Tunnel reverse slope excavation drainage construction method

Abstract

The embodiment of the invention discloses a tunnel counter-slope excavation drainage construction method which comprises the following steps: constructing a certain distance in a tunnel after construction of a tunnel portal is completed, and completing primary support; constructing a drainage pipeline by using a horizontal directional drill, wherein the pipeline is parallel to the tunnel and is slightly lower than or equal to the excavation bottom elevation of the tunnel; the pipeline is gradually dismantled in the tunnel excavation process, so that a water inlet of the drainage pipeline follows the long sub-surface until the tunnel is communicated; after the tunnel is communicated, low-grade concrete can be selected to be backfilled in the pipeline or reserved for other purposes according to the design. By means of the construction method, the safety margin during construction can be effectively increased, the construction efficiency of tunnel reverse slope excavation is improved, and the effects of energy conservation, emission reduction and green construction can be achieved when the electricity consumption of water pumping and drainage is large.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of civil engineering, and in particular to a construction method for tunnel excavation. Background Art

[0002] When excavating a tunnel with a slope, the slope from the entrance to the top is the downslope, and the reverse slope is the reverse slope. Generally, the downslope is the best choice, which makes it easier to drain water during construction, especially for tunnels with a lot of water seepage. However, for the sake of construction efficiency, a two-way tunnel entry scheme will be adopted, or the downslope construction work surface will be inconvenient to carry out. Drainage is more troublesome during reverse slope construction of the tunnel. Reverse slope drainage is one of the important processes in the construction of long and large tunnels, and it is the key to safe tunnel construction. Therefore, a reasonable drainage system is an important guarantee for achieving rapid tunnel construction, ensuring construction safety, and the physical and mental health of construction personnel.

[0003] At present, the traditional construction method is to build drainage ditches and water collection wells when excavating the reverse slope tunnel, and use water pumps to pump out the water to the drainage ditch outside the tunnel in stages. The disadvantages of the traditional construction method are: 1. If the tunnel is long and deep, the efficiency of using the water collection well is low; 2. If there is a sudden heavy rain and the drainage facilities outside the tunnel are not good, the rainwater outside the tunnel will flow into the tunnel, and the traditional drainage method will affect the construction efficiency; 3. If the amount of water in the tunnel is large and the tunnel is deep, more electricity will be consumed for pumping and draining. Summary of the invention

[0004] At present, the traditional construction method is to build drainage ditches and water collection wells during reverse slope tunnel excavation, and use water pumps to pump water out of the tunnel in stages. In order to solve some defects of the traditional construction method, a tunnel reverse slope excavation drainage construction technology was invented. This tunnel reverse slope excavation drainage method includes: after the construction of the tunnel portal is completed, a certain distance is constructed into the tunnel and initial support is completed; the drainage pipeline is constructed using horizontal directional drilling (or other non-grooving construction methods). The pipeline should be parallel to the tunnel and slightly lower than or equal to the elevation of the bottom surface of the tunnel excavation; during the tunnel excavation process, the pipeline is gradually removed so that the water inlet of the drainage pipeline follows the long sub-face until the tunnel is connected. After the tunnel is connected, low-grade concrete can be backfilled in the pipeline according to the design or reserved for other uses.

[0005] The purpose of the embodiment of the present invention is to provide a new drainage technical solution during tunnel reverse slope construction, which can effectively increase the safety margin during construction, improve the construction efficiency of tunnel reverse slope excavation, and when the electricity consumption of pumping and drainage is high, it can play a role in energy saving, emission reduction and green construction.

[0006] To achieve the above objectives, the embodiments of the present invention mainly provide the following technical solutions:

[0007] The first step is to construct a certain distance into the tunnel after the construction of the tunnel portal is completed and complete the initial support.

[0008] The second step is to use horizontal directional drilling (or non-grooving methods such as jacking and tamping) to construct drainage pipes. The pipes should be parallel to the tunnel and slightly lower than or equal to the bottom elevation of the tunnel excavation.

[0009] The third step is to gradually remove the pipes during the tunnel excavation process so that the water inlet of the drainage pipe follows the long sub-face until the tunnel is through. During the excavation process, a solid steel inner support can be inserted into the pipe opening to protect the exposed pipe and prevent falling stones from damaging the pipe. After the blasting is completed and the slag is unearthed, the solid steel inner support can be pulled out to ensure smooth drainage.

[0010] The fourth step is that after the tunnel is completed, you can choose to backfill the pipe with low-grade concrete or keep it for other uses based on the design. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The present invention is a flow chart of a construction method for constructing drainage pipes first during reverse slope excavation of a tunnel in an ideal state according to an embodiment of the present invention.

[0012] Figure 2 This is a flow chart of the construction method of using horizontal directional drilling to drain water during reverse slope excavation of a tunnel under non-ideal conditions.

[0013] Figure 3 This is a cross-sectional view of a tunnel excavation according to an embodiment of the present invention, in which the drainage pipe constructed using horizontal directional drilling is at the lowest point of the tunnel section.

[0014] Figure 4 It is a deformation method of drainage using horizontal directional drilling.

[0015] Figure 5 In order to protect the drainage pipe during blasting excavation, solid steel inner supports are required.

[0016] Figure 6 This is a diagram of a solid steel internal support structure. DETAILED DESCRIPTION

[0017] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0018] In the following description, specific details such as specific processes, materials, and machinery are provided for the purpose of illustration rather than limitation so as to provide a thorough understanding of the present invention. However, it should be clear to those skilled in the art that the present invention can be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known operating instruments, sensitization methods, etching methods, and materials are omitted so as not to obscure the description of the present invention with unnecessary details.

[0019] In the description of the present invention, it should be understood that the terms “first” and “second” are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0020] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] Figure 1 The flowchart of the construction method of the tunnel reverse slope excavation and first construction of drainage pipes in the ideal state of the embodiment of the present invention. Figure 1 As shown in the figure, the construction method of tunnel reverse slope excavation is to construct drainage pipes first:

[0022] The first step is to construct a certain distance into the tunnel after the construction of the tunnel portal is completed and complete the initial support.

[0023] The second step is to use horizontal directional drilling (or non-grooving methods such as jacking and tamping) to construct drainage pipes. The pipes should be parallel to the tunnel and slightly lower than or equal to the bottom elevation of the tunnel excavation.

[0024] The third step is to gradually remove the pipes during the tunnel excavation process so that the water inlet of the drainage pipe follows the long sub-face until the tunnel is through. During the excavation process, a solid steel inner support can be inserted into the pipe opening to protect the exposed pipe and prevent falling stones from damaging the pipe. After the blasting is completed and the slag is unearthed, the solid steel inner support can be pulled out to ensure smooth drainage.

[0025] The fourth step is that after the tunnel is completed, you can choose to backfill the pipe with low-grade concrete or keep it for other uses based on the design.

[0026] Figure 2 This is a flow chart of the construction method of using horizontal directional drilling to drain water in reverse slope excavation of tunnels under non-ideal conditions. At this time, the drainage pipe is not exactly at the bottom elevation of the tunnel, and the drainage pipe is not exposed as the tunnel advances. This requires digging out the drainage pipe and then temporarily connecting a section of the drainage pipe to the bottom elevation of the tunnel.

[0027] Figure 3 This is a cross-sectional view of a tunnel excavation according to an embodiment of the present invention, in which the drainage pipe constructed using horizontal directional drilling is at the lowest point of the tunnel section.

[0028] Figure 4 It is a modified method of drainage using horizontal directional drilling. Instead of constructing drainage pipes along the direction of the tunnel, when the tunnel drainage is not smooth, it uses horizontal directional drilling to construct a small-diameter inclined shaft with a negative inclination to directly divert water out of the mountain.

[0029] Figure 5 In order to protect the drainage pipe during blasting excavation, a solid steel inner support is required. In order to prevent stones from damaging the drainage pipe during tunnel excavation, a solid steel inner support needs to be inserted into the pipe to prevent the pipe from being damaged and causing drainage failure. After the blasting is completed and the slag is unearthed, the solid steel inner support is pulled out to ensure smooth drainage.

[0030] Figure 6 This is a diagram of the structure of a solid steel inner support. The diameter of the solid steel inner support is slightly smaller than the diameter of the pipe, but the diameter of the outer retaining ring is larger than the pipe, preventing the inner support from completely entering the pipe and being unable to be pulled out.

[0031] In addition, the method of constructing drainage pipes by horizontal directional drilling mentioned in a tunnel reverse slope excavation drainage construction technology in an embodiment of the present invention does not exclude the use of other construction methods such as ramming pipe method, jacking pipe method, shield method, etc. Other structures and functions are known to technicians in this field and will not be described in detail to reduce redundancy.

[0032] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solution of the present invention should be included in the scope of protection of the present invention.

Claims

1. A tunnel reverse slope excavation and drainage construction method, characterized in that: include: When excavating the tunnel in reverse slope, the drainage pipes are first constructed using horizontal directional drilling; the exposed drainage pipes are gradually removed during the tunnel excavation process; If the drainage pipe is not exposed during the excavation process, it can be filled with low-grade concrete after the tunnel excavation is completed or reserved for other uses; when blasting excavation, a solid steel inner support is inserted into the drainage pipe opening before blasting, and the solid steel inner support is pulled out after the blasting is completed and the slag is unearthed to ensure smooth drainage. The construction of drainage pipes can be done by horizontal directional drilling, or by pipe jacking, pipe tamping, shield tunneling, shallow buried tunneling, etc. In this case, the drainage pipes constructed first were constructed by horizontal directional drilling, which does not exclude the right to use other construction methods.

2. Solid steel inner support to prevent pipelines from being damaged by falling rocks during tunnel excavation.

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