Acoustic emission testing structure for relaxation depth of cavern of jointed rock mass
By setting up observation branch holes and laying a test structure of acoustic emission probes in multiple test sections in hydropower projects, the problem of surrounding rock failure caused by prone to relaxation of the physical and chemical rock mass is solved, real-time monitoring and safety of the slack depth of the underground caverns is achieved. Quick analysis of stable state.
Patent Information
- Application Number
- CN202420636385.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-29
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2034-03-29
AI Technical Summary
In hydropower projects, physical and chemical rock mass is prone to relax, resulting in damage to surrounding rock, loosening of the top arch and side walls, and cracking of the bottom plate. The existing testing technology is difficult to effectively monitor and deal with, affecting the safety and cost of the project.
A slack depth acoustic emission testing structure of the stapling depth of the rock mass chamber was designed. By setting observation branch holes and multiple test sections in the underground chamber, acoustic emission probes were arranged to form an acoustic emission matrix, and the top arch and side walls were monitored and positioned in real time. and the slack range and degree of the base plate.
Accurate measurement of the slack depth of rock mass around the jointed rock mass cave chamber is achieved, the degree of damage and fracture is predicted, the safety and stability of the cave chamber is ensured, and the engineering risks and costs are reduced.
Smart Images
Figure CN222166941U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of hydropower engineering construction, and in particular to a jointed rock mass cavern relaxation depth acoustic emission test structure. Background Art
[0002] Large underground caverns are important hub buildings that are indispensable to the construction of hydropower projects. Their safe construction is directly related to the success of the project. As the environment of hydropower underground caverns becomes increasingly complex and joints and fissures develop, the testing and treatment of the relaxation depth of jointed rock mass is a key technical issue for large underground cavern projects and faces huge challenges.
[0003] The main characteristics of jointed rock mass are that it is easy to relax after engineering excavation and is sensitive to the scale of excavation. After relaxation, the bearing capacity of the rock mass decreases and the self-stabilizing ability weakens, which can easily lead to surrounding rock damage phenomena such as loosening and falling of the top arch and side walls, cracking of the bottom plate, etc., causing construction delays and increasing engineering disposal costs. When the relaxation is serious, it may even endanger the lives of construction workers. In-situ acoustic emission testing technology has the significant advantage of non-contact, long-distance and long-term monitoring of rock damage and fracture. It can test and grasp the relaxation range and degree of jointed rock mass in real time. Therefore, a suitable acoustic emission test structure for the relaxation depth of jointed rock mass caverns is crucial. Utility Model Content
[0004] An embodiment of the present application provides a jointed rock cavern relaxation depth acoustic emission test structure, which can timely capture the relaxation degree of the rock around the jointed rock cavern, thereby facilitating the goal of quickly judging the safety and stability state of the jointed rock cavern.
[0005] The jointed rock cavern relaxation depth acoustic emission test structure provided in the embodiment of the present application comprises: an underground cavern and an observation branch cavern, wherein the number of the observation branch caverns is two, and the two observation branch caverns are respectively located on both sides of the underground cavern along the width direction;
[0006] A first test section, wherein the first test section includes a plurality of first boreholes, the first boreholes are connected to the observation branch cave and the top arch and the side wall of the underground cave, and an acoustic emission probe is arranged in the first borehole; the number of the first test sections is multiple, and the multiple first test sections are arranged at intervals along the length direction of the underground cave;
[0007] The second test section includes a second borehole, the second borehole extends obliquely downward along the lower side wall of the underground cavern to a preset depth, and an acoustic emission probe is arranged in the second borehole; the number of the second test sections is multiple, and the multiple second test sections are arranged at intervals along the length direction of the underground cavern.
[0008] In addition, the jointed rock mass cavern relaxation depth acoustic emission test structure provided in the embodiment of the present application may also have the following additional technical features:
[0009] In an optional scheme, for the same first test section, the number of the first boreholes drilled by each observation branch tunnel into the underground cavern is not less than 3, and the number of the acoustic emission probes arranged in each of the first boreholes is not less than two, and the acoustic emission probes in the first boreholes are arranged adjacent to the top arch and side walls of the underground cavern.
[0010] In an optional scheme, for the same second test section, the number of the second boreholes is two, and the two second boreholes are respectively located on both sides of the underground cavern, the number of the acoustic emission probes set in each second borehole is not less than 3, and the acoustic emission probes in the second boreholes are located below the bottom plane of the underground cavern.
[0011] In an optional scheme, the underground cavern is divided into a first excavation layer, a second excavation layer and a third excavation layer according to the excavation order during excavation, and the second borehole is drilled at the bottom corners on both sides of the second excavation layer after the excavation of the second excavation layer is completed.
[0012] In an optional scheme, the width of the underground cavern is defined as L4, the distance between the underground cavern and the observation branch cavern is defined as L1, the interval between two adjacent first test sections is defined as L2, and the interval between two adjacent second test sections is defined as L3, then: 4≤L1 / L4≤5, the length of L2 is approximately 10m, and the length of L3 is approximately 10m.
[0013] In an optional scheme, the jointed rock cavern relaxation depth acoustic emission test structure has a working state. In the working state, the acoustic emission probes of two adjacent first test sections form an acoustic emission matrix, and are used to monitor and locate the relaxation range and degree of the top arch and side wall surrounding rock of the underground cavern, and the acoustic emission probes in two adjacent second test sections form an acoustic emission matrix, and are used to monitor and locate the relaxation range and degree of the floor surrounding rock of the underground cavern.
[0014] The beneficial effects of the embodiments of the present application are:
[0015] The acoustic emission test structure for relaxation depth of jointed rock cavern in the embodiment of the present application performs relaxation test of the top arch side wall surrounding rock of the underground cavern through the first test section, and performs relaxation test of the floor surrounding rock of the underground cavern through the second test section. The monitoring matrix formed by the acoustic emission probes of different test sections is used to measure the relaxation depth of the rock mass around the jointed rock cavern, and then predict the degree of damage and rupture of the cavern, so as to ensure the safety and smooth construction of the cavern.
[0016] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a schematic diagram of the plan layout of the jointed rock cavern relaxation depth acoustic emission test structure of the present application;
[0018] Figure 2 for Figure 1 AA cross-sectional structural diagram;
[0019] Figure 3 for Figure 1 Schematic diagram of the BB cross-sectional structure.
[0020] Figure numerals: underground cavern 1, observation branch cave 2, first test section 3, first borehole 31, acoustic emission probe 4, second test section 5, second borehole 51, first excavation layer 6, second excavation layer 7, third excavation layer 8.
[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION
[0022] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.
[0023] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.
[0024] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.
[0025] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.
[0026] It should be noted that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.
[0027] After the excavation of the jointed rock cavern, relaxation failure will inevitably occur, and there may even be instability failures such as the side wall and top arch falling off, the bottom plate bulging and cracking. The difference in the relaxation depth test structure of the large underground cavern means that there are differences in the test instruments, test methods, and layout forms, which may lead to differences in the relaxation range and relaxation degree of the surrounding rock. The selection of a reasonable relaxation depth test structure for the large underground cavern is very important for the stability of the entire jointed rock cavern. Therefore, the embodiment of the present application provides a jointed rock cavern relaxation depth acoustic emission test structure, which arranges an acoustic emission test matrix by setting an observation branch hole and utilizing the free space formed by layered excavation, and real-time monitoring of the relaxation depth of the top arch, side wall and bottom plate area of the easily relaxed jointed rock cavern is performed, and the relaxation degree of the surrounding rock around the jointed rock cavern is captured in time, thereby achieving the goal of rapid judgment of the safe and stable state of the jointed rock cavern.
[0028] The jointed rock cavern relaxation depth acoustic emission test structure in the embodiment of the present application is mainly used in hydropower underground projects, especially in easily relaxed jointed rock cavern projects, especially in large underground cavern projects with an equivalent cavern diameter of more than 10m. This article also describes the technical scheme and technical effects by taking its application in hydropower underground projects as an example. Of course, the jointed rock cavern relaxation depth acoustic emission test structure in the embodiment of the present application can also be used in other similar monitoring environments, which will not be elaborated in this article.
[0029] like Figure 1-3As shown, the embodiment of the present application provides a jointed rock cavern relaxation depth acoustic emission test structure, which mainly includes an underground cavern 1, an observation branch cavern 2, a first test section 3 and a second test section 5. Among them, the number of observation branch caverns 2 is two, and the two observation branch caverns 2 are respectively located on both sides of the underground cavern 1 along the width direction; the first test section 3 includes a plurality of first boreholes 31, the first boreholes 31 connect the observation branch cavern 2 and the top arch and side wall of the underground cavern 1, and an acoustic emission probe 4 is arranged in the first borehole 31; the number of first test sections 3 is multiple, and the multiple first test sections 3 are arranged at intervals along the length direction of the underground cavern 1; the second test section 5 includes a second borehole 51, the second borehole 51 extends downward along the lower side wall of the underground cavern 1 to a preset depth, and an acoustic emission probe 4 is arranged in the second borehole 51; the number of second test sections 5 is multiple, and the multiple second test sections 5 are arranged at intervals along the length direction of the underground cavern 1.
[0030] In this embodiment, the observation branch holes 2 are symmetrically arranged on both sides of the underground cavern 1 along the width direction, and the cave cross-sectional area of the observation branch holes 2 is smaller than the cave cross-sectional area of the underground cavern 1. The first borehole 31 can be pre-drilled to the top arch and side wall area of the underground cavern 1 through the observation branch holes 2 before the underground cavern 1 is excavated, and the acoustic emission probe 4 is further buried. When performing monitoring work, the acoustic emission probes 4 of two adjacent first test sections 3 form an acoustic emission matrix, which can effectively monitor and locate the relaxation range and degree of the top arch and side wall surrounding rock of the underground cavern 1.
[0031] In this embodiment, the acoustic emission test structure for relaxation depth of jointed rock caverns performs relaxation test of the top arch side wall surrounding rock of the underground cavern 1 through the first test section 3, and performs relaxation test of the floor surrounding rock of the underground cavern 1 through the second test section 5. It uses the monitoring matrix formed by the acoustic emission probes 4 of different test sections to measure the relaxation depth of the rock mass around the jointed rock cavern, and then predict the degree of damage and rupture of the cavern, so as to ensure the safety and smooth construction of the cavern.
[0032] like Figure 1-2 As shown, in a specific embodiment, at the same first test section 3, the number of first boreholes 31 drilled by each observation branch hole 2 into the underground cavern 1 is not less than 3, and the number of acoustic emission probes 4 arranged in each first borehole 31 is not less than two, and the acoustic emission probes 4 in the first borehole 31 are arranged close to the top arch and side wall positions of the underground cavern 1. By arranging the acoustic emission probes 4 at multiple positions, the monitoring accuracy of the top arch and side wall positions of the underground cavern 1 can be guaranteed, and the relaxation degree of the surrounding rock of the jointed rock cavern at the corresponding position can be captured in time.
[0033] like Figure 1 and Figure 3As shown, in a specific embodiment, the number of the second boreholes 51 in the same second test section 5 is two, and the two second boreholes 51 are respectively located on both sides of the underground cavern 1. The number of acoustic emission probes 4 arranged in each second borehole 51 is not less than 3, and the acoustic emission probes 4 in the second borehole 51 are located below the floor plane of the underground cavern 1. Similarly, by the second boreholes 51 extending downward and outward from the underground cavern 1 and the acoustic emission probes 4 arranged in multiple positions in the second boreholes 51, the monitoring accuracy of both sides of the floor of the underground cavern 1 can be guaranteed, and the relaxation degree of the surrounding rock around the jointed rock cavern at the corresponding position can be captured in time. When performing monitoring work, the acoustic emission probes 4 in two adjacent second test sections 5 form an acoustic emission matrix, which can effectively monitor and locate the relaxation range and degree of the surrounding rock of the floor of the underground cavern 1.
[0034] like Figure 2-3 As shown, in a specific embodiment, the underground cavern 1 is divided into a first excavation layer 6, a second excavation layer 7 and a third excavation layer 8 according to the excavation order during excavation, and the second borehole 51 is drilled and formed at the bottom corners on both sides of the second excavation layer 7 after the excavation of the second excavation layer 7 is completed. Specifically, during excavation and arrangement, the underground cavern 1 is first excavated in layers, and before the bottom layer is excavated (before the third excavation layer 8 in this example is excavated), the free space formed by the upper excavation (the first excavation layer 6 and the second excavation layer 7 in this example) is utilized to drill holes in the bottom corners on both sides of the cavern to the cavern floor, and the holes intersect the side walls at a small angle, and then the acoustic emission probe 4 is arranged in the holes.
[0035] like Figure 1 As shown, in a specific embodiment, the width of the underground cavern 1 is defined as L4, the spacing between the underground cavern 1 and the observation branch cavern 2 is defined as L1, the spacing between two adjacent first test sections 3 is defined as L2, and the spacing between two adjacent second test sections 5 is defined as L3, then: 4≤L1 / L4≤5, the length of L2 is approximately 10m, and the length of L3 is approximately 10m. It should be noted that the "approximately 10m" mentioned in this embodiment means that the length is 10m with a certain error. Generally speaking, such an error can be considered to be within the range of approximately 10m as long as it is less than 1m.
[0036] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. An acoustic emission test structure for relaxation depth of jointed rock caverns. It is characterized in that include: An underground cavern and an observation branch cavern, wherein the number of the observation branch caverns is two, and the two observation branch caverns are respectively located on both sides of the underground cavern in the width direction; A first test section, wherein the first test section includes a plurality of first boreholes, the first boreholes are connected to the observation branch cave and the top arch and the side wall of the underground cave, and an acoustic emission probe is arranged in the first borehole; the number of the first test sections is multiple, and the multiple first test sections are arranged at intervals along the length direction of the underground cave; The second test section includes a second borehole, the second borehole extends obliquely downward along the lower side wall of the underground cavern to a preset depth, and an acoustic emission probe is arranged in the second borehole; the number of the second test sections is multiple, and the multiple second test sections are arranged at intervals along the length direction of the underground cavern.
2. The jointed rock mass cavern relaxation depth acoustic emission test structure according to claim 1, It is characterized in that In the same first test section, the number of the first boreholes drilled by each observation branch tunnel into the underground cavern is not less than 3, and the number of the acoustic emission probes arranged in each of the first boreholes is not less than two, and the acoustic emission probes in the first boreholes are arranged close to the top arch and side walls of the underground cavern.
3. The jointed rock mass cavern relaxation depth acoustic emission test structure according to claim 1 or 2, It is characterized in that In the same second test section, the number of the second boreholes is two, and the two second boreholes are respectively located on both sides of the underground cavern, the number of the acoustic emission probes arranged in each second borehole is not less than 3, and the acoustic emission probes in the second boreholes are located below the bottom plane of the underground cavern.
4. The jointed rock mass cavern relaxation depth acoustic emission test structure according to claim 3, It is characterized in that The underground cavern is divided into a first excavation layer, a second excavation layer and a third excavation layer according to an excavation order during excavation, and the second borehole is drilled at the bottom corners on both sides of the second excavation layer after the excavation of the second excavation layer is completed.
5. The jointed rock mass cavern relaxation depth acoustic emission test structure according to claim 3, It is characterized in that Define the width of the underground cavern as L4, the distance between the underground cavern and the observation branch cavern as L1, the interval between two adjacent first test sections as L2, and the interval between two adjacent second test sections as L3, then: 4≤L1 / L4≤5, the length of L2 is approximately 10m, and the length of L3 is approximately 10m.
6. The jointed rock mass cavern relaxation depth acoustic emission test structure according to any one of claims 1-2 or 4-5, It is characterized in that The jointed rock mass cavern relaxation depth acoustic emission test structure has a working state. In the working state, the acoustic emission probes of two adjacent first test sections form an acoustic emission matrix, and are used to monitor and locate the relaxation range and degree of the top arch and side wall surrounding rock of the underground cavern. The acoustic emission probes in two adjacent second test sections form an acoustic emission matrix, and are used to monitor and locate the relaxation range and degree of the floor surrounding rock of the underground cavern.