A method for preventing and controlling rock burst in the arch waist of a tunnel constructed by TBM

Abstract

The present application discloses a method for preventing and controlling rock bursts in the waist of a tunnel constructed by TBM. This method optimizes the design of the original support system of the TBM tunnel and applies a secondary lining in advance to the waist of the TBM tunnel. Without increasing the original support construction, it effectively prevents rock bursts at the waist, thereby greatly improving construction efficiency. The method of the present invention has the advantages of simple procedures, easy use, and low cost. The method can quickly seal the excavated rock mass, and has good operability for personnel. Without increasing the support procedures and materials, it improves the efficiency of the synchronous construction of the secondary lining of the TBM tunnel, effectively reduces the frequency of rock bursts, and reduces the safety risks of construction personnel in rock burst tunnel construction. At the same time, the materials in this method can be reused, which greatly reduces the construction cost.

Description

Technical Field

[0001] The present application relates to the technical field of underground engineering tunnel construction, and in particular to a method for preventing and controlling rock bursts in a tunnel waist during TBM construction. Background Art

[0002] Rockburst is a dynamic phenomenon in which the elastic deformation energy accumulated in the rock mass of an underground project is suddenly released due to excavation or other external disturbances, resulting in the explosion and ejection of the surrounding rock. Rockbursts are highly sudden, random, and dangerous, directly threatening the safety of construction workers and equipment and impacting construction progress. They have become a major challenge in underground engineering worldwide. Currently, deep rock projects in my country are increasing in number, buried at ever-greater depths. As the depth increases, the geological environment in which the rock mass occurs becomes more complex, the ground stress increases, and rockbursts become more prominent and severe. Therefore, in-depth research on rockburst prevention and control technologies is of great theoretical and practical significance.

[0003] In TBM tunneling, the probability of rockbursts ahead of the tunnel face causing engineering disasters is relatively low. Currently, research focuses on preventing and controlling rockbursts in the surrounding rock mass. This primarily involves optimizing support system design to absorb as much energy as possible from rock failure, reducing the energy release rate while maximizing surrounding rock strength and maintaining the integrity of the support system after a rockburst. For example, for severe rockbursts, support units such as shotcrete mesh and arch frames are used in synergistic fashion. These interconnected support units form a unified system for rockburst prevention and control. The thickness of shotcrete is designed based on the rockburst severity; the higher the severity, the thicker the shotcrete. In principle, energy-absorbing anchor bolts should be selected to actively absorb energy and better dissipate the enormous impact energy of a rockburst. These methods are effective for severe rockbursts and above. They can also be used for moderate rockbursts, such as those occurring at the crown or base of an arch. However, these support methods are less effective when the rockburst occurs in the tunnel haunch, which is common. This is primarily because TBM tunnels have limited working space at the arch crown and arch base, while the limited working space at the arch waist makes complex support difficult. Moderate rockbursts pose a relatively minor risk. Stopping the machine to install anchor bolts or shotcrete at the arch waist significantly reduces construction efficiency, increasing project time and costs. However, rockbursts at the arch waist can easily cause falling rock to injure workers. Furthermore, a rockburst at the arch waist, where the TBM grippers operate, can at best prevent the grippers from providing support for the TBM, or at worst damage the gripper cylinders, delaying construction progress. Summary of the Invention

[0004] In view of this, the present application provides a method for preventing and controlling rock bursts at the arch waist of a tunnel during TBM construction, which can effectively prevent rock bursts at the arch waist and greatly improve construction efficiency.

[0005] The present application provides a method for preventing and controlling rock burst in a tunnel haunch during TBM construction, comprising the following steps:

[0006] Step 1: After the initial concrete pouring to expose the tunnel surrounding rock, the arch waist secondary lining is poured on the concrete mixing trolley, and the inverted arch block is laid at the tunnel arch bottom, and the inverted arch block is installed on the steel arch frame;

[0007] Step 2: Install the fixing devices on the steel arch frame at the junction of the inverted arch block and the arch frame, and on the front steel arch frame, and install the wooden board through the fixing devices;

[0008] Step 3: Install the curved steel pipe on the steel arch frame and fix the curved steel pipe on the wooden board;

[0009] Step 4: Pour concrete into the formwork constructed in steps (1) to (3). After the concrete is fully solidified, remove the curved steel pipe, wooden board and fixing device, and then repeat steps (1) to (3) to cast the arch waist.

[0010] Optionally, the inverted arch block is provided with a groove, and the groove is used to install the inverted arch block on the steel arch frame.

[0011] Optionally, the arch waist secondary lining is 40~50m away from the tunnel face.

[0012] Optionally, the arc-shaped steel pipe is a hollow steel pipe.

[0013] Optionally, the depth of the groove is the same as the distance between the upper and lower wing plates of the arch.

[0014] Optionally, the fixing device includes assembled fixing bolts and a row of steel bars, and the fixing bolts are provided with a slot for clamping the wooden board.

[0015] Optionally, the wall thickness of the arc-shaped steel pipe is 2-3 mm.

[0016] The above-mentioned method for preventing and controlling rock bursts in the haunch of a TBM-constructed tunnel is based on an optimized design of the support system, i.e., the pre-implantation of a secondary lining at the haunch of the TBM tunnel. This effectively prevents rock bursts at the haunch without increasing the existing support construction, thereby greatly improving construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present application apparent.

[0018] Figure 1 Schematic diagram of the tunnel arch haunch casting formwork provided in an embodiment of the present application.

[0019] Figure 2 Three views of the inverted arch block provided in the embodiment of the present application.

[0020] Figure 3Schematic diagram of the tunnel arch haunch casting formwork provided in an embodiment of the present application.

[0021] Figure 4 A schematic structural diagram of the fixing device provided in an embodiment of the present application.

[0022] Figure 5 A schematic diagram of the structure of the steel bar row fixing the wooden board provided in an embodiment of the present application.

[0023] The components in the figure are identified as follows:

[0024] 1-steel arch frame; 2-wooden board; 3-arc-shaped steel pipe; 4-wooden board; 5-fixing device; 6-fixing bolt; 7-rebar row; 8-tunnel; 9-concrete spraying trolley; 10-secondary lining; 11-inverted arch block. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0026] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0027] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0028] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0029] The method for preventing and controlling rock burst in a tunnel under TBM construction according to the present application includes the following steps:

[0030] S1: The arch haunch secondary lining 10 is poured at the concrete spraying trolley 9, about 50m away from the tunnel face. At this time, the surrounding rock of the exposed tunnel 8 has been initially sprayed with concrete, and the steel arch frame 1 has also been assembled.

[0031] like Figure 1 As shown. The inverted arch block 11 is laid at the arch bottom of the TBM tunnel 8. The width of the inverted arch block is reasonably determined according to the laying distance of the arch frame of the tunnel 8. In this example, the width of the inverted arch block is 90cm. At the same time, a 150mm groove is opened in the middle of the inverted arch block 11 in advance ( Figure 2 ), the groove depth is the same as the distance between the upper and lower wing plates of the steel arch frame 1, so that the inverted arch block 11 can be installed on the steel arch frame 1.

[0032] S2: Weld the fixing device 5 to the steel arch frame 1 at the junction of the inverted arch block 11 and the arch frame, and also weld the fixing device 5 at the same position of the front steel arch frame 1. Then place the wooden board 2 on the fixing device 5. The wooden board is 10 cm wide and 2 m long. Then arrange the wooden boards 2 in sequence along the direction of the arch frame. After a certain number of wooden boards 2 are reached, weld another fixing device 5 at the steel arch frame 1, and then install the wooden boards 2 again until the predetermined height is reached. According to the length of the wooden board, 1.8 m can be cast at a time along the excavation method, that is, four steel arch frames.

[0033] The fixing device 5 is composed of fixed fixing bolts 6 and steel bar rows 7. Figure 5 After the steel bar row 7 is welded to the steel arch frame 1, there is a slot on its upper part to clamp the wooden board 4, while minimizing the gap between the upper and lower wooden boards to ensure the quality of the arch waist secondary lining casting.

[0034] S3: Process an arc-shaped steel pipe 3 along the steel arch frame 1 with the same curvature as the arch frame, place the arc-shaped steel pipe 3 on the wooden board 2, the arc-shaped steel pipe 3 is about 3m long and 2.5mm thick, and then use iron wire to fix the arc-shaped steel pipe 3 to the connecting bolts of the steel arch frame 1.

[0035] S4: Pour the prepared concrete into the formwork constructed in S1-3. In this example, plain concrete is used. After 48 hours, when the concrete solidifies and reaches its initial strength, remove the curved steel pipe 3, wooden board 4, and fixing device 5 in sequence. Repeat the above steps to cast the arch waist once more.

[0036] Compared with the prior art, the present invention has the following beneficial effects: the method proposed by the present invention optimizes the design of the original support system of the TBM tunnel, pre-installs the secondary lining 10 at the arch waist position of the TBM tunnel, effectively prevents rock bursts at the arch waist without increasing the original support construction, and greatly improves construction efficiency. The method of the present invention has the advantages of simple process, convenient use, and low cost. The method can quickly seal the excavated rock mass, has good operator operability, and improves the efficiency of the synchronous construction of the secondary lining of the TBM tunnel without increasing the support process and materials, effectively reduces the frequency of rock bursts, and reduces the safety risks of construction personnel in rock burst tunnel construction. At the same time, the materials in the method can be reused, which greatly reduces construction costs.

[0037] The above is only a preferred specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in this application should be covered by the scope of protection of the present application.

Claims

1. A method for preventing and controlling rock burst in a tunnel haunch constructed by TBM, characterized in that: The following steps are involved: Step 1: After the initial concrete pouring to expose the tunnel surrounding rock, the secondary arch waist lining is poured on the concrete mixing trolley, and the inverted arch block is laid at the tunnel arch bottom. The inverted arch block is provided with a groove for mounting the inverted arch block on the steel arch frame. Step 2: Install the fixing devices on the steel arch frame at the junction of the inverted arch block and the arch frame, and on the front steel arch frame, and install the wooden board through the fixing devices; the fixing devices include assembled fixing bolts and steel bars, and the fixing bolts have slots for clamping the wooden board; Step 3: Install the curved steel pipe on the steel arch frame and fix the curved steel pipe on the wooden board; Step 4: Pour concrete into the formwork constructed in steps (1) to (3). After the concrete is fully solidified, remove the curved steel pipe, wooden board and fixing device, and then repeat steps (1) to (3) to cast the arch waist.

2. The method for preventing and controlling rock burst in a tunnel constructed by TBM according to claim 1, characterized in that: The second lining of the arch waist is 40~50m away from the heading face.

3. The method for preventing and controlling rock burst in a tunnel constructed by TBM according to claim 1, characterized in that: The arc-shaped steel pipe is a hollow steel pipe.

4. The method for preventing and controlling rock burst in a tunnel constructed by TBM according to claim 1, characterized in that: The depth of the groove is the same as the distance between the upper and lower wing plates of the arch.

5. The method for preventing and controlling rock burst in a TBM-constructed tunnel arch waist according to claim 3, characterized in that: The wall thickness of the arc-shaped steel pipe is 2-3 mm.

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