A construction method for supporting structure of underground passage based on dark excavation through reinforced concrete trench

Abstract

The invention belongs to the field of building construction engineering, and discloses a construction method based on a support structure of an underground passageway dug under a reinforced concrete pipe trench. The support structure comprises two rows of high-pressure rotary jet piles symmetrically arranged below the two sides of an existing reinforced concrete pipe trench, each of which is embedded in the foundation bearing layer; a steel pipe is inserted and connected in the high-pressure rotary jet pile, and the bottom end of the steel pipe is embedded in the foundation bearing layer; the top ends of the steel pipes on both sides are fixedly connected by horizontally arranged I-beams to form a "gate" type support structure; all "gate" type support structures are connected in series through channel steels; two groups of vertical steel pipe columns are symmetrically arranged on the top surface of each I-beam, and a steel plate is arranged on the top surface of the steel pipe column to contact and support the bottom elevation surface of the existing reinforced concrete pipe trench foundation. This support method has a simple process and low requirements on the surrounding environment. By supporting the reinforced concrete pipe trench, the technical problem of a newly built reinforced concrete underground passage structure passing under the reinforced concrete pipe trench is solved, and the technical problem of the overlap of the existing pipe trench and the newly built underground passage elevation is effectively solved.

Description

Technical Field

[0001] The invention belongs to the field of building construction engineering, and specifically relates to a construction method based on a supporting structure of a dark-dig underground passage passing through a reinforced concrete pipe trench, and is a construction method for a newly built reinforced concrete underground passage passing through an existing reinforced concrete pipe trench. Background Art

[0002] With the development of the economy, construction investment has increased, and many new or expanded construction projects have emerged. Due to the influence of various factors such as planning and investment at the time, during construction, the functional channels of the new or expanded construction projects will pass under the existing project supporting facilities trenches and integrated pipeline corridors. In addition, in order to ensure the height of the underground energy channel space, the design unit will make the top of the new underground channel close to the original project supporting facilities trenches and integrated pipeline corridors. This may eventually lead to a slowdown in the progress of the new project or the demolition and rerouting of the original project supporting facilities. However, the demolition or rerouting of the original project supporting facilities will increase the construction cost and is more likely to have a major impact on normal production and life. Therefore, feasible support measures should be taken to properly handle the supporting facilities to reduce investment costs and social impacts and ensure the smooth implementation of the project. Summary of the invention

[0003] The present invention aims to solve the technical problem of a newly built reinforced concrete underground passage passing under an existing reinforced concrete pipe trench, and further provides a construction method based on a support structure of an underground passage secretly excavated under the reinforced concrete pipe trench. The method can not only ensure the safety and quality of the reinforced concrete pipe trench during construction, but also has high efficiency and low cost.

[0004] The present invention adopts the following technical solution:

[0005] A supporting structure for an underground passageway dug under a reinforced concrete pipe trench comprises two rows of high-pressure rotary jet piles symmetrically arranged below the two sides of an existing reinforced concrete pipe trench, the high-pressure rotary jet piles on both sides are evenly spaced and arranged along the longitudinal direction of the existing reinforced concrete pipe trench, and each high-pressure rotary jet pile is embedded in the foundation bearing layer; a steel pipe is inserted and connected into the high-pressure rotary jet pile, and the bottom end of the steel pipe is embedded in the foundation bearing layer; the top ends of the steel pipes on both sides are fixedly connected by horizontally arranged I-beams to form a "gate" type supporting structure; all the "gate" type supporting structures along the longitudinal direction of the existing reinforced concrete pipe trench are connected in series through channel steels, and the channel steels are arranged along the longitudinal direction of the existing reinforced concrete pipe trench and connected to the two ends of the I-beams; two groups of vertical steel pipe columns are symmetrically arranged on the top surface of each I-beam, and the top surface of the steel pipe column is provided with a steel plate that contacts and supports the bottom elevation surface of the foundation of the existing reinforced concrete pipe trench.

[0006] The belly of the I-beam is provided with a plurality of stiffening ribs.

[0007] A support construction method for a dark-dig underground passage passing through a reinforced concrete pipe trench, the construction steps are as follows:

[0008] 1) Determine the length of the existing reinforced concrete pipe trench that needs to be treated based on the impact range of the newly built reinforced concrete underground passage structure;

[0009] 2) Carry out the first earthwork excavation according to the length range of the existing reinforced concrete trench that needs to be treated. The specific excavation dimensions are: the excavation length is the length of the existing reinforced concrete trench that needs to be treated, the excavation width on one side of the existing reinforced concrete trench is the width of the existing reinforced concrete trench + 1m, and the excavation width on the other side is not less than 2.5m, and the excavation depth is the bottom elevation of the existing reinforced concrete trench foundation;

[0010] 3) High-pressure jet grouting piles are constructed symmetrically on both sides of the existing reinforced concrete trench. The high-pressure jet grouting piles are evenly spaced and arranged along the longitudinal direction of the existing reinforced concrete trench. The depth of the high-pressure jet grouting piles is determined according to the geological conditions to ensure that they are embedded in the foundation bearing layer;

[0011] 4) After the high-pressure jet grouting pile is formed, the seamless steel pipe is inserted immediately. The steel pipe first sinks naturally by gravity. After the natural sinking stops, the steel pipe is pressed to the bottom elevation of the existing reinforced concrete trench foundation by applying pressure on the top of the steel pipe. The steel pipe is embedded in the foundation bearing layer;

[0012] 5) Manually dig holes at the bottom of the existing reinforced concrete trench foundation according to the positions of high-pressure jet grouting piles on both sides of the existing reinforced concrete trench;

[0013] 6) After the hole is dug, use a chain to insert the I-beam into the hole on the wider side of the existing reinforced concrete trench and place it on the top of the steel pipe inserted into the high-pressure jet grouting pile. The top elevation of the steel pipe is cut according to the actual height, and the contact surface between the I-beam and the top of the steel pipe is connected by welding;

[0014] 7) Since the top elevation of the new reinforced concrete underground passage structure slab is the same as the bottom elevation of the existing reinforced concrete pipe trench foundation, the upper part of the I-beam inside the new reinforced concrete underground passage structure uses steel pipe columns and top steel plates to support the existing reinforced concrete pipe trench;

[0015] 8) After the above steps are completed, the earthwork excavation construction of the new reinforced concrete underground passage structure shall be carried out. During the earthwork excavation construction, it shall be ensured that the construction machinery shall not disturb the high-pressure jet grouting piles and the inserted steel pipes.

[0016] Before the earthwork excavation construction described in step 8), the following two steps need to be completed:

[0017] 1) Install stiffening ribs on the belly of the I-beam to increase the rigidity of the I-beam;

[0018] 2) To prevent the I-beam from tilting and overturning due to uneven pressure, all the ends of the I-beams on the same side are connected in series with channel steels, and the contact surfaces between the I-beams and the channel steels are welded.

[0019] The earthwork excavation in step 8) is carried out by combining mechanical and manual methods. The earthwork within 1m around the high-pressure rotary jet grouting piles and within 500mm of the bottom of the existing reinforced concrete trench is excavated manually, and the rest is excavated mechanically.

[0020] The hole size in step 5) is the outer contour size of the I-beam.

[0021] The embedding depth of the high-pressure jet grouting piles relative to the foundation bearing layer is not less than 8m.

[0022] The spacing of high-pressure jet grouting piles along the longitudinal direction of the existing reinforced concrete trench is 1.6m to 2.5m.

[0023] The distance between the center of the high-pressure jet grouting pile and the existing reinforced concrete pipe trench is no more than 1m.

[0024] The embedding depth of the steel pipe relative to the foundation bearing layer is 8m.

[0025] The advantages and positive effects of the present invention are as follows: by supporting the reinforced concrete pipe trench, the problem that the newly built reinforced concrete underground passage structure cannot be constructed, the demolition or re-routing of the original project supporting facilities leads to increased construction costs, and it is more likely to cause major problems affecting normal production and life, and by only processing the newly built reinforced concrete underground passage section, the construction period of the new project is reduced, the construction cost is reduced, and at the same time, through node optimization, the problem of overlapping between the existing reinforced concrete pipe trench elevation and the new structure slab top elevation is effectively solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A top view of the present invention;

[0027] Figure 2 for Figure 1 Front view of the supporting structure;

[0028] Figure 3 for Figure 1 Side view of the support structure;

[0029] Figure 4 This is a schematic diagram of the inner supporting structure of the newly built reinforced concrete underground passage;

[0030] Figure 5 is the structural diagram of the stiffening rib;

[0031] In the figure: 1- high-pressure jet grouting piles, 2- steel pipes, 3- I-beams (H-shaped steels), 4- steel pipe columns, 5- steel plates, 6- channel steels, 7- stiffening ribs, 8- existing reinforced concrete trenches, 9- schematic diagram of foundation pit excavation slopes, 10- newly built reinforced concrete underground passage structure. DETAILED DESCRIPTION

[0032] The present invention adopts Figure 1-4 The supporting structure of the underground passageway dug under the reinforced concrete pipe trench shown in the figure comprises two rows of high-pressure rotary jet piles 1 symmetrically arranged below the two sides of the existing reinforced concrete pipe trench 8, the high-pressure rotary jet piles 1 on both sides are evenly spaced and arranged along the longitudinal direction of the existing reinforced concrete pipe trench 8, and each high-pressure rotary jet pile 1 is embedded in the foundation bearing layer;

[0033] A steel pipe 2 is inserted and connected into the high-pressure jet grouting pile 1, and the bottom end of the steel pipe 2 is embedded in the foundation bearing layer;

[0034] The tops of the steel pipes 2 on both sides are fixedly connected by horizontally arranged I-beams 3 to form a "door" type support structure; all the "door" type support structures along the longitudinal direction of the existing reinforced concrete trench 8 are connected in series through channel steels 6, and the channel steels 6 are arranged along the longitudinal direction of the existing reinforced concrete trench 8 and connected to the two ends of the I-beams 3;

[0035] Two groups of vertical steel pipe columns 4 are symmetrically arranged on the top surface of each I-beam 3 , and a steel plate 5 is arranged on the top surface of the steel pipe column 4 for contacting and supporting the bottom elevation surface of the existing reinforced concrete trench 8 foundation.

[0036] The belly of the I-beam 3 is provided with a plurality of stiffening ribs 7 .

[0037] Taking a certain project as an example, the construction process of the support structure is further explained below:

[0038] 1) Determine the length of the existing reinforced concrete pipe trench 8 to be processed in combination with the influence range of the newly built reinforced concrete underground passage structure 10. In this embodiment, the length of the existing reinforced concrete pipe trench 8 to be processed in combination with the influence range of the newly built reinforced concrete underground passage structure 10 is determined to be the outer side of the upper opening of the foundation pit slope 9.

[0039] 2) The first earthwork excavation is carried out within the length range of the reinforced concrete trench that needs to be treated. The specific excavation dimensions are: the excavation length is the length of the existing reinforced concrete trench 8 that needs to be treated, the excavation width on one side of the existing reinforced concrete trench 8 is the width of the existing reinforced concrete trench 8 + 1m, and the excavation width on the other side is not less than 2.5m, and the excavation depth is the bottom elevation of the foundation of the existing reinforced concrete trench 8.

[0040] 3) High-pressure jet grouting piles 1 are constructed symmetrically on both sides of the existing reinforced concrete pipe trench 8. The depth of the high-pressure jet grouting piles 1 is determined according to the geological conditions and embedded into the foundation bearing layer. Before the construction of the high-pressure jet grouting piles 1, the location of the newly built reinforced concrete underground passage structure 10 must be avoided, and sufficient construction operation space must be reserved. In this embodiment, the diameter of the high-pressure jet grouting piles 1 is 600mm, the distance between the center of the high-pressure jet grouting piles 1 on both sides of the existing reinforced concrete pipe trench 8 and the existing reinforced concrete pipe trench 8 is 1m, the horizontal spacing of the high-pressure jet grouting piles 1 is 1.6m to 2.5m, and the length of the high-pressure jet grouting piles 1 is embedded 8m.

[0041] 4) After the high-pressure jet grouting pile 1 is formed, the seamless steel pipe 2 is immediately inserted, and the steel pipe 2 first sinks naturally by gravity. After the natural sinking stops, the steel pipe 2 is pressed to the bottom elevation of the existing reinforced concrete trench 8 foundation by applying pressure on the top of the steel pipe 2, and the steel pipe 2 is embedded in the foundation bearing layer. In this embodiment, the seamless steel pipe 2 has a wall thickness of 10mm and a diameter of Ф325, and the embedded length of the steel pipe 2 is 8m.

[0042] 5) According to the positions of the high-pressure jet grouting piles 1 on the north and south sides of the existing reinforced concrete trench 8, artificial holes are dug at the bottom of the foundation of the existing reinforced concrete trench 8. The artificial holes are constructed using a Luoyang shovel. Before construction, marks are made on both sides of the existing reinforced concrete trench 8, and holes are dug along the marks close to both sides of the bottom of the foundation of the existing reinforced concrete trench 8. In this embodiment, the hole size is 350×350mm for the outer contour size of the I-beam 3.

[0043] 6) After the hole is dug, the H-shaped steel 3 (350×350×12×19) is inserted into the hole on the wider side of the existing reinforced concrete pipe trench 8 by using a chain, and placed on the top of the steel pipe 2 inserted into the high-pressure rotary grouting pile 1. The top elevation of the steel pipe 2 is cut according to the actual height, and the contact surface of the H-shaped steel 3 and the top of the steel pipe 2 is welded. In this embodiment, the size of the H-shaped steel 3 is 350×350×12×19, and the top of the steel pipe 2 is finely cut to ensure that the H-shaped steel 3 is in close contact with the top of the steel pipe 2 while pressing against the existing reinforced concrete pipe trench 8.

[0044] 7) Since the top elevation of the newly built reinforced concrete underground passage structure 10 is the same as the bottom elevation of the foundation of the existing reinforced concrete pipe trench 8, the upper part of the inner H-shaped steel 3 of the newly built reinforced concrete underground passage structure 10 adopts a 500mm high steel pipe column 4 to support the steel plate 5 to support the reinforced concrete pipe trench 8. The specific method is: the H-shaped steel 3 on the top of the inner steel pipe 2 of the newly built reinforced concrete underground passage structure 10 is 500mm lower than the elevation of the outer H-shaped steel 3 of the newly built reinforced concrete underground passage structure 10. After the installation of the inner H-shaped steel 3 of the newly built reinforced concrete underground passage structure 10 is completed, 500mm high steel pipe columns 4 are installed vertically below the existing reinforced concrete pipe trench 8 walls on both sides of the top of the H-shaped steel 3. Before installation, cast-in-place concrete is poured into the steel pipe columns 4 and vibrated to make it dense. After solidification, the steel pipe columns 4 are installed and welded to the upper part of the H-shaped steel 3. After welding, the steel plate 5 is installed on the top of the steel pipe columns 4 to press against the bottom of the reinforced concrete pipe trench slab. In this embodiment, the steel pipe column 4 has a wall thickness of 10 mm, a diameter of Φ219, a cast-in-place concrete strength grade of C30, and a steel plate 5 size of 300×300×20.

[0045] 8) In order to strengthen the rigidity of the H-shaped steel 3 at the bottom of the 500mm high steel pipe column 4, stiffening ribs 7 need to be installed on the belly of the H-shaped steel 3 before the construction of the 500mm high steel pipe column 4.

[0046] 9) To prevent the H-beam 3 from tilting and overturning due to uneven pressure, all the ends of the H-beam 3 on the same side are connected in series with channel steel 6, and the contact surface between the H-beam 3 and the channel steel 6 is welded. In this example, the channel steel model is 20a.

[0047] 10) After all steps 1 to 9 are completed, earthwork excavation construction of the new reinforced concrete underground passage structure 10 is carried out. During earthwork excavation construction, it is necessary to ensure that the construction machinery does not disturb the high-pressure rotary jet grouting piles 1 and the inserted steel pipes 2. In this example, earthwork excavation of the new reinforced concrete underground passage structure 10 is carried out by combining mechanical and manual methods. The earthwork within the 1m range around the high-pressure rotary jet grouting piles 1 and the 500mm range at the bottom of the existing reinforced concrete pipe trench 8 is excavated manually, and the rest is excavated mechanically.

[0048] This support method has a simple construction process and has low requirements for the surrounding environment. By supporting the reinforced concrete pipe trench, it solves the technical problem of the newly built reinforced concrete underground passage structure passing under the reinforced concrete pipe trench, and effectively solves the technical problem of the overlapping elevation of the existing pipe trench and the newly built underground passage.

[0049] The above-mentioned embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person skilled in the art, several modifications, improvements and substitutions can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the attached claims.

Claims

1. A construction method based on a support structure of an underground passageway dug under a reinforced concrete trench, the support structure comprising: Two rows of high-pressure jet grouting piles (1) are symmetrically arranged below the two sides of the existing reinforced concrete pipe trench (8), the high-pressure jet grouting piles (1) on both sides are evenly spaced and arranged along the longitudinal direction of the existing reinforced concrete pipe trench (8), and each high-pressure jet grouting pile (1) is embedded in the foundation bearing layer; A steel pipe (2) is inserted and connected into the high-pressure jet grouting pile (1), and the bottom end of the steel pipe (2) is embedded in the bearing layer of the foundation; The top ends of the steel pipes (2) on both sides are fixedly connected by horizontally arranged I-beams (3) to form a "gate"-shaped support structure; all the "gate"-shaped support structures along the longitudinal direction of the existing reinforced concrete pipe trench (8) are connected in series through channel steels (6); the channel steels (6) are arranged along the longitudinal direction of the existing reinforced concrete pipe trench (8) and connected to both ends of the I-beams (3); Two groups of vertical steel pipe columns (4) are symmetrically arranged on the top surface of each I-beam (3), and a steel plate (5) is arranged on the top surface of the steel pipe column (4) for contacting and supporting the bottom elevation surface of the foundation of the existing reinforced concrete trench (8); The belly of the I-beam (3) is provided with a plurality of stiffening ribs (7); It is characterized in that the construction steps are as follows: 1) Determine the length of the existing reinforced concrete pipe trench (8) that needs to be treated based on the impact range of the newly built reinforced concrete underground passage structure (10); 2) Performing the first earthwork excavation according to the length range of the existing reinforced concrete pipe trench (8) to be treated, the specific excavation dimensions are: the excavation length is the length of the existing reinforced concrete pipe trench (8) to be treated, the excavation width on one side of the existing reinforced concrete pipe trench (8) is the width of the existing reinforced concrete pipe trench (8) + 1m, the excavation width on the other side is not less than 2.5m, and the excavation depth is the bottom elevation of the foundation of the existing reinforced concrete pipe trench (8); 3) High-pressure jet grouting piles (1) are constructed symmetrically on both sides of the existing reinforced concrete pipe trench (8), the high-pressure jet grouting piles (1) are evenly spaced and arranged along the longitudinal direction of the existing reinforced concrete pipe trench (8), and the depth of the high-pressure jet grouting piles (1) is determined according to geological conditions to ensure that they are embedded in the foundation bearing layer; 4) After the high-pressure jet grouting pile (1) is formed, the seamless steel pipe (2) is immediately inserted, and the steel pipe (2) first sinks naturally by gravity. After the natural sinking stops, the steel pipe (2) is pressed to the bottom elevation of the existing reinforced concrete trench (8) foundation by applying pressure on the top of the steel pipe (2), and the steel pipe (2) is embedded in the foundation bearing layer; 5) Manually dig holes at the bottom of the foundation of the existing reinforced concrete pipe trench (8) according to the positions of the high-pressure jet grouting piles (1) on both sides of the existing reinforced concrete pipe trench (8); 6) After the hole is dug, the I-beam (3) is inserted into the hole on the wider side of the existing reinforced concrete trench (8) by using a fall chain and placed on the top of the steel pipe (2) inserted into the high-pressure jet grouting pile (1). The top elevation of the steel pipe (2) is cut according to the actual height, and the contact surface between the I-beam (3) and the top of the steel pipe (2) is connected by welding; 7) Since the top elevation of the newly built reinforced concrete underground passage structure (10) is the same as the bottom elevation of the foundation of the existing reinforced concrete pipe trench (8), the upper part of the inner I-beam (3) of the newly built reinforced concrete underground passage structure (10) uses a steel pipe column (4) and a top steel plate (5) to support the existing reinforced concrete pipe trench (8); 8) After the above steps are completed, earth excavation construction of the new reinforced concrete underground passage structure (10) is carried out. During the earth excavation construction, it is necessary to ensure that the construction machinery does not disturb the high-pressure jet grouting piles (1) and the inserted steel pipes (2).

2. A construction method based on a support structure of an underground passageway dug under a reinforced concrete trench according to claim 1, characterized in that: Before the earthwork excavation construction described in step 8), the following two steps need to be completed: 1) Installing stiffening ribs (7) on the belly of the I-beam (3) to increase the rigidity of the I-beam (3); 2) In order to prevent the I-beam (3) from tilting and overturning due to uneven pressure, the ends of the I-beam (3) on the same side are all connected in series using channel steels (6), and the contact surfaces of the I-beam (3) and the channel steels (6) are connected by welding.

3. The construction method of the supporting structure of an underground passage based on a dark excavation through a reinforced concrete trench according to claim 1 is characterized in that: The earthwork excavation in step 8) is carried out by combining mechanical and manual methods. The earthwork within the range of 1m around the high-pressure jet grouting pile (1) and within the range of 500mm at the bottom of the existing reinforced concrete trench (8) is excavated manually, and the rest is excavated mechanically.

4. The construction method of the supporting structure of an underground passage based on a dark excavation through a reinforced concrete trench according to claim 1 is characterized in that: The hole size in step 5) is the outer contour size of the I-beam (3).

5. The construction method of the supporting structure of an underground passage based on a dark excavation through a reinforced concrete trench according to claim 1 is characterized in that: The embedding depth of the high-pressure jet grouting pile (1) relative to the foundation bearing layer is not less than 8m.

6. The construction method of the supporting structure of an underground passage based on a dark excavation through a reinforced concrete pipe trench according to claim 1 is characterized in that: The spacing of the high-pressure jet grouting piles (1) along the longitudinal direction of the existing reinforced concrete pipe trench (8) is 1.6m to 2.5m.

7. The construction method of the supporting structure of an underground passage based on a dark excavation through a reinforced concrete trench according to claim 1 is characterized in that: The distance between the center of the high-pressure jet grouting pile (1) and the existing reinforced concrete pipe trench (8) is no more than 1 m.

8. The construction method of the supporting structure of an underground passage based on a dark excavation through a reinforced concrete trench according to claim 1 is characterized in that: The embedding depth of the steel pipe (2) relative to the foundation bearing layer is 8m.

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