Existing tunnel rerouting conversion well

Abstract

The conversion well is connected with a reserved section and an abandoned section of a tunnel and temporarily blocks the reserved section and the abandoned section of the tunnel, the conversion well comprises a fender post, a lining structure and a reinforcing structure, the fender post is used for enclosing a foundation pit, an all-casing slewing drilling machine is adopted for secant pile construction, a pile body penetrates through the reserved section of the existing tunnel and is embedded into bedrock, and the lining structure is arranged on the lining structure. The lining structure is arranged in a foundation pit and comprises a wall plate and a top plate of a reserved hole casing pipe, and the casing pipe is in lap joint with a newly-built tunnel through an annular steel plate. The reinforcing structure comprises a water stop closed loop formed by grouting reinforcement of soil outside a newly-built tunnel opening and reinforcement of soil around a tunnel through MJS construction method piles, and for a waste section, plugging operation is adopted to ensure the stability of a site; for the reserved section, the structural stability and waterproof control of the joint of the new tunnel and the old tunnel are emphatically achieved, and temporary measures in the construction period and permanent measures in the later use stage are taken into consideration.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, specifically to a conversion well for rerouting existing tunnels. Background Technology

[0002] Tunnels are important structures widely used in various municipal and water conservancy facilities, and there are currently a huge number of them in my country. Existing long tunnels typically have significant longitudinal extension and depth, making maintenance work quite difficult and complex. The construction of adjacent buildings and municipal road systems can affect the structural safety and durability of tunnels, while the existence of tunnels can also pose certain safety hazards to the structural safety of newly constructed adjacent buildings and municipal road systems. In addition, it is common for new projects to intersect with existing tunnels at the same level. Therefore, it is necessary to conduct research on tunnel relocation schemes. Tunnel realignment projects generally include the sealing of abandoned sections of the tunnel, temporary reinforcement during construction and permanent reinforcement after construction of the retained sections, and the construction of the new sections of the tunnel, involving sealing, transfer shaft design, reinforcement and protection, and waterproofing treatment. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a conversion well for rerouting existing tunnels, so as to realize the sealing of abandoned sections of tunnels, construction of new sections, and reinforcement, protection and waterproofing of retained sections.

[0004] To achieve the above objectives, this invention provides a conversion shaft for rerouting an existing tunnel. This conversion shaft connects the retained section and the abandoned section of the tunnel and provides temporary sealing. It includes retaining piles, an inner lining structure, and a reinforcement structure. The retaining piles are used to protect the excavation pit and are constructed using a full-casing rotary drilling rig with interlocking piles. The piles penetrate the existing retained section of the tunnel and embed themselves in the bedrock. The inner lining structure is located within the excavation pit and includes a wall panel and a top plate with a pre-installed steel casing. The steel casing is connected to the new tunnel via a circumferential steel plate. The reinforcement structure includes grouting reinforcement of the soil outside the new tunnel entrance and MJS method pile reinforcement of the soil surrounding the tunnel to form a water-stopping closed loop. Furthermore, after the retained and abandoned sections of the tunnel are temporarily sealed, lightweight concrete is grouted inside the tunnel. The portion of the conversion shaft that needs to be demolished is not grouted.

[0005] Furthermore, before the construction of the retaining piles, steel arch frames are installed inside the tunnel retaining section. The horizontal spacing of the steel arch frames is 2 meters, and the I-beams of the steel arch frames are connected by full penetration 3-corner welds.

[0006] Furthermore, after the newly constructed tunnel is completed, the retaining piles and lightweight concrete of the remaining section are removed, the steel arch frame is dismantled, and the inner steel sleeve is welded to the steel plate of the tunnel inner wall.

[0007] Furthermore, the water-stopping closed loop of the reinforcement structure uses expansive concrete to seal the connection section of the steel plate on the inner wall of the welded inner steel sleeve tunnel, and the MJS method is used to reinforce the land around the tunnel retaining section.

[0008] Furthermore, the sealing section is divided into compartments by masonry partition walls, and vertical shafts are formed at the top of each compartment through drilled holes for filling with filler material. This invention has the following beneficial effects:

[0009] (1) The construction method of the present invention provides a mature solution for the realignment of existing tunnels. For abandoned sections, sealing operations are carried out to ensure the stability of the site. For retained sections, the focus is on solving the structural stability and waterproofing control at the junction of the old and new tunnels, taking into account both temporary measures during construction and permanent measures in the later use stage.

[0010] (2) In the construction method of the present invention, the construction process of the new tunnel can be selected from "drill and blast method", "pipe jacking method" or "shield method". Considering that the tunnel is generally buried at a large depth and the soil along the line is mostly hard soil, if the open excavation scheme is adopted, a pile + internal support scheme with greater rigidity is required, which has a long construction period and high cost.

[0011] (3) The vertical pile + internal support system of the construction method of the present invention is well adapted to the hydrogeological conditions, surrounding environment and underground obstacles of the construction site, has a good water-stopping effect, high overall rigidity and a certain obstacle-clearing ability. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the overall rerouting of the existing tunnel according to the present invention;

[0014] Figure 2 This is a schematic diagram of the conversion well of the present invention;

[0015] Figure 3 This is a schematic diagram of the conversion well profile of the present invention;

[0016] Figure 4 This is a schematic cross-sectional view of the soil reinforcement treatment outside the tunnel at the conversion well according to the present invention;

[0017] Figure 5 This is a cross-sectional schematic diagram of the steel arch support inside the tunnel retaining section at the conversion well of the present invention;

[0018] Figure 6 This is a schematic diagram showing the connection between the conversion well of the present invention and the existing tunnel;

[0019] Figure 7 This is a schematic diagram of the grouting and sealing scheme for abandoned tunnel sections according to the present invention.

[0020] In the diagram: 1. Converter shaft, 2. Newly constructed tunnel, 3. Retained section of tunnel, 4. Abandoned section of tunnel, 5. Retaining piles, 6. Lining structure of the converter shaft, 7. Steel arch frame inside the retained section of tunnel, 8. MJS method piles, 9. Support inside the converter shaft pit, 10. Circumferential steel plate, 11. Steel sleeve reserved at the tunnel entrance, 12. Expansive concrete, 13. Cast-in-place shaft, 14. Compartmentalized cast-in-place concrete, 15. Compartmentalized partition wall. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0024] Figure 1 This is a schematic diagram of the overall rerouting of an existing tunnel in the construction method of this invention, as shown in the embodiment of the invention. Figure 1 As shown in the figure, in an embodiment of the present invention, an existing tunnel realignment conversion shaft 1 is used to connect the retained section 3 and the abandoned section 4 for temporary sealing. The retained section 3 is connected to the conversion shaft 1, and the abandoned section 4 is filled after the new tunnel 2 is completed.

[0025] Specifically, lightweight concrete is used as the material for the temporary sealing of the retained section 3 and the abandoned section 4, so that it can be easily removed later. The lightweight concrete is filled by grouting inside the tunnel. The grouting range is within the construction influence range of the retaining piles 5 on the existing tunnel retained section 3 and abandoned section 4. The part of the conversion well 1 that needs to be removed in the middle cannot be grouted.

[0026] like Figure 2 and Figure 3 As shown in the figure, an existing tunnel realignment conversion shaft according to an embodiment of the present invention further includes: retaining piles 5, an inner lining structure 6, and a reinforcement structure 8. The retaining piles 5 are used to reinforce the foundation pit, and the inner lining structure 8 is installed inside the foundation pit.

[0027] Specifically, the retaining pile 5 is constructed using a full-casing rotary drilling rig with interlocking piles. The pile penetrates the existing tunnel section and embeds itself into the bedrock. Subsequently, water-stopping and soil reinforcement work at the tunnel entrance is carried out. Only after the retaining piles, water-stopping, and soil reinforcement work at the tunnel entrance meet the specified age and strength requirements can the foundation pit be excavated.

[0028] Specifically, the interface between the conversion shaft 1 and the retained section 3 of the tunnel needs to be reinforced. For example... Figure 6 As shown, a steel arch frame 7 is installed inside the tunnel retaining section 3. In some embodiments, the horizontal spacing of the steel arch frames 7 is set to 2 meters, depending on the tunnel cross-section size and structural stress conditions, and the I-beams of the steel arch frames 7 are connected by full penetration fillet welds.

[0029] Specifically, such as Figure 5 As shown, this embodiment uses the MJS method to reinforce the land around the tunnel preservation section, including multiple MJS method piles 8 to reinforce the outer periphery of the tunnel preservation section 3 and the conversion well 1, and the tunnel preservation section 3 is temporarily sealed to form a water passage section.

[0030] A circumferential steel plate 10 is pre-embedded in the retained section 3 of the tunnel, and the space between the circumferential steel plate 10 and the inner wall of the retained section 3 is filled with cement mortar. The inner lining structure 6 includes the wall panel and top plate of the reserved steel sleeve 11. The steel sleeve 11 is connected to the newly built tunnel 2 by the circumferential steel plate 10, and the dimensions of the steel sleeve 11 are consistent with the dimensions of the newly built tunnel 2. Figure 7 As shown, the steel casing reserved in the inner lining of the conversion shaft 1 is connected to the circumferential steel plate 10 pre-embedded in the tunnel retention section 3, and sealed with expansive concrete 12.

[0031] Before construction of the new tunnel 2, the land within a certain range outside the tunnel entrance needs to be reinforced by grouting. The construction technology of the new tunnel 2 can be selected from the cross-section of the new tunnel 2 and the geological conditions along the route, using the "drill and blast method", "pipe jacking method" or "shield tunneling method", starting construction from one end of the conversion shaft 1 and completing the receiving at the other end of the conversion shaft 1.

[0032] like Figure 7As shown, after the newly constructed tunnel 2 is completed, the two ends of the abandoned section 4 will be temporarily sealed before the sealing operation begins. The abandoned section 4 will be divided into compartments by constructing partition walls 15, and vertical shafts 13 will be formed at the top of each compartment through drilling. Concrete pump trucks and hoppers will be used to directly pour filler 14 into the tunnel through the vertical shafts 13 until the concrete reaches 500mm below the existing ground level in the shafts. Currently, commonly used fillers are plain concrete or gravel. Considering factors such as ease of construction, filling effect, and economy, the C15 concrete pouring scheme is preferred.

[0033] The above specific embodiments are for illustrative purposes only and are not intended to limit the invention. Any corresponding changes, equivalent substitutions, improvements, etc., made by those skilled in the art within the technical solution and concept of the present invention without creative effort should fall within the protection scope of the claims of the present invention.

Claims

1. A conversion shaft for rerouting existing tunnels, characterized in that, The conversion well connects the retained section and the abandoned section of the tunnel and temporarily seals them. It includes retaining piles, an inner lining structure, and a reinforcement structure. The retaining piles are used to protect the foundation pit and are constructed using a full-casing rotary drilling rig with interlocking piles. The piles penetrate the existing retained section of the tunnel and embed themselves into the bedrock. The inner lining structure is located in the foundation pit and includes the wall panel and top plate of the pre-reserved steel casing. The steel casing is connected to the new tunnel through a circumferential steel plate. The reinforcement structure includes grouting reinforcement of the soil outside the new tunnel entrance and MJS method pile reinforcement of the soil around the tunnel to form a water-stopping closed loop.

2. The existing tunnel realignment conversion well as described in claim 1, characterized in that, After the retained and abandoned sections of the tunnel are temporarily sealed, lightweight concrete is injected into the tunnel interior. The portion of the conversion shaft that needs to be demolished cannot be grouted.

3. A conversion shaft for rerouting an existing tunnel as described in claim 2, characterized in that, Before the construction of the retaining piles, steel arch frames were installed inside the tunnel retaining section. The horizontal spacing of the steel arch frames was 2 meters, and the I-beams of the steel arch frames were connected by full penetration 3-corner welds.

4. A conversion shaft for rerouting an existing tunnel as described in claim 3, characterized in that, After the newly constructed tunnel is completed, the retaining piles and lightweight concrete of the remaining section are removed, the steel arch frame is dismantled, and the inner steel sleeve is welded to the steel plate of the tunnel inner wall.

5. A conversion shaft for rerouting an existing tunnel as described in claim 4, characterized in that, The water-stopping closed loop of the reinforcement structure is sealed with expansive concrete to seal the connection section of the steel plate of the inner wall of the welded inner steel sleeve tunnel, and the MJS method is used to reinforce the land around the tunnel retaining section.

6. A conversion shaft for rerouting an existing tunnel as described in claim 5, characterized in that, The sealing section is divided into compartments by masonry partition walls, and vertical shafts are formed at the top of each compartment by drilling, which are used to fill the filling material.

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