Tunnel structure and construction method suitable for TBM crossing of high-pressure, water-rich active faults

Abstract

The present invention discloses a tunnel structure suitable for TBM traversal of high-pressure, water-rich active faults, relating to the field of tunnel engineering. From the outside in, it comprises, in order, a curtain grouting ring, a primary support, a secondary support, and a secondary lining, with hinged expansion joints provided between adjacent secondary linings. The hinged expansion joints comprise, from top to bottom, an externally attached plastic waterstop, a polyethylene foam plastic board, an embedded memory alloy steel plate, and a polysulfide building sealant. During construction, the present invention utilizes a dual primary support solution, enabling the structure to adapt to certain deformations, conforming to the design concept of the New Austrian Tunneling Method (NETM). Simultaneously, through the reinforcement of the secondary primary support, the secondary primary support ensures structural safety during construction. The present invention also relates to a construction method for this tunnel structure suitable for TBM traversal of high-pressure, water-rich active faults.

Description

Technical Field

[0001] The present invention relates to the field of tunnel engineering, and more specifically to a tunnel structure suitable for TBM traversal of high-pressure, water-rich active faults; the present invention also relates to a construction method of the tunnel structure suitable for TBM traversal of high-pressure, water-rich active faults. Background Art

[0002] Shield TBM tunnel construction is one of the commonly used methods; however, it currently faces many challenges in tunnel crossing. Shield TBM tunnel crossing will inevitably encounter active fault zones. However, the existing mature tunnel engineering solutions with active faults are mostly for tunnels using mining methods. Shield TBM tunnels have significantly poorer adaptability when facing active faults.

[0003] In actual construction, when a shield TBM tunnel needs to cross an active fault, a common practice is to build an inclined shaft in advance and use a mining method tunnel, and then let the TBM push through empty; but this method has many disadvantages; from an environmental perspective, it causes great damage to the surrounding environment, affecting the balance and stability of the ecology; in terms of economy, it is not ideal, and a lot of additional costs are added, such as the cost of inclined shaft construction and related supporting projects; moreover, the early construction of the inclined shaft has high requirements on the construction period of the entire project, which can easily lead to an extension of the construction period and affect the overall progress of the project.

[0004] In addition, the current construction of shield TBMs for high-pressure, water-rich active faults still has the following limitations:

[0005] 1) The shield TBM cannot achieve an increase in internal clearance and cannot meet the specification requirements for increased internal clearance;

[0006] 2) Due to the limited number of pre-reinforcement holes in shield TBMs, the eye ring cannot be sealed. As a result, the shield TBM cannot solve the high head problem through curtain grouting. The drainage design is often based on drainage, which is not environmentally friendly.

[0007] 3) Due to the limited pre-reinforcement holes of the shield TBM, the pre-reinforcement effect is poor. The fractured section of the water-rich fault should be supported in a timely manner, and the surrounding rock ring should be sealed. Conventional composite lining cannot achieve both sealing the surrounding rock ring and timely support.

[0008] 4) In addition, after the initial support is installed, due to size limitations, the conventional shield TBM cannot simultaneously meet the space requirements for the formwork trolley, construction organization, ventilation, and belt conveyor. Therefore, the reinforced concrete secondary lining (8-12m each time) cannot be immediately installed. As a result, the initial support cannot remain stable for a long time in the high-pressure water-rich crushing section.

[0009] Therefore, it is necessary to develop a tunnel structure and construction method that is environmentally friendly, economical, has a short construction period, and is structurally stable and suitable for TBM crossing of high-pressure, water-rich active faults. Summary of the Invention

[0010] The first object of the present invention is to overcome the deficiencies of the above-mentioned background technology and provide a tunnel structure suitable for TBM crossing of high-pressure and water-rich active faults.

[0011] The second object of the present invention is to provide a construction method for a tunnel structure suitable for TBM crossing of a high-pressure, water-rich active fault.

[0012] To achieve the first objective, the present invention provides a technical solution: a tunnel structure suitable for TBM traversal of a high-pressure, water-rich active fault, characterized in that: from the outside to the inside, it comprises a curtain grouting ring, a primary support, a secondary primary support, and a secondary lining, with hinged expansion joints provided between adjacent secondary linings;

[0013] The hinged deformation joint includes, from top to bottom, an external plastic waterstop, a polyethylene foam plastic board, an embedded memory alloy steel plate and a polysulfide building sealant; both ends of the external plastic waterstop are located between the secondary lining and the secondary primary support, and the middle part is a lower convex part protruding downward; both ends of the embedded memory alloy steel plate are located in the secondary lining, and the middle part is an upper convex part protruding upward; the top of the polyethylene foam plastic board is in contact with the bottom of the lower convex part, and the bottom is in contact with the top of the upper convex part.

[0014] In the above technical solution, non-woven fabric and waterproof board are sequentially arranged between the secondary primary support and the secondary lining from top to bottom.

[0015] In order to achieve the above second objective, the technical solution of the present invention is: a construction method for a tunnel structure suitable for TBM traversal of a high-pressure, water-rich active fault, characterized by comprising the following steps:

[0016] Step 1, Excavation: After the TBM excavates and exposes a ring, the supporting equipment is used to expand the excavation to a radius of 30-50 cm, and the pre-grouting is used to reinforce the area;

[0017] Step 2: Primary support and curtain grouting: After the TBM excavates and exposes a ring, the exposed surrounding rock is immediately primed with steel fiber shotcrete using a device carried by the rear vehicle. Curtain grouting is then performed 10 m in advance. The circumferential spacing of the curtain grouting is 0.5 m, and the overlap of the curtain grouting is no less than 3 m.

[0018] Step 3, secondary primary support construction: After the primary support solidifies, embed a steel section of not less than 120 and spray concrete to seal it to complete the secondary primary support;

[0019] Step 4: Construction of reinforced concrete secondary lining: After the TBM equipment passes through the active fault zone, the secondary lining is uniformly constructed and hinged expansion joints are constructed; the initial surrounding rock load is borne by the curtain grouting ring, primary support, and secondary primary support.

[0020] In the above technical solution, in step 2, curtain grouting breaks the primary support of the steel fiber shotcrete, reinforces the surrounding rock ring and stops water, and ensures a 5m curtain grouting circle.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1) The present invention can meet the demand for increasing the clearance inside the shield TBM through the technical solution of post-excavation expansion.

[0023] 2) The curtain grouting of the present invention forms a 5m grouting reinforcement ring to resist high water head, mainly blocks water, and is environmentally friendly.

[0024] 3) During the construction period of the present invention, the double primary support technical solution is used, and the structure can adapt to a certain deformation, which is in line with the design concept of the New Austrian Tunneling Method. At the same time, through the reinforcement of the secondary primary support, the secondary primary support can meet the structural safety during the construction period.

[0025] 4) The three-layer structure of the present invention is permanently operational, and through the segment articulation design, the adaptability of the structure to active fracture creep can be effectively improved.

[0026] 5) The internal clearance of the present invention is increased, so that when a structural fault occurs, there is space for repair during operation.

[0027] 6) The hinged deformation joint of the present invention is provided with an Ω-shaped embedded memory alloy steel plate, which can adapt to deformation while having a certain memory recovery ability and can withstand a water head within 100m.

[0028] 7) The present invention is environmentally friendly, economical, has low construction period requirements and a stable structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the present invention.

[0030] Figure 2 This is the front layout of the full-section curtain grouting drilling.

[0031] Figure 3 for Figure 2 Sectional layout diagram at AA in the middle.

[0032] Figure 4 This is the waterproof structure diagram of the equal-thickness lining deformation joint in the active fracture section.

[0033] Figure 5This is the waterproof structural diagram of the deformation joint where the active fracture and the inactive fracture lining of unequal thickness are connected.

[0034] Figure 6 It is a structural diagram of the embedded memory alloy steel plate.

[0035] Figure 7 This is a structural diagram of an external plastic waterstop. DETAILED DESCRIPTION

[0036] The following detailed description of the embodiments of the present invention is given in conjunction with the accompanying drawings, which do not limit the present invention but are merely examples. The advantages of the present invention will become clearer and easier to understand through the description.

[0037] As can be seen from the accompanying drawings, the tunnel structure suitable for TBM traversal of high-pressure, water-rich active faults comprises, from the outside to the inside, a curtain grouting ring 100, a primary support 200, a secondary primary support 300, and a secondary lining 400. Hinged expansion joints 500 are provided between adjacent secondary linings 400.

[0038] like Figure 4-Figure 7 As shown, the hinged deformation joint 500 includes an external plastic waterstop 510, a polyethylene foam plastic board 520, an embedded memory alloy steel plate 530 and a polysulfide building sealant 540 from top to bottom; both ends of the external plastic waterstop 510 are located between the secondary lining 400 and the secondary primary support 300, and the middle part is a downwardly protruding lower convex part 511; both ends of the embedded memory alloy steel plate 530 are located in the secondary lining 400, and both ends of the embedded memory alloy steel plate 530 are provided with inclined parts 532 with an inclination angle of 45 degrees, and the middle part is an upwardly protruding upper convex part 531; the top of the polyethylene foam plastic board 520 is in contact with the bottom of the lower convex part 511, and the bottom is in contact with the top of the upper convex part 531.

[0039] like Figure 4 and Figure 5 As shown, a non-woven fabric 610 and a waterproof sheet 620 are sequentially arranged from top to bottom between the secondary primary support 300 and the secondary lining 400 .

[0040] The construction method of a tunnel structure suitable for TBM traversal of a high-pressure, water-rich active fault comprises the following steps:

[0041] Step 1, Excavation: After the TBM excavates and exposes a ring, it is expanded by supporting equipment. The radius of the expanded part 720 is 30-50cm to ensure that the internal clearance meets the clearance requirements of the active fracture. It is also reinforced by pre-grouting.

[0042] like Figure 2 and Figure 3As shown in the figure, step 2, primary support and curtain grouting: After the TBM excavation exposes a ring, the exposed surrounding rock is immediately subjected to a primary support of 200m with steel fiber shotcrete by the equipment carried by the rear supporting vehicle to seal the surrounding rock in time; and curtain grouting is carried out 10m in advance; the circumferential spacing of the curtain grouting is 0.5m, and the overlap of the curtain grouting is not less than 3m;

[0043] Step 3, secondary primary support construction: After the primary support 200 is solidified, embed a steel section of not less than 120 and spray concrete to seal it, completing the secondary primary support 300 to ensure the safety of the tunnel structure;

[0044] Step 4: Construction of reinforced concrete secondary lining: After the TBM equipment passes through the active fault zone, a secondary lining of 400 mm is uniformly constructed, and a hinged expansion joint of 500 mm is constructed. The initial surrounding rock load is borne by the curtain grouting ring of 100 mm, the primary support of 200 mm, and the secondary support of 300 mm.

[0045] like Figure 2 and Figure 3 As shown, in step 2, curtain grouting breaks the primary support 200 of the steel fiber shotcrete, reinforces the surrounding rock ring and stops water, and ensures a 5m curtain grouting circle 100.

[0046] In actual use, after the TBM has excavated, the circular excavation equipment carried by the TBM is used to expand the radius by 30-50cm to meet the requirements for increased clearance.

[0047] The supporting structure consists of three parts: primary support of 200, curtain grouting + secondary primary support of 300, and secondary lining of cast-in-place reinforced concrete of 400.

[0048] like Figure 4 and 5 As shown, after the spacing of the deformation joints is determined according to the characteristic parameters of the active fracture, the hinged deformation joint 500 is set. The hinged deformation joint 500 is composed of an external plastic waterstop 510 and an Ω-shaped embedded memory alloy steel plate 530 to resist high water head; the embedded memory alloy steel plate 530 can adapt to water heads within 100m; the external plastic waterstop 510 is set in an inverted Ω shape, with a certain surplus length, which can adapt to the deformation and tensioning of the active fracture, and the embedded memory alloy steel plate 530 can also adapt to deformation.

[0049] The external plastic waterstop 510 is supported on the polyethylene foam plastic board 520 to ensure that it is not broken by the high water head; the innermost side of the lining is filled with polysulfide building sealant 540.

[0050] Other parts not described belong to the prior art.

Claims

1. A tunnel structure suitable for TBM traversal of high-pressure, water-rich active faults, characterized by: From the outside to the inside, it includes a curtain grouting ring (100), a primary support (200), a secondary primary support (300), and a secondary lining (400), and hinged deformation joints (500) are provided between adjacent secondary linings (400); The hinged deformation joint (500) comprises, from top to bottom, an external plastic waterstop (510), a polyethylene foam plastic plate (520), an embedded memory alloy steel plate (530), and a polysulfide building sealant (540); both ends of the external plastic waterstop (510) are located between the secondary lining (400) and the secondary primary support (300), and the middle portion is a downwardly protruding lower convex portion (511); both ends of the embedded memory alloy steel plate (530) are located within the secondary lining (400), and the middle portion is an upwardly protruding upper convex portion (531); the top of the polyethylene foam plastic plate (520) contacts the bottom of the lower convex portion (511), and the bottom contacts the top of the upper convex portion (531); The initial surrounding rock load is borne by the curtain grouting ring (100), the primary support (200), and the secondary support (300); the curtain grouting forms a 5m grouting reinforcement ring (100) to resist high water head; during construction, the double primary support technology solution is used to enable the structure to adapt to deformation; Inclined portions (532) are provided at both ends of the embedded memory alloy steel plate (530), with an inclination angle of 45 degrees; The hinged deformation joint (500) is formed by an externally attached plastic waterstop (510) and an Ω-shaped embedded memory alloy steel plate (530) to resist high water heads; the embedded memory alloy steel plate (530) can adapt to water heads within 100 m; the externally attached plastic waterstop (510) is arranged in an inverted Ω shape, has a surplus length, and can adapt to the deformation and tension of the active fracture, and the embedded memory alloy steel plate (530) can adapt to deformation.

2. The tunnel structure suitable for TBM traversal of a high-pressure, water-rich active fault according to claim 1, characterized in that: A non-woven fabric (610) and a waterproof board (620) are sequentially arranged between the secondary primary support (300) and the secondary lining (400) from top to bottom.

3. The construction method of a tunnel structure suitable for TBM traversal of a high-pressure, water-rich active fault according to claim 2, characterized in that: The following steps are involved: Step 1, Excavation: After the TBM excavates and exposes a ring, the supporting equipment is used to expand the excavation to a radius of 30-50cm, and the pre-grouting is used to reinforce the area; Step 2, primary support and curtain grouting: After the TBM excavation exposes a ring, the exposed surrounding rock is immediately subjected to primary support (200) of steel fiber shotcrete by the device carried by the rear, and curtain grouting is applied 10m in advance; the circumferential spacing of the curtain grouting is 0.5m, and the overlap of the curtain grouting is not less than 3m; Step 3, construction of secondary primary support: after the primary support (200) solidifies, pre-embed a steel section of not less than 120, and spray concrete to seal it, completing the secondary primary support (300); Step 4, construction of reinforced concrete secondary lining: After the TBM equipment passes through the active fault zone, the secondary lining (400) is uniformly constructed and the hinged deformation joint (500) is constructed; the initial surrounding rock load is borne by the curtain grouting ring (100), the primary support (200), and the secondary support (300).

4. The construction method of a tunnel structure suitable for TBM traversal of a high-pressure, water-rich active fault according to claim 3, characterized in that: In step 2, curtain grouting breaks the primary support (200) of the steel fiber shotcrete, reinforces the surrounding rock ring and stops water, and ensures a 5m curtain grouting circle (100).

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