A method for constructing a tunnel with full ring pre-built and then excavated

Abstract

The embodiment of the present application discloses a method for constructing a dark-cut tunnel with a whole ring of pre-built structures and then excavated, which can solve the problems of high risk in dark-cut tunnel construction, construction difficulties, small application range of pipe curtain structures, and a large number of circumferential joints in the tunnel. The method includes: before tunnel excavation, first excavate the soil in the lining range around the tunnel in a whole ring, and push in the whole ring of pre-built lining; then excavate the soil in the tunnel under the protection of the whole ring of pre-built lining. Among them, the excavation of the soil in the lining range of the tunnel adopts circular cutterheads arranged in sequence along the contour of the tunnel, and the adjacent cutterheads are staggered front and back, and the excavation contours overlap to form a space along the contour of the tunnel; the whole ring of pre-built lining structure of the tunnel follows the cutterhead excavation equipment, pushes into the contour space around the tunnel, and forms a whole ring of pre-support structure. The construction method of the present application is used for dark-cut construction with large spans and complex conditions.

Description

Technical Field

[0001] The invention relates to the field of tunnel construction, and in particular to a method for constructing a whole-ring pre-built and then excavated dark-trail tunnel. Background Art

[0002] With the continuous development of my country's urbanization process, the construction of underpasses such as railways, roads, subway stations, etc. is often restricted by factors such as ground transportation, pipeline distribution, surrounding building environment, engineering geology and hydrogeology. The construction method of pre-building and then excavating the tunnel is often adopted. This can better solve the tunnel construction problems such as large spans and small construction settlements. However, there are also various problems in actual construction.

[0003] In the prior art, in order to solve the problems of many blocks, complicated procedures, large deformation of support structure and large ground settlement during the construction of dark excavation method, pipe curtain structure method and Japan's MMST (Multiple Micro Shield Tunneling Method) and other methods have been proposed. Among them, the pipe curtain structure method is that before the tunnel is excavated, usually a large-diameter steel pipe is pushed into the tunnel periphery by a pipe jacking machine and other devices, and then workers enter the steel pipe to cut the steel pipe, and then cast the annular reinforced concrete structure. However, there are the following problems in construction: First, construction workers need to enter a smaller steel pipe space to construct the pre-support structure, which makes the construction difficult, the work intensity is high, and the lining quality is difficult to guarantee; second, because many single steel pipes need to be cut and connected into an integral support structure, the number of joints between the annular lining structure is large, resulting in a problem of low overall stiffness of the pre-support structure.

[0004] In addition, Japan's MMST method is aimed at rectangular tunnels in soft soil. It adopts horizontal and vertical multi-disc rectangular shield machines for excavation. The lining is a rectangular steel box structure, and the height of the steel box structure must meet the requirements of manual construction. Before tunnel excavation, the reinforced concrete structure is cast in a circular direction, and then the tunnel is excavated. However, there are the following problems in its construction method and lining structure: First, under conditions of large span and large soil cover, the rectangular support structure will have a large mid-span bending moment and the support structure is unstable; second, since it is necessary to connect the various steel box lining structures into an overall pre-support structure through segmented construction, there are construction errors between the steel box linings, resulting in low stiffness of the overall pre-support structure. Summary of the invention

[0005] In view of this, an embodiment of the present application provides a method for constructing a full-ring pre-built and then excavated dark-cut tunnel, which can solve the problems of high risk and difficulty in tunnel construction, small application range of the pipe curtain structure, and a large number of tunnel annular joints.

[0006] In order to achieve the above-mentioned purpose, the embodiment of the present application provides a method for constructing a tunnel with a whole ring pre-built and then excavated. The method includes: excavating the soil in the lining range around the tunnel in a whole ring before excavating the tunnel, and pushing in the whole ring of pre-built lining; excavating the soil in the tunnel under the protection of the whole ring of pre-built lining. Specifically, before excavating the tunnel, first excavate the soil in the lining range around the tunnel in a whole ring to form a whole ring of pre-support space. In addition, while excavating the lining range of the tunnel in a whole ring, push in the whole ring of pre-built lining structure to support the whole ring of pre-support space; after the pre-support structure of the whole ring of the tunnel reaches the strength, excavate the soil in the tunnel. In this way, a whole ring of excavation space can be formed by excavating once, and a whole ring of pre-built lining can be pushed in once, eliminating the number of pre-support joints in the tunnel section, avoiding the problems of difficulty in connecting the structural joints during segmented construction, and the accumulation of construction errors between segments leading to difficulties in construction at the final sealing point.

[0007] In a possible implementation of the present application, the soil body in the lining range of the whole-ring excavated tunnel includes: the soil body in the lining range around the whole-ring excavated tunnel is excavated by multiple interlocking pipe jacking machines, and the multiple pipe jacking machines are arranged in a whole-ring shape along the tunnel contour. Among them, compared with a single pipe jacking machine, the design of multiple interlocking pipe jacking machines arranged in a whole-ring shape along the tunnel contour allows it to form a whole-ring excavation contour at one time when excavating along the excavation direction, greatly improving the excavation efficiency.

[0008] In a possible implementation of the present application, multiple pipe jacking machines use circular rotating cutter discs. Here, the circular rotating cutter disc is less likely to have blind spots that the cutter disc cannot reach compared to cutter discs of other shapes such as rectangles.

[0009] In a possible implementation of the present application, the cutter discs between adjacent pipe jacking machines are staggered and arranged front and back, and the excavation contours of the cutter discs overlap. With such a design, it is possible to achieve an intersection of the excavation contours of two adjacent cutter discs, that is, there will be overlapping space between adjacent excavation holes. When multiple mutually engaged pipe jacking machines excavate and advance, a connected pre-support space is formed between multiple excavation holes.

[0010] In a possible implementation of the present application, a full ring of prefabricated lining is arranged within the excavation range of multiple pipe jacking machines. Here, the full ring of prefabricated lining is arranged in the excavation space of the full ring shape to support the excavation space of the full ring shape.

[0011] In a possible implementation of the present application, after the soil in the lining range of the entire ring excavation tunnel is pushed into the entire ring of pre-built lining, the method further includes: filling the gap between the entire ring of pre-built lining and the excavation profile of the cutterhead with a building filler. The presence of the building filler can prevent the deformation of the surrounding rock from exerting a large direct force on the entire ring of pre-built lining.

[0012] In a possible implementation of the present application, the building filler is a mixture of one or more of mud and mortar.

[0013] In a possible implementation of the present application, the whole ring prefabricated lining includes a box-type shell, and the building filler is filled in the gap between the box-type shell and the excavation profile of the cutter head. In this way, the presence of the building filler can better transfer the extrusion stress from the surrounding rock to the box-type shell, so that the box-type shell is subjected to approximately uniform force, thereby avoiding the deformation of the surrounding rock from generating a large direct force on the box-type shell.

[0014] In a possible implementation of the present application, the cutter heads of multiple pipe jacking machines have the same excavation diameter. This can reduce the types of machines and reduce costs, and can make the excavation profile regular, thereby reducing the difficulty of pre-support construction.

[0015] In a possible implementation of the present application, the cutter discs of the multiple pipe jacking machines have different excavation diameters. This structure makes the excavation profile more flexible and has a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 One of the flow charts of a method for constructing a complete ring pre-built and then excavated dark tunnel provided in an embodiment of the present application;

[0017] Figure 2 A second flow chart of a method for constructing a complete ring pre-built tunnel and then excavating it in a dark tunnel provided in an embodiment of the present application;

[0018] Figure 3 A schematic diagram of the structure of a plurality of mutually engaged pipe jacking machines in a complete ring provided in an embodiment of the present application;

[0019] Figure 4 A schematic diagram of the structure of a full-ring prefabricated lining provided in an embodiment of the present application;

[0020] Figure 5 A schematic diagram of a tunnel cross-section structure of a method for pre-building a whole ring of tunnels with the same cutter head diameter provided in an embodiment of the present application;

[0021] Figure 6 A schematic diagram of a tunnel cross-section structure of a method for constructing a tunnel with a full ring of pre-built and then excavated dark tunnels with different cutter head diameters provided in an embodiment of the present application;

[0022] Figure 7 The embodiment of the present application provides Figure 5 and Figure 6 Schematic diagram of the cross section along the AA line;

[0023] Figure 8A large-scale drawing of a tunnel annular excavation of a full-ring interlocking pipe jacking machine under multiple equal-diameter cutterheads provided in an embodiment of the present application;

[0024] Fig. 9 A large-scale drawing of a tunnel circular excavation of a full-ring interlocking pipe jacking machine under multiple unequal diameter cutter heads provided in an embodiment of the present application.

[0025] Reference numerals:

[0026] 1-full ring interlocking pipe jacking machine; 11-first cutter disc; 12-second cutter disc; 2-excavation profile; 3-full ring prefabricated lining; 31-box-type shell; 311-annular rib plate; 4-building filler. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the specific technical solution of the present application will be further described in detail below in conjunction with the drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application, but are not used to limit the scope of the present application.

[0028] In the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more.

[0029] In addition, in the embodiments of the present application, directional terms such as "up", "down", "left" and "right" are defined relative to the orientation of the components in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they may change accordingly according to the changes in the orientation of the components in the drawings.

[0030] In the embodiments of the present application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0031] In the embodiments of the present application, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0032] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0033] The embodiment of the present application provides a method for constructing a tunnel with a whole ring pre-built and then excavated. The pre-support structure of the tunnel is first constructed in a whole ring, and the soil in the tunnel is excavated under the protection of the tunnel pre-support structure. Specifically, before excavating the tunnel, the soil in the lining range around the tunnel is first excavated in a whole ring, and at the same time, the whole ring of pre-built lining is pushed in and placed in the excavation space of the whole ring of tunnel lining; after the tunnel pre-support structure reaches the strength, the soil in the tunnel is excavated. The use of this method for constructing a tunnel with a whole ring pre-built and then excavated can eliminate the number of joints in the tunnel ring, improve the overall stiffness of the pre-support structure, have high construction efficiency, and can be applied to various geological conditions. Therefore, it can be widely used in the construction of tunnels and underground projects with large spans, shallow cover, and underpasses of existing buildings that are difficult to construct.

[0034] In order to realize the above technical features, the present application embodiment provides a method for constructing a full-ring pre-built tunnel and then digging it, referring to Figure 1 , mainly including the following steps:

[0035] Step S1, excavating the soil in the lining range around the tunnel in a whole ring before tunnel excavation, and jacking in the whole ring of pre-built lining;

[0036] Step S2, excavating the soil in the tunnel under the protection of the entire ring of pre-built lining.

[0037] Among them, in step S1, before tunnel excavation, the whole ring of excavated tunnel lining range soil is first formed into a whole ring of pre-support space; in addition, while the whole ring of excavated tunnel lining range is being excavated, a whole ring of pre-built lining structure is pushed in along the tunnel section to support the excavated holes formed by the whole ring of excavated tunnel lining range soil, i.e., the pre-support lining space. This method reduces the construction difficulty, improves the construction efficiency, and can eliminate the number of joints of the tunnel ring pre-support structure, thereby improving the overall stiffness of the pre-support structure.

[0038] In step S2, after the tunnel pre-support structure reaches the required strength, the soil in the tunnel can be excavated to form a tunnel frame, and the structural waterproof layer, secondary lining and internal structure can be constructed according to the structural design plan to complete the tunnel construction. In particular, a concrete lining structure can also be constructed in the pre-support structure according to the requirements of structural durability, safety and other aspects.

[0039] The above method can form a whole ring of tunnel pre-support space in one excavation, which greatly improves the excavation efficiency; in addition, since the lining structure is a whole ring pre-built lining structure, the number of joints of the annular lining structure of the tunnel section is directly eliminated, which greatly improves the overall stiffness of the pre-support structure.

[0040] In some embodiments, reference Figure 1 , Figure 3 , Figure 4 and Figure 5 , the soil body in the lining range of the whole ring excavation tunnel includes: the soil body in the lining range around the whole ring excavation tunnel is excavated by multiple mutually interlocking pipe jacking machines, and the multiple pipe jacking machines are arranged in a whole ring shape along the tunnel contour shape, that is, a whole ring interlocking pipe jacking machine 1. Among them, the whole ring interlocking pipe jacking machine 1 can be composed of multiple detachably connected circular pipe jacking machines, and a connecting component is arranged on the side wall of the circular pipe jacking machine, and the connecting component can be one of a threaded connection component and a snap connection component. In this way, multiple pipe jacking machines can be connected into a whole ring shape, so that a whole ring of tunnel section can be formed in one excavation; in addition, the form of detachable connection increases the use scope of the whole ring interlocking pipe jacking machine 1, so that it can be adjusted according to the size of the pre-support space of the tunnel to be excavated, and multiple circular pipe jacking machines are connected together to cooperate with each other to obtain the excavation surface of the required size, which solves the problem of inefficient construction due to the mismatch between the excavation surface of a single pipe jacking machine and the size of the pre-support space of the tunnel to be excavated. Here, each of the pipe jacking machines that constitute the full-ring interlocking pipe jacking machine 1 is provided with a circular rotating cutter disc device and a driving device, which is connected to the cutter disc device and is used to drive the cutter disc device to operate. The cutter disc device includes a central large cutter disc, the center of which is set on the central axis of the pipe jacking machine along the excavation direction and its circumference is tangent to the plane where the side wall of the pipe jacking machine is located, or a number of small cutter discs or rollers and other tools are added according to the needs of the project to achieve a good cutting effect to meet various stratum excavation requirements.

[0041] Specifically, before excavating the tunnel pre-support structure space, a starting working pit is set up as a working pit for assembling and excavating the whole-ring interlocking pipe jacking machine 1. In step S1, the whole-ring interlocking pipe jacking machine 1 is used to excavate the whole-ring prebuilt lining 3 space of the tunnel. The excavation thrust of the whole-ring interlocking pipe jacking machine 1 is provided by the starting jack, and is transmitted to the multiple excavation cutter discs of the whole-ring interlocking pipe jacking machine 1 through the whole-ring prebuilt lining 3. At the same time, the whole-ring prebuilt lining 3 closely follows the interlocking pipe jacking machine 1 and is pushed in along the excavation direction to support the excavation space. Among them, when the tunnel excavation length is long and the friction around the whole-ring interlocking pipe jacking machine 1 is too large, a relay relay can be set in the tunnel to ensure that the whole-ring interlocking pipe jacking machine 1 can excavate forward smoothly. Compared with a single pipe jacking machine, this method uses a plurality of interlocking pipe jacking machines arranged in a ring shape along the tunnel contour, so that when excavating along the excavation direction, a full ring excavation contour 2 can be formed in one excavation, which greatly improves the excavation efficiency and reduces the construction risk.

[0042] It should be noted that the whole ring length of the whole ring interlocking pipe jacking machine 1 can be changed to adapt to different construction pre-support structure requirements. For example, when the circumferential length of the whole ring pre-support space of the construction tunnel is long, the circumferential length of the whole ring interlocking pipe jacking machine 1 can be appropriately increased, and the length of the circumferential excavation profile 2 of the whole ring interlocking pipe jacking machine 1 will increase; in addition, the excavation profile 2 of the whole ring interlocking pipe jacking machine 1 can also be adjusted by changing the circumferential arrangement and circumferential length of the whole ring interlocking pipe jacking machine 1 to adapt to different tunnel excavation profile 2 requirements. In this way, its engineering application range can be increased.

[0043] It should be further explained that the circumferential length of the full ring interlocking pipe jacking machine 1 refers to the length of the circumferential structure of the multiple pipe jacking machines arranged along the tunnel contour shape. The circumferential length is comprehensively determined by engineering conditions, the size of the pre-support space, etc.

[0044] Reference Figure 3 , Figure 6 and Figure 7 , many pipe jacking machines use circular rotating cutter discs. Specifically, during the excavation of the whole-ring interlocking pipe jacking machine 1 along the tunnel direction, the circular rotating cutter disc is used to crush rocks, cut soil, etc., thereby forming an excavation hole space. Among them, cutting tools such as rollers can also be configured on the cutter disc to meet the requirements of excavation in various strata. In addition, during the excavation of the whole-ring interlocking pipe jacking machine 1 along the tunnel direction, the circular rotating cutter disc is less likely to have blind spots that the cutter disc cannot reach, compared with cutter discs of other shapes such as rectangles.

[0045] In some embodiments, reference Figure 3 , Figure 5 , Figure 7 and Figure 8 The cutterheads between adjacent pipe jacking machines are staggered and arranged front and back, and the cutterhead excavation profiles 2 overlap. Therefore, when the full-ring interlocking pipe jacking machine 1 advances forward, the cutterhead excavation profiles 2 will intersect, thereby forming a connected space between the excavated holes, that is, forming a connected pre-support lining space.

[0046] It should be noted that the height H of the intersection of the cutter head excavation profile 2 is determined by the height H of the full ring prefabricated lining 3 structure followed by the full ring bite pipe jacking machine 1, and can be greater than or equal to the height H of the segmented prefabricated lining 3. In this way, the full ring prefabricated lining 2 can be placed in the excavated hole.

[0047] Further, refer to Figure 4 , Figure 5 and Figure 6, the whole ring of prefabricated lining 3 is arranged within the excavation range of the whole ring bite pipe jacking machine 1. Specifically, the prefabricated lining structure of the whole ring of the tunnel is assembled into a whole ring of prefabricated lining 3 in the working pit and closely follows the cutter head excavation equipment, and is pushed into the space of the excavation contour 2 around the tunnel to form a whole ring of tunnel lining structure. Here, the whole ring of prefabricated lining 3 is arranged in the excavation space to support the excavation space.

[0048] It should be noted that the circumferential length of the full-ring precast lining 3 should be less than or equal to the circumferential length of the full-ring interlocking pipe jacking machine 1 so that the full-ring precast lining 3 can be placed in the excavation space.

[0049] In some examples, reference Figure 2 and Figure 4 After step S1, the method includes: filling the gap between the whole ring precast lining 3 and the excavation profile 2 of the cutter head with a building filler 4. The existence of the building filler 4 can prevent the surrounding rock deformation from generating a large direct force on the whole ring precast lining 3.

[0050] Further, refer to Figure 2 and Figure 4 The building filler 4 is a mixture of one or more of mud and mortar.

[0051] In some embodiments, reference Figure 4 , Figure 5 and Figure 7 The whole ring prefabricated lining 3 includes a box-type shell 31, and the building filler 4 is filled in the gap between the box-type shell 31 and the excavation profile 2 of the cutter head. Among them, the inner wall of the box-type shell 31 is provided with an annular rib 311 extending toward the axis, and the setting of the annular rib 311 can improve the rigidity of the whole ring prefabricated lining 3 structure; the existence of the building filler 4 can better transfer the extrusion stress from the surrounding rock to the box-type shell 31, so that the box-type shell 31 is subjected to approximately uniform force, and the deformation of the surrounding rock is prevented from exerting a large direct force on the box-type shell 31.

[0052] In some embodiments, reference Figure 5 and Figure 8 , the cutter heads of multiple pipe jacking machines have the same excavation diameter. In this way, on the one hand, the types of machines can be reduced and their production costs can be reduced; on the other hand, the entire excavation profile 2 can be made into a regular shape, thereby reducing the difficulty of construction pre-support.

[0053] In some embodiments, reference Figure 3 , Figure 6 and Fig. 9 , the cutter heads of multiple pipe jacking machines have different excavation diameters. Figure 3 , Figure 6 and Fig. 9The cutter disc of the full-ring interlocking pipe jacking machine 1 includes a first cutter disc 11 and a second cutter disc 12, and the diameter of the second cutter disc 12 is larger than the diameter of the first cutter disc 11. In addition, along the direction in which the full-ring interlocking pipe jacking machine 1 is arranged side by side, a second cutter disc 12 is arranged after every N first cutter discs 11, where N is a positive integer. In this way, the excavation hole space corresponding to the second cutter disc 12 with a large diameter should be able to accommodate construction personnel to conveniently carry out construction operations in the pre-support space, such as constructing a concrete lining structure in the pre-support structure. This structure makes the excavation profile 2 more flexible, the construction is easy, and the application range is wider.

[0054] The serial numbers of the embodiments of the present application are only for description and do not represent the advantages and disadvantages of the embodiments. The above are only preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for constructing a tunnel with full ring pre-built and then excavated, characterized in that: The method comprises: Step 1: excavate the soil in the lining range around the tunnel in a whole ring before tunnel excavation, and push in the whole ring of pre-built lining; Step 2, excavating the soil in the tunnel under the protection of the full ring pre-built lining; The excavation of the whole ring uses a plurality of mutually interlocking pipe jacking machines to excavate the soil in the lining range around the tunnel, and the plurality of pipe jacking machines are arranged in a whole ring shape along the contour of the tunnel; The excavation thrust is transmitted to the multiple excavation cutter discs of the pipe jacking machine through the whole ring of prebuilt lining. At the same time, the whole ring of prebuilt lining is pushed in along the excavation direction with the pipe jacking machine to support the excavation space.

2. The method for constructing a tunnel with full ring pre-built and then excavated according to claim 1 is characterized in that: A plurality of the pipe jacking machines adopt a circular rotating cutter disc.

3. The method for constructing a tunnel with full ring pre-built and then excavated according to claim 2 is characterized in that: The cutter discs between adjacent pipe jacking machines are staggered in front and back arrangement, and the excavation contours of the cutter discs overlap.

4. The method for constructing a tunnel with full ring pre-built and then excavated according to claim 1 is characterized in that: The full-ring prefabricated lining is arranged within the excavation range of a plurality of the full-ring-shaped pipe jacking machines.

5. The method for constructing a tunnel with full ring pre-built and then excavated according to claim 4 is characterized in that: After step 1 and before step 2, the method includes: The gap between the full ring of precast lining and the excavation profile of the cutterhead is filled with construction fill.

6. The method for constructing a tunnel with full ring pre-built and then excavated according to claim 5 is characterized in that: The building filler is a mixture of one or more of mud and mortar.

7. The method for constructing a tunnel with full ring pre-built and then excavated according to claim 5 is characterized in that: The full-ring precast lining comprises a box-type outer shell, and the building filler is filled in a gap between the box-type outer shell and the excavation contour of the cutterhead.

8. The method for constructing a tunnel with full ring pre-built and then excavated according to claim 2 is characterized in that: The excavation diameters of the cutter discs of the plurality of pipe jacking machines are the same.

9. The method for constructing a tunnel with full ring pre-built and then excavated according to claim 2 is characterized in that: The excavation diameters of the cutter discs of the plurality of pipe jacking machines are different.

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