A tunnel excavation face front stress disturbance test structure

Abstract

The utility model provides a kind of tunnel excavation face front stress disturbance test structure, including the test hole of diameter D, the initial face front of test hole is equipped with auxiliary hole, the excavation of auxiliary hole is located the rear of initial face, the side hole wall of auxiliary hole towards test hole is equipped with monitoring hole group, monitoring hole group includes the several monitoring holes of being uniformly distributed in the height direction and axis direction of auxiliary hole, several monitoring holes are arranged with acoustic emission detector and surrounding rock stress meter at interval, can whole process capture face front stress concentration, realize the effective monitoring of face front stress disturbance, avoid the defect that traditional monitoring cannot truly reflect the influence of tunneling process to face front stress disturbance, can provide reliable monitoring data for the control of face front stress risk especially rockburst risk, support optimization adjustment etc. of tunnel.

Description

Technical Field

[0001] This utility model relates to the field of tunnel excavation technology, and in particular to a stress disturbance test structure in front of the tunnel face. Background Technology

[0002] Real-time monitoring of surrounding rock stress disturbance during tunnel excavation is crucial for timely understanding of the surrounding rock's safety status, objectively evaluating project stability, conducting feedback analysis and design optimization, and making scientific decisions regarding engineering problems. In traditional tunnel monitoring designs, due to limitations in construction schedule and space, monitoring instruments are typically placed behind the tunnel face, lagging behind by tens or even hundreds of meters. This results in the acquisition of incomplete data on the mechanical disturbances to the surrounding rock caused by tunnel excavation; statistics show that over 70% of the data is lost. This information is vital for assessing surrounding rock stability, optimizing support design, and scheduling construction. In particular, stress disturbances ahead of the tunnel face are more susceptible to spatiotemporal effects, significantly impacting both the stability of the tunnel face and the surrounding rock behind it. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a stress disturbance testing structure in front of the tunnel face, which can solve the problem that traditional tunnel monitoring instruments are placed behind the tunnel face, making it difficult to capture stress disturbance data in front of the tunnel face.

[0004] Therefore, the present invention adopts the following technical solution: A stress disturbance testing structure for tunnel face includes a test tunnel with a diameter of D. An auxiliary tunnel is provided in front of the initial face of the test tunnel. The excavation site of the auxiliary tunnel is located behind the initial face. A group of monitoring holes is provided on one side wall of the auxiliary tunnel facing the test tunnel. The group of monitoring holes includes several monitoring holes evenly distributed in the height and axial directions of the auxiliary tunnel. Acoustic emission detectors and surrounding rock stress gauges are arranged at intervals in the several monitoring holes.

[0005] Based on the above technical solutions, the present invention may also adopt the following further technical solutions, or combine these further technical solutions: The distance between the initial working face and the auxiliary hole is greater than or equal to 3D.

[0006] The distance between the excavation site and the initial working face is greater than or equal to 10D.

[0007] The monitoring holes located at the highest point in the height direction of the auxiliary tunnel are inclined upwards by 10°, the monitoring holes located at the lowest point in the height direction of the auxiliary tunnel are inclined downwards by 10°, and the monitoring holes located on both sides of the axis of the auxiliary tunnel are inclined outwards by 10°. The group of monitoring holes covers the stress disturbance area of ​​the initial working face.

[0008] The distance between two adjacent monitoring holes in the longitudinal direction is 75mm to 100mm, and the distance between two adjacent monitoring holes in the transverse direction is 150mm to 200mm.

[0009] Compared with the prior art, this utility model has the following advantages and beneficial effects: it can capture the stress concentration in front of the tunnel face throughout the entire process, realize the effective monitoring of stress disturbance in front of the tunnel face, and avoid the defects of traditional monitoring that cannot truly reflect the impact of the tunneling process on stress disturbance in front of the tunnel face. It can provide reliable monitoring data for controlling stress risks in front of the tunnel face, especially rockburst risks, and optimizing and adjusting tunnel support. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the auxiliary tunnel excavation structure of this utility model.

[0011] Figure 2 and Figure 3 This is a schematic diagram of the distribution of the monitoring well group of this utility model.

[0012] Figure 4 This is a schematic diagram showing the distribution of the acoustic emission detector and the surrounding rock stress gauge of this utility model. Detailed Implementation

[0013] To enable those skilled in the art to better understand the technical solution of this utility model, the preferred embodiments of this utility model are described below in conjunction with specific examples. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote elements with the same or similar functions throughout. However, it should be understood that the drawings are for illustrative purposes only and should not be construed as limiting this utility model. To better illustrate this embodiment, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product size. It is understandable for those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting this utility model.

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0015] This utility model provides a stress disturbance testing structure in front of the tunnel face, including a test tunnel 1 with a diameter of D, an auxiliary tunnel 2 in front of the initial face 11 of the test tunnel 1, the excavation 21 of the auxiliary tunnel 2 being located behind the initial face 11, and a group of monitoring holes on one side wall of the auxiliary tunnel 2 facing the test tunnel 1, the group of monitoring holes including a number of monitoring holes 5 evenly distributed in the height direction and axial direction of the auxiliary tunnel 2, and acoustic emission detectors 3 and surrounding rock stress gauges 4 arranged at intervals in the number of monitoring holes 5.

[0016] The distance between the initial working face 11 and the auxiliary tunnel 2 is greater than or equal to 3D, covering the boundary zone between the plastic and elastic zones in front of the initial working face 11.

[0017] The distance between the excavation point 21 and the initial working face 11 is greater than or equal to 10D to avoid affecting the stress concentration distribution near the working face.

[0018] like Figure 1 As shown, auxiliary tunnel 2 detours from excavation point 21, making two right-angle turns to reach the front of test tunnel 1.

[0019] Several monitoring holes 5 located at the highest point in the height direction of auxiliary tunnel 2 are inclined upward by 10°, several monitoring holes 5 located at the lowest point in the height direction of auxiliary tunnel 2 are inclined downward by 10°, and several monitoring holes 5 located on both sides of the axis of auxiliary tunnel 2 are inclined outward by 10°. The monitoring hole group covers the stress disturbance area of ​​the initial working face 11.

[0020] The distance between two adjacent monitoring holes 5 in the longitudinal direction is 75mm~100mm, and the distance between two adjacent monitoring holes 5 in the transverse direction is 150mm~200mm.

[0021] In this embodiment, a plurality of monitoring holes 5 are arranged in 7 columns along the axial direction of the auxiliary hole 2, wherein the distance between the first and second columns is 150mm, the distance between the second and third columns, the third and fourth columns, the fourth and fifth columns, and the fifth and sixth columns is 200mm, and the distance between the sixth and seventh columns is 200mm; a plurality of monitoring holes 5 are arranged in 4 rows along the height direction of the auxiliary hole 2, wherein the distance between the first and second rows is 75mm, the distance between the second and third rows, the third and fourth rows, and the distance between the fourth row and the bottom of the auxiliary hole 2 is 100mm; the distance between the initial working face 11 and the auxiliary hole 2 is 1000mm, and the distance between the initial working face 11 and the front end of the monitoring hole 5 is 100mm.

[0022] Acoustic emission and stress meter are currently the most effective means of monitoring stress disturbance in surrounding rock. This utility model adopts both acoustic emission and stress meter methods for simultaneous monitoring. The acoustic emission test and surrounding rock stress test holes are arranged alternately to avoid mutual interference between the boreholes.

[0023] During the implementation of this embodiment, the tunneling rate should be maintained as much as possible during the excavation of test tunnel 1. If TBM tunneling is used, continuous tunneling should be maintained. If drill-and-blast excavation is used, the tunneling advance should be controlled, and each step of excavation should not exceed 1 tunnel diameter. It is also recommended to use fine blasting to avoid disturbing the stress concentration in front of the tunnel face.

[0024] By organizing the curves showing the relationship between excavation step length and stress and acoustic emission time, the curves showing the variation law of stress disturbance can be obtained.

[0025] Based on the description and drawings of this utility model, those skilled in the art can easily manufacture or use the stress disturbance test structure in front of the tunnel excavation face of this utility model, and can produce the positive effects described in this utility model.

[0026] It should be noted that the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this utility model are intended to cover non-exclusive inclusion. The terms "installed," "set," "equipped with," "connected," "connected," and "sleeve-in" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two mechanisms, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0027] In the description of this utility model, it should be understood that the terms "one end," "the other end," "outer side," "inner side," "horizontal," "end," "length," "outer end," "left," and "right," 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 utility model and simplifying the description, and do not indicate or imply that the mechanism 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 utility model. The terms "first" and "second" are also used only for the sake of brevity in description and do not indicate or imply relative importance.

[0028] Furthermore, in practicing the claims of this utility model, those skilled in the art can understand and influence variations to the disclosed embodiments through a study of the drawings, the disclosure, and the appended claims. Additionally, in the claims and description, words such as "comprising" and "containing" do not exclude other elements or steps, and non-plural nouns do not exclude their plural forms.

[0029] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the scope of the present utility model. All equivalent changes and modifications made in accordance with the present utility model are covered by the scope of the claims of the present utility model, and will not be listed here.

Claims

1. A stress disturbance testing structure in front of the tunnel face, characterized in that, The test hole (1) has a diameter of D. An auxiliary hole (2) is provided in front of the initial working face (11) of the test hole (1). The excavation point (21) of the auxiliary hole (2) is located behind the initial working face (11). A monitoring hole group is provided on one side wall of the auxiliary hole (2) facing the test hole (1). The monitoring hole group includes several monitoring holes (5) evenly distributed in the height direction and axial direction of the auxiliary hole (2). Acoustic emission detectors (3) and surrounding rock stress gauges (4) are arranged at intervals in the several monitoring holes (5).

2. A test structure for stress disturbance in front of a tunneling face as claimed in claim 1, characterized in that The distance between the initial working face (11) and the auxiliary hole (2) is greater than or equal to 3D.

3. A test structure for stress disturbance in front of a tunneling face according to claim 1 or 2, characterized in that The distance between the excavation site (21) and the initial working face (11) is greater than or equal to 10D.

4. The stress disturbance test structure in front of the tunnel face as described in claim 1, characterized in that, The monitoring holes (5) located at the highest point in the height direction of the auxiliary hole (2) are inclined upward by 10°, the monitoring holes (5) located at the lowest point in the height direction of the auxiliary hole (2) are inclined downward by 10°, and the monitoring holes (5) located on both sides of the axis of the auxiliary hole (2) are inclined outward by 10°. The monitoring hole group covers the stress disturbance area of ​​the initial working face (11).

5. A test structure for stress disturbance in front of a tunneling face as claimed in claim 1, characterized in that The distance between two adjacent monitoring holes (5) in the longitudinal direction is 75mm~100mm, and the distance between two adjacent monitoring holes (5) in the transverse direction is 150mm~200mm.

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