Segmental lining structure capable of applying prestress and construction method thereof

Abstract

The invention provides a segmental lining structure capable of applying prestress and a construction method.The segmental lining structure comprises a plurality of segments arranged in the circumferential direction of a tunnel, a grouting layer is arranged between the segments and surrounding rock of the tunnel, and a prestress part is arranged between at least part of every two adjacent segments; and annular extrusion is generated on the pipe pieces on the two sides, so that the pipe pieces have annular prestress. According to the duct piece lining structure, by arranging the prestress pieces between the adjacent duct pieces to apply prestress to the duct pieces, the effect of counteracting part of duct piece tension caused by tunnel internal pressure is achieved, and the tension resistance of the duct piece lining structure is improved; therefore, the problems that an existing lining structure is directly pulled by self reinforced concrete, so that the structure is rapidly cracked, and the bearing capacity is insufficient are solved. Compared with a conventional concrete duct piece used in the high internal pressure environment, the duct piece lining structure reduces surrounding rock damage and duct piece reinforcement amount, and has good economical efficiency on the basis of guaranteeing structural bearing safety.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel engineering, and in particular relates to a segment lining structure capable of applying prestress and a construction method thereof. Background Art

[0002] As the scope of tunnel application expands, the number of operating high-pressure tunnels is gradually increasing. Among them, compressed air energy storage tunnels, as an emerging application scenario, have attracted the attention of many researchers and designers. Compressed air energy storage tunnels compress and store air inside the tunnel structure, and release the compressed air and convert it into electrical energy output when generating electricity. Given the operating characteristics of compressed air energy storage technology, tunnels need to withstand a high internal air pressure, and this internal air pressure will change repeatedly with the cycle of energy storage and release.

[0003] Generally, under the action of external water and soil loads, the tunnel structure is in an eccentrically compressed state, and reinforced concrete lining is widely used. For compressed air energy storage tunnels, the operating conditions are more complicated: when the internal pressure is low, the lining mainly bears the external water and soil loads; when the internal pressure is high, the lining and the surrounding rock need to jointly bear the water and soil loads and the high internal pressure. In view of this special operating condition, conventional compressed air energy storage tunnels use reinforced concrete lining and steel shell lining, and asphalt is filled between the reinforced concrete lining and the steel shell. This lining structure shows good adaptability in conventional compressed air energy storage tunnel applications. However, when higher requirements are placed on the efficiency and economic value of energy storage power generation, the internal pressure of compressed air energy storage will become higher and higher.

[0004] Under this high gas storage pressure, the above lining structure has the following problems:

[0005] 1. Since the tensile strength of cast-in-place reinforced concrete is much lower than its compressive strength, under the continuous action of high internal pressure, the structure is in a tensile state, and a large number of cracks will appear in the reinforced concrete. After the pressure is released, the bearing capacity of the cracked reinforced concrete is greatly reduced, which is not enough to continue to bear the external water and soil loads. If the structural function requirements are to be met, the amount of structural reinforcement needs to be increased, which will lead to an increase in project investment.

[0006] 2. The above lining structure is subjected to tensile deformation under the action of internal pressure, and the deformation transmission causes the surrounding rock to be tensile, aggravating the damage of the surrounding rock. After the pressure is released, the surrounding rock is prone to cracking and collapse, and the lining structure will be subjected to greater pressure from the loose surrounding rock, which is not conducive to the overall stability of the tunnel surrounding rock.

[0007] Therefore, the existing lining structures mentioned above cannot adapt to the high internal pressure environment of compressed gas energy storage, and it is urgent to develop a new type of tunnel lining structure to meet the high internal pressure technical requirements of compressed gas energy storage. Summary of the invention

[0008] The purpose of the present invention is to provide a prestressed segment lining structure to overcome the problem that the existing lining structure is susceptible to tensile cracking under high internal pressure conditions and causes tensile damage to the surrounding rock around the tunnel.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] A segment lining structure capable of applying prestress comprises a plurality of segments arranged circumferentially along a tunnel, a grouting layer being arranged between the segments and the surrounding rock of the tunnel, and a prestressed member being arranged between at least two adjacent segments to produce circumferential extrusion on the segments on both sides so that the segments have circumferential prestress.

[0011] Furthermore, a prestressed member is provided between each two adjacent pipe segments.

[0012] Furthermore, the pipe segment is provided with a fixing assembly for pre-fixing with the surrounding rock.

[0013] Furthermore, the fixing assembly includes a force transmission anchor rod and an end plate, wherein the end plate is pre-buried in the pipe segment, one end of the force transmission anchor rod is fixedly connected to the end plate, and the other end is anchored in the surrounding rock.

[0014] Furthermore, a plurality of the force transmission anchor rods are arranged at equal intervals in the circumferential direction on the surrounding rock.

[0015] Furthermore, the prestressed member is a wedge block, and the end of the segment in contact with the wedge block has an inclined surface that matches the side surface of the wedge block, and two adjacent inclined surfaces are symmetrically arranged to form a wedge-shaped space for installing the wedge block, and one side of the short side of the wedge-shaped space is arranged close to the surrounding rock.

[0016] Furthermore, the wedge blocks are fixed to the adjacent pipe segments by welding or seam grouting.

[0017] Furthermore, grouting holes are reserved on the pipe segment for injecting grout into the gap between the pipe segment and the surrounding rock to form a grouting layer.

[0018] Furthermore, a pressure regulating component for controlling the prestress is pre-buried in the pipe segment.

[0019] In addition, the present invention also provides a construction method for the above-mentioned segment lining structure, comprising the following steps:

[0020] S1. Excavate the surrounding rock of the tunnel by drilling and blasting to form a circular excavation section;

[0021] S2, assemble the segments and initially fix the segments circumferentially to the surrounding rock;

[0022] S3, injecting grout into the gap between the pipe segment and the surrounding rock to form a grouting layer to connect and fix the pipe segment and the surrounding rock;

[0023] S4. Install a prestressed member between two adjacent segments and generate annular extrusion on the segments on both sides so that the segments on both sides have annular prestress.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The prestressed segment lining structure provided by the present invention achieves the effect of offsetting part of the tension on the segments caused by the internal pressure of the tunnel by arranging prestressed parts between adjacent segments to apply prestress to the segments, thereby improving the tensile strength of the segment lining structure, thereby avoiding the problem of rapid structural cracking and insufficient bearing capacity caused by direct tension on the reinforced concrete of the existing lining structure.

[0026] (2) The prestressed segment lining structure provided by the present invention is suitable for high internal pressure environments. Compared with conventional concrete segments used in high internal pressure environments, it reduces surrounding rock damage and segment reinforcement, and has good economy while ensuring structural load-bearing safety.

[0027] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of a segment lining structure capable of applying prestress according to the present invention;

[0029] Figure 2 It is a partial structural schematic diagram of the segment assembly in the segment lining structure of the present invention;

[0030] Figure 3 It is a schematic diagram of the local structure of grouting after the segments are assembled in the segment lining structure of the present invention;

[0031] Figure 4 It is a schematic diagram of the installation of wedge blocks in the segment lining structure of the present invention.

[0032] Explanation of the accompanying reference numerals: 1. segment; 2. wedge; 3. force transmission anchor rod; 4. grouting layer; 5. surrounding rock; 6. end plate; 7. wedge-shaped space; 8. gap. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a conflicting connection or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0037] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, this embodiment provides a segment lining structure that can apply prestress, including multiple segments 1 arranged along the circumferential direction of the tunnel. Specifically, the outer arc side of the segment 1 is close to the surrounding rock 5 of the tunnel, and the inner arc side of the segment 1 faces the internal space of the tunnel; a grouting layer 4 is arranged between the segment 1 and the surrounding rock 5 of the tunnel, which is used to grout the gap between the surrounding rock 5 and the segment 1; a prestressed member is arranged between at least two adjacent segments 1 to produce circumferential extrusion on the segments 1 on both sides, so that the segment 1 has circumferential prestress. Among them, the segment 1 adopts a prefabricated reinforced concrete lining segment, and the size and number of segments 1 can be determined according to the size of the tunnel, surrounding rock conditions, etc.

[0038] For compressed air energy storage tunnels, in the deflation stage, the air pressure in the tunnel is low, and the segment 1 mainly bears the external water and soil loads, and is in an eccentric compression state. Through the grouting layer 4, the overall structure has good resistance to confining pressure; in the gas storage stage, the air pressure in the tunnel is high, and the segment 1 and the surrounding rock 5 jointly bear the internal high pressure and are in a tensile state. The prestressed member provides prestress to the segment 1, and the tensile resistance of the segment 1 is fully exerted. At the same time, the joint between the segment 1 and the prestressed member also provides a buffer space for the tension deformation of the overall structure. Compared with the conventional integral cast-in-place lining structure, the risk of structural cracking and surrounding rock instability under high internal pressure is greatly reduced. In this embodiment, by arranging prestressed members between adjacent segments 1 to apply prestress to the segment 1, the effect of offsetting part of the segment tension caused by the internal pressure of the tunnel is achieved, and the tensile resistance of the segment lining structure is improved, thereby avoiding the problem of rapid structural cracking and insufficient bearing capacity caused by the direct tension of the reinforced concrete of the existing lining structure.

[0039] Specifically, in this embodiment, the number of segments 1 and prestressed parts, as well as the arrangement positions of the prestressed parts, are determined according to the actual load distribution, etc.; prestressed parts may be arranged only between some segments 1, or between every two adjacent segments 1. In this embodiment, it is preferably designed that a prestressed part is arranged between every two adjacent segments 1.

[0040] In order to accurately control the prestress of the segment 1 so that it can better offset the internal pressure of the tunnel, it is optimized that a pressure regulating component for controlling its prestress can be pre-buried in the segment 1, and the pressure regulating component includes segment internal force monitoring, segment center pressure detection and pressure relief device.

[0041] Preferably, a grouting hole is reserved on the segment 1. After the segment 1 is initially fixed on the surrounding rock 5, grouting is injected into the gap 8 between the segment 1 and the surrounding rock 5 through the grouting hole to form a grouting layer 4. In this embodiment, the outer arc surface of the segment 1 and the inner surface of the surrounding rock 5 are closely fitted by filling grouting, so as to stabilize the segment 1.

[0042] As for the preliminary fixing method of the pipe segment 1 on the surrounding rock 5, a fixing component for pre-fixing with the surrounding rock 5 can be provided on the pipe segment 1. Figure 1 and Figure 2As shown, the fixing assembly specifically includes a force transmission anchor rod 3 and an end plate 6, one end of the force transmission anchor rod 3 is fixedly connected to the end plate 6, the end plate 6 and the end of the force transmission anchor rod 3 are pre-buried in the segment 1 in advance, and the other end of the force transmission anchor rod 3 is driven into and anchored in the surrounding rock 5 around the tunnel. In this embodiment, when installing the segment 1, the free end of the force transmission anchor rod 3 is driven into the surrounding rock 5 along the radial direction of the circular tunnel, and the force transmission anchor rod 3 is used to achieve the purpose of preliminarily fixing the segment 1. At the same time, the force transmission anchor rod 3 forms an anchoring area around the tunnel, which improves the strength and rigidity of the surrounding rock 5, thereby improving the tensile strength and bearing capacity of the segment lining structure.

[0043] Furthermore, the plurality of force transmission anchor rods 3 are arranged at equal intervals in the circumferential direction on the surrounding rock 5 to ensure the uniformity of the circumferential tensile force of the segment lining structure.

[0044] As a specific implementation method, Figure 1 and Figure 4 As shown, the prestressed member adopts a wedge block 2, which is a prefabricated reinforced concrete wedge block; and the end face of the pipe segment 1 in contact with the wedge block 2 is designed to be an inclined surface that matches the side face of the wedge block 2. During installation, the inclined surfaces of two adjacent pipe segments 1 are symmetrically arranged at intervals to form a wedge-shaped space 7 for installing the wedge block 2, and one side of the short side of the wedge-shaped space 7 is arranged close to the surrounding rock 5. The size of the wedge-shaped space 7 is designed so that when the wedge block 2 is inserted into the wedge space 7, it can produce annular extrusion on the pipe segments 1 on both sides; when the wedge block 2 is installed, it is inserted into the wedge space 7 from the long side of the wedge space 7 along the radial direction of the tunnel, and after the wedge block 2 is installed, the wedge block 2 is fixed to the adjacent pipe segment 1 by welding or joint grouting. This embodiment adopts a prefabricated assembled structure of "segment + wedge block", and utilizes the joints between adjacent blocks to buffer the tension deformation of the tunnel lining under the action of high internal pressure, thereby avoiding the problem of rapid cracking and insufficient bearing capacity of the existing lining structure caused by direct tension of its own reinforced concrete.

[0045] The specific construction process of the above-mentioned segment lining structure includes the following steps:

[0046] S1. Excavate the surrounding rock 5 of the tunnel by drilling and blasting to form a circular excavation section.

[0047] S2, assembling the segments 1, arranging the prefabricated segments 1 along the circumferential direction of the tunnel, and preliminarily fixing them on the surrounding rock 5 with force-transmitting anchor rods 3.

[0048] Specifically, holes are drilled in the surrounding rock 5 along the radial direction of the tunnel, and the holes are evenly distributed along the circumference of the tunnel; when installing the pipe segment 1, the free end of the force transmission anchor rod 3 is driven into the hole of the surrounding rock 5 along the radial direction of the tunnel.

[0049] S3, temporarily sealing the wedge-shaped space 7 formed between two adjacent segments 1, and injecting slow-setting slurry into the gap 8 between the segment 1 and the surrounding rock 5 through the grouting holes reserved in the segment 1 to form a grouting layer 4.

[0050] S4, release the temporary blockage of the wedge-shaped space 7, insert the extrusion wedge 2 into the wedge-shaped space 7 to apply annular prestress F to the segments 1 on both sides of the wedge 2, use the pressure regulating assembly provided in the segment 1 to control the prestress F, and then fix the wedge 2 by welding or joint grouting.

[0051] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A prestressed segment lining structure, characterized in that: It comprises a plurality of segments arranged circumferentially along the tunnel, a grouting layer is arranged between the segments and the surrounding rock of the tunnel, and a prestressed member is arranged between at least two adjacent segments to produce circumferential extrusion on the segments on both sides so that the segments have circumferential prestress.

2. The prestressed segment lining structure according to claim 1, characterized in that: A prestressed member is provided between each two adjacent pipe segments.

3. The prestressed segment lining structure according to claim 1 or 2, characterized in that: The pipe segment is provided with a fixing assembly for pre-fixing with the surrounding rock.

4. The prestressed segment lining structure according to claim 3, characterized in that: The fixing assembly comprises a force transmission anchor rod and an end plate, wherein the end plate is pre-buried in the pipe segment, one end of the force transmission anchor rod is fixedly connected to the end plate, and the other end is anchored in the surrounding rock.

5. The prestressed segment lining structure according to claim 4, characterized in that: The plurality of force transmission anchor rods are arranged at equal intervals in the circumferential direction on the surrounding rock.

6. The prestressed segment lining structure according to claim 1 or 2, characterized in that: The prestressed member is a wedge block, and the end of the pipe segment in contact with the wedge block has an inclined surface that matches the side surface of the wedge block, and two adjacent inclined surfaces are symmetrically arranged at intervals to form a wedge-shaped space for installing the wedge block, and one side of the short side of the wedge-shaped space is set close to the surrounding rock.

7. The prestressed segment lining structure according to claim 6, characterized in that: The wedge blocks are fixed to the adjacent pipe segments by welding or joint grouting.

8. The prestressed segment lining structure according to claim 1 or 2, characterized in that: Grouting holes are reserved on the pipe segment for injecting grout into the gap between the pipe segment and the surrounding rock to form a grouting layer.

9. The prestressed segment lining structure according to claim 1 or 2, characterized in that: A pressure regulating component for controlling the prestress is pre-buried in the pipe segment.

10. The construction method of the segment lining structure according to any one of claims 1 to 9, characterized in that: The steps include: S1. Excavate the surrounding rock of the tunnel by drilling and blasting to form a circular excavation section; S2, assemble the segments and initially fix the segments circumferentially to the surrounding rock; S3, injecting grout into the gap between the pipe segment and the surrounding rock to form a grouting layer to connect and fix the pipe segment and the surrounding rock; S4. Install a prestressed member between two adjacent segments and generate annular extrusion on the segments on both sides so that the segments on both sides have annular prestress.

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