Tunnel construction method and equipment

Abstract

The present application relates to the technical field of tunnel construction, in particular to a tunnel construction method and equipment, which adopts the method of first constructing a bite pipe ring, then performing freezing water stop construction on the outer periphery of the bite pipe ring, then pouring concrete in the bite pipe ring after the completion of the freezing water stop construction, to form a stable supporting structure in the geological body, and then performing tunnel excavation construction, so that when the tunnel is constructed by the freezing method, the geological body is divided into a to-be-excavated area for forming the tunnel and a non-excavated area outside the tunnel by the pipe curtain structure, on the basis of which, when the to-be-excavated area is excavated by the construction personnel, a stable frozen structure can be formed, and there will be no safety hazards in the excavation process due to insufficient strength of the geological body.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a tunnel construction method and equipment. Background Technology

[0002] The pipe jacking freezing method is a construction method that combines "pipe jacking + freezing pre-support and mining method tunneling". Among them, the pipe jacking consists of large steel pipes arranged around the tunnel and along the entire length of the tunnel to provide strong support and protect the tunnel construction safety; while freezing involves freezing the soil between the steel pipes and the surrounding soil into frozen soil, forming a water-stop curtain.

[0003] In layman's terms, this method involves pre-installing a steel protective casing along the outline of the tunnel excavation, and then excavation takes place inside the casing. The protective casing consists of a series of large steel pipes arranged in sequence and artificial frozen soil. The final pipe liner for this section of the tunnel excavation project consisted of 36 steel pipes with a diameter of 1.62 meters, forming an elliptical tunnel excavation cross-section that is 18 meters wide and 22 meters high, equivalent to the height of a 7-story building.

[0004] The conventional freezing method involves directly driving freezing pipes into the soil and circulating a refrigerant (a type of brine cooled to below -30°C, cold but not freezing) inside the pipes, thus creating frozen soil around them. However, this won't work here because the tunnel route is curved, making it impossible to lay freezing pipes directly in the soil. The only feasible way to implement freezing pipes is to place them inside large steel pipes.

[0005] However, when using the pipe-jacking freezing method in tropical regions, the persistently high temperatures cause the resulting geological formations to exhibit permafrost that easily thaws, preventing the formation of stable frozen structures. Current technologies typically address this by increasing the freezing frequency. However, even increasing the freezing frequency cannot completely resolve the defects of permafrost thawing and the inability to form stable frozen structures when using freezing methods in tropical regions. Summary of the Invention

[0006] The main objective of this invention is to provide a tunnel construction method and equipment, which aims to solve the technical problem in related technologies that even if the freezing frequency is increased, it is still impossible to completely solve the problem of permafrost melting easily and the inability to form a stable frozen structure when using the freezing method in tropical regions.

[0007] To achieve the above objectives, in a first aspect, the present invention proposes a tunnel construction method, comprising the following steps: In the target construction area, a launching well and a receiving well are constructed respectively; wherein, a launching portal is provided on the side wall of the launching well, and a receiving portal is formed on the side wall of the receiving well opposite to the launching well; Along the direction from the starting tunnel portal to the receiving tunnel portal, the pilot component is jacked up at the starting tunnel portal; wherein, the pilot component is an independent steel pipe; Using the pilot member as a guide, the interlocking pipe ring construction is carried out from the starting tunnel portal; wherein, the area enclosed by the interlocking pipe ring is the area to be excavated, and the cavity of the interlocking pipe ring forms an area to be poured. Freezing and water-stopping construction is carried out on the outer periphery of the interlocking pipe ring; Concrete is poured into the area to be poured to form a pipe curtain structure; excavation is carried out in the area to be excavated to form the tunnel.

[0008] Optionally, the step of constructing a launching well and a receiving well in the target construction area includes: Two retaining structures are constructed in the target construction area; The two retaining structures are excavated and constructed to a preset elevation to form a first construction well and a second construction well, respectively; wherein, the first construction well has a starting portal formed on one side wall, and the second construction well has a receiving portal formed on one side wall opposite to the first construction well; The geological bodies on the rear side of the sidewall of the launching portal and the rear side of the receiving portal are reinforced respectively to construct the launching shaft and the receiving shaft accordingly.

[0009] Optionally, the step of reinforcing the geological body behind the sidewall of the launching portal and the geological body behind the sidewall of the receiving portal to construct the launching well and the receiving well includes: using two rows of plain concrete bored piles to reinforce the geological body behind the sidewall of the launching portal to construct the launching well. The geological body behind the side wall of the receiving tunnel portal is reinforced by a combination of triaxial mixing piles and jet grouting piles, so as to construct the launching well and the receiving well accordingly.

[0010] Optionally, the plain concrete bored pile is φ1000mm@800mm, and the reinforcement width of the plain concrete bored pile is 29m. The bottom end of all the plain concrete bored piles extends into the moderately weathered rock layer by at least 2m.

[0011] Optionally, the step of reinforcing the geological body behind the sidewall of the receiving tunnel portal using a combination of triaxial mixing piles and jet grouting piles to construct the launching shaft and the receiving shaft includes: Jet grouting piles were used to reinforce the geological body on the rear side wall of the receiving tunnel entrance, forming the first reinforcement zone; The geological body behind the side wall of the receiving tunnel is reinforced by using triaxial mixing piles to form a second reinforcement zone that is spaced apart from the first reinforcement zone; wherein the second reinforcement zone is located on the side of the first reinforcement zone away from the receiving tunnel.

[0012] Optionally, both the jet grouting piles and the triaxial mixing piles are Φ850mm@600mm, the second reinforcement zone has a length of 5m along the direction from the starting tunnel to the receiving tunnel, a reinforcement width of 28.019m, and the bottom ends of all the jet grouting piles and all the triaxial mixing piles extend downwards at least 3m to form the bottom of the outer contour line of the pipe curtain structure.

[0013] Optionally, the step of reinforcing the geological bodies behind the sidewalls of the launching tunnel and the receiving tunnel to construct the launching tunnel and the receiving tunnel further includes: The area of ​​geological bodies within at least 3 meters outside the outline of the receiving portal and the outline of the launching portal is designated as a reinforced zone. The strong reinforcement zone on the rear side wall of the launching portal and the strong reinforcement zone on the rear side wall of the receiving well are reinforced respectively to construct the launching well and the receiving well accordingly.

[0014] Optionally, the step of constructing the interlocking pipe ring from the starting portal using the pilot member as a guide includes: Using the pilot member as a guide, multiple steel pipes arranged circumferentially at intervals along the starting portal are sequentially pushed in from the starting portal to form an interlocking pipe ring, thus completing the construction of the interlocking pipe ring.

[0015] Optionally, the step of pouring concrete into the area to be poured to form a pipe curtain structure includes: Along the length extension direction of the tube ring, at least two spaced target cutting areas are respectively provided on each of the steel pipes of the interlocking tube ring; Along the length extension direction of the pipe ring, all the target cutting areas in the pipe ring are cut according to the target cutting area to form a casting area connecting all the steel pipes within the interlocking pipe ring; wherein, the target cutting area is smaller than the area of ​​the target cutting area; Concrete is poured into the area to be poured to form the pipe curtain structure.

[0016] Optionally, the step of excavating the area to be excavated to form the tunnel includes: Excavation work is carried out on the area to be excavated to form a support area; Secondary lining construction is carried out in the area to be supported to form a secondary lining layer; The tunnel is formed by constructing ancillary structures on the inner bottom wall of the secondary lining layer; wherein the ancillary structures include internal structures, road surfaces, and finishing structures.

[0017] Based on the same inventive concept, in a second aspect, the present invention proposes a construction equipment for performing the construction method described in the first aspect.

[0018] The present invention has the following beneficial effects: 1) The technical solution of this invention involves constructing a launching shaft and a receiving shaft in the target construction area. Along the direction from the launching portal to the receiving portal, a pilot jacking operation is performed at the launching portal. Using the pilot jacking as a guide, a combined pipe jacking machine is used to construct an interlocking pipe ring from the launching portal. Freezing and water-stopping are performed on the outer periphery of the interlocking pipe ring. Concrete is then poured into the interlocking pipe ring to form a pipe curtain structure. Excavation is then carried out within the pipe curtain structure to form a tunnel. This invention employs a method of first constructing the interlocking pipe ring, then performing freezing and water-stopping on its outer periphery, and finally pouring concrete within the interlocking pipe ring to form a stable support structure within the geological body before proceeding with tunnel excavation. This allows the invention to divide the geological body into an excavation area for tunnel formation and an excavation-free area outside the tunnel when using the freezing method for tunnel construction.

[0019] 2) Based on this, when construction workers excavate the area to be excavated, a stable frozen structure can be formed, and there will be no safety hazards during the excavation process due to insufficient strength of the geological body. Even if the frozen soil melts, it will not affect the normal construction of the tunnel. This solves the technical problem that even if the freezing frequency is increased, it is still not possible to completely solve the problem of frozen soil melting easily and the inability to form a stable frozen structure when using the freezing method in tropical regions. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating a tunnel construction method as exemplified by the present invention; Figure 2 for Figure 1 The flowchart of step S100 in the example is shown below; Figure 3 for Figure 2 The flowchart of step S130 in the example is shown; Figure 4 for Figure 1 The flowchart of step S500 in the example is shown below; Figure 5 for Figure 1 The flowchart of step S600 in the example is shown below; Figure 6 Flowcharts of some exemplary embodiments of the present invention; Figure 7 This is a schematic diagram of the construction well as an example of the present invention; Figure 8 This is a schematic diagram illustrating the structural relationship between the pilot component and the construction well, as exemplified by the present invention. Attached image description: Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of the mechanisms in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0024] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0026] The inventive concept of the present invention will be further explained below with reference to some specific embodiments.

[0027] Please see Figures 1 to 8 This invention proposes a tunnel construction method, comprising the following steps: S100. In the target construction area, a launching shaft and a receiving shaft 200 are constructed respectively; wherein, a launching portal is provided on the side wall of the launching shaft, and a receiving portal is formed on the side wall of the receiving shaft 200 opposite to the launching shaft. In this embodiment, during the construction of the launching well and receiving well 200, reinforcement is required for both the launching end of the launching well and the receiving end of the receiving well 200. The specific reinforcement scheme is as follows: The launching end of the launching well is reinforced using two rows of φ1000mm@800mm plain concrete bored piles. The bored piles have a width of approximately 29m and a depth of 2m into the moderately weathered (W2) layer. The receiving end of the receiving well 200 is reinforced using a combination of triaxial mixing piles 300 and jet grouting piles 400. A row of Φ850mm@600mm jet grouting piles 400 is constructed near the working well side, and the outside of the jet grouting piles 400 is reinforced with Φ850mm@600mm triaxial mixing piles 300. The second reinforcement zone has a length of 5m along the direction from the starting tunnel to the receiving tunnel, and a reinforcement width of 28.019m. It divides the geological body area within at least 3m outside the outline of the receiving tunnel and the outline of the starting tunnel into (the area within 3m outside the top and bottom edges of the circular jacking pipe is the strong reinforcement zone, and the rest is the weak reinforcement zone).

[0028] S200. Along the direction from the starting tunnel portal to the receiving tunnel portal, the pilot section is jacked up at the starting tunnel portal; the pilot section is an independent steel pipe. In this embodiment, a circular pipe jacking machine can be used for the jacking construction of the pilot component. The machine is positioned parallel to the axis along the outline of the structural cross-section, and a 2.2m diameter circular steel pipe is jacked segment by segment at the positions of the pilot pipe and the independent steel pipe. The jacking sequence is from bottom to top, alternating between the two, until the jacking construction of the pilot component is completed.

[0029] It should be specifically and clearly stated that in this embodiment, the pilot component is an independent steel pipe, and the independent steel pipe is preferably a circular steel pipe with a diameter of 2.2m.

[0030] S300, using the pilot component as a guide, the interlocking pipe ring construction is carried out from the starting tunnel portal; the area enclosed by the interlocking pipe ring is the area to be excavated, and the cavity of the interlocking pipe ring forms an area to be poured. In this embodiment, multiple interlocking pipe assemblies are used, each consisting of three steel pipes arranged side-by-side and interlocking. The central circular steel pipe has a diameter of 2.1m, and the two outer circular steel pipes have diameters of 2.0m. A guide pipe transition section is located in front of the cutterhead of the pipe jacking machine on the central circular pipe. The transition section corresponds to the position of the pilot guide pipe and is longitudinally connected to the pilot guide pipe using rigid or flexible joints. The wall of the transition section is concave at the cutterhead position. The cutterhead of the combined pipe jacking machine is located on both sides of the transition section. The combined pipe jacking machine and the interlocking pipe body advance along the trajectory of the pilot guide pipe, simultaneously pushing the pilot guide pipe out and receiving it at the receiving well 200, until the construction of the interlocking pipe ring is completed.

[0031] S400, perform freezing and water-stopping construction on the outer periphery of the interlocking pipe ring; In this embodiment, during the freezing and water-stopping construction, freezing pipes are arranged on both the inner and outer sides of the gap between two adjacent sets of steel pipes, forming a frozen body in the gap between the two pipes. The frozen body should encompass the cut area of ​​the steel pipes, and its thickness along the radial direction of the tunnel should meet the shear resistance requirements. The frozen body should be solidified before the steel pipes are cut, and should be maintained in a frozen state during the cutting, welding, and support erection processes of the steel pipes.

[0032] S500, pour concrete into the area to be poured to form a pipe curtain 100 structure; In this embodiment, before pouring concrete into the cavity within the interlocking pipe ring, the entire ring pipe curtain 100 structure steel pipe needs to be cut and supported, internal pins welded, and the concrete within the pipe curtain 100 structure poured in layers and sections. Vertically, it is divided into upper, middle, and lower layers, with each pouring section being 5-6 meters long.

[0033] Concrete can be poured in the following ways: First, the corresponding steel pipes in each section of the tube curtain 100 are cut to connect the multiple steel pipes to form a curtain wall cavity. Then, the tube curtain 100 is divided into three layers, and the connection points between the multiple steel pipes in the tube curtain 100 are welded layer by layer. Concrete is then poured into the curtain wall cavity layer by layer. Next, the above steps are repeated for each section of the tube curtain 100 so that multiple sections of the tube curtain 100 are connected in sequence along the extension direction of the steel pipes to form a tube curtain 100 group, thus completing the construction.

[0034] Simultaneously, during the specific cutting process, the steel pipes are cut in the target cutting area between adjacent interlocking steel pipe groups, or between interlocking steel pipe groups and independent steel pipes, and connected with steel plates. Steel pipe supports are installed between the steel plates to facilitate load-bearing. The steel pipes should be cut in sections at intervals. Before cutting, temporary steel columns are installed on both sides of the steel pipe corresponding to the target cutting area to provide temporary support during the cutting process. Then, the steel plates are cut at certain intervals, the soil between the pipes is excavated, and adjacent steel pipes are connected with steel plates at the opening positions. After the connecting steel plates are welded to the steel pipes, steel pipe supports are installed between the connecting steel plates as a permanent support structure. After the steel pipe supports are erected, the temporary steel columns can be removed.

[0035] It should be specifically and clearly stated that, in this embodiment, the shear resistance requirement is a well-known requirement in the prior art, and will not be repeated here.

[0036] This invention employs a construction method for a single section of pipe curtain 100, which involves first cutting the connecting portion between two adjacent steel pipes in the pipe curtain 100, and then welding and pouring concrete on each steel pipe layer by layer. Multiple steel pipes in a single section of pipe curtain 100 are vertically layered, and the welding of each layer of steel pipes and the pouring of concrete are carried out alternately to form a pipe curtain 100 structure that combines a single section of steel pipe and concrete. The above steps are performed on each section of pipe curtain 100 to complete the construction of the pipe curtain 100 group.

[0037] It should be specifically and clearly stated that, in this embodiment, before pouring the pipe curtain 100, the pipe curtain 100 structure that has been jacked from the starting shaft to the receiving shaft 200 needs to be divided into multiple cyclic advance sections according to the cyclic advance sections of tunnel construction, in the direction from the starting shaft to the receiving shaft 200. When constructing the pipe curtain 100 corresponding to each cyclic advance section, the entire pipe curtain 100 needs to be divided into upper, middle and lower layers in a top-to-bottom order; and then the lower, middle and upper layers can be poured with concrete in a bottom-to-top order.

[0038] S600: Excavate the area to be excavated to form a tunnel.

[0039] In this embodiment, the technical solution of the present invention involves constructing a launching shaft and a receiving shaft 200 in the target construction area. Along the direction from the launching portal to the receiving portal, a pilot jacking operation is performed at the launching portal. Using the pilot jacking as a guide, a combined pipe jacking machine is used to construct an interlocking pipe ring from the launching portal. Freezing and water-stopping construction is carried out on the outer periphery of the interlocking pipe ring. Concrete is then poured into the interlocking pipe ring to form a pipe curtain 100 structure. Excavation is then carried out within the pipe curtain 100 structure to form a tunnel. The technical solution of the present invention employs the method of first constructing the interlocking pipe ring, then performing freezing and water-stopping construction on the outer periphery of the interlocking pipe ring, and finally pouring concrete inside the interlocking pipe ring after completing the freezing and water-stopping construction, in order to form a stable structure within the geological body. The method of constructing a support structure and then excavating the tunnel allows the geological body to be divided into an excavation area for tunnel formation and a non-excavation area outside the tunnel when using the freezing method for tunnel construction. Based on this, when the construction personnel excavate the excavation area, a stable frozen structure can be formed, and there will be no safety hazards during the excavation process due to insufficient strength of the geological body. Even if the permafrost melts, it will not affect the normal construction of the tunnel. This solves the technical problem in related technologies that even if the freezing frequency is increased, it is still not possible to completely solve the problem of permafrost melting easily and the inability to form a stable frozen structure when using the freezing method in tropical regions.

[0040] In some specific embodiments, step S100 includes: S110. Construct two retaining structures in the target construction area; It should be specifically and clearly stated that in this embodiment, the construction method of the example retaining structure can directly use the conventional construction method in the prior art. This embodiment has not improved or designed it, so it will not be described in detail here. However, it can be exemplified that the construction and maintenance structure methods that can be used in this embodiment include, but are not limited to, interlocking pipe pile method, bored cast-in-place pile method and underground continuous wall method.

[0041] S120. Excavate and construct the two retaining structures to the preset elevation to form the first construction shaft and the second construction shaft respectively; wherein, the first construction shaft has a starting portal on one side wall, and the second construction shaft has a receiving portal on one side wall opposite to the first construction shaft. S130. Reinforce the geological bodies on the rear side of the sidewall of the launching portal and the rear side of the receiving portal respectively, so as to construct the launching shaft and the receiving shaft 200 respectively.

[0042] In this embodiment, the receiving shaft 200 and the launching shaft are constructed in this manner, which allows construction personnel to take turns carrying out tunnel construction, thereby improving construction efficiency.

[0043] In some specific embodiments, step S130 includes: S131. Two rows of plain concrete bored piles were used to reinforce the geological body behind the side wall of the starting tunnel portal to form the starting shaft. This ensured the construction efficiency of the starting shaft and also ensured that the steel pipe would not be affected by the hardness of the reinforced geological body during the subsequent pipe jacking construction.

[0044] S132. The geological body on the rear side of the receiving tunnel portal is reinforced by a combination of three-axis mixing piles 300 and jet grouting piles 400, so as to construct the launching well and receiving well 200.

[0045] In this embodiment, a triaxial mixing pile 300 and a jet grouting pile 400 are installed at the receiving well 200 location, so that the geological body at the end of the receiving well 200 can be effectively reinforced, ensuring the stability of the receiving well 200.

[0046] It should be specifically and clearly stated that, in this embodiment, the construction sequence of the launching well and the receiving well 200 can be carried out simultaneously or the launching well can be constructed first, followed by the receiving well 200. However, in this embodiment, it is preferred that they be carried out simultaneously.

[0047] In some specific embodiments, the plain concrete bored piles are φ1000mm@800mm, and the reinforcement width of the plain concrete bored piles is 29m. The bottom end of all plain concrete bored piles extends into the moderately weathered rock layer to a predetermined depth, wherein the predetermined depth is at least 2m.

[0048] In this embodiment, this method can effectively reduce the construction time at the starting wellhead and improve construction efficiency. At the same time, setting the reinforcement width to 29m can also make the geological body through the starting wellhead form a stable structure.

[0049] In some specific embodiments, step S132 includes: S132a. 400 jet grouting piles were used to reinforce the geological body on the back side of the side wall near the receiving tunnel entrance, forming the first reinforcement zone. S132b. Using three-axis mixing piles 300, the geological body behind the side wall of the receiving tunnel is further reinforced to form a second reinforcement zone that is separated from the first reinforcement zone; wherein, the second reinforcement zone is located on the side of the first reinforcement zone away from the receiving tunnel.

[0050] In this embodiment, by means of this method, the present invention can ensure that after the receiving well 200 is reinforced, the stress performance of the geological body behind the receiving well 200 is effectively guaranteed, and there is no hidden danger such as the receiving well 200 collapsing due to excessive pressure of the geological body.

[0051] In some specific embodiments, the jet grouting piles 400 and the triaxial mixing piles 300 are both Φ850mm@600mm. The length of the second reinforcement zone along the direction from the starting tunnel to the receiving tunnel is 5m, and the reinforcement width is 28.019m. The bottom ends of all jet grouting piles 400 and all triaxial mixing piles 300 extend downward to form the outer contour line of the pipe curtain 100 structure with a preset thickness of at least 3m.

[0052] In this embodiment, the construction time at the starting wellhead can be effectively reduced, and the construction efficiency can be improved. At the same time, setting the reinforcement width to 5m can also make the geological body through the starting wellhead form a stable structure.

[0053] In some specific embodiments, step S130 further includes: A131. The area of ​​geological bodies within at least 3m beyond the outline of the receiving portal and the outline of the originating portal shall be designated as a reinforced zone. A132. Reinforcement construction shall be carried out on the rear side wall reinforcement zone of the launching portal and the rear side wall reinforcement zone of the receiving shaft 200 respectively, so as to construct the launching shaft and the receiving shaft 200 accordingly.

[0054] By reinforcing only the reinforced area, this invention can save materials and reduce construction costs during use.

[0055] In some specific embodiments, step S300 includes: Using the pilot component as a guide, multiple steel pipes arranged circumferentially along the starting portal are sequentially pushed in from the starting portal to form an interlocking pipe ring, thus completing the construction of the interlocking pipe ring.

[0056] In this embodiment, the pipe curtain 100 is constructed, which enables the present invention to avoid construction safety risks caused by factors such as poor geological stability during tunnel construction.

[0057] In some specific embodiments, step S500 includes: S510. Along the length extension direction of the pipe ring, at least two spaced target cutting areas are respectively set on each steel pipe of the interlocking pipe ring. It should be specifically and clearly stated that, in this embodiment, the spacing between the various cutting positions in the example is preferably 1m.

[0058] S520. Along the length of the pipe ring, all target cutting areas in the pipe ring are cut according to the target cutting area to form a pouring area that connects all steel pipes within the interlocking pipe ring; wherein, the target cutting area is smaller than the area of ​​the target cutting area. In this embodiment, the purpose of setting up temporary steel columns is to prevent deformation after cutting. In this embodiment, the cutting method includes, but is not limited to, acetylene cutting.

[0059] S530. Pour concrete in the area to be poured to form the pipe curtain 100 structure.

[0060] In this embodiment, the method of forming the pipe curtain 100 by pouring concrete solves the hidden danger of poor geological stability caused by the melting of frozen soil due to excessively high temperature in related technologies.

[0061] In some specific embodiments, step S600 includes: S610. Excavate the area to be excavated to form a support zone; S620. Secondary lining construction is carried out in the area to be supported to form a secondary lining layer. S630. The auxiliary structures are constructed on the inner bottom wall of the secondary lining layer to form a tunnel; the auxiliary structures include the internal structure, the road surface and the finishing structure.

[0062] Based on the same inventive concept, in a second aspect, the present invention proposes a construction method for performing the examples described in the foregoing embodiments.

[0063] Of course, in some exemplary embodiments, the tunnel construction method of the present invention can also be implemented in the manner described in the following example: S10. Construct the launching and receiving working shafts and complete the main structure of the working shafts; The starting end of the working well is reinforced by two rows of plain concrete bored piles φ1000@800. The bored piles are approximately 29m wide and 2m deep into the moderately weathered (W2) layer.

[0064] The receiving end of the working shaft is reinforced using a combination of 300mm triaxial mixing piles and 400mm jet grouting piles. A row of 400mm Φ850@600mm jet grouting piles is constructed near the working shaft, and 300mm Φ850@600mm triaxial mixing piles are used for reinforcement outside the 400mm jet grouting piles. The reinforcement zone has a longitudinal length of 5m, a reinforcement width of 28.019m, and a reinforcement depth of 3m from the ground to the bottom edge of the 100mm section of the circular jacking pipe (the 3m area outside the top and bottom edges of the circular jacking pipe is the strong reinforcement zone, and the rest is the weak reinforcement zone).

[0065] S20, independent steel pipe / pilot pipe jacking; Using a circular pipe jacking machine, circular steel pipes with a diameter of 2.2m are jacked in sections along the outline of the structure's cross-section, parallel to the axis, at the positions of the pilot guide and independent steel pipes. The jacking sequence is from bottom to top, alternating between the two.

[0066] S30. Use a combined pipe jacking machine to jack in the interlocking pipe body; The combined pipe body consists of a central 2.1m diameter circular steel pipe and two 2.0m diameter circular steel pipes on either side, interlocking. A guide pipe transition section is located in front of the cutterhead of the pipe jacking machine, with the transition section corresponding to the pilot pipe. Longitudinally, it is connected to the pilot pipe using rigid or flexible joints. The wall of the transition section is concave at the cutterhead position. The cutterhead of the combined pipe jacking machine is located on both sides of the transition section. The combined pipe jacking machine and the interlocking pipe body advance along the trajectory of the pilot pipe, simultaneously jacking it out for reception at the receiving shaft 200.

[0067] S40, Freezing stop; Freezing pipes are arranged on both the inner and outer sides in the gap between two adjacent sets of steel pipes, forming a frozen body in the gap. The frozen body should encompass the cut area of ​​the steel pipes, and its thickness along the radial direction of the tunnel should meet the shear resistance requirements. The frozen body should be solidified before the steel pipes are cut and should remain frozen during the cutting, welding, and support erection processes.

[0068] S50, steel pipe cutting support; Between adjacent interlocking steel pipe groups, or between an interlocking steel pipe group and an independent steel pipe, the steel pipes are cut at designated positions and connected with steel plates. Steel pipe supports are installed between the steel plates to facilitate load-bearing. The steel pipes should be cut in sections at intervals. Before cutting, temporary steel columns are installed on both sides of the predetermined cutting position within the steel pipe to provide temporary support during cutting. Then, steel plates are cut at intervals, the soil between the pipes is excavated, and adjacent steel pipes are connected at the openings using steel plates. After the connecting steel plates are welded to the steel pipes, steel pipe supports are installed between the connecting steel plates as a permanent support structure. Once the steel pipe supports are in place, the temporary steel columns can be removed.

[0069] S60, pour 100mm concrete for the pipe jacking; After the cutting and support of the 100mm diameter pipe jacking structure are completed, internal pins are welded, and concrete is poured in layers and sections within the 100mm diameter pipe jacking structure. Vertically, it is divided into upper, middle, and lower layers, with each pouring section being 5-6m long.

[0070] S70. Excavation of earthwork within the existing structure; After the secondary lining is constructed, the internal structural equipment is installed, and the interior decoration is completed, the road surface can be laid, and the tunnel is completed.

[0071] Based on the same technical concept, in a second aspect, the present invention proposes a construction equipment for tunnel construction using the tunnel construction method of the first aspect.

[0072] The technical solution of this invention involves constructing a launching shaft and a receiving shaft 200 in the target construction area. Along the direction from the launching portal to the receiving portal, a pilot jacking operation is performed at the launching portal. Using the pilot jacking as a guide, a combined pipe jacking machine is used to construct an interlocking pipe ring from the launching portal. Freezing and water-stopping are performed on the outer periphery of the interlocking pipe ring. Concrete is then poured into the interlocking pipe ring to form a pipe curtain 100 structure. Excavation is then carried out within the pipe curtain 100 structure to form a tunnel. This technical solution employs the method of first constructing the interlocking pipe ring, then performing freezing and water-stopping on its outer periphery, and finally pouring concrete within the interlocking pipe ring after the freezing and water-stopping is completed, to form a stable support structure within the geological mass. The method of tunnel excavation and construction, when using the freezing method for tunnel construction, utilizes the pipe curtain 100 structure to divide the geological body into the excavation area to be formed for tunnel formation and the non-excavation area outside the tunnel. On this basis, when the construction personnel excavate the excavation area, a stable frozen structure can be formed, and there will be no safety hazards during the excavation process due to insufficient strength of the geological body. Even if the permafrost melts, it will not affect the normal construction of the tunnel. Thus, it solves the technical problem in related technologies that even if the freezing frequency is increased, it is still not possible to completely solve the problem of permafrost melting easily and the inability to form a stable frozen structure when using the freezing method in tropical regions.

[0073] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A tunnel construction method, characterized in that, Includes the following steps: In the target construction area, a launching well and a receiving well are constructed respectively; wherein, a launching portal is provided on the side wall of the launching well, and a receiving portal is formed on the side wall of the receiving well opposite to the launching well; Along the direction from the starting tunnel portal to the receiving tunnel portal, the pilot component is jacked up at the starting tunnel portal; wherein, the pilot component is an independent steel pipe; Using the pilot member as a guide, interlocking pipe ring construction is carried out from the starting tunnel portal; wherein, the area enclosed by the interlocking pipe ring is the area to be excavated, and a pouring area is formed inside the cavity of the interlocking pipe ring; the step of using the pilot member as a guide to carry out interlocking pipe ring construction from the starting tunnel portal includes: using the pilot member as a guide, sequentially pushing in multiple steel pipes arranged circumferentially at intervals along the starting tunnel portal to enclose and form an interlocking pipe ring, thereby completing the construction of the interlocking pipe ring; Freezing and water-stopping construction is carried out on the outer periphery of the interlocking pipe ring; The process involves pouring concrete into the area to be poured to form a pipe curtain structure. This step includes: along the length of the pipe ring, setting at least two spaced target cutting areas on each of the steel pipes of the interlocking pipe ring; cutting all the target cutting areas in the pipe ring according to the target cutting area along the length of the pipe ring to form a pouring area connecting all the steel pipes within the interlocking pipe ring; wherein the target cutting area is smaller than the area of ​​the target cutting area; and pouring concrete into the pouring area to form the pipe curtain structure. The area to be excavated is excavated to form the tunnel.

2. The tunnel construction method as described in claim 1, characterized in that, The steps of constructing a launching well and a receiving well in the target construction area include: Two retaining structures are constructed in the target construction area; The two retaining structures are excavated and constructed to a preset elevation to form a first construction well and a second construction well, respectively; wherein, the first construction well has a starting portal formed on one side wall, and the second construction well has a receiving portal formed on one side wall opposite to the first construction well; The geological bodies on the rear side of the sidewall of the launching portal and the rear side of the receiving portal are reinforced respectively to construct the launching shaft and the receiving shaft accordingly.

3. The tunnel construction method as described in claim 2, characterized in that, The step of reinforcing the geological formations behind the sidewalls of the launching portal and the receiving portal, respectively, to construct the launching shaft and the receiving shaft, includes: Two rows of plain concrete bored piles were used to reinforce the geological body behind the side wall of the starting tunnel portal in order to construct the starting well. The geological body behind the side wall of the receiving tunnel portal is reinforced by a combination of triaxial mixing piles and jet grouting piles, so as to construct the launching well and the receiving well accordingly.

4. The tunnel construction method as described in claim 3, characterized in that, The bottom of all the plain concrete bored piles extends into the moderately weathered rock layer to a predetermined depth.

5. The tunnel construction method as described in claim 3, characterized in that, The step of reinforcing the geological body behind the sidewall of the receiving tunnel portal using a combination of triaxial mixing piles and jet grouting piles, in order to construct the launching shaft and the receiving shaft, includes: Jet grouting piles were used to reinforce the geological body on the rear side wall of the receiving tunnel entrance, forming the first reinforcement zone; The geological body behind the side wall of the receiving tunnel is reinforced by using triaxial mixing piles to form a second reinforcement zone that is spaced apart from the first reinforcement zone; wherein the second reinforcement zone is located on the side of the first reinforcement zone away from the receiving tunnel.

6. The tunnel construction method as described in claim 5, characterized in that, The bottom ends of all the jet grouting piles and all the triaxial mixing piles extend downwards to form the outer contour line of the pipe curtain structure with a predetermined bottom thickness.

7. The tunnel construction method as described in claim 2, characterized in that, The step of reinforcing the geological bodies behind the sidewalls of the launching portal and the receiving portal, respectively, to construct the launching shaft and the receiving shaft, further includes: The area of ​​geological bodies within at least 3m beyond the outline of the receiving tunnel and the outline of the launching tunnel is designated as a reinforced zone. The strong reinforcement zone on the rear side wall of the launching portal and the strong reinforcement zone on the rear side wall of the receiving well are reinforced respectively to construct the launching well and the receiving well accordingly.

8. A construction equipment, characterized in that, The step of excavating the area to be excavated to form the tunnel, for performing the construction method as described in any one of claims 1 to 7, includes: Excavation work is carried out on the area to be excavated to form a support area; Secondary lining construction is carried out in the area to be supported to form a secondary lining layer; The tunnel is formed by constructing ancillary structures on the inner bottom wall of the secondary lining layer; wherein the ancillary structures include internal structures, road surfaces, and finishing structures.

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