Bidirectional jacking backfill system in the same starting shaft and its construction and dismantling methods

Abstract

This invention discloses a bidirectional pipe jacking back support system within a single starting shaft, along with its construction and dismantling methods. A ribbed back wall serves as the back support for the pipe jacking, enabling simultaneous bidirectional pipe jacking operations, accelerating the construction period, and reducing the impact of various factors such as engineering conditions on the construction schedule. The base utilizes the existing back wall of the pipe jacking working shaft, maximizing the use of existing resources and minimizing waste of manpower and financial resources. The back wall structure is constructed simultaneously with the main structure of the pipe jacking shaft. The starting pipe jacking working shaft employs a retaining structure with a continuous underground wall and internal supports, also serving as a ventilation opening for subsequent pipe gallery maintenance. This approach ensures structural integrity, accelerates the construction period, fully utilizes the structure, and reduces costs.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering technology, specifically relating to a bidirectional jacking backing system for pipe jacking within the same starting well and its construction and dismantling methods. Background Technology

[0002] In the construction of integrated utility tunnel projects, when two or more sections of pipe jacking are required, the usual approach is to proceed in stages. This traditional method allows for a relatively large backing system for the pipe jacking equipment, which can be installed using the rear wall of the working shaft, simplifying design and construction. Currently, common backing structures include sheet pile, gravity, and prefabricated types. Prefabricated backing requires precast components; while sheet pile backing does not offer the same stability and torsional resistance as gravity backing, it suffers from large structural dimensions. Staged construction results in long construction periods and idle working surfaces, which is particularly disadvantageous for projects with ample resources and tight schedules. Furthermore, if a problem occurs in one section of the pipe jacking operation, it will directly affect subsequent operations, making the construction period highly susceptible to various factors such as project conditions.

[0003] Based on the aforementioned technical problems in the existing technology, this invention proposes a bidirectional jacking backing system for pipe jacking within the same starting well, as well as its construction and dismantling methods. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a bidirectional jacking backing system for pipe jacking within the same starting well, as well as its construction and dismantling methods.

[0005] The present invention adopts the following technical solution:

[0006] On one hand, the present invention provides a method for constructing and dismantling a backing system for bidirectional pipe jacking within the same starting shaft. The backing system includes a base plate and a first ribbed backing wall and a second ribbed backing wall fixed to the base plate, as well as a first reinforced concrete diagonal brace and a second reinforced concrete diagonal brace fixed to the base plate. The method for constructing and dismantling the backing system includes:

[0007] Step 1: The first ribbed back wall and the second ribbed back wall are constructed simultaneously with the main structure of the jacking well.

[0008] Step 2: The starting jacking shaft adopts a support method of underground continuous wall combined with internal bracing, and the main structure of the jacking shaft is constructed.

[0009] Step 3: Before the shield tunneling machine starts and receives the tunnel, the soil layer is reinforced and water is stopped. The reinforcement of the starting shaft end is carried out by ultra-high pressure jet grouting piles and dewatering wells are arranged.

[0010] Step 4: The contact surfaces of the first rib-type back wall and the second rib-type back wall with the pipe jacking machine are distributed with the reaction force of the main jacking cylinder by the steel sleeve backrest. The backrest is fixed to the first rib-type back wall and the second rib-type back wall by pre-embedded steel bars. The gaps are filled with C25 fine stone concrete to complete the construction of the bidirectional jacking backrest system in the same starting well.

[0011] Step 5: After the construction of the main structure of the first basement level side wall within the starting well hoisting hole area is completed and reaches the required strength, the pipe jacking machine is hoisted and assembled to begin pipe jacking.

[0012] Step 6: After the jacking pipe is completed, the first rib-type back wall, the second rib-type back wall, the first reinforced concrete diagonal brace, and the second reinforced concrete diagonal brace are cut and removed using a wire saw, and the main structure top slab within the hole area is restored by cast-in-place.

[0013] Furthermore, in step 3, before the shield machine starts and is received, the soil layer within a range of 1.5 times the length of the pipe jacking machine and 3m outside the outer edge of the tunnel is reinforced and waterproofed.

[0014] Furthermore, in step 3, a dewatering well is placed every 15m at a distance of 2m outside the edge of the end reinforcement line.

[0015] Furthermore, step 6 includes:

[0016] Step 6.1: Prepare cutting tools, mark the cutting position, and use a water drill to make holes to fix the cutting equipment.

[0017] Step 6.2: Cut the first ribbed back wall and the second ribbed back wall, as well as the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace.

[0018] Furthermore, in step 6.2, when cutting the first ribbed back wall and the second ribbed back wall, as well as the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace, a drilling machine is used in conjunction with a wire saw for construction and the construction of lifting holes for the cutting blocks. When encountering blind spots during the cutting process, the drilling machine is used to open up the blind spots to complete the entire cutting construction.

[0019] Furthermore, in step 6.2, when cutting the first ribbed back wall and the second ribbed back wall, as well as the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace, the cutting is carried out in the order from the outside to the inside and from the top to the bottom.

[0020] Furthermore, in step 6.2, when cutting the first ribbed back wall and the second ribbed back wall, and the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace, the cutting length is ≤2m.

[0021] Furthermore, in step 6.2, when cutting the first ribbed back wall and the second ribbed back wall, as well as the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace, each cutting block is temporarily lifted and fixed in advance through the lifting hole to prevent the cutting block from collapsing.

[0022] Furthermore, step 6.1 includes: providing water and electricity to the construction site; setting up temporary retaining walls and drainage facilities around the cutting area.

[0023] Further, step 6.1 includes: spraying paint to mark the concrete entity to be cut off, cutting off the concrete support, the first ribbed back wall and the second ribbed back wall in sections; calculating the weight of the cut sections to meet the load requirements of the lifting equipment, and then cutting them into sections.

[0024] Furthermore, step 6.1 includes: when using a water drill for cutting, erecting a temporary scaffold; fixing the water drill equipment at the location where the hole is to be drilled, and securing the side of the water drill with expansion bolts.

[0025] On the other hand, the present invention provides a bidirectional jacking backing system for pipe jacking in the same starting well, comprising: a base plate and a first rib-type backing wall and a second rib-type backing wall fixed on the base plate, a first reinforced concrete diagonal brace and a second reinforced concrete diagonal brace fixed on the base plate, wherein the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace are located between the first rib-type backing wall and the second rib-type backing wall.

[0026] Furthermore, a concrete leveling layer is provided on the base plate, and the concrete leveling layer is made of C20 plain concrete.

[0027] Furthermore, the bidirectional jacking backing system within the same starting shaft also includes a steel casing, which is fixedly installed on the first ribbed back wall and the second ribbed back wall. Reinforcing bars welded to the steel casing are pre-embedded in the first ribbed back wall and the second ribbed back wall. The gaps between the first ribbed back wall, the second ribbed back wall, and the steel casing are filled with a C25 fine stone concrete layer.

[0028] Furthermore, the heights of the first and second reinforced concrete diagonal braces are flush with the heights of the first and second ribbed back walls.

[0029] The beneficial effects of this invention are:

[0030] 1. The construction and dismantling method of the backing system for bidirectional pipe jacking within the same starting shaft described in this invention uses a ribbed backing wall as the backing support for pipe jacking, enabling simultaneous bidirectional pipe jacking operations. This enhances the safety design within the starting shaft and features rapid construction, reliable technology, reduced material consumption, and shorter construction period. It also reduces the impact of various factors such as project conditions on the construction period. The base adopts the existing backing wall of the pipe jacking working shaft, which can maximize the use of existing resources, reduce the waste of manpower and financial resources, and lower project costs. Each section of pipe jacking uses a steel sleeve backing to distribute the reaction force of the main jacking cylinder, which can prevent the shaft wall from being damaged due to local reaction force exceeding the bearing capacity, ensuring the safety of pipe jacking construction.

[0031] 2. The construction and dismantling method of the back wall system for bidirectional jacking of pipe in the same starting shaft described in this invention involves the simultaneous construction of the back wall structure and the main structure of the jacking shaft. The starting jacking working shaft adopts the support of the underground continuous wall structure in conjunction with the internal support, and also serves as the ventilation opening for subsequent pipe gallery operation and maintenance. While ensuring the integrity of the structure and accelerating the construction period, the structure is fully utilized and the cost is reduced. The reinforced concrete ribs and diagonal braces of the jacking back wall system are dismantled by cutting them in sections with a wire saw, following the order from the outside to the inside and from top to bottom, which accelerates the construction period and avoids the risk of cracking of the working shaft structure caused by mechanical or manual demolition. At the same time, it is beneficial to environmental protection. Attached Figure Description

[0032] Figure 1 This is a plan view of the bidirectional jacking backing system within the same starting well as described in this embodiment of the invention;

[0033] Figure 2 This is a schematic elevation view of the bidirectional jacking backing system within the same starting well as described in this embodiment of the invention.

[0034] Figure 3 This is a reinforcement diagram of the slab-type back wall and the diagonal bracing structure described in the embodiment of the present invention;

[0035] In the figure, 1-base plate, 21-first ribbed back wall, 22-second ribbed back wall, 31-first reinforced concrete diagonal brace, 32-second reinforced concrete diagonal brace, 4-steel casing, 5-C25 fine aggregate concrete layer, 6-horizontal main reinforcement, 7-vertical main reinforcement, 8-diagonal main reinforcement. Detailed Implementation

[0036] To better understand the above-mentioned objectives, features and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0037] In the embodiments of this application, a bidirectional jacking backing system for pipe jacking in the same starting well and a method for constructing and dismantling the bidirectional jacking backing system for pipe jacking in the same starting well are provided.

[0038] Example

[0039] like Figure 1-2 As shown, the bidirectional jacking backing system in the same starting well includes: a base plate 1 and a first ribbed backing wall 21 and a second ribbed backing wall 22 fixed on the base plate 1, a first reinforced concrete diagonal brace 31 and a second reinforced concrete diagonal brace 32 fixed on the base plate 1, wherein the first reinforced concrete diagonal brace 31 and the second reinforced concrete diagonal brace 32 are located between the first ribbed backing wall 21 and the second ribbed backing wall 21;

[0040] In the above embodiments, the ribbed structure adopted by the first ribbed back wall 21 and the second ribbed back wall 22 has better stability and torsional resistance than traditional sheet pile, gravity and prefabricated structures. At the same time, it does not require prefabricated components, has small structural size and good integrity.

[0041] The height of the first ribbed rear wall 21 and the second ribbed rear wall 22 is 4.8m;

[0042] The first ribbed back wall 21 and the second ribbed back wall 22 are laterally connected to the central partition wall of each compartment. The wall thickness of the first ribbed back wall 21 and the second ribbed back wall 22 is 1000mm, and the main reinforcement extends into the bottom plate 1 by no less than 1000mm. The steel sleeve box 4 is fixedly installed on the first ribbed back wall 21 and the second ribbed back wall 22. The first ribbed back wall 21 and the second ribbed back wall 22 are pre-embedded with steel bars that are welded to the steel sleeve box 4. The gaps between the first ribbed back wall 21 and the second ribbed back wall 22 and the steel sleeve box 4 are filled with C25 fine stone concrete.

[0043] The dimensions of the steel casing 4 are 4500mm × 2000mm × 30mm;

[0044] The base plate is provided with a concrete leveling layer, which is made of C20 plain concrete.

[0045] In the above embodiment, the thickness of the concrete leveling layer is 1050mm, and the upper main reinforcement extends at least 1000mm.

[0046] The heights of the first reinforced concrete diagonal brace 31 and the second reinforced concrete diagonal brace 32 are flush with the heights of the first ribbed back wall 21 and the second ribbed back wall 22.

[0047] In the above embodiments, such as Figure 3 As shown, the lower parts of the first reinforced concrete diagonal brace 31 and the second reinforced concrete diagonal brace 32 extend into the concrete leveling layer and connect with the bottom cushion layer of the starting well. The first reinforced concrete diagonal brace 31 and the second reinforced concrete diagonal brace 32 have a plate thickness of 600mm. The first reinforced concrete diagonal brace 31 and the second reinforced concrete diagonal brace 32 are provided with horizontal main bars 6, vertical main bars 7, and diagonal main bars 8. The horizontal main bars 6 include Several HRB400 grade steel bars of @100, the vertical main reinforcement 7 including Several HPB300 grade hook bars of @400, the oblique main bars 8 include 6 bars arranged along the edge of the slab. HRB400 grade steel bars.

[0048] The construction method of the bidirectional jacking backing system within the same starting well includes:

[0049] S1, the first ribbed back wall 21 and the second ribbed back wall 21 are constructed simultaneously with the main structure of the jacking well.

[0050] S2, the starting jacking shaft adopts a support method of underground continuous wall combined with internal bracing, and the main structure of the jacking shaft is constructed.

[0051] S3, before the shield tunneling starts and receives, the soil layer is reinforced and water-stopped. The reinforcement of the starting shaft end adopts ultra-high pressure jet grouting pile stratum reinforcement and dewatering wells are arranged.

[0052] S4, the contact surfaces of the first ribbed back wall 21 and the second ribbed back wall 22 with the pipe jacking machine are distributed to the main jacking cylinder reaction force by the steel sleeve box 4 backrest. The backrest is fixed to the first ribbed back wall 21 and the second ribbed back wall 22 by pre-embedded steel bars welded and fixed. The gaps are filled and compacted with C25 fine stone concrete layer 5 to complete the construction of the backrest system for bidirectional pipe jacking in the same starting well.

[0053] In S3 of the above embodiment, it includes:

[0054] S3.1, Before the shield tunneling machine starts and is received, the soil layer within a range of 1.5 times the length of the tunnel jacking machine and 3m outside the outer edge of the tunnel shall be reinforced and waterproofed.

[0055] S3.2, 2m outside the edge of the end reinforcement line, one dewatering well is arranged every 15m.

[0056] The dismantling method for the backfill system after bidirectional pipe jacking in the same starting well includes:

[0057] S5, after the main structure of the basement side wall of the starting well hoisting hole area is completed and reaches the required strength, the pipe jacking machine is hoisted and assembled to start pipe jacking;

[0058] S6. After the jacking pipe is completed, the first ribbed back wall 21 and the second ribbed back wall 21, the first reinforced concrete diagonal brace 31 and the second reinforced concrete diagonal brace 32 are removed by wire saw cutting, and the main structure top plate of the hole area is restored by cast-in-place.

[0059] In S6 of the above embodiment, the following is included:

[0060] S6.1, Prepare cutting tools, mark the cutting position, and use a water drill to make holes to fix the cutting equipment;

[0061] S6.2, cut the first ribbed back wall 21 and the second ribbed back wall 22, and the first reinforced concrete diagonal brace 31 and the second reinforced concrete diagonal brace 32.

[0062] S6.1 includes:

[0063] S6.1.1, Ensure water and electricity are supplied to the construction site; set up temporary retaining walls and drainage facilities around the cutting area;

[0064] S6.1.2, the concrete entities to be cut are marked with paint, and the concrete support, the first rib-type back wall 21 and the second rib-type back wall 21 are cut into blocks; the weight of the cut blocks is calculated to meet the load requirements of the lifting equipment, and the blocks are cut into blocks.

[0065] S6.1.3 When using a water drill for cutting, erect a temporary scaffold; fix the water drill equipment at the location where the hole is to be drilled, and secure the side of the water drill with expansion bolts.

[0066] S6.2 includes:

[0067] When cutting the first ribbed back wall 21 and the second ribbed back wall 22, and the first reinforced concrete diagonal brace 31 and the second reinforced concrete diagonal brace 32, a drilling machine is used in conjunction with a wire saw and the hoisting holes of the cutting blocks are constructed. When encountering a cutting blind spot during the cutting process, the drilling machine is used to open the blind spot and complete the entire cutting construction.

[0068] When cutting the first ribbed back wall 21 and the second ribbed back wall 22, and the first reinforced concrete diagonal brace 31 and the second reinforced concrete diagonal brace 32, the cutting shall be carried out in the order from the outside to the inside and from the top to the bottom.

[0069] When cutting the first ribbed back wall 21 and the second ribbed back wall 22, and the first reinforced concrete diagonal brace 31 and the second reinforced concrete diagonal brace 32, cut them into blocks ≤2m in size.

[0070] When cutting the first ribbed back wall 21 and the second ribbed back wall 22, and the first reinforced concrete diagonal brace 31 and the second reinforced concrete diagonal brace 32, each cutting block is temporarily lifted and fixed in advance through the lifting hole to prevent the cutting block from collapsing.

[0071] This invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims.

Claims

1. A method for constructing and dismantling a backing structure for bidirectional pipe jacking within a single starting shaft, wherein the backing structure includes a base plate and a first ribbed backing wall and a second ribbed backing wall fixed to the base plate, and a first reinforced concrete diagonal brace and a second reinforced concrete diagonal brace fixed to the base plate, characterized in that... The construction and demolition methods include: Step 1: The first ribbed back wall and the second ribbed back wall are constructed simultaneously with the main structure of the jacking well. Step 2: The starting jacking shaft adopts a support method of underground continuous wall combined with internal bracing, and the main structure of the jacking shaft is constructed. Step 3: Before the shield tunneling machine starts and receives the tunnel, the soil layer is reinforced and water is stopped. The reinforcement of the starting shaft end is carried out by ultra-high pressure jet grouting piles and dewatering wells are arranged. Step 4: The contact surfaces of the first rib-type back wall and the second rib-type back wall with the pipe jacking machine are distributed with the reaction force of the main jacking cylinder by the steel sleeve backrest. The backrest is fixed to the first rib-type back wall and the second rib-type back wall by pre-embedded steel bars. The gaps are filled with C25 fine stone concrete to complete the construction of the backrest structure for bidirectional pipe jacking in the same starting well. Step 5: After the construction of the main structure of the first basement level side wall within the starting well hoisting hole area is completed and reaches the required strength, the pipe jacking machine is hoisted and assembled to begin pipe jacking. Step 6: After the jacking pipe is completed, the first ribbed back wall, the second ribbed back wall, the first reinforced concrete diagonal brace, and the second reinforced concrete diagonal brace are removed by cutting with a wire saw. The main structure roof slab within the hole area is then cast in place. Step 6.1: Prepare cutting tools, mark the cutting position, and use a water drill to fix the cutting equipment; connect water and electricity to the construction site; set up temporary water retaining walls and drainage facilities around the cutting area. The concrete structures to be cut are marked with paint, and the concrete support, the first ribbed back wall, and the second ribbed back wall are cut into sections; the weight of the cut sections is calculated to meet the load requirements of the lifting equipment, and then the sections are cut into sections. When using a water drill for cutting, erect a temporary scaffold; fix the water drill equipment at the location where the hole is to be drilled, and secure the side of the water drill with expansion bolts; Step 6.2, cut the first ribbed back wall and the second ribbed back wall, and the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace: When cutting the first ribbed back wall and the second ribbed back wall, as well as the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace, a drilling machine is used in conjunction with a wire saw for construction and the construction of the hoisting holes for the cutting blocks. When encountering blind spots during the cutting process, a drilling machine is used to open up the blind spots and complete the entire cutting construction. When cutting the first ribbed back wall and the second ribbed back wall, as well as the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace, the cutting length shall be ≤2m. When cutting the first ribbed back wall and the second ribbed back wall, as well as the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace, each cutting block is temporarily lifted and fixed in advance through the lifting hole to prevent the cutting block from collapsing.

2. A backfill structure for bidirectional pipe jacking in the same starting well, applicable to the method described in claim 1, characterized in that, include: The base plate and the first rib-type back wall and the second rib-type back wall fixed on the base plate, the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace fixed on the base plate, the base plate is provided with a concrete leveling layer, the concrete leveling layer is C20 plain concrete, wherein the first reinforced concrete diagonal brace and the second reinforced concrete diagonal brace are located between the first rib-type back wall and the second rib-type back wall. The base plate is provided with a concrete leveling layer, which is made of C20 plain concrete. The steel casing is fixedly installed on the first ribbed back wall and the second ribbed back wall. The first ribbed back wall and the second ribbed back wall are pre-embedded with reinforcing bars that are welded to the steel casing. The gaps between the first ribbed back wall, the second ribbed back wall and the steel casing are filled with C25 fine stone concrete.

3. The bidirectional jacking backfill structure within the same starting well as described in claim 2, characterized in that, The heights of the first and second reinforced concrete diagonal braces are flush with the heights of the first and second ribbed back walls.

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