Construction method of tunnel pipe curtain structure

Abstract

The invention discloses a construction method of a tunnel pipe roofing structure, and relates to the technical field of tunnel pipe roofing construction.The construction method comprises the steps that a pipe body group is jacked into a tunnel wall, and high-strength steel bars are used for restraining the pipe body group to enable the pipe body group to be tightly attached; the pipe body groups which are tightly attached under the tension of the steel bars can provide bearing capacity and play a role of a waterproof curtain at the same time. Meanwhile, in order to guarantee good fitting of the pipe body groups, on the tunnel section, the steel bars pass through the steel pipe walls and the circle center of the section to connect the pipe body groups into a whole. In the axial direction of the tunnel, a plurality of annular steel bar structures are arranged at intervals, and it is guaranteed that the pipe body group does not deflect while being drawn close. The method has the outstanding advantages of being high in construction practicability, convenient to control construction quality, good in reinforcing effect, particularly good in water stopping effect, safe, reliable and the like.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel pipe-roof construction, in particular to a tunnel pipe-roof structure and a construction method. Background Art

[0002] After decades of development, the construction methods of urban tunnel engineering have evolved from the initial single open-cut method to the current shield method, the New Austrian Tunneling Method, the shallow buried dark excavation method, as well as the top pipe method, the pipe shed method, the box culvert method and other methods. The construction technology has been continuously developed and improved, and a special discipline system has been initially formed, which has greatly promoted the rapid development of urban underground engineering construction. However, these methods have their own advantages and disadvantages and their own suitable construction conditions. The open-cut construction method seriously interferes with traffic and damages the environment in busy sections of the city. The dark excavation shield method solves these problems, but its flexibility is poor, especially the expensive shield machinery, which greatly increases the project cost. In addition, the cross-section utilization rate is also low. Due to the limitations of the shield machinery, there are great limitations for the construction of large-span underground projects. The jacking method is generally used for the construction of small tunnels such as municipal pipelines with smaller diameters; the New Austrian Tunneling Method is very suitable for rock tunnels, and soil tunnels need to be reinforced, but it is more difficult for shallow buried soft soil tunnels. The pipe-roof method has been widely used in the construction of underground projects in rock and soft soil with low water levels. It is difficult to carry out large-span underground projects in saturated soft soil due to the influence of groundwater, and it also causes great environmental pollution and has a great impact on the surface and surrounding environment. The excavation surface must be kept stable during the construction of the box culvert method, and the project cost is also high due to the influence of the high groundwater level.

[0003] The design and construction of underwater tunnels in coastal cities are very different from mountain tunnels and urban tunnels, with the following main technical characteristics: the difficulty and investment of deep-water geological surveys are high, and the risk of missed surveys and distorted survey results is high; the possibility of sudden water and mud caused by the construction and excavation of high-permeability rock and soil bodies is high, and most of them have direct hydraulic connection with seawater, so it is very difficult to achieve high-precision construction water exploration and water control. In order to meet the requirements of construction safety and surface settlement deformation control for the construction of tunnels under rivers, oceans or other structures in coastal cities, the pipe curtain method is used to push steel pipe sections into the soil through pipe jacking equipment to form a pipe row, forming a curved steel shell concrete lining superimposed structure, which has the functions of both initial support structure and permanent bearing structure, can effectively control stratum deformation under shallow overburden conditions, give full play to the mechanical properties of tunnel construction materials, and there is no noise, vibration, or mud pollution during construction, which has little impact on the surrounding geological environment and social environment, and can operate continuously around the clock. However, since the rock and soil around the underwater tunnel construction area is in a saturated state, the overlying water body can provide unlimited groundwater supply to the construction area, which brings great risks to the public using the pipe curtain method.

[0004] At present, in order to block groundwater and prevent soil erosion between pipes, the latest measure is to combine the pipe curtain method with the artificial freezing method to form a new "pipe curtain freezing method". This method can effectively isolate groundwater during construction and has good safety and reliability. The pipe curtain freezing method construction process is currently the most advanced construction method for constructing underwater large-span and large-section underground projects, especially in urban areas with dense buildings and busy traffic sections, and has extremely obvious advantages for ultra-shallow buried and ultra-large-section tunnel projects.

[0005] However, in the tunnel construction by pipe curtain freezing method, the pipe curtain and the frozen wall play the role of bearing and stopping water together, but the freezing method construction has the following disadvantages:

[0006] (1) The construction process is complex, the steps are cumbersome, and freezing and thawing take a long time.

[0007] (2) Due to the freeze-thaw cycle, the ground can easily rise and fall, which has a great impact on surrounding structures.

[0008] (3) The working process has a great impact on the ambient temperature and uses chemicals, which can easily cause ecological problems. Summary of the invention

[0009] The present invention provides a tunnel pipe curtain structure and a construction method, aiming to solve the above-mentioned problems.

[0010] To achieve the above object, the present invention provides a tunnel pipe roof structure and a construction method, comprising the following steps:

[0011] Step 1: Construct the launching and receiving working wells;

[0012] Step 2: Arrange a pipe body deviation monitoring system for real-time monitoring of the pipe body position;

[0013] Step 3: Use a pipe jacking machine to jack the pilot pipe, along the contour line of the structure cross section parallel to the axial direction, and jack the pipe body in sections at the position of the pilot pipe;

[0014] Step 4: Use a pipe jacking machine to push the independent pipe body, drill holes and insert tensioning pieces every 2m in the direction of the central axis of the independent pipe body, and install a hydraulic steel cable shrinking machine;

[0015] Step 5: Use a pipe jacking machine to push the engaged pipe body; the pipe jacking machine pushes the engaged pipe body along the trajectory of the pilot pipe, and at the same time pushes the pilot pipe out and receives it in the receiving well;

[0016] Step 6: Use a tensioning piece to tighten the independent pipe body and the engaged pipe body through a hydraulic cable shrinking machine;

[0017] Step 7: Repeat the process of pushing in independent pipes or interlocking pipes in sequence, and use a tensioning member to tighten each pipe with the previously pushed-in pipe until all pipes are pushed in and tightened to form a pipe group with an annular structure;

[0018] Step 8: Use a tensioning piece to tighten all the pipes along the pipe group;

[0019] Step 9: Cutting and supporting between pipe bodies. Between adjacent interlocking pipe body groups, or between interlocking pipe body groups and independent pipe bodies, the pipe bodies are cut at set positions and connected with steel plates. Steel pipe supports are set at the steel plates to facilitate the bearing of the steel plates. Cutting of steel pipes should be carried out in sections. Before cutting, temporary steel columns are set on both sides of the steel pipes corresponding to the predetermined cutting positions, which serve as temporary supports when cutting the steel pipes. Then, the steel plates are cut at a certain interval, the soil between the pipes is excavated, and the adjacent two steel pipes are connected with steel plates at the opening positions. After the welding of the connecting steel plates and the steel pipes is completed, steel pipe supports are set between the connecting steel plates as permanent support structures. After the steel pipe supports are erected, the temporary steel columns are removed.

[0020] Step 10: Pour pipe curtain concrete. After the cutting and support of the entire pipe curtain structure steel pipe are completed, weld the internal pins, and pour the concrete inside the pipe curtain structure in layers and sections. It is divided into three layers vertically: upper, middle and lower.

[0021] Preferably, the deviation of the pipe jacking process is ±30 cm.

[0022] Preferably, in a soft soil area, the pipe body below the tunnel is jacked in first, and then the pipe body above the tunnel is jacked in.

[0023] Preferably, when pouring the pipe curtain concrete, the length of each pouring section along the longitudinal direction of the pipe body is 5-6m.

[0024] Preferably, the tensioning member is a steel bar. The pipe body group adopts Q355B steel pipe body material. The diameter of the pipe body is 2-2.5m.

[0025] Compared with the prior art, it has the following beneficial effects:

[0026] (1) In coastal areas, in tunnel projects below the groundwater level, this structure does not require the construction of a refrigeration station, and the construction cost is much lower than the pipe curtain freezing method.

[0027] (2) The present invention uses steel bar tightening instead of artificial freezing, which can greatly shorten the construction period.

[0028] (3) The present invention can effectively avoid the effects of frost heave and thaw settlement caused by artificial freezing technology.

[0029] (4) No chemicals are used during the work process, which is more in line with green and low-carbon requirements and has little impact on the ecology. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only preferred embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A flow chart of a construction method of a tunnel pipe roof structure for this application;

[0032] Figure 2 This is the axial layout of the tunnel for this application;

[0033] Figure 3 This is a vertical cross-sectional view of the tunnel of this application.

[0034] Figure numerals: 1-tube body; 2-tensioning member. DETAILED DESCRIPTION

[0035] In order to make it easier to understand the structure of the present invention and the functional features and advantages that can be achieved, the preferred embodiments of the present invention are described in detail with reference to the drawings as follows:

[0036] Example:

[0037] like Figures 1 to 3 As shown, the present invention provides a construction method of a tunnel pipe-roof structure, comprising the following steps:

[0038] Step 1: Build the starting and receiving working shafts and complete the main structure of the working shafts;

[0039] Step 2: Arrange a pipe body 1 displacement monitoring system for real-time monitoring of the position of the pipe body 1, so that the displacement of the pipe body 1 can be monitored in real time during the tightening process of the pipe body 1 to prevent the pipe body 1 from rotating in the axial direction, resulting in incomplete tightening of the pipe body 1;

[0040] Step 3: Use a pipe jacking machine to jack the pilot pipe, along the contour line of the structure cross section parallel to the axial direction, and jack the pipe body 1 in sections at the position of the pilot pipe;

[0041] Step 4: Use a pipe jacking machine to push in an independent pipe body (first pipe body), drill holes and insert tensioning members 2 every 2m in the direction of the central axis of the independent pipe body, and install a hydraulic steel cable shrinking machine;

[0042] Step 5: Use a pipe jacking machine to push in the engaged pipe body (second pipe body); the pipe jacking machine pushes the engaged pipe body along the trajectory of the pilot pipe and pushes out the pilot pipe at the same time to receive it in the receiving well;

[0043] Step 6: Use the tensioning member 2 to tighten the independent pipe body and the engaged pipe body through a hydraulic cable shrinking machine;

[0044] Step 7: Repeat the process of pushing in independent pipes or interlocking pipes in sequence. Each time a pipe 1 is pushed in, the tensioning member 2 is used to tighten it with the previously pushed in pipe 1 until all pipes 1 are pushed in and tightened to form a pipe group of annular structure, so that it has a water-stopping function.

[0045] Step 8: Use the tensioning member 2 to tighten all the tube bodies 1 along the tube body group;

[0046] Step 9: Cut and support between pipe bodies 1. Between adjacent interlocking pipe bodies 1 groups, or between interlocking pipe bodies 1 groups and independent pipe bodies 1, pipe bodies 1 are cut at set positions and connected with steel plates. Steel pipe supports are set at the steel plates to facilitate the bearing of the steel plates. Cutting of steel pipes should be carried out in sections. Before cutting, temporary steel columns are set on both sides of the steel pipes corresponding to the predetermined cutting positions, which serve as temporary supports when cutting steel pipes. Then, the steel plates are cut at a certain interval, the soil between the pipes is excavated, and the adjacent two steel pipes are connected with steel plates at the opening positions. After the welding of the connecting steel plates and the steel pipes is completed, steel pipe supports are set between the connecting steel plates as permanent support structures. After the steel pipe supports are erected, the temporary steel columns are removed.

[0047] Step 10: Pour pipe curtain concrete. After the cutting and support of the entire pipe curtain structure steel pipe are completed, weld the internal pins, and pour the concrete inside the pipe curtain structure in layers and sections. It is divided into three layers vertically: upper, middle and lower.

[0048] This application is mainly used in the construction of saturated shallow soil tunnels in coastal areas. The construction is simple, time-saving, has little disturbance to the soil, and is environmentally friendly.

[0049] The present application constrains the pipe body group to fit tightly by pushing the pipe body group into the tunnel wall and using high-strength steel bars. The pipe body group that fits tightly under the tension of the steel bars can provide bearing capacity while serving as a water-stop curtain. The pipe body group is composed of multiple triple pipe bodies 1 and a single pipe body 1, and the steel bars (tightening pieces) are HRB500 hot-rolled ribbed grade IV steel bars. In order to ensure that the pipe body group fits well, the steel bars connect the pipe body group as a whole through the steel pipe wall and the center of the cross section on the tunnel cross section. In the axial direction of the tunnel, an annular steel bar structure is set every 2m to ensure that the pipe body group does not deflect while being pulled closer. The present invention has the outstanding advantages of strong construction practicality, convenient construction quality control, good reinforcement effect, especially good water-stopping effect, and safety and reliability. Furthermore, the design of the jacking position of the pipe body 1 takes into account the displacement of the pipe curtain after tensioning, which causes the tunnel cross section to become smaller, and the deviation of the jacking process of the pipe body 1 is ±30cm.

[0050] Furthermore, in the soft soil area, the pipe body 1 below the tunnel is pushed in first, and then the pipe body 1 above the tunnel is pushed in.

[0051] Furthermore, when pouring the pipe curtain concrete, the length of each pouring section along the longitudinal direction of the pipe body 1 is 5-6m.

[0052] Furthermore, the tensioning member 2 is a steel bar. The pipe body group adopts a steel pipe made of Q355B steel pipe body 1 material. The diameter of the pipe body 1 is 2-2.5m. The steel bar constrained pipe curtain structure of the present application is mainly composed of two parts: the first part is an annular combined pipe body group, a single steel pipe has an inner diameter of 2000mm, a wall thickness of 200mm, and is made of Q355B steel. The second part is the steel bar, that is, the tensioning member 2 adopts HRB500 hot-rolled ribbed IV grade steel bar. The tightening of the steel bar can press the pipe body group against each other, play a water-stopping role, and at the same time increase the integrity and bearing capacity of the pipe body group. The pipe body group is welded into one after being tightened by the steel bar, further increasing its bearing capacity.

[0053] Furthermore, each time a new pipe body 1 is pushed in, it is immediately tightened with steel bars to make it close to the other pipe bodies 1 that have been pushed in, so as to avoid excessive resistance and deformation during the final tightening.

[0054] The above are only preferred embodiments of the present invention, and do not limit the present invention in any form. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the above technical content without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any changes, modifications, equivalent changes and modifications made to the above embodiments based on the technology of the present invention without departing from the content of the technical solution of the present invention belong to the protection scope of the present technical solution.

Claims

1. A construction method for a tunnel pipe-roof structure, characterized in that: The following steps are involved: Step 1: Construct the launching and receiving working wells; Step 2: Arrange a pipe body deviation monitoring system for real-time monitoring of the pipe body position; Step 3: Use a pipe jacking machine to jack the pilot pipe, along the contour line of the structure cross section parallel to the axial direction, and jack the pipe body in sections at the position of the pilot pipe; Step 4: Use a pipe jacking machine to push the independent pipe body, drill holes and insert tensioning pieces every 2m in the direction of the central axis of the independent pipe body, and install a hydraulic steel cable shrinking machine; Step 5: Use a pipe jacking machine to push the engaged pipe body; the pipe jacking machine pushes the engaged pipe body along the trajectory of the pilot pipe, and at the same time pushes the pilot pipe out and receives it in the receiving well; Step 6: Use a tensioning piece to tighten the independent pipe body and the engaged pipe body through a hydraulic cable shrinking machine; Step 7: Repeat the process of pushing in independent pipes or interlocking pipes in sequence, and use a tensioning member to tighten each pipe with the previously pushed-in pipe until all pipes are pushed in and tightened to form a pipe group with an annular structure; Step 8: Use a tensioning piece to tighten all the pipes along the pipe group; Step 9: Cutting and supporting between pipe bodies. Between adjacent interlocking pipe body groups, or between interlocking pipe body groups and independent pipe bodies, the pipe bodies are cut at set positions and connected with steel plates. Steel pipe supports are set at the steel plates to facilitate the bearing of the steel plates. Cutting of steel pipes should be carried out in sections. Before cutting, temporary steel columns are set on both sides of the steel pipes corresponding to the predetermined cutting positions, which serve as temporary supports when cutting the steel pipes. Then, the steel plates are cut at a certain interval, the soil between the pipes is excavated, and the adjacent two steel pipes are connected with steel plates at the opening positions. After the welding of the connecting steel plates and the steel pipes is completed, steel pipe supports are set between the connecting steel plates as permanent support structures. After the steel pipe supports are erected, the temporary steel columns are removed. Step 10: Pour pipe curtain concrete. After the cutting and support of the entire pipe curtain structure steel pipe are completed, weld the internal pins, and pour the concrete inside the pipe curtain structure in layers and sections. It is divided into three layers vertically: upper, middle and lower.

2. The construction method of the tunnel pipe-roof structure according to claim 1, characterized in that: The deviation of the pipe body jacking process is ±30cm.

3. The construction method of the tunnel pipe-roof structure according to claim 2, characterized in that: In soft soil areas, the pipe below the tunnel is pushed in first, followed by the pipe above the tunnel.

4. The construction method of the tunnel pipe-roof structure according to claim 1, characterized in that: When pouring the pipe curtain concrete, the length of each pouring section along the longitudinal direction of the pipe body is 5-6m.

5. The construction method of the tunnel pipe-roof structure according to claim 1, characterized in that: The tensioning member is a steel bar.

6. The construction method of the tunnel pipe-roof structure according to claim 1, characterized in that: The pipe body group is made of Q355B steel pipe body material.

7. The construction method of the tunnel pipe-roof structure according to claim 6, characterized in that: The diameter of the pipe body is 2-2.5m.

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