Tunnel surrounding rock strength detection anchor rod active reinforcement system and method

Abstract

This invention discloses an active reinforcement system for anchor bolts used for detecting the strength of surrounding rock in tunnels. The system includes an anchor bolt body, with multiple ultrasonic transmitters installed at the top of the body and multiple ultrasonic receivers installed at the inner edge. A hydraulic channel is provided inside the anchor bolt body. This invention can detect and adaptively adjust the state of the surrounding rock in real time, preventing instability or over-reinforcement of the surrounding rock.

Description

Technical Field

[0001] This invention relates to the field of surrounding rock reinforcement, and in particular to an active reinforcement system and method for anchor bolts used for detecting the strength of surrounding rock in tunnels. Background Technology

[0002] Rock bolt support is a key technology for reinforcing surrounding rock and maintaining stability in geotechnical engineering projects such as slopes, tunnels, and underground caverns. The main function of traditional rock bolts is to provide support force, but traditional rock bolt support cannot measure the real-time mechanical state and key strength parameters of the surrounding soil and rock, and the parameters it relies on are all derived from geological surveys and limited laboratory data.

[0003] After installation, traditional rock bolts provide essentially a fixed support force. When creep or stress redistribution occurs in the surrounding rock, the rock bolts cannot automatically adjust their support force according to changes in the rock condition, thus failing to achieve adaptive reinforcement. As deformation continues to develop, the fixed support force may not be able to prevent failure, until the rock bolts are pulled out or broken, ultimately leading to failure.

[0004] In engineering projects, monitoring systems (such as inclinometers, convergence meters, and stress gauges) and reinforcement systems (anchor bolts) are typically designed, installed, and operated independently. Monitoring data requires manual interpretation to determine whether reinforcement measures are necessary. This process is inherently delayed and relies on manual judgment, making it difficult to establish an efficient and reliable closed loop. By the time the monitoring system issues a warning, the surrounding rock may have already undergone irreversible and severe deformation, missing the optimal time for reinforcement. Summary of the Invention

[0005] The purpose of this invention is to provide a system and method for active reinforcement of anchor bolts for detecting the strength of surrounding rock in tunnels, in order to solve the above-mentioned technical problems.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: An active reinforcement system for anchor bolts used for testing the strength of surrounding rock in tunnels includes an anchor bolt body. Multiple ultrasonic transmitters are installed at the top of the anchor bolt body, and multiple ultrasonic receivers are installed at the inner edge of the anchor bolt body. A hydraulic channel is provided inside the anchor bolt body.

[0007] Preferably, the ultrasonic transmitter is an ultrasonic transducer or an excitation elastic wave source, and the detection wave excitation frequency is 10kHz to 200kHz.

[0008] Preferably, the ultrasonic receiver is an ultrasonic sensor.

[0009] A method for active reinforcement of anchor bolts for testing the strength of surrounding rock in tunnels, comprising: S1: Determine the initial elastic modulus and initial Poisson's ratio of the surrounding rock based on the initial surrounding rock conditions, historical exploration data and design values ​​to facilitate the judgment of whether the surrounding rock needs to be reinforced. If reinforcement is required, insert the anchor body (3) into the rock body to support the rock body. S2: Longitudinal and transverse waves are emitted by the ultrasonic transmitter (1) at the end of the anchor body (3), and the reflected and transmitted waves of the surrounding rock are received by the ultrasonic receiver (2) arranged along the anchor body (3). The excitation frequency is selected at 20–80 kHz to continuously monitor the surrounding rock. S3: Calculate the wave velocity in the surrounding rock using the known ultrasonic wave propagation time and path; Longitudinal wave velocity: ; Transverse wave velocity: ; S4: The wave velocity data (longitudinal wave and transverse wave) obtained by ultrasonic measurement can be combined with the following steps to deduce the intensity parameters; Elastic modulus: ; Poisson's ratio: ; S5: By comparing the calculated elastic modulus and Poisson's ratio with the original elastic modulus and Poisson's ratio, if the elastic modulus... And Poisson's ratio If the surrounding rock strength is stable, reinforcement is required; otherwise, no reinforcement is needed. S6: Determine reinforcement requirements based on regional conditions and engineering needs, and determine grouting flow rate and grouting material type according to regional conditions and engineering needs; S7: Start the hydraulic grouting pump and inject the reinforcing grout into the surrounding rock through the hydraulic channel (4) set inside the anchor body (3). During the grouting process, the grout is fully diffused in the cracks, pores and loose areas of the surrounding rock and forms a stable reinforced body.

[0010] Preferably, it also includes S8: comparing the real-time collected data with the standard reinforcement pressure values ​​in the database to select the reinforcement pressure most suitable for the current surrounding rock conditions.

[0011] Preferably, data is collected and analyzed in real time using an ultrasonic transmitter and receiver. If the elastic modulus and Poisson's ratio of the surrounding rock decrease, more grouting material is added so that the grout can make a denser contact with the surrounding rock in the cracks, providing more support. If the surrounding rock is stable or over-reinforced, grouting is stopped to ensure that the reinforcement pressure does not exceed the bearing capacity of the surrounding rock, avoiding waste and over-reinforcement.

[0012] The beneficial effects of this invention are: This invention designs an active reinforcement system and method for anchor bolts used in tunnels to detect the strength of surrounding rock. This system provides real-time monitoring and adaptive adjustment of the surrounding rock to prevent instability or over-reinforcement. If the elastic modulus and Poisson's ratio of the surrounding rock decrease relative to the original data, the grouting flow rate is increased, and more grouting material is added, allowing the grout to make denser contact with the surrounding rock in the fissures, providing greater support. If the surrounding rock is stable or over-reinforced, grouting is stopped to avoid waste and over-reinforcement. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of an active reinforcement system and method for detecting the strength of surrounding rock in tunnels according to the present invention; Reference numerals: 1. Ultrasonic transmitter; 2. Ultrasonic receiver; 3. Anchor bolt body; 4. Hydraulic channel. Detailed Implementation

[0014] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0015] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0016] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Example

[0017] like Figure 1As shown, a tunnel surrounding rock strength testing anchor bolt active reinforcement system is characterized by: including an anchor bolt body 3, with multiple ultrasonic transmitters 1 installed at the top inside the anchor bolt body 3, multiple ultrasonic receivers 2 installed at the inner edge of the anchor bolt body 3, and a hydraulic channel 4 provided inside the anchor bolt body 3. The ultrasonic transmitters 1 are ultrasonic transducers or excitation elastic wave sources, with a detection wave excitation frequency of 10kHz to 200kHz, and the ultrasonic receivers 2 are ultrasonic sensors.

[0018] A method for active reinforcement of anchor bolts for testing the strength of surrounding rock in tunnels, comprising: S1: Determine the initial elastic modulus and initial Poisson's ratio of the surrounding rock based on the initial surrounding rock conditions, historical exploration data and design values ​​to facilitate the judgment of whether the surrounding rock needs to be reinforced. If reinforcement is required, insert the anchor body 3 into the rock mass to support the rock mass. S2: Longitudinal and transverse waves are emitted by the ultrasonic transmitter 1 at the end of the anchor body 3, and the reflected and transmitted waves of the surrounding rock are received by the ultrasonic receiver 2 arranged along the anchor body 3. The excitation frequency is selected between 20 and 80 kHz to ensure appropriate penetration depth and crack sensitivity, and to continuously monitor the surrounding rock. S3: Calculate the wave velocity in the surrounding rock using the known ultrasonic wave propagation time and path; the change in wave velocity is closely related to the density, elastic modulus and other properties of the surrounding rock. Longitudinal wave velocity: ; Transverse wave velocity: ; in, and d represents the propagation time of the longitudinal wave and the transverse wave, respectively, and d represents the propagation distance.

[0019] S4: The wave velocity data (longitudinal wave and transverse wave) obtained by ultrasonic measurement can be combined with the following steps to deduce the intensity parameters; Elastic modulus: ; Poisson's ratio: ; S5: By comparing the calculated elastic modulus and Poisson's ratio with the original elastic modulus and Poisson's ratio, if the elastic modulus... And Poisson's ratio If the surrounding rock strength is stable, reinforcement is required; otherwise, no reinforcement is needed. S6: Determine reinforcement requirements based on regional conditions and engineering needs. First, determine the geological conditions of the area; the types of surrounding rock mainly include soft rock, medium-strength rock mass, and hard rock mass. Additionally, the engineering environment needs to be determined; tunnels include ordinary tunnels, railway tunnels, and deep-buried tunnels, and the reinforcement requirements differ depending on the level of the project. Determine the grouting flow rate and grouting material type (generally ordinary cement mortar or composite grout) based on regional conditions and engineering needs. S7: Start the hydraulic grouting pump and inject reinforcing grout into the surrounding rock through the hydraulic channel 4 set inside the anchor body 3. During the grouting process, the grout is fully diffused in the cracks, pores and loose areas of the surrounding rock and forms a stable reinforced body. S8: Compare the real-time collected data with the standard reinforcement pressure values ​​in the database to select the most suitable reinforcement pressure for the current surrounding rock conditions. The ultrasonic transmitter 1 and ultrasonic receiver 2 collect and analyze the data in real time. If the elastic modulus and Poisson's ratio of the surrounding rock decrease, more grouting material is added so that the grout can make a denser contact with the surrounding rock in the cracks and provide more support. If the surrounding rock is stable or over-reinforced, grouting is stopped to ensure that the reinforcement pressure does not exceed the bearing capacity of the surrounding rock and to avoid waste and over-reinforcement.

[0020] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A tunnel surrounding rock strength testing anchor rod active reinforcement system, characterized in that: The anchor bolt body (3) includes multiple ultrasonic transmitters (1) installed on the top of the anchor bolt body (3), multiple ultrasonic receivers (2) installed on the inner edge of the anchor bolt body (3), and a hydraulic channel (4) provided inside the anchor bolt body (3).

2. The active reinforcement system for anchor bolts used for testing the strength of surrounding rock in tunnels according to claim 1, characterized in that: The ultrasonic transmitter (1) adopts an ultrasonic transducer or an excitation elastic wave source, and the detection wave excitation frequency is 10kHz to 200kHz.

3. The active reinforcement system for tunnel surrounding rock strength testing anchor bolts according to claim 1, characterized in that: The ultrasonic receiver (2) is an ultrasonic sensor.

4. The method for active reinforcement of anchor bolts for testing the strength of surrounding rock in tunnels according to claim 1, characterized in that: include: S1: Determine the initial elastic modulus and initial Poisson's ratio of the surrounding rock based on the initial surrounding rock conditions, historical exploration data and design values ​​to facilitate the judgment of whether the surrounding rock needs to be reinforced. If reinforcement is required, insert the anchor body (3) into the rock body to support the rock body. S2: Longitudinal and transverse waves are emitted by the ultrasonic transmitter (1) at the end of the anchor body (3), and the reflected and transmitted waves of the surrounding rock are received by the ultrasonic receiver (2) arranged along the anchor body (3). The excitation frequency is selected at 20–80 kHz to continuously monitor the surrounding rock. S3: Calculate the wave velocity in the surrounding rock using the known ultrasonic wave propagation time and path; Longitudinal wave velocity: ; Transverse wave velocity: ; S4: The wave velocity data (longitudinal wave and transverse wave) obtained by ultrasonic measurement can be combined with the following steps to deduce the intensity parameters; Elastic modulus: ; Poisson's ratio: ; S5: By comparing the calculated elastic modulus and Poisson's ratio with the original elastic modulus and Poisson's ratio, if the elastic modulus... And Poisson's ratio If the surrounding rock strength is stable, reinforcement is required; otherwise, no reinforcement is needed. S6: Determine reinforcement requirements based on regional conditions and engineering needs, and determine grouting flow rate and grouting material type according to regional conditions and engineering needs; S7: Start the hydraulic grouting pump and inject the reinforcing grout into the surrounding rock through the hydraulic channel (4) set inside the anchor body (3). During the grouting process, the grout is fully diffused in the cracks, pores and loose areas of the surrounding rock and forms a stable reinforced body.

5. The method for active reinforcement of tunnel surrounding rock strength testing anchor bolts according to claim 4, characterized in that: It also includes S8: comparing real-time collected data with standard reinforcement pressure values ​​in the database to select the most suitable reinforcement pressure for the current surrounding rock conditions.

6. The method for active reinforcement of anchor bolts for testing the strength of surrounding rock in tunnels according to claim 5, characterized in that: Data is collected and analyzed in real time using an ultrasonic transmitter (1) and an ultrasonic receiver (2). If the elastic modulus and Poisson's ratio of the surrounding rock decrease, more grouting material is added so that the grout can make a denser contact with the surrounding rock in the cracks and provide more support. If the surrounding rock is stable or over-reinforced, grouting should be stopped to ensure that the reinforcement pressure does not exceed the bearing capacity of the surrounding rock, thus avoiding waste and over-reinforcement.

Images