Intelligent detection method for three-dimensional fractures of surrounding rock of segmented roadway in different stress environments

Abstract

The invention discloses a segmented roadway surrounding rock three-dimensional crack intelligent detection method in different stress environments. The method comprises the following steps: S1, preparation work; collecting data and manufacturing an intelligent detection anchor rod; s2, installing the intelligent detection anchor rod; the intelligent detection anchor rods serve as supporting anchor rods to be embedded in the surrounding rock, and at least two intelligent detection anchor rods are embedded in each section of roadway; s3, monitoring the three-dimensional fracture in real time; the intelligent detection anchor rods are started for monitoring, monitoring data of the intelligent detection anchor rods are uploaded to a central monitoring system, and a three-dimensional model of the section of roadway crack is established. A traditional anchor rod is replaced by the intelligent detection anchor rod, so that the anchor rod has the supporting effect of the traditional anchor rod, real-time monitoring of roadway surrounding rock cracks is achieved through the intelligent detection anchor rod, follow-up roadway stability maintenance is facilitated, meanwhile, data during stress fluctuation driven by rock burst or blasting can be removed, and compared with a traditional method, the method has the advantages that the method is simple and convenient. The method is suitable for crack detection in different stress environments.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel surrounding rock crack detection, and specifically relates to a three-dimensional crack intelligent detection method for segmented tunnel surrounding rocks under different stress environments. Background Art

[0002] As an important part of mineral mining and urban transportation, maintaining the stability of underground tunnels is an essential task. At present, anchor rods are buried in underground tunnels as initial support for the tunnels. During the operation of underground tunnels, they will be subject to various external forces, shock waves, etc. Under the action of external forces, the cracks generated in the initial stage of tunnel excavation will continue to develop, which can easily lead to tunnel collapse.

[0003] In order to prevent tunnel collapse, the tunnel is regularly inspected for cracks, and corresponding measures are taken according to the inspection results. In the prior art, there are two ways to detect tunnels. One is to drill the core of the tunnel surrounding rock manually, and then observe the cracks of the tunnel surrounding rock through equipment or naked eyes; the other is to walk directly in the tunnel through equipment to detect the conditions of the tunnel. The former is to detect and judge the conditions of the tunnel surrounding rock cracks, which is forward-looking, but the operation is cumbersome, and in the detection process, it is not only necessary to avoid the stress fluctuations caused by impact ground pressure or blasting, but also to accelerate the development of tunnel surrounding rock cracks, thereby further accelerating the collapse of the tunnel. Although the latter will not affect the cracks of the tunnel surrounding rock, it can only simply perform a surface inspection of the tunnel, which is not forward-looking. Summary of the invention

[0004] The present invention proposes an intelligent detection method for three-dimensional cracks in the surrounding rock of segmented tunnels under different stress environments, which can not only realize real-time monitoring of the cracks in the surrounding rock of the tunnel, but also will not accelerate the development of the cracks in the surrounding rock of the tunnel.

[0005] To this end, the technical solution adopted by the present invention is: a method for intelligent detection of three-dimensional cracks in surrounding rocks of segmented tunnels under different stress environments, comprising the following steps:

[0006] S1: Preparation: Collect detailed information on geological data, rock characteristics and surrounding stress states in the area where the tunnel is located, determine whether the area needs to detect crack characteristics in the tunnel surrounding rock, and make intelligent detection anchors when it is determined that detection is necessary;

[0007] S2: Installation of intelligent detection anchor rods; During the tunnel excavation process, the intelligent detection anchor rods are buried in the surrounding rock as support anchor rods, and at least two intelligent detection anchor rods are buried in each tunnel section. After the intelligent detection anchor rods are buried, a preliminary functional test is carried out on the intelligent detection anchor rods to ensure their stability and normal operation;

[0008] S3: Real-time monitoring of three-dimensional cracks. After each section of tunnel excavation is completed, the intelligent detection anchor rod is started for monitoring. At the same time, the monitoring data of the intelligent detection anchor rod is uploaded to the central monitoring system for data processing and analysis to establish a three-dimensional model of the cracks in this section of the tunnel.

[0009] As a preferred embodiment of the above scheme, the intelligent detection anchor rod includes an anchor rod and a three-dimensional crack detection device arranged on the anchor rod. An anchor rod fixing assembly for fixing the anchor rod position is arranged near the rear end of the anchor rod. The anchor rod includes an anchor head with a front end convenient for burying in the surrounding rock and a hollow anchor rod body with support at the rear end.

[0010] Further preferably, the three-dimensional crack detection device includes a strain sensor for detecting surrounding rock stress, a signal generator capable of emitting a signal for detecting cracks, a signal receiver for receiving the signal emitted by the signal generator, and a start button for starting the signal generator, the strain sensor and the signal generator are both arranged in the middle part of the hollow anchor body, the start button is arranged at the rear end of the hollow anchor body, the rear end and the middle part of the hollow anchor body are both provided with signal receivers, a control connection line passing through the hollow anchor body is arranged between the signal generator and the start button, the strain sensor and the signal receiver are both equipped with a signal transmission line capable of transmitting signals to the central monitoring system, and one end of the signal transmission line on the strain sensor is arranged in the hollow anchor body.

[0011] Further preferably, in S2, the detection range R can be determined according to the following formula:

[0012]

[0013] Where d1 is the distance between the signal receiver on any intelligent detection anchor and the corresponding signal generator, and d2 is the distance between the signal generator on any other intelligent detection anchor and the signal receiver.

[0014] Further preferably, the anchor rod fixing assembly comprises a backing plate and a fixing nut which are sequentially sleeved on the hollow anchor rod body in front and back, and the hollow anchor rod body is provided with an external thread which can be threadedly connected with the fixing nut.

[0015] Beneficial effects of the present invention:

[0016] 1) Intelligent detection anchors are used to replace traditional anchors, so that the anchors not only have the support function of traditional anchors, but also can realize real-time monitoring of tunnel surrounding rock cracks through intelligent detection anchors, so as to facilitate the subsequent maintenance of tunnel stability. At the same time, the real-time monitoring of intelligent detection anchors can eliminate the data of stress fluctuations caused by impact ground pressure or blasting. Compared with the traditional method that needs to avoid stress fluctuations caused by impact ground pressure or blasting, it is suitable for crack detection under different stress environments.

[0017] 2) At least two intelligent detection anchors are installed in each tunnel section, which can not only effectively increase the detection range and provide more comprehensive tension and shear crack distribution data, but also ensure the accuracy of the monitoring data by ensuring that some of the intelligent detection anchors can operate stably even if some of them fail due to external forces. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Illustration of the detection range after two intelligent detection anchors are buried in the tunnel Figure 1 .

[0019] Figure 2 Illustration of the detection range after two intelligent detection anchors are buried in the tunnel Figure 2 .

[0020] Figure 3 Schematic diagram of real-time monitoring after two intelligent detection anchors are buried in the tunnel.

[0021] Figure 4 Schematic diagram of intelligent anchor detection.

[0022] Explanation of the accompanying drawings: intelligent detection anchor rod A, tunnel B, central monitoring system C, anchor rod 10, anchor head 11, hollow anchor rod body 12, three-dimensional crack detection device 20, strain sensor 21, signal generator 22, signal receiver 23, start button 24, anchor rod fixing assembly 30, pad 31, fixing nut 32. DETAILED DESCRIPTION

[0023] The present invention will be further described below by way of embodiments and in conjunction with the accompanying drawings:

[0024] like Figure 1-4 As shown, a method for intelligent detection of three-dimensional cracks in surrounding rock of segmented tunnels under different stress environments mainly includes the following steps:

[0025] Step 1: Preparation. Collect detailed information on the geological data, rock characteristics and surrounding stress state of the area where tunnel B is located, determine whether the crack characteristics in the tunnel surrounding rock need to be detected in this area, and when it is determined that detection is necessary, make intelligent detection anchor A.

[0026] The intelligent detection anchor is mainly composed of an anchor 10, a three-dimensional crack detection device 20 and an anchor fixing assembly 30. A three-dimensional crack detection device is arranged on the anchor, which is used to detect the crack condition and stress state of the surrounding rock of the tunnel. An anchor fixing assembly for fixing the anchor position is arranged near the rear end of the anchor, which is used to fix the anchor after the anchor is buried.

[0027] The anchor rod 10 comprises an anchor head 11 with a front end convenient for embedding into the surrounding rock and a hollow anchor rod body 12 with a supporting function at the rear end, wherein the anchor head is provided with a conical embedding end with a front end and a fixing end at the rear end for fixing on the hollow anchor rod body, and the length and diameter of the entire anchor rod and the hardness of the hollow anchor rod body are determined according to the surrounding rock to be embedded. Preferably, the entire anchor head is made of steel material.

[0028] The three-dimensional crack detection device includes a strain sensor 21 for detecting surrounding rock stress, a signal generator 22 capable of sending signals for detecting cracks, a signal receiver 23 for receiving signals sent by the signal generator, and a start button 24 for starting the signal generator. The strain sensor and the signal generator are both arranged in the middle of the hollow anchor body, the start button is arranged at the rear end of the hollow anchor body, the signal receiver is arranged at the rear end and the middle of the hollow anchor body, a control connection line passing through the hollow anchor body is arranged between the signal generator and the start button, and a signal transmission line capable of transmitting signals to the central monitoring system is provided on the strain sensor and the signal receiver, and one end of the signal transmission line on the strain sensor is arranged in the hollow anchor body.

[0029] The anchor bolt fixing assembly includes a backing plate 31 and a fixing nut 32 which are sequentially sleeved on the hollow anchor bolt body, wherein the backing plate is used to determine the embedding depth of the anchor bolt, and the fixing nut is used to fix the position of the backing plate on the anchor bolt. An external thread which can be screwed with the fixing nut is arranged on the hollow anchor bolt body.

[0030] Step 2: Installation of smart detection anchor rods. During the tunnel excavation process, the installation position and angle of the anchor rods are measured and marked according to the design requirements to ensure that the smart detection anchor rods can be correctly buried in the surrounding rock as support anchor rods, and at least two smart detection anchor rods are buried in each tunnel section. After the smart detection anchor rods are buried, the smart detection anchor rods are preliminarily tested for their functions to ensure their stability and normal operation.

[0031] When burying the intelligent detection anchor, first clean up the debris in the tunnel to ensure that the installation location is clean and tidy to reduce the interference of the intelligent detection anchor during operation.

[0032]

[0033] Where d1 is the distance between the signal receiver and the corresponding signal generator on any intelligent detection anchor, and d2 is the distance between the signal generator and the signal receiver on any other intelligent detection anchor. Figure 1 and Figure 2 As shown, when two intelligent detection anchor rods are buried, the detection range can be hemispherical or spherical.

[0034] Since at least two intelligent detection anchor rods are buried in each section of the tunnel, not only the number is increased, resulting in a comprehensive detection range, but multiple intelligent detection anchor rods also have a synergistic effect. That is, the signal receiver of each intelligent detection anchor rod can receive the signal sent by the signal generator on the other intelligent detection anchor rods, and then through the identification of the central monitoring system, the monitoring result of each intelligent detection anchor rod can be mutually verified. When the intelligent detection anchor rod is buried in different directions, it can not only monitor the cracks in the first direction, but also monitor the inclined cracks, thereby ensuring the accuracy and comprehensiveness of the monitoring results.

[0035] Step 3: Real-time monitoring of three-dimensional cracks. After each section of tunnel excavation is completed, the intelligent detection anchor is started for monitoring, and the monitoring data of the intelligent detection anchor is uploaded to the central monitoring system C for data processing and analysis to establish a three-dimensional model of the cracks in this section of the tunnel. The central monitoring system can conduct in-depth analysis of the data transmitted by the intelligent detection anchor, so as to identify the changing pattern of the cracks and their relationship with the surrounding stress environment; at the same time, it can also combine statistics and data mining technology to establish a three-dimensional model of the cracks, as well as existing technologies for predicting the stability of the surrounding rock and the development trend of the cracks. It is best to establish a corresponding pre-tightening mechanism in the central monitoring system. When the cracks are detected to develop to the preset threshold, the system can automatically issue an alarm to determine the timely response of relevant personnel, and can also provide a preliminary solution for strengthening the tunnel based on the monitoring results.

[0036] During the operation of the tunnel, it is necessary to regularly inspect the intelligent detection anchor rods to ensure that they can provide stable support and that the three-dimensional detection device therein can operate stably, so as to ensure the accuracy of the monitoring data.

Claims

1. A method for intelligent detection of three-dimensional cracks in surrounding rock of segmented tunnels under different stress environments, characterized in that: The steps include: S1: Preparation: Collect detailed information on geological data, rock characteristics and surrounding stress states in the area where the tunnel is located, determine whether the area needs to detect crack characteristics in the tunnel surrounding rock, and make intelligent detection anchors when it is determined that detection is necessary; S2: Installation of intelligent detection anchor rods; During the tunnel excavation process, the intelligent detection anchor rods are buried in the surrounding rock as support anchor rods, and at least two intelligent detection anchor rods are buried in each tunnel section. After the intelligent detection anchor rods are buried, a preliminary functional test is carried out on the intelligent detection anchor rods to ensure their stability and normal operation; S3: Real-time monitoring of three-dimensional cracks. After each section of tunnel excavation is completed, the intelligent detection anchor rod is started for monitoring. At the same time, the monitoring data of the intelligent detection anchor rod is uploaded to the central monitoring system for data processing and analysis to establish a three-dimensional model of the cracks in this section of the tunnel.

2. The method for intelligent detection of three-dimensional cracks in surrounding rock of segmented tunnels under different stress environments according to claim 1, characterized in that: The intelligent detection anchor rod comprises an anchor rod and a three-dimensional crack detection device arranged on the anchor rod. An anchor rod fixing assembly for fixing the anchor rod position is arranged near the rear end of the anchor rod. The anchor rod comprises an anchor head at the front end for easy burial in the surrounding rock and a hollow anchor rod body with support at the rear end.

3. The method for intelligent detection of three-dimensional cracks in surrounding rock of segmented tunnels under different stress environments according to claim 2, characterized in that: The three-dimensional crack detection device includes a strain sensor for detecting surrounding rock stress, a signal generator capable of emitting a signal for detecting cracks, a signal receiver for receiving the signal emitted by the signal generator, and a start button for starting the signal generator. The strain sensor and the signal generator are both arranged in the middle part of the hollow anchor body, the start button is arranged at the rear end of the hollow anchor body, the rear end and the middle part of the hollow anchor body are both provided with a signal receiver, a control connection line passing through the hollow anchor body is arranged between the signal generator and the start button, the strain sensor and the signal receiver are both equipped with a signal transmission line capable of transmitting signals to a central monitoring system, and one end of the signal transmission line on the strain sensor is arranged in the hollow anchor body.

4. The method for intelligent detection of three-dimensional cracks in surrounding rock of segmented tunnels under different stress environments as claimed in claim 3, characterized in that: In S2, the detection range R can be determined according to the following formula Where d1 is the distance between the signal receiver on any intelligent detection anchor and the corresponding signal generator, and d2 is the distance between the signal generator on any other intelligent detection anchor and the signal receiver.

5. The method for intelligent detection of three-dimensional cracks in surrounding rock of segmented tunnels under different stress environments as claimed in claim 2, characterized in that: The anchor rod fixing assembly comprises a backing plate and a fixing nut which are sequentially sleeved on the hollow anchor rod body in front and back order, and the hollow anchor rod body is provided with an external thread which can be threadedly connected with the fixing nut.

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