A method for tunneling construction of a shield tunnel

Abstract

The application belongs to the field of shield tunnel construction, and particularly relates to a construction method for shield tunnel entry, which comprises the following steps: first step: a mine method is used to excavate a tunnel entry section and initially support a distance, and the tunnel excavation and initial support contour line is continuously adjusted during the construction process, so that the formed initial support is zigzag; second step: a mold building method is used to form a secondary lining layer of the tunnel entry section; third step: a cutter head of a shield machine, a support ring of the shield machine and a shield machine advancing system are advanced to a working face; fourth step: a counterforce device is installed on the surface of the secondary lining layer; fifth step: an assembling system and an earth removal system are installed, and the shield machine is pushed empty with the counterforce device as a fulcrum until the working face; and sixth step: the shield machine is normally advanced, and the application has the advantages of reliable construction quality, saved working hours and saved materials.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of shield tunnel construction, and particularly relates to a construction method for shield tunnel entry. BACKGROUND

[0002] In the construction of a tunnel, the shield method is relatively common. The conventional shield method entry portal needs to be provided with a negative ring and a counterforce support. The shield machine propulsion system acts force on the counterforce support through the negative ring to push the shield cutterhead forward to excavate, and the shield cutterhead enters the portal after breaking the reinforced concrete pile row.

[0003] The conventional shield method tunnel entry mode has the following disadvantages:

[0004] (1) The conventional shield method entry portal needs to be provided with a negative ring and a counterforce support, which increases the cost and working hours;

[0005] (2) The conventional shield machine entry mode needs to damage the reinforced concrete pile row structure. In the process of cutting the reinforced concrete pile row, the shield cutterhead is damaged;

[0006] (3) When the tunnel is buried deep, in order to avoid safety accidents such as surrounding rock instability at the portal, the conventional shield method entry mode needs to reinforce a large range of soil, which is not economical in cost;

[0007] (4) In addition, under some special conditions, such as in order for the shield machine to enter the portal, the subway usually needs to be specially provided with a shield well, the width of the shield well is slightly larger than other sections, which causes the surrounding pile to have a convex external corner, which is not conducive to the stability of the structure and increases the safety risk;

[0008] (5) When the shield machine enters the portal in a steep mountain, the external counterforce support cannot be provided, which makes it difficult to enter the portal smoothly;

[0009] (6) After the conventional shield machine entry mode causes safety accidents such as surrounding rock instability at the portal, it is difficult to deal with;

[0010] The tunnel portal is often a high-risk section of construction. Once safety accidents such as surrounding rock instability occur at the portal, it is very difficult to deal with. In order to solve the above technical problems in the conventional shield method entry construction method, the present application provides a new shield tunnel entry construction method. SUMMARY

[0011] The present application aims to provide a new shield method tunnel entry construction method, which solves the defects of high cost and long working hours in the conventional shield method entry construction method.

[0012] In order to solve the above technical problems, the present application provides a shield method tunnel entry construction method, the construction sequence of which is as follows,

[0013] (1)First step: the tunnel entrance section is excavated by the mine method and is initially supported, and the tunnel excavation and initial support contour line is continuously adjusted during construction, so that the formed initial support is "sawtooth-shaped", and a plurality of "wedges" are formed after the secondary lining is poured;

[0014] (2) Second step: the secondary lining of the tunnel entrance is constructed by the mold pouring method, and in order to ensure that the secondary lining can provide sufficient counterforce, the secondary lining can also be fixed together with the system anchor rod end;

[0015] (3) Third step: first advance the cutter head, shield machine support ring and shield machine propulsion system to the working face;

[0016] (4) Fourth step: install the counterforce device on the surface of the secondary lining concrete. The tunnel bottom is poured with reinforced concrete as the counterforce device and is closely connected with the original secondary lining. The side wall and arch part use prefabricated steel counterforce supports as the counterforce device, which are closely connected with the secondary lining concrete through anchor bolt holes. The prefabricated steel counterforce supports are connected with each other through counterforce support connecting bolt holes.

[0017] (5) Fifth step: install the assembly system and the unearthing system (not shown in the figure), and perform shield empty pushing with the counterforce device as the fulcrum until the working face;

[0018] (6) Sixth step: normally advance the shield machine.

[0019] The invention has the following technical features relative to the conventional tunnel construction method of the shield method:

[0020] (1) The tunnel entrance is often a high-risk section for construction, and after the occurrence of safety accidents such as surrounding rock instability at the tunnel entrance using the conventional shield machine tunneling method, it is difficult to deal with. The tunneling construction method of the invention is more flexible and easy to deal with.

[0021] (2) In order for the shield machine to enter the tunnel, the subway usually needs to specially set up a shield well, and the width of the shield well is slightly larger than that of other sections, resulting in a convex external corner of the retaining pile, which is not conducive to structural stability. In the invention, the shield machine does not need external counterforce devices, and the above-mentioned shortcomings do not exist.

[0022] (3) The conventional shield machine tunneling method needs to destroy the reinforced concrete pile structure, and the shield machine cutter head will be damaged during the cutting process of the reinforced concrete pile structure. The invention avoids this construction link.

[0023] (4) Secondary lining is poured according to the shape of "wedge", and the secondary lining is pressed more tightly when providing counterforce for the shield machine, which can provide effective counterforce for the advance of the shield machine.

[0024] (5) The invention does not need a negative ring and does not need to set a counterforce support outside the hole, saving the cost and working hours of the negative ring and the counterforce support.

[0025] (6) When the tunnel is buried deep, the traditional hole entry method needs to reinforce a larger range of soil, and the hole entry of the invention only needs to reinforce the soil around the tunnel.

[0026] (7) When the shield machine is advancing in a steep mountain, the external counterforce support cannot be provided, and the method of the invention can be used. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of the first step: the tunnel entrance section is excavated by the mine method and the initial support;

[0028] Figure 2 is a schematic diagram of the second step: secondary lining support is carried out at the tunnel entrance;

[0029] Figure 3 is a schematic diagram of the third step: the position of the cutter head of the shield machine, the support ring of the shield machine and the shield machine advancing device system;

[0030] Figure 4 is a schematic diagram of the fourth step: installing the counterforce device on the surface of the secondary lining concrete;

[0031] Figure 5 is a schematic diagram of the fifth step: using the counterforce device as a fulcrum to push the shield empty;

[0032] Figure 6 is a schematic diagram of the sixth step: the shield machine is running normally;

[0033] Figure 7 is Figure 4 the cross-sectional view of A-A;

[0034] Figure 8 is a front view of the prefabricated steel counterforce support;

[0035] Figure 9 is a right view of the prefabricated steel counterforce support;

[0036] Figure 10 is a top view of the prefabricated steel counterforce support.

[0037] The markings in the diagram correspond to: 1-surrounding rock, 2-initial support, 3-secondary lining layer, 4-shield cutterhead, 5-shield propulsion system, 6-shield support ring, 7-precast steel reaction support, 71-rectangular support base plate, 72-rectangular support side plate, 73-triangular support panel, 8-reinforced concrete base plate; 9-shield segment; 10-anchor bolt hole; 11-reaction support connection bolt hole. Detailed Implementation

[0038] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0039] Example:

[0040] like Figures 1-10 As shown, a method for tunneling using the shield tunneling method includes the following steps: First, the tunnel entrance section is excavated using the mining method and initially supported 2. During construction, the tunnel excavation face and the outline of the initial support are continuously adjusted. The initial support 2 is "serrated". Second, a secondary lining layer 3 is formed at the tunnel entrance using a cast-in-place method. Third, the shield machine cutterhead 4, shield machine support ring 5, and shield machine propulsion system 5 are advanced to the tunnel face. Fourth, a reaction device is installed on the surface of the secondary lining layer 3. The reaction device includes reinforced concrete cast at the tunnel bottom. The reinforced concrete base slab 8 and multiple precast steel reaction supports 7 used in the sidewalls and arch are tightly connected to the secondary lining layer 3. The precast steel reaction supports 7 are tightly connected to the secondary lining layer 3 by bolts through anchor bolt holes 10. The multiple precast steel reaction supports 7 are bolted together by reaction support connecting bolt holes 11. Step 5: Install the assembly system and soil removal system (not shown in the figure), and use the reaction device as the fulcrum to push the shield machine in dry motion until the tunnel face. Step 6: The shield machine advances normally.

[0041] In the optimized solution described above, the surrounding rock 1 is pre-reinforced before the first step of tunnel excavation.

[0042] In the optimized solution, in the second step of the above technical solution, the secondary lining construction is carried out in a "wedge" shape.

[0043] In the technical scheme, the specific structure of the prefabricated steel counterforce support 7 is limited, that is, the prefabricated steel counterforce support 7 is fixedly connected by a rectangular support bottom plate 71, a rectangular support side plate 72 and two triangular support face plates 73, wherein the rectangular support side plate 72 is located at the right side of the rectangular support bottom plate 71, one straight angle side of the triangular support face plate 73 is located at the upper side of the rectangular support bottom plate 71, and the other straight angle side of the triangular support face plate 73 is located at the left side of the rectangular support side plate 72; the counterforce support connecting bolt hole 11 transversely penetrates the triangular support face plate 72, and the anchoring bolt hole 10 vertically penetrates the rectangular support bottom plate 71.

[0044] In the technical scheme, the system anchor rod is arranged in the tunnel entrance section, and the secondary lining layer 3 formed in the second step is fixed with the system anchor rod end.

[0045] In the fifth step, the shield segment 9 is arranged in the inner layer of the shield machine support ring 6 in the installation and assembly system.

[0046] In the technical scheme, the installation and assembly system and the unearthing system are prior art, and are known by those skilled in the art, and thus will not be described in detail,

[0047] The above embodiment is only a detailed description of a tunnel construction method of a shield tunnel provided by the present application, and is only used for helping to understand the method and the core idea of the present application. It should be pointed out that, for those skilled in the art, some improvements and modifications can be made to the present application without departing from the present application, and these improvements and modifications also fall within the protection scope of the present application.

Claims

1. A method for tunnel entry construction using the shield tunneling method, characterized in that, Includes the following steps: Step 1: The tunnel entrance section is excavated and initially supported using the mining method. During the construction process, the tunnel excavation face and the outline of the initial support are continuously adjusted to make the formed initial support "serrated". Step 2: The secondary lining at the tunnel entrance is constructed using a cast-in-place method to form the secondary lining layer; Step 3: First, advance the tunnel boring machine cutterhead, tunnel boring machine support ring, and tunnel boring machine propulsion system to the working face; Step 4: Install reaction devices on the surface of the secondary lining layer. The reaction devices include a reinforced concrete base slab poured at the bottom of the tunnel and multiple precast steel reaction supports used in the sidewalls and arch. The reinforced concrete base slab poured at the bottom of the tunnel is tightly connected to the secondary lining layer. The precast steel reaction supports are bolted to the secondary lining layer through anchor bolt holes. The multiple precast steel reaction supports are bolted together with each other through reaction support connecting bolt holes. Step 5: Install the shield machine assembly system and soil removal system, and use the reaction device as a fulcrum to push the shield machine in dry motion until the working face; Step 6: The tunnel boring machine advances normally; In the second step described above, multiple "wedges" are formed after the secondary lining is poured. The prefabricated steel reaction support is composed of a rectangular support base plate, a rectangular support side plate, and two triangular support panels fixedly connected together. The rectangular support side plate is located on the right side of the rectangular support base plate, one right-angled side of the triangular support panel is located on the top of the rectangular support base plate, and the other right-angled side of the triangular support panel is located on the left side of the rectangular support side plate. The reaction support connecting bolt holes penetrate the triangular support panels laterally, and the anchor bolt holes penetrate the rectangular support base plate vertically.

2. The method for tunneling using the shield method according to claim 1, characterized in that: Before the first step of tunnel excavation, depending on the surrounding rock conditions, advanced pre-reinforcement measures are adopted inside the tunnel.

3. The method for tunneling using the shield method according to claim 1, characterized in that: A system of anchor bolts driven into the surrounding rock is installed at the tunnel entrance section, and the secondary lining layer formed in the second step is fixed together with the end of the system anchor bolts.

4. The method for tunneling using the shield method according to claim 1, characterized in that: In the fifth step, shield tunnel segments are used, which are arranged in the inner layer of the shield machine support ring.

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