Tunnel deformation control system with high strength super toughness and construction method thereof

Abstract

The application discloses a tunnel deformation control system with high strength and super toughness and a construction method thereof, and the system comprises an active supporting layer, a pressure-releasing deformation layer and a main bearing layer; the active supporting layer is formed by hanging a net and spraying concrete, and the net is fixed on the inner wall of the tunnel through anchor cables and anchor rods; the pressure-releasing deformation layer is composed of filling materials and high-strength springs; and the main bearing layer is made of corrugated plates made of materials with high longitudinal and lateral strength and rigidity. The corrugated plates with high strength and rigidity are arranged to replace the traditional steel arch structure, so that the defects of insufficient strength and rigidity of the existing supporting structure are overcome; secondly, the pressure-releasing deformation layer is of an integral structure, so that the problem of local stress concentration caused by the deformation of surrounding rock is avoided, the active supporting and passive supporting are combined, and the role of the anchor rod is effectively played; the high-strength springs in the pressure-releasing deformation layer can not only provide supporting elastic force, but also provide a large deformation, so that the range of the surrounding rock damage circle is reduced.

Description

Technical Field

[0001] This invention relates to the field of tunnel support structure design and construction, and in particular to a tunnel deformation control system with high strength and ultra-toughness and its construction method. Background Technology

[0002] Traditional tunnel deformation control employs a "yield-then-resistance, resistance-oriented, and resistance-yield combined" approach. This involves increasing the strength and stiffness of support materials, increasing support layer thickness, and installing localized pressure-yielding joints and limiters to ensure both the toughness and strength of the support structure. However, because current pressure-yielding methods are localized, stress concentration is widespread, increasing the likelihood of structural instability. Furthermore, the strength limits of the steel arches and shotcrete materials used are significantly insufficient under the pressure of large tunnel deformations. Therefore, improving the overall strength and toughness of the support structure is crucial for coping with large tunnel deformations. Summary of the Invention

[0003] In view of the above, the present invention provides a tunnel deformation control system with high strength and ultra-toughness and its construction method.

[0004] A tunnel deformation control system with high strength and ultra-toughness includes, from the outer layer to the inner layer of the tunnel, an active support layer, a pressure-relief deformation layer and a main load-bearing layer.

[0005] The active support layer includes a wire mesh, which is fixed to the inner wall of the tunnel by anchor cables and anchor rods, and shotcrete is sprayed onto the wire mesh to form an active support layer.

[0006] The compression-deformation layer consists of a filler material with high compressibility and a high-strength spring;

[0007] The main load-bearing layer is made of corrugated plates of materials with high strength and stiffness in both the longitudinal and transverse directions;

[0008] The active support layer and the main load-bearing layer are connected together by elastic connection components to form a whole.

[0009] Based on the above technical solutions, as a preferred embodiment, the elastic connection component includes a partition plate, a circular tube, a high-strength spring, and a corrugated plate. The partition plate is provided with the interface between the active support layer and the pressure-relief deformation layer. One end of the circular tube is connected to the partition plate, and the other end is connected to the corrugated plate. The corrugated plate is located on the side where the main bearing layer and the pressure-relief deformation layer are connected. The high-strength spring is set inside the circular tube and can extend and retract along the axial direction of the circular tube.

[0010] Based on the above technical solutions, as a preferred option, the length of the high-strength spring shall not exceed the thickness of the compression deformation layer.

[0011] Based on the above technical solutions, as a preferred option, a constraint rod is provided on the active support layer to enhance the support strength of the active support layer.

[0012] Based on the above technical solutions, as a preferred option, the main bearing layer is provided with a filling material injection port and a surrounding rock deformation monitoring port.

[0013] Based on the above technical solutions, as a preferred embodiment, the anchor cable located on one side of the main bearing layer is locked by the anchor cable joint, and the anchor rod is locked by the anchor rod joint; a connecting pad and a locking pad are provided between the anchor cable joint or the anchor rod joint and the main bearing layer.

[0014] Based on the above technical solutions, as a preferred option, the corrugated plate is a steel corrugated plate or a basalt fiber corrugated plate, and its thickness and waveform can be adjusted according to actual conditions.

[0015] Based on the above technical solutions, the preferred filling material is a modified rigid polyurethane foam filler with large deformation capacity, good waterproof durability and certain strength.

[0016] A construction method for a tunnel deformation control system with high strength and ultra-toughness, employing the aforementioned system, includes the following steps:

[0017] Step 1: Design the span, waveform, thickness, circumferential and longitudinal width of the corrugated plate according to the cross-sectional shape of the excavated tunnel, and design the length and arrangement of the anchor cables and anchor rods;

[0018] Step 2: Install steel mesh on the excavated tunnel wall and spray concrete to quickly seal the surrounding rock and form an active support layer;

[0019] Step 3: Pre-set the flexible connection components at the predetermined anchor cable hole or anchor bolt hole positions;

[0020] Step 4: The corrugated sheets are spliced ​​on site. After the splicing is completed, the reinforcement support work and the installation of anchor cables and anchor rods are carried out under the protection of the corrugated sheets.

[0021] Step 5: After installing the anchor cables and anchor rods, lock them in place using the anchor cable joints, anchor rod joints, or locking devices;

[0022] Step Six: Inject the filler material through the reserved filler material injection port, injecting from low to high.

[0023] Step 7: Install displacement monitoring points on the corrugated plate, and at the same time, install measuring points in the reserved surrounding rock deformation monitoring ports. The surrounding rock deformation monitoring ports are constructed using an anchor drilling rig.

[0024] Step 8: Repeat steps 1 through 7 until all excavated tunnels are supported.

[0025] After the completion of step seven above, it is necessary to continuously monitor the deformation of the corrugated plate and the surrounding rock. When the deformation of the surrounding rock exceeds the warning value, the monitoring should be strengthened. When the deformation of the corrugated plate exceeds the warning value, the strength of the main bearing layer needs to be quickly reinforced.

[0026] The present invention has the following beneficial effects:

[0027] (1) This invention overcomes the shortcomings of insufficient strength and stiffness of existing support structures by replacing the traditional steel arch frame structure with a high-strength, high-rigidity corrugated plate; moreover, the corrugated plate can be pre-processed in the factory, and its quality is guaranteed.

[0028] (2) The present invention sets up a pressure-relief deformation layer of the overall structure, which avoids the problem of local stress concentration caused by the deformation of the surrounding rock, realizes the combination of active support and passive support, and effectively plays the role of anchor bolts.

[0029] (3) High-strength springs are provided in the pressure deformation layer and the elastic connection component connecting the main bearing layer and the active support layer of the present invention. The high-strength springs can not only provide support elasticity, but also provide a large amount of deformation, thereby reducing the range of the surrounding rock damage zone. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall control system of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of the elastic connection component in this invention;

[0032] Figure 3 This is a diagram illustrating the deformation control mechanism of the control system of the present invention.

[0033] In the diagram: 1-Active support layer; 2-Main load-bearing layer; 3-Pressure deformation layer; 4-Anchor cable; 5-Anchor rod; 6-Anchor cable joint; 7-Anchor rod joint; 8-Constraint rod; 9-Partition plate; 10-Circular pipe; 11-Elastic connection assembly; 12-High-strength spring; 13-Connecting plate; 14-Locking plate; 15-Locking component; 16-Corrugated plate. Detailed Implementation

[0034] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0035] refer to Figure 1 and Figure 2 The present invention provides a tunnel deformation control system with high strength and ultra-toughness. The system includes an active support layer 1, a pressure-relief deformation layer 3 and a main bearing layer 2, which are arranged from the outer layer to the inner layer of the tunnel.

[0036] Active support layer 1 provides active support for the surrounding rock. After the tunnel is excavated, steel mesh is quickly hung on the rock wall and fixed to the inner wall of the tunnel by anchor cables 4 and anchor rods 5. Shotcrete is sprayed onto the mesh to form active support layer 1, which avoids further weathering of the surrounding rock.

[0037] The innermost layer of the tunnel is the main bearing layer 2, which plays a major supporting role; the compressive deformation layer 3 is set between the main bearing layer 2 and the active support layer 1, which plays a role in buffering deformation.

[0038] The active support layer 1 and the main load-bearing layer 2 are connected by an elastic connection component 11 to form a whole. The anchor cable 4 and the anchor rod 5 transfer the load on the active support layer 1 to the main load-bearing layer 2 through the elastic connection component 11.

[0039] The main load-bearing layer 2 is made of high-strength materials with high longitudinal and transverse strength and stiffness, and the corrugated plates can be prefabricated in the factory and quickly assembled on site.

[0040] Corrugated sheets can be made of steel or basalt fiber. They can also be assembled from U-shaped high-strength steel plates, insert plates, rectangular steel plates, and other closed steel plates. In short, any high-strength and high-rigidity support structure that meets actual needs can be used.

[0041] The thickness and waveform of the corrugated plate can be adjusted according to actual conditions, and its overall strength and stiffness will also change. Constraint rods 8 can also be added at the troughs of the corrugated plate to further enhance its load-bearing capacity; these constraint rods 8 are formed by injecting concrete into a steel pipe.

[0042] The main bearing layer 2 has a pre-reserved filling material injection port and a surrounding rock deformation monitoring port. The filling material injection port is used to inject filling material into the outside of the main bearing layer 2 to form a pressure-relief deformation layer 3; the surrounding rock deformation monitoring port is used to install a surrounding rock deformation monitoring instrument to continuously monitor the deformation of the surrounding rock.

[0043] When the main load-bearing layer 2 of a single-layer structure cannot meet the requirements, the strength can be improved by superimposing corrugated steel plates on the sides of the main load-bearing layer 2 and adding constraint rods 8.

[0044] The elastic connection assembly 11 connecting the main bearing layer 2 and the active support layer 1 includes a partition plate 9, a round tube 10, a high-strength spring 12, and a corrugated plate 16.

[0045] The partition plate 9 is provided with the interface between the active support layer 1 and the pressure deformation layer 3; one end of the round pipe 10 is connected to the partition plate 9, and the other end is connected to the corrugated plate 16. The corrugated plate 16 is located on the side where the main bearing layer 2 and the pressure deformation layer 3 are connected and is arc-shaped, which is adapted to the waveform of the corrugated plate.

[0046] High-strength springs 12 are installed inside the circular tube 10 and can extend and retract along the axial direction of the circular tube 10 to resist confining pressure deformation. The high-strength springs 12 are pre-installed on the outside of the main bearing layer 2. The number and elastic stiffness of the high-strength springs are determined by the large deformation level. The higher the deformation level, the larger the number of springs and the greater the elastic stiffness. The length of the springs cannot exceed the thickness of the compression deformation layer 3.

[0047] Round tube 10 is a high-strength round steel tube.

[0048] The anchor cable 4 located on one side of the main bearing layer 2 is locked by the anchor cable joint 6, and the anchor rod 5 is locked by the anchor rod joint 7. A connecting pad 13 and a locking pad 14 are provided between the anchor cable joint 6 or the anchor rod joint 7 and the main bearing layer 2. Both the connecting pad 13 and the locking pad 14 are arc-shaped structures that are adapted to the waveform of the corrugated plate. The connecting pad 13 is located on the side close to the corrugated pad 16.

[0049] After the anchor cable 4 and anchor rod 5 are installed, the deformed surrounding rock will compress the interlayer pad 9. The interlayer pad 9 will transmit the compressive pressure to the round tube 10 and the high-strength spring 12, and then to the corrugated plate. The corrugated plate, as the main support, effectively provides reaction force for the anchor rod 5, further compensating for the deformation of the anchor rod 5 itself, and realizing active support.

[0050] The compression deformation layer 3 is composed of a filler material with high compressibility and a high-strength spring.

[0051] The filling material is modified rigid polyurethane foam. Of course, other materials with large deformation capacity, good waterproof durability, and certain strength can also be used. The high-strength springs inside the filling material are designed to enhance the elastic deformation of the compression deformation layer 3, so as to absorb more deformation pressure from the surrounding rock.

[0052] refer to Figure 3 Based on the characteristic curve of the surrounding rock, since the initial stress of the surrounding rock is relatively high under high ground stress, according to the traditional support design concept, strong support is required to achieve effective deformation control. However, due to the characteristics of the support material, the support strength that can be achieved at present can only reach the state of P1. In order to achieve deformation control, the support strength of P2 must be achieved, which is not easy to achieve at present.

[0053] The high-strength, ultra-tough support control system of this invention, without the high-strength spring 12, has the following overall support characteristic curve: Figure 3As shown in ABCD, in the initial stage of support, the shotcrete mesh and anchor bolts 5 of the active support layer 1 provide a certain supporting force, as shown in section AB. When the shotcrete mesh yields, the deformation of the surrounding rock will directly act on the yielding deformation layer 3, resulting in significant deformation, but the overall bearing capacity does not increase significantly, as shown in section BC. When the deformation of the yielding deformation layer 3 reaches its limit, the load will directly act on the main bearing layer 2, at which point the bearing capacity will increase rapidly, as shown in section CD. Since section CD uses a corrugated plate structure, its bearing capacity is much higher than that of the current steel frame structure. Therefore, its strength P3 is higher than P1, exhibiting high strength characteristics. The existence of the deformation space of the yielding deformation layer 3 will greatly enhance the deformation capacity of the overall structural system, that is, u3 is much larger than the values ​​of u1 and u2. Therefore, the structure exhibits significant toughness characteristics.

[0054] If a high-strength spring 12 is installed in the pressure deformation layer 3, the overall support characteristic curve is AB'B. ＂ C'D', where AB' mainly represents the support effect of active support layer 1, B'B ＂ For the process of individual compression deformation of the filling material, when the high-strength spring 12 participates in the deformation, its curve enters B. ＂ Section C' effectively improved the support capacity. When the main load-bearing layer 2 also began to play its role, the curve entered section C'D'.

[0055] By observing the different patterns of the two curves, we can adjust various parameters of the ultra-strong and high-toughness support structure according to the characteristics of large deformation of the surrounding rock, thereby achieving controllable deformation and structural safety, effectively addressing large deformation problems, and providing the structure with a certain safety redundancy, which can serve as a safety reserve during the operation period.

[0056] A construction method for a tunnel deformation control system with high strength and ultra-toughness, employing the aforementioned system, includes the following steps:

[0057] Step 1: Design the span, waveform, thickness, circumferential and longitudinal width of the corrugated plate according to the cross-sectional shape of the excavated tunnel, and design the length and arrangement of the anchor cable 4 and anchor rod 5;

[0058] Step 2: Install steel mesh on the excavated tunnel wall and spray concrete to quickly seal the surrounding rock and form an active support layer 1;

[0059] Step 3: Pre-set the elastic connection component 11 at the predetermined anchor cable hole or anchor bolt hole position;

[0060] Step 4: The corrugated sheets are spliced ​​on site. After the splicing is completed, the reinforcement support work and the installation of anchor cables 4 and anchor rods 5 are carried out under the protection of the corrugated sheets.

[0061] Step 5: After installing anchor cable 4 and anchor rod 5, lock them using anchor cable joint 6, anchor rod joint 7 or locking device 15;

[0062] Step Six: Inject the filler material through the reserved filler material injection port, injecting from low to high.

[0063] Step 7: Set up displacement monitoring points on the corrugated plate, and at the same time, embed measuring points in the reserved surrounding rock deformation monitoring ports. The surrounding rock deformation monitoring ports are constructed by anchor drilling rig, and steel bars are embedded in the monitoring ports. Deformation measuring marks are led out through the steel bars to realize the observation of surrounding rock deformation.

[0064] Step 8: Repeat steps 1 through 7 until all excavated tunnels are supported.

[0065] After the completion of step seven, it is necessary to continuously monitor the deformation of the corrugated plate and the surrounding rock. When the deformation of the surrounding rock exceeds the warning value, the monitoring should be strengthened. When the deformation of the corrugated plate exceeds the warning value, the strength of the main bearing layer 2 needs to be quickly reinforced.

[0066] The deformation layer 3 is installed after the main load-bearing layer 2 has been assembled and its ends have been sealed.

[0067] The above description is merely a preferred embodiment of the present invention, and does not represent all possible forms of the present invention. The scope of protection of the present invention is not limited to such specific statements and embodiments. Various other modifications and improvements can be made based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and these modifications and improvements are still within the scope of protection of the present invention.

Claims

1. A construction method for a tunnel deformation control system with high strength and ultra-toughness, characterized in that, The tunnel deformation control system includes: The tunnel consists of an active support layer (1), a pressure-deformation layer (3), and a main load-bearing layer (2) from the outer layer to the inner layer. The active support layer (1) includes a wire mesh, which is fixed to the inner wall of the tunnel by anchor cables (4) and anchor rods (5), and the active support layer (1) is formed by spraying concrete onto the wire mesh. The pressure-deformation layer (3) is composed of a filler material with high compressibility and a high-strength spring; The main load-bearing layer (2) is made of a corrugated plate of material with high strength and stiffness in both the longitudinal and transverse directions; The active support layer (1) and the main load-bearing layer (2) are connected as a whole by an elastic connection component (11); The elastic connection assembly (11) includes a partition plate (9), a circular tube (10), a high-strength spring (12), and a corrugated plate (16). The partition plate (9) is disposed at the interface between the active support layer (1) and the pressure-relief deformation layer (3). One end of the circular tube (10) is connected to the partition plate (9), and the other end is connected to the corrugated plate (16). The corrugated plate (16) is located on the side where the main bearing layer (2) and the pressure-relief deformation layer (3) are connected. The high-strength spring (12) is disposed inside the circular tube (10) and can extend and retract along the axial direction of the circular tube (10). The length of the high-strength spring (12) does not exceed the thickness of the pressure-deformation layer (3); The main bearing layer (2) is provided with a filling material injection port and a surrounding rock deformation monitoring port; The anchor cable (4) located on one side of the main bearing layer (2) is locked by the anchor cable joint (6), and the anchor rod (5) is locked by the anchor rod joint (7); a connecting pad (13) and a locking pad (14) are provided between the anchor cable joint (6) or the anchor rod joint (7) and the main bearing layer (2). The construction method includes the following steps: Step 1: Design the span, waveform, thickness, circumferential and longitudinal width of the corrugated plate according to the cross-sectional shape of the excavated tunnel, and design the length and arrangement of the anchor cable (4) and anchor rod (5); Step 2: Install steel mesh on the excavated tunnel wall and spray concrete to quickly seal the surrounding rock and form an active support layer (1). Step 3: Pre-set the elastic connection component (11) at the predetermined anchor cable hole or anchor bolt hole position; Step 4: The corrugated plates are spliced ​​on site. After the splicing is completed, the reinforcement support work and the installation of anchor cables (4) and anchor rods (5) are carried out under the protection of the corrugated plates. Step 5: After installing the anchor cable (4) and anchor rod (5), lock them in place using the anchor cable joint (6), anchor rod joint (7), or locking device (15); Step Six: Inject the filler material through the reserved filler material injection port, injecting from low to high. Step 7: Install displacement monitoring points on the corrugated plate, and at the same time, install measuring points in the reserved surrounding rock deformation monitoring ports. The surrounding rock deformation monitoring ports are constructed using an anchor drilling rig. Step 8: Repeat steps 1 through 7 until all excavated tunnels are supported.

2. The construction method of the tunnel deformation control system with high strength and ultra-toughness according to claim 1, characterized in that: After the completion of step seven, it is necessary to continuously monitor the deformation of the corrugated plate and the surrounding rock. When the deformation of the surrounding rock exceeds the warning value, the monitoring should be strengthened. When the deformation of the corrugated plate exceeds the warning value, the strength of the main bearing layer (2) should be quickly reinforced.

3. The construction method of the tunnel deformation control system with high strength and ultra-toughness according to claim 1, characterized in that: The active support layer (1) is provided with a constraint rod (8) to enhance the support strength of the active support layer (1).

4. The construction method of the tunnel deformation control system with high strength and ultra-toughness according to any one of claims 1 to 3, characterized in that: The corrugated plate is a steel corrugated plate or a basalt fiber corrugated plate, and its thickness and waveform can be adjusted according to actual conditions.

5. The construction method of the tunnel deformation control system with high strength and ultra-toughness according to claim 4, characterized in that: The filling material is a modified rigid polyurethane foam filler with large deformation capacity, good waterproof durability and certain strength.

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