Tunnel structure suitable for high-pressure water-rich active fault TBM crossing and construction method thereof

Abstract

The invention discloses a tunnel structure suitable for high-pressure water-rich active fault TBM crossing, and relates to the field of tunnel engineering. The structure sequentially comprises a curtain grouting ring, a primary primary support, a secondary primary support and secondary linings from outside to inside, wherein a hinge deformation joint is arranged between every two adjacent secondary linings; the hinge deformation joint sequentially comprises an externally-pasted plastic water stop belt, a polyethylene foam plastic plate, a middle-buried memory alloy steel plate and a polysulfide building sealant from top to bottom. According to the technical scheme of the double primary supports in the construction period, the structure can adapt to certain deformation, the design concept of the new Austrian method is met, and meanwhile through reinforcement of the secondary primary supports, the structural safety in the construction period can be met during construction of the secondary primary supports; the invention further relates to a construction method of the tunnel structure suitable for high-pressure water-rich active fault TBM crossing.

Description

Technical Field

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

[0002] The shield TBM tunnel construction is one of the common methods; however, there are many challenges in tunnel crossing at present; it is inevitable that the shield TBM tunnel crossing will encounter active fault zones; most of the existing mature tunnel engineering solutions for active faults are for tunnels using the mining method technology. When the shield TBM tunnel faces active faults, its adaptability is significantly poor.

[0003] In actual construction, when the shield TBM tunnel needs to cross an active fault, the common practice is to build an inclined shaft in advance and use the 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 and affects the balance and stability of the ecosystem; in terms of economy, it is not ideal either, increasing a lot of additional costs, such as the cost of inclined shaft construction and related supporting projects; moreover, the early construction of the inclined shaft has a high requirement for the construction period of the whole project, which is likely to lead to an extension of the construction period and affect the overall progress of the project.

[0004] In addition, there are also the following limitations in the current shield TBM construction for high-pressure water-rich active faults: 1) The shield TBM cannot increase the internal clear span and cannot meet the requirements of the specification for increasing the internal clear span. 2) Due to the limited advanced reinforcement holes of the shield TBM, the circumferential ring cannot be closed, resulting in the shield TBM being unable to solve the problem of high water head through curtain grouting. Usually, it is a drainage design scheme mainly based on drainage, which is not environmentally friendly. 3) Due to the limited advanced reinforcement holes of the shield TBM, the advanced reinforcement effect is poor. For the water-rich fault broken section, timely support should be carried out, and the surrounding rock circle should be closed. The conventional composite lining cannot simultaneously achieve the closure of the surrounding rock circle and timely support. 4) In addition, after the initial support is constructed, due to size limitations of the conventional shield TBM, the back-up system cannot simultaneously meet the space requirements of the formwork trolley, construction organization, ventilation, and belt conveyor, and the reinforced concrete secondary lining (8 - 12m each time) cannot be constructed immediately, resulting in the initial support being unable to maintain stability for a long time in the high-pressure water-rich broken section.

[0005] Therefore, it is necessary to develop a tunnel structure suitable for the shield TBM to cross a high-pressure water-rich active fault and its construction method that are environmentally friendly, economically good, have low requirements for the construction period, and have stable structures. Summary of the Invention

[0006] The first object of the present invention is to overcome the deficiencies of the above-mentioned background technology and to provide a tunnel structure suitable for TBM crossing of high-pressure and water-rich active faults.

[0007] 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.

[0008] In order to achieve the above first purpose, the technical solution of the present invention is: a tunnel structure suitable for TBM crossing of high-pressure water-rich active faults, characterized in that: from the outside to the inside, it includes a curtain grouting ring, a primary support, a secondary primary support, and a secondary lining, and a hinged deformation joint is provided between adjacent secondary linings; 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.

[0009] In the above technical solution, non-woven fabric and waterproof board are arranged in sequence from top to bottom between the secondary primary support and the secondary lining.

[0010] In order to achieve the above second purpose, the technical solution of the present invention is: a construction method for a tunnel structure suitable for a high-pressure water-rich active fault TBM to pass through, characterized in that it comprises the following steps: 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 for reinforcement; Step 2, primary support and curtain grouting: After the TBM excavates and exposes a ring, the primary support of steel fiber shotcrete is immediately applied to the exposed surrounding rock through the device carried by the rear supporting equipment, 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 solidifies, embed a steel section of not less than I20, and spray concrete to seal it, completing the secondary primary support; 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 the hinged deformation joints are constructed; the initial surrounding rock load is borne by the curtain grouting ring, the first primary support and the second primary support.

[0011] In the above technical solution, in step 2, curtain grouting breaks the primary support of the steel fiber shotcrete, reinforces and stops the surrounding rock circle, and ensures a 5m curtain grouting circle.

[0012] Compared with the prior art, the present invention has the following advantages: 1) Through the technical solution of post-matching and excavation expansion, the present invention can meet the requirement of increasing the internal clear span of the shield TBM.

[0013] 2) The curtain grouting of the present invention forms a 5m grouting reinforcement ring to resist high water heads, mainly for blocking, and is environmentally friendly.

[0014] 3) During the construction period of the present invention, through the technical solution of double primary linings, the structure can adapt to a certain amount of deformation, which conforms to the design concept of the New Austrian Tunneling Method. At the same time, through the strengthening of the secondary primary lining, the structural safety during the construction period can be satisfied when the secondary primary lining is constructed.

[0015] 4) The three-layer structure of the present invention operates permanently, and through the segment hinge design, it can effectively improve the adaptability of the structure to the creep of active faults.

[0016] 5) The internal clear span of the present invention is increased, and there is space for repair during the operation period after the structural dislocation caused by the fault.

[0017] 6) The articulated deformation joint of the present invention is provided with an Ω-shaped embedded shape memory alloy steel plate, which can adapt to deformation and has a certain memory recovery ability, and can resist water heads within 100m.

[0018] 7) The present invention is environmentally friendly, has good economy, has low requirements for the construction period, and has a stable structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of the present invention.

[0020] Figure 2 is a front layout diagram of the full-section curtain grouting holes.

[0021] Figure 3 is Figure 2 the sectional layout diagram at A-A in

[0022] Figure 4 the waterproof structure diagram of the deformation joint of the equal-thickness lining in the active fault section.

[0023] Figure 5 is the waterproof structure diagram of the deformation joint where the unequal-thickness linings of the active fault and the inactive fault are connected.

[0024] Figure 6 is the schematic structural diagram of the embedded shape memory alloy steel plate.

[0025] Figure 7 is the schematic structural diagram of the external pasted plastic waterstop. DETAILED DESCRIPTION OF THE INVENTION

[0026] The implementation of the present invention will be described in detail below with reference to the accompanying drawings. However, they do not limit the present invention and are only for illustration purposes. At the same time, the advantages of the present invention will become clearer and easier to understand through the description.

[0027] Referring to the accompanying drawings, it can be seen that the tunnel structure suitable for TBM crossing of high-pressure water-rich active faults includes, from outside to inside, a curtain grouting ring 100, a primary shotcrete support 200, a secondary shotcrete support 300, a secondary lining 400, and a hinged deformation joint 500 is provided between adjacent secondary linings 400; As Figures 4 - 7 shown, the hinged deformation joint 500 includes, from top to bottom, an external plastic waterstop 510, a polyethylene foam plastic board 520, a buried shape 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 shotcrete support 300, and the middle part is a downward convex part 511; both ends of the buried shape memory alloy steel plate 530 are located inside the secondary lining 400, inclined parts 532 are provided at both ends of the buried shape memory alloy steel plate 530 with an inclination angle of 45 degrees, and the middle part is an upward convex part 531; the top of the polyethylene foam plastic board 520 contacts the bottom of the downward convex part 511, and the bottom contacts the top of the upward convex part 531.

[0028] As Figure 4 and Figure 5 shown, a non-woven fabric 610 and a waterproof board 620 are arranged between the secondary shotcrete support 300 and the secondary lining 400 from top to bottom.

[0029] A construction method for a tunnel structure suitable for TBM crossing of high-pressure water-rich active faults includes the following steps: Step 1, excavation: After the TBM advances and exposes one ring, the excavation is carried out through the rear support equipment. The radius of the excavated part 720 is 30 - 50 cm to ensure that the excavation of the internal clearance meets the active clearance requirements of the active fault; and pre-grouting reinforcement is carried out through advanced grouting. As Figure 2 and Figure 3 shown, Step 2, primary shotcrete support and curtain grouting: After the TBM advances and exposes one ring, the primary shotcrete support 200 of steel fiber shotcrete is immediately applied to the exposed surrounding rock through the device carried by the rear support to seal the surrounding rock in time; and curtain grouting is carried out 10 m in advance. The circumferential spacing of the curtain grouting is 0.5 m, and the overlap of the curtain grouting is not less than 3 m. Step 3, construction of the secondary shotcrete support: After the primary shotcrete support 200 solidifies, a steel section not less than I20 is embedded, and concrete is sprayed for sealing to complete the secondary shotcrete support 300; to ensure the safety of the tunnel structure. Step 4, Construction of Reinforced Concrete Secondary Lining: After the TBM equipment passes through the active fault zone, the secondary lining 400 is constructed uniformly, and the articulated deformation joint 500 is constructed; the initial surrounding rock load in the early stage is borne by the curtain grouting ring 100, the primary initial support 200, and the secondary initial support 300.

[0030] As Figure 2 and Figure 3 shown, in Step 2, the curtain grouting breaks through the primary initial support 200 of the steel fiber shotcrete, reinforces and stops water for the surrounding rock circle, and ensures a 5m curtain grouting ring 100.

[0031] In actual use, after the TBM tunnels through, the circumferential excavation equipment carried by the TBM is used to expand the excavation with a radius of 30 - 50cm to meet the requirement of increased clearance.

[0032] The support structure includes three parts: the primary initial support 200, the curtain grouting + secondary initial support 300, and the cast-in-place reinforced concrete secondary lining 400.

[0033] As Figure 4 and 5 shown, after determining the deformation joint spacing according to the characteristic parameters of the active fault, the articulated deformation joint 500 is set. The articulated deformation joint 500 is resisted by the external plastic waterstop 510 plus the Ω-shaped embedded shape memory alloy steel plate 530 against high water heads; the embedded shape 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 tension of the active fault, and the embedded shape memory alloy steel plate 530 can also adapt to the deformation.

[0034] The external plastic waterstop 510 is supported on the polyethylene foam plastic board 520 to ensure that it is not crushed by high water heads; the innermost side of the lining is filled with polysulfide building sealant 540.

[0035] Other parts not described are all prior arts.

Claims

1. A tunnel structure applicable to the TBM crossing of a high-pressure water-rich active fault, characterized in that: It successively includes a curtain grouting ring (100), a primary initial support (200), a secondary initial support (300), and a secondary lining (400) from outside to inside, and a hinged deformation joint (500) is arranged between adjacent secondary linings (400); The hinged deformation joint (500) successively includes an external pasted plastic waterstop (510), a polyethylene foam plastic board (520), a buried shape memory alloy steel plate (530), and a polysulfide building sealant (540) from top to bottom; both ends of the external pasted plastic waterstop (510) are located between the secondary lining (400) and the secondary initial support (300), and the middle part is a downward convex part (511); both ends of the buried shape memory alloy steel plate (530) are located inside the secondary lining (400), and the middle part is an upward convex part (531); the top of the polyethylene foam plastic board (520) contacts the bottom of the convex part (511), and the bottom contacts the top of the convex part (531).

2. The tunnel structure applicable to the TBM crossing 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 successively arranged between the secondary initial support (300) and the secondary lining (400) from top to bottom.

3. The construction method of the tunnel structure applicable to the TBM crossing of high-pressure water-rich active faults according to claim 2, characterized in that, It includes the following steps: Step 1, excavation: After a ring is exposed by TBM tunneling, the radius is enlarged by 30 - 50 cm through the rear support equipment, and pre-grouting is carried out by advanced grouting for reinforcement; Step 2, primary initial support and curtain grouting: After a ring is exposed by TBM tunneling, a primary initial support (200) of steel fiber shotcrete is immediately applied to the exposed surrounding rock through the device carried by the rear support, and curtain grouting is carried out 10 m in advance; the circumferential spacing of the curtain grouting is 0.5 m, and the overlap of the curtain grouting is not less than 3 m; Step 3, construction of the secondary initial support: After the primary initial support (200) solidifies, a section steel not less than I20 is embedded, and shotcrete is sprayed for sealing to complete the secondary initial support (300); Step 4, construction of the 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 load of the surrounding rock in the early stage is borne by the curtain grouting ring (100), the primary initial support (200), and the secondary initial support (300).

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

Images