collapse of the tunnel surrounding rock block.

To achieve the above objectives, one or more embodiments of the present disclosure provide the following technical solutions:

In the first aspect, a tunnel surrounding rock block collapse monitoring system based on natural vibration frequency is disclosed, including: a tunnel laser vibration measurement system, a wireless vibration monitoring system, and a block collapse disaster prediction system;

The laser vibrometer system collects the natural vibration frequency of the dangerous block exposed by tunnel excavation, and is used to quickly determine the stable state of the dangerous block;

The wireless vibration monitoring system monitors the natural vibration frequency of the dangerous block in real time for the supported dangerous block, and transmits the monitoring data to the block collapse disaster prediction system in real time;

The block collapse disaster prediction system is used to predict the collapse risk of tunnel surrounding rock blocks.

In a further technical solution, the tunnel laser vibrometer system includes a host of a laser vibrometer, and a compensation vibration sensor is installed on the host to measure the vibration of the instrument itself caused by the complex environment of the tunnel, and to eliminate the above-mentioned vibration in the final measurement result, as the final monitoring data.

In a further technical solution, the dangerous block exposed by the tunnel excavation is sprayed with reflective paint, and the data at the reflective paint is measured by the host of the laser vibrometer.

In a further technical solution, after the host computer of the laser vibrometer obtains the monitoring data, it analyzes the change law of the natural vibration frequency of the rock mass based on the dynamic characteristic parameters such as the velocity and acceleration of the rock mass.

In a further technical solution, the wireless vibration monitoring system includes a wireless displacement sensor, a wireless speed sensor and a wireless acceleration sensor, which are used to collect dynamic characteristic parameters such as rock mass displacement, speed and acceleration;

The wireless displacement sensor, the wireless speed sensor and the wireless acceleration sensor are respectively arranged on the surface of the dangerous block, and anchoring materials are used to couple the sensors with the surrounding rock.

In the second aspect, a method for monitoring the collapse of tunnel surrounding rock blocks based on the natural vibration frequency is disclosed, including:

For the dangerous blocks exposed by tunnel excavation, the natural vibration frequency of the dangerous blocks is collected to quickly determine the stable state of the dangerous blocks;

For the dangerous block after support, the natural vibration frequency of the dangerous block is monitored in real time, and the monitoring data is transmitted to the block collapse disaster prediction system in real time;

The block collapse disaster prediction system is used to predict the collapse risk of tunnel surrounding rock blocks.

A further technical solution is to spray reflective paint on the identified dangerous surrounding rock blocks in the tunnel, then set up the host of the laser vibrometer, measure the data at the reflective paint through the host of the laser vibrometer, and then analyze the danger For the stable state of the blocks, mechanical exclusion shall be adopted for the unstable and low-risk blocks, and the dangerous blocks shall be supported for the unstable and high-risk blocks.

A further technical solution is to deploy a wireless vibration monitoring system for the highly dangerous blocks that have been supported, and place a wireless displacement sensor, a wireless speed sensor, and a wireless acceleration sensor on the surface of the dangerous block, and use anchoring materials The sensor is coupled with the surrounding rock to monitor the collapse of the dangerous surrounding rock block.

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

Aiming at the dangerous blocks exposed by tunnel excavation, the present invention collects the natural vibration frequency of the dangerous blocks through the laser vibration measurement system, quickly judges the stable state of the dangerous blocks, and provides scientific basis for taking corresponding support measures. The natural vibration frequency of the dangerous block is monitored in real time through the wireless vibration monitoring system, and the monitoring data is transmitted to the block collapse disaster prediction system in real time. Through this system, the collapse risk of the tunnel surrounding rock block is predicted, and the tunnel surrounding rock The monitoring and early warning of block collapse is conducive to realizing the safe construction of tunnel engineering and avoiding the occurrence of tunnel surrounding rock block collapse disasters.

The invention solves the difficult problem that the traditional monitoring means of stress, strain and displacement are difficult to capture the effective imminent disaster information of the collapse of surrounding rock blocks. Compared with previous studies, this monitoring method can realize real-time monitoring of the evolution state of the tunnel surrounding rock dangerous block support before and after, and escort the safe construction of the tunnel project.

The invention can accurately identify the catastrophic precursor information of the collapse of the surrounding rock block of the tunnel. For the dangerous blocks exposed by tunnel excavation, the stable state of the dangerous blocks can be quickly judged by the laser vibration measurement system, which provides a scientific basis for taking corresponding support measures, and saves a lot of time and construction costs. For the dangerous block after support, the wireless vibration monitoring system monitors the stable state of the dangerous block in real time, dynamically predicts the collapse risk of the tunnel surrounding rock block, and realizes the monitoring and early warning of the collapse of the tunnel surrounding rock block.

Through the correlation and combined analysis of displacement information and natural vibration frequency information, during the process of key block instability, the displacement of the block continues to increase, while the natural frequency of vibration gradually decreases. The analysis process is mainly based on the natural vibration frequency, and the steep drop of vibration frequency and the slow rise of displacement are the main evidences of instability, which can improve the reliability of the identification of collapse catastrophe precursors of surrounding rock blocks in tunnels.

The patent has a simple structure and a reasonable design, can effectively monitor the collapse disaster of the surrounding rock block of the tunnel in real time, guarantee the safe construction of the tunnel project, and is convenient for wide-scale popularization and application.

The invention mainly aims at the key block monitoring system, and enriches and perfects the monitoring method for the natural vibration frequency of the key block in the tunnel. For the identified block, the laser vibrometer is firstly used for monitoring. The laser vibrometer is a non-contact measurement, which is simple, fast and economical. Then, for the supported block, the contact wireless sensor is used for monitoring. This scheme is more perfect, more practical, more economical than the existing schemes, and can better meet the needs of tunnel construction.

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

Description of drawings

The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure, and the exemplary embodiments and descriptions of the present disclosure are used to explain the present disclosure, and do not constitute improper limitations to the present disclosure.

FIG. 1 is a schematic structural diagram of a system according to an embodiment of the present disclosure;

In the figure, 1. Dangerous blocks exposed by tunnel excavation; 2. Dangerous blocks after support in the tunnel; 3. Tunnel surrounding rock; 4. Host of laser vibrometer; 5. Data analysis software; 6. Compensation Vibration sensor; 7. Laser source; 8. Reflective paint; 9. Wireless displacement sensor; 10. Wireless speed sensor; 11. Wireless acceleration sensor; 12. Sound and light module; 13. Wireless transmission system; 14. Block collapse disaster prediction system.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present disclosure. Unless defined otherwise, 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 disclosure belongs.

It should be noted that the terminology used herein is only for describing specific embodiments, and is not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural, and it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, they mean There are features, steps, operations, means, components and/or combinations thereof.

In the case of no conflict, the embodiments in the present disclosure and the features in the embodiments can be combined with each other.

Embodiment one

This embodiment discloses a tunnel surrounding rock block collapse monitoring system based on the natural vibration frequency, including a tunnel laser vibration measurement system, a wireless vibration monitoring system and a block collapse disaster prediction system. In the tunnel surrounding rock 3, for tunnel excavation For the exposed dangerous block 1, the natural vibration frequency of the dangerous block is collected by the laser vibration measurement system, and the stable state of the dangerous block is quickly judged, which provides a scientific basis for taking corresponding support measures. Body 2, the natural vibration frequency of the dangerous block is monitored in real time through the wireless vibration monitoring system, and the monitoring data is transmitted to the block collapse disaster prediction system in real time. Collapse monitoring and early warning.

Predict the collapse risk of the surrounding rock block of the tunnel, specifically: during the instability process of the key block, the displacement of the block continues to rise, while the natural vibration frequency gradually decreases. The analysis process is mainly based on the natural vibration frequency, and the main basis for instability is the sudden drop of the vibration frequency and the slow rise of the displacement. When this situation occurs, there is a risk of collapse of the tunnel surrounding rock block.

The tunnel laser vibrometer system includes a laser vibrometer host 4 and data analysis software 5 .

In order to adapt to the complex environment of the tunnel, the host of the laser vibrometer is equipped with a compensation vibration sensor 6 to measure the vibration of the instrument itself caused by construction blasting, rock drilling, spray anchor, etc., and remove this part of the vibration from the final measurement results. Accurate acquisition of monitoring data is finally realized.

In order to adapt to the environment with high dust concentration and high humidity in the tunnel, the host of the laser vibrometer adopts dual laser sources 7, in which the positioning laser wavelength is 600mm, the measuring laser wavelength is 1550nm, the focusing mode is automatic focusing, and the maximum testing distance is 150m.

In order to adapt to the dark environment of the tunnel, the tunnel laser vibration measurement system uses reflective paint 8 as the reflection light source. After the dangerous block of the tunnel is exposed, the reflective paint is sprayed on the block, and the data at the reflective paint is measured by the host of the laser vibrometer. Including block displacement, velocity, acceleration.

The data analysis software can analyze the change law of the natural vibration frequency of the rock mass based on the dynamic characteristic parameters such as the velocity and acceleration of the rock mass.

Analyzing the change law of the natural vibration frequency of the rock mass specifically refers to: Aiming at the velocity and acceleration information of the block, the frequency spectrum of the block is obtained through Fourier transform. vibration frequency.

The wireless vibration monitoring system includes a wireless displacement sensor 9, a wireless speed sensor 10 and a wireless acceleration sensor 11, which are used to collect dynamic characteristic parameters such as rock mass displacement, speed and acceleration.

The wireless vibration monitoring system is equipped with an acousto-optic module 12. When the block collapse disaster prediction system releases early warning information, the acousto-optic module can simultaneously emit sound and flash to release early warning information.

The wireless vibration monitoring system transmits the monitoring data to the block collapse disaster prediction system 14 through the wireless transmission system 13 .

The block collapse disaster prediction system analyzes the change law of the natural vibration frequency of the rock mass based on the dynamic characteristic parameters such as the velocity and acceleration of the rock mass, and integrates and analyzes the displacement monitoring data of the block to predict the collapse risk of the surrounding rock block of the tunnel, and the risk level It is divided into 5 levels, that is, red risk level Ⅰ, orange risk level Ⅱ, yellow risk level Ⅲ, blue risk level Ⅳ, and green risk level Ⅴ.

The data analysis software only analyzes the vibration characteristics of the block, such as the natural vibration frequency, through the velocity and acceleration information of the block, while the system analyzes the collapse risk of the block by fusing and analyzing the natural vibration frequency and displacement information.

During fusion, during the instability process of key blocks, the displacement of the blocks continues to rise, while the natural vibration frequency gradually decreases. The analysis process is mainly based on the natural vibration frequency, and the main basis for instability is the sudden drop of vibration frequency and the slow rise of displacement.

The present invention first uses a laser vibrometer to monitor the identified block. The laser vibrometer belongs to non-contact measurement, which is simple, fast and economical. Then, the supported block is monitored by a contact wireless sensor.

First of all, the traditional laser vibrometer is difficult to apply in the tunnel. There are problems with the layout of measuring points, the method of excitation, the location of excitation, especially the problem of information extraction. The vibration of the instrument equipment is the key to this method. Therefore, the present invention realizes accurate acquisition of monitoring data by installing a compensation vibration sensor on the laser vibrometer to measure the vibration of the instrument itself caused by construction.

Secondly, there is the problem of wireless sensors, which need to monitor the displacement, speed, acceleration, wireless charging and other functions of the block, and can simultaneously send out sound and light warning information, which is impossible for traditional sensors.

Embodiment two

The purpose of this embodiment is to provide the above-mentioned method for monitoring the collapse of tunnel surrounding rock blocks based on natural vibration frequency, which includes the following steps:

A. Identify the dangerous surrounding rock blocks exposed in the excavated section according to the preliminary survey and drilling data of the tunnel, the advanced geological forecast data and the face construction data.

B. For the identified dangerous surrounding rock blocks in the tunnel, spray reflective paint on the blocks, and then set up the host of the laser vibrometer in a place with less vibration and a wide field of vision, and measure the reflective paint through the host of the laser vibrometer data, and then analyze the stable state of dangerous blocks based on data analysis software. For unstable and low-risk blocks, mechanical exclusion can be adopted. For unstable and high-risk blocks, the The dangerous blocks are supported by means of local anchorage and joint reinforcement.

C. Set up a wireless vibration monitoring system for the highly dangerous blocks that have been supported, and place a wireless displacement sensor, a wireless speed sensor, and a wireless acceleration sensor on the surface of the dangerous block, and use anchoring materials to connect the sensors and The surrounding rock is coupled together, and the anchoring agent is used to couple the sensor with the surrounding rock, which can improve the accuracy of data collection, and the acquired data is the vibration data of the block itself. Surrounding rock block collapse disaster monitoring is carried out on the dangerous surrounding rock block.

D. Through the block collapse disaster prediction system, the displacement monitoring data of the block and the change law of the natural vibration frequency are fused and analyzed, and the risk level of the block collapse of the tunnel surrounding rock is predicted. The risk level is divided into 5 levels, that is, the red risk of level I, Level Ⅱ orange risk, level Ⅲ yellow risk, level Ⅳ blue risk, and level Ⅴ green risk, according to the real-time predicted risk level, take corresponding measures such as issuing disaster warning notices, notifying personnel to evacuate, and timely reinforcing dangerous blocks and dangerous areas. Avoid the occurrence of collapse disasters of tunnel surrounding rock blocks.

Those skilled in the art should understand that each module or each step of the above-mentioned present disclosure can be realized by a general-purpose computer device, and optionally, they can be realized by a program code executable by the computing device, so that they can be stored in a The device is executed by a computing device, or they are made into individual integrated circuit modules, or multiple modules or steps among them are made into a single integrated circuit module for realization. This disclosure is not limited to any specific combination of hardware and software.

The above descriptions are only preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.

Although the specific implementation of the present disclosure has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present disclosure. Those skilled in the art should understand that on the basis of the technical solutions of the present disclosure, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present disclosure.

Claims (3)

1. A tunnel surrounding rock mass collapse monitoring method based on natural vibration frequency is characterized in that,

aiming at the dangerous block uncovered by tunnel excavation, collecting the natural vibration frequency of the dangerous block for rapidly judging the stable state of the dangerous block;

monitoring the natural vibration frequency of the dangerous block in real time aiming at the supported dangerous block, and transmitting the monitoring data to a block collapse disaster prediction system in real time;

the block collapse disaster prediction system is used for predicting the collapse risk of the tunnel surrounding rock blocks;

the method comprises the following steps of (1) carrying out predictive analysis on the collapse risk of a tunnel surrounding rock block, wherein the inherent vibration frequency is taken as a main basis, and the rapid decrease and slow increase of the vibration frequency and the displacement are taken as main basis for judging instability;

spraying reflective paint on the blocks aiming at the identified dangerous surrounding rock blocks in the tunnel, erecting a laser vibration meter host at other positions, measuring data at the reflective paint positions through the laser vibration meter host, then analyzing the stable state of the dangerous blocks, and supporting the unstable blocks with higher danger by adopting a mechanical elimination processing mode for the blocks with instability and lower danger;

aiming at a block with high risk after supporting, laying a wireless vibration monitoring system, respectively laying a wireless displacement sensor, a wireless speed sensor and a wireless acceleration sensor on the surface of the dangerous block, coupling the sensors and surrounding rocks together by using an anchoring material, and monitoring the collapse disaster of the surrounding rock block on the dangerous surrounding rock block;

after the laser vibration meter host acquires monitoring data, analyzing the change rule of the inherent vibration frequency of the rock mass based on the speed and acceleration dynamic characteristic parameters of the rock mass;

analyzing the change rule of the natural vibration frequency of the rock mass based on the characteristic parameters of the speed and acceleration of the rock mass: and obtaining a spectrogram of the object block by Fourier transform according to the speed and acceleration information of the block, wherein the frequency value of the maximum amplitude point in the spectrogram is the natural vibration frequency of the block.

2. The method for monitoring the collapse of the tunnel surrounding rock mass body based on the natural vibration frequency as claimed in claim 1, wherein the tunnel laser vibration measurement system comprises a laser vibration meter host, and a compensation vibration sensor is installed on the host and is used for measuring the vibration of the instrument itself caused by the complex environment of the tunnel and rejecting the vibration in the final measurement result as finally obtained monitoring data.

3. The method for monitoring the collapse of the surrounding rock mass of the tunnel based on the natural vibration frequency as claimed in claim 1, wherein the wireless vibration monitoring system comprises a wireless displacement sensor, a wireless speed sensor and a wireless acceleration sensor, and is used for acquiring characteristic parameters of displacement, speed and acceleration of the rock mass;

the wireless displacement sensor, the wireless speed sensor and the wireless acceleration sensor are respectively arranged on the surface of the dangerous block body, and the sensors and the surrounding rock are coupled together by using an anchoring material.

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