Urban underground excavation tunnel construction method

Abstract

The invention relates to the field of tunnel construction, and discloses an urban underground excavation tunnel construction method which comprises the following steps: (1) measuring and positioning: calculating a box culvert distance, and manufacturing a box culvert finished product in a factory; (2) working well construction is conducted, specifically, a back wall, a guide pier and a hole are machined in the working well along a straight line, the back wall, the guide pier, the hole and the receiving well are located in the same vertical plane, and pipe shed construction is conducted in the hole to reinforce the hole; (3) equipment installation: horizontally installing a jack at the lower part of the back wall, and then installing a sliding plate structure on a guide pier at the front end of the jack; (4) box culvert jacking: installing a steel blade angle at the advancing section of the first box culvert, pushing the box culvert to the receiving well along the hole by a jack, and breaking the soil by the steel blade angle in the process; and the tunnel is excavated. The box culvert is used for forming the supporting body of the tunnel, the construction efficiency is effectively improved, and the safety of the tunnel is guaranteed.

Description

Technical Field

[0001] The invention relates to the field of tunnel construction, and in particular to a method for constructing an urban dark tunnel. Background Art

[0002] In today's urban construction, pipe jacking operations in town projects often face the shortage of urban land, intricate underground pipelines, cross-process construction, and complex address conditions. Therefore, pipe jacking is often used as a construction method for municipal underground trenchless projects, but the existing pipe jacking operations have extremely high restrictions on size, so the commonly used pipe jacking operations are mainly used for small-sized and short-distance pipelines. Tunnels are underground projects in cities. In order to reduce the impact on ground traffic and the environment, underground digging is generally used for construction. However, the characteristics of tunnel and underground project construction are: 1. Greatly affected by geology and hydrology; 2. Small working space; 3. Shallow working depth easily leads to ground subsidence; 4. Large amount of excavated earthwork. For long tunnel construction, it is more convenient to use shield method or mining method. However, for short-distance tunnels, such as crossing streets and avoiding ground buildings, the shield method and mining method have a long preparatory period. If short-distance tunnel construction is carried out, the overall efficiency of the project is low and the cost is high. Therefore, a construction method suitable for short-distance urban tunnels is needed. Summary of the invention

[0003] The purpose of the present invention is to solve the problems in the background technology and provide a method for urban dark tunnel construction. The method uses a jacking pipe to excavate the tunnel, effectively filling the gap in the rapid excavation of large-size tunnels in municipal engineering.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] A method for constructing an urban dark tunnel comprises the following steps:

[0006] 1) Measurement and positioning: Calculate the length between the working well and the receiving well according to the tunnel construction length, design the box culvert based on the length and the size of the tunnel, and make the finished box culvert in the factory;

[0007] 2) Working pit construction: After the working pit is excavated, concrete is poured at the bottom and around the working pit to harden the site, and then the back wall, guide pier and opening are processed along a straight line away from the receiving well. The back wall, guide pier and opening are in the same vertical plane as the receiving well, and a pipe shed is installed in the opening to reinforce the opening;

[0008] 3) Jacking equipment installation: Install the jack horizontally at the lower part of the back wall, with the working direction of the jack facing the receiving well, and then install the slide plate structure on the guide pier at the front end of the jack;

[0009] 4) Box culvert jacking: Install the steel blade angle at the forward section of the first box culvert, and then hoist it into the working well by a crane. The box culvert is pushed along the hole to the receiving well by a jack. During this process, the steel blade angle breaks the soil;

[0010] 5) Tunnel excavation: During the process of box culvert jacking, the soil inside the box culvert is excavated and discharged from the box culvert channel, and then lifted out of the working well by a crane until the first box culvert is moved out of the receiving well, at which point the tunnel excavation is completed.

[0011] The box culvert includes a top plate, a wall plate and a bottom plate. The top plate and the bottom plate are arranged in parallel. Two wall plates are located on both sides of the top plate and the bottom plate, and together with the top plate and the floor, they enclose the outline of the box culvert. The end surfaces at both ends of the box culvert are processed with mutually matching sealing male and female buckles.

[0012] There are two groups of jacks, which are symmetrically arranged at the left and right ends of the box culvert.

[0013] The sealing male and female buckle comprises two supporting rings, and the opposite side walls of the two supporting rings are processed with male and female interfaces that match each other, and the inner walls on both sides of the female interface are installed with expansion sealants that match the male interface.

[0014] A water collecting trough is processed on the bottom plate of the box culvert, and adjacent water collecting troughs are connected to a water collecting well in sequence. The water collecting well is located in a working well or a receiving well.

[0015] The steel blade angle is in the shape of a trapezoid which is wide at the top and narrow at the bottom.

[0016] The urban dark tunnel construction method provided by the present invention has the following beneficial effects:

[0017] (1) By installing a jack in the working pit to push the prefabricated box culvert into the tunnel, the box culvert is used to form the main support of the tunnel, which effectively improves the construction efficiency. At the same time, the ceiling operation and working pit pouring can improve the structural strength of the tunnel entrance and ensure the safety of the tunnel;

[0018] (2) The integrated box culvert prefabricated in the factory can be directly used as the main body of the tunnel, eliminating the need to dig out earth and reinforce the tunnel during the traditional tunnel excavation process, effectively saving manpower investment;

[0019] (3) By processing the sealing male and female buckles at both ends of the box culvert, the sealing effect between the box culverts can be improved to reduce the overflow of water in the tunnel and effectively ensure the safety of the tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A schematic diagram of the structure provided by an embodiment of the present invention.

[0022] Figure 2 A schematic diagram of the cross-sectional profiles of adjacent box culverts provided in an embodiment of the present invention.

[0023] Figure numerals: 1. working well; 2. receiving well; 3. box culvert; 4. sealing male and female buckles; 5. jack; 6. steel blade angle. DETAILED DESCRIPTION

[0024] Example

[0025] like Figure 1 As shown, the urban dark tunnel construction method provided in this embodiment includes the following steps:

[0026] (1) Measurement and positioning: The length between the working shaft 1 and the receiving shaft 2 is calculated according to the tunnel construction length. The box culvert 3 is designed in combination with the length and the size of the tunnel. The finished box culvert 3 is manufactured in the factory. The box culvert 3 includes a top plate, a wall plate and a bottom plate. The top plate and the bottom plate are arranged in parallel. Two wall plates are located on both sides of the top plate and the bottom plate, and together with the top plate and the floor plate, they enclose the outline of the box culvert 3. The length, width and height dimensions of the finished box culvert 3 are 2×4×3.8 m.

[0027] (2) Construction of working pit 1: After the excavation of working pit 1, concrete is poured at the bottom and around the working pit 1 to harden the site. The hardened site mainly consists of ground beams and floors. First, the steel cage is tied according to the size of working pit 1. The steel bar welding joints need to be staggered to prevent the steel bar skeleton from being dislocated and deformed during pouring. When installing the side wall steel bars, the steel bar skeleton is reinforced to make it horizontal and vertical. After the steel bars are tied, the casting mold is assembled using a combined steel formwork, and the support is connected with φ48.3㎜ steel pipes and fasteners. Then, the back wall, guide pier and opening are processed along a straight line away from the receiving well 2. The back wall, guide pier and opening are in the same vertical plane as the receiving well 2. The cross section of the back wall is a right-angle trapezoid with a top width of 1697mm, a bottom width of 1000mm and a height of 4050mm. C35 reinforced concrete is poured, and the exposed surface of the reinforced concrete is equipped with a double-layer steel mesh with a specification of HRB400φ22@100; there are 6 guide piers, and the net space of the guide piers is greater than the width of the box; and pipe shed construction is installed in the opening to reinforce the opening. The outer diameter of the pipe shed guide tube is 108mm, the wall thickness is 6mm, and the section assembly reaches the advanced support length. The circumferential spacing of the guide tube is 38~46mm, the external insertion angle is 1~3°, and the length is 10m and 11m. Each section of hot-rolled seamless steel pipe with a length of 3~4m is connected by threaded buckles, and the number of joints in the same section shall not exceed 50% of the total number of steel pipes. Pipe spacing: Circumferential spacing 380㎜~460㎜, see drawing markings for details.

[0028] (3) Installation of jacking equipment: Jacks 5 are installed horizontally at the lower part of the back wall. There are two groups of jacks 5. The two groups of jacks 5 are symmetrically arranged at the left and right ends of the box culvert 3. By adjusting the force of the two groups of jacks 5, the forward direction of the box culvert 3 can be fine-tuned. The working direction of the jacks 5 is toward the receiving well 2. The jacks 5 include structures such as jacking, cylinder brackets, and jacking irons. Then, a slide plate structure is installed on the guide pier at the front end of the jack 5. The slide plate structure can improve the flexibility of the movement of the box culvert 3 and reduce friction. The slide plate is a reinforced concrete plate with a thickness of 300 mm, a width of 4100 mm, and a length of 10000 mm. It is equipped with HRB400φ12@200 steel mesh. A longitudinal slope of 0.5% is set along the length direction, which is consistent with the longitudinal slope of the box culvert 3. In order to ensure that the box culvert 3 can start and slide forward smoothly on the slide, a lubricating layer should be made on the top of the slide and covered with an isolation layer. The lubricating layer is made of engine oil and talcum powder in a ratio of 3:7, with a laying thickness of 3mm, and the isolation layer is made of oil felt.

[0029] (4) Jacking of box culvert 3: Install steel blade 6 at the forward section of the first box culvert 3, and then hoist it into the working well 1 by a crane. Push the box culvert 3 along the opening to the receiving well 2 by a jack 5. During this process, the steel blade 6 breaks the soil. The steel blade 6 is a trapezoidal body that is wide at the top and narrow at the bottom. On the one hand, the steel blade 6 serves as a soil cutting tool and a protective top plate during the manual excavation process during the jacking process. On the other hand, it serves as a protective measure for the post-casting belt of the established comprehensive management connection section.

[0030] (5) Tunnel excavation: During the process of jacking the box culvert 3, the soil inside the box culvert 3 is excavated and discharged from the channel of the box culvert 3. It is then lifted out of the working shaft 1 by a crane until the first box culvert 3 is removed from the receiving shaft 2. At this point, the tunnel excavation is completed.

[0031] In order to improve the sealing effect of the box culvert 3, Figure 2 As shown, the end faces at both ends of the box culvert 3 are processed with mutually matching sealing male and female buckles 4, and the sealing male and female buckles 4 include two supporting rings, and the opposite side walls of the two supporting rings are processed with mutually matching male and female interfaces, and the inner walls on both sides of the female interface are installed with expansion sealants matching the male interface.

[0032] In order to reduce the impact of ground seepage on the safety of the tunnel, a water collecting trough is processed on the bottom plate of the box culvert 3, and adjacent water collecting troughs are connected to the water collecting well in sequence. The water collecting well is located in the working well 1 or the receiving well 2.

[0033] The above is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any modification and replacement based on the technical solution and inventive concept provided by the present invention shall be included in the protection scope of the present invention. It should be noted that the structures or components illustrated in the drawings are not necessarily drawn to scale, and the present invention omits the description of known components and processing technologies and processes to avoid unnecessary limitation of the present invention.

Claims

1. A method for constructing an urban dark tunnel, characterized in that: The following steps are involved: 1) Measurement and positioning: the length between the working well (1) and the receiving well (2) is calculated according to the tunnel construction length, the box culvert (3) is designed in combination with the length and the size of the tunnel, and the finished box culvert (3) is manufactured in the factory; 2) Working pit construction: After the working pit (1) is excavated, concrete is poured at the bottom and around the working pit (1) to harden the site, and then a back wall, a guide pier and an opening are processed along a straight line away from the receiving pit (2). The back wall, the guide pier and the opening are in the same vertical plane as the receiving pit (2), and a pipe shed is installed in the opening to reinforce the opening; 3) Installation of jacking equipment: A jack (5) is horizontally installed at the lower part of the back wall, with the working direction of the jack (5) facing the receiving shaft (2), and then a slide plate structure is installed on the guide pier at the front end of the jack (5); 4) Box culvert jacking: Install the steel blade (6) at the forward section of the first box culvert (3), and then hoist it into the working well (1) by a crane. The box culvert (3) is pushed along the hole to the receiving well (2) by a jack (5). During this process, the steel blade (6) breaks the soil. 5) Tunnel excavation: During the process of pushing the box culvert (3) forward, the soil inside the box culvert (3) is excavated and discharged from the box culvert (3) channel and lifted out of the working shaft (1) by a crane until the first box culvert (3) is removed from the receiving shaft (2). At this time, the tunnel excavation is completed.

2. The urban dark tunnel construction method according to claim 1, characterized in that: The box culvert (3) comprises a top plate, a wall plate and a bottom plate, wherein the top plate and the bottom plate are arranged in parallel, two wall plates are located on both sides of the top plate and the bottom plate, and together with the top plate and the floor plate, form the outline of the box culvert (3), and the end surfaces at both ends of the box culvert (3) are processed with mutually matching sealing male and female buckles (4).

3. The urban dark tunnel construction method according to claim 2, characterized in that: There are two groups of jacks (5), and the two groups of jacks (5) are symmetrically arranged at the left and right ends of the box culvert (3).

4. The urban dark tunnel construction method according to claim 2, characterized in that: The sealing male and female buckle (4) comprises two supporting rings, and mutually matching male and female interfaces are processed on the opposite side walls of the two supporting rings, and expansion sealants matching the male interfaces are installed on the inner walls on both sides of the female interfaces.

5. The urban dark tunnel construction method according to claim 1 or 2, characterized in that: The bottom plate of the box culvert (3) is machined with water collecting grooves, and adjacent water collecting grooves are connected to water collecting wells in sequence. The water collecting wells are located in the working well (1) or the receiving well (2).

6. The urban dark tunnel construction method according to claim 1, characterized in that: The steel blade angle (6) is in the shape of a trapezoid which is wide at the top and narrow at the bottom.

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