Large-section close-range left-right parallel rectangular pipe jacking structure

Abstract

This invention discloses a large-section, closely spaced, parallel rectangular jacking pipe structure, comprising a rectangular jacking pipe structure, including a left-line rectangular pipe section and a right-line rectangular pipe section, with an intermediate soil layer between the left and right-line rectangular pipe sections. Several transverse prestressed tie rods penetrating the intermediate soil layer are connected between the right inner wall of the left-line rectangular pipe section and the left inner wall of the right-line rectangular pipe section. The two ends of the transverse prestressed tie rods are anchored to the inner walls of the left and right-line rectangular pipe sections. By applying prestress, the left-line rectangular pipe section, the intermediate soil layer, and the right-line rectangular pipe section are compressed and connected into a single structure. This invention, by applying transverse prestress, actively and tightly clamps the thin intermediate soil layer between the two large-section rectangular jacking pipes, placing the intermediate soil layer under triaxial compression. This completely changes the brittle mechanical properties of the soil in traditional passive reinforcement methods, transforming the originally most dangerous instability source, the "weak interlayer," into a "structural core layer" that improves overall stiffness.

Description

Technical Field

[0001] This invention relates to the field of trenchless underground engineering, specifically to a structure for large-section, closely spaced parallel rectangular pipe jacking tunnels, which achieves overall structural connection and soil reinforcement through transverse prestressing. Background Technology

[0002] Large-section, closely spaced, parallel rectangular pipe jacking refers to the simultaneous or sequential jacking of two large-section rectangular tunnels in the same shallow buried stratum. They are side by side with parallel axes, but the soil separating them is very thin.

[0003] This typically occurs in the following scenarios:

[0004] A two-way separated urban underground expressway (left and right lanes running side by side);

[0005] The main structure of the subway station was constructed using the rectangular pipe jacking method.

[0006] Large underground shopping streets or pedestrian crossings with two parallel passageways.

[0007] Rectangular pipe jacking refers to a construction method that uses a pipe jacking machine with a rectangular cross-section to push pipe sections into the soil layer one by one using jacks to form underground space. Compared with traditional circular pipe jacking, rectangular pipe jacking has a higher space utilization rate. For example, when building underground tunnels, the rectangular space does not require backfilling the arch bottom, but the stress, attitude control and backfilling effect are more complex.

[0008] Large cross-sections refer to rectangular cross-sections with very large dimensions. Generally, a cross-section with a width exceeding 6 meters and a height exceeding 4 meters can be called a "large cross-section." Some engineering cases even have cross-sections that are 10 meters wide and 7 meters high or more, which is equivalent to creating a flat rectangular space the size of a basketball court underground. These are mainly used in subway stations, underground expressways, and integrated utility tunnels.

[0009] "Close-range parallelism" refers to two rectangular pipe jacking tunnels arranged horizontally, one on the left and one on the right, with a very small net distance between them, i.e., the thickness of the soil between them. "Close-range" generally means that the net distance is less than one tunnel diameter or cross-sectional span, sometimes even only 2 to 3 meters, which is much smaller than the conventional "safe distance".

[0010] When constructing two-way separated urban underground roads or utility tunnels, two rectangular pipe jacking tunnels are often excavated side-by-side. When the thickness of the inter-tunnel soil is extremely thin, far less than one tunnel diameter, the traditional approach involves grouting to reinforce the intermediate soil or installing isolation piles. However, this method has a fatal flaw:

[0011] Passive protection is unreliable: Soil disturbed by repeated construction is prone to brittle fracture even after reinforcement, leading to ground subsidence.

[0012] Force separation and easy deformation: The huge thrust of the subsequent jacking pipe will push the preceding tunnel, causing the rectangular structure to tilt and crack. Since there is no effective connection between the two structures, they cannot jointly resist external forces.

[0013] Poor long-term stability: Under loads such as earthquakes and groundwater during the operation period, the thin soil interlayer will still gradually weaken. Summary of the Invention

[0014] To address the shortcomings of existing technologies, this invention provides a structure that can actively form a stable whole with two large-section rectangular jacking pipes and the intermediate soil, significantly improving the overall deformation resistance and facilitating construction.

[0015] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0016] A large-section, closely spaced, parallel rectangular pipe jacking structure includes a left-line rectangular pipe section and a right-line rectangular pipe section, with an intermediate soil mass between the left-line rectangular pipe section and the right-line rectangular pipe section;

[0017] Several transverse prestressed tie rods penetrating the intermediate soil are connected between the right inner wall of the left rectangular tube section and the left inner wall of the right rectangular tube section.

[0018] The transverse prestressed tie rods are anchored at both ends to the inner walls of the left and right rectangular pipe sections. By applying prestress, the left rectangular pipe section, the middle soil, and the right rectangular pipe section are compressed and connected into an integral structure.

[0019] Preferably, guide steel sleeves are pre-embedded in the corresponding side walls of the left and right rectangular tube sections, and the transverse prestressed tie rods are inserted in the guide steel sleeves.

[0020] Preferably, the guide steel sheath is pre-embedded in a matrix pattern every 1.0-2.0 meters along the longitudinal direction of the left and right rectangular pipe sections.

[0021] Preferably, the outer wall of the guide steel sleeve is provided with a water-stop flange in the middle.

[0022] Preferably, the transverse prestressed tie rod is a finely rolled threaded steel bar or an unbonded steel strand, and the tensioning prestress value of the transverse prestressed tie rod is 50-100kN.

[0023] Preferably, both ends of the transverse prestressed tie rod are locked with anchors.

[0024] Preferably, an anchor plate is provided between the anchor and the guide steel sleeve, the left rectangular tube section and the right rectangular tube section, and multiple sealing rings are provided between the anchor plate and the guide steel sleeve, the left rectangular tube section and the right rectangular tube section.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) By applying transverse prestress, the present invention actively clamps the thin layer of soil in the middle between two large cross-section rectangular jacking pipes, so that the middle soil is under triaxial compression. This completely changes the mechanical properties of the soil that is prone to brittle fracture in the traditional passive reinforcement method, and turns the "weak soil sandwich" that was originally the most dangerous source of instability into a "structural core layer" that improves the overall stiffness.

[0027] (2) After the left and right double holes of the present invention are connected by matrix-type transverse prestressed tie rods, they work together with the soil in the middle to form a huge "H"-shaped composite section. Compared with the two independent jacking pipes, its transverse bending moment of inertia increases by tens of times, which enables the structure to effectively resist the upper load, eccentric pressure and later operation vibration, and reduce the relative displacement of the jacking pipe to less than 0.3mm, avoiding the stubborn problem of cracking of rectangular structures due to insufficient torsional stiffness.

[0028] (3) The present invention eliminates mutual disturbance during construction and has excellent settlement control effect. The transverse prestress, as a strong "internal support", can effectively constrain the existing structure during the first and second pipe jacking, greatly reducing the squeezing deflection caused by the jacking force of the second pipe jacking. At the same time, the active compaction of the intermediate soil compensates for the stress loss caused by construction disturbance, so that the surface settlement trough changes from superimposed deterioration to a significant reduction.

[0029] (4) The transverse prestressed tie rod of the present invention, as a permanent structural component, combined with multiple waterproof sealing and anchoring anti-corrosion measures, can meet the stress compensation requirements.

[0030] (5) The entire process of this invention is completed inside the left and right rectangular pipe sections. The prefabrication, horizontal directional drilling and prestressing tensioning are all highly integrated mature technologies. There is no need for large-area grouting reinforcement, isolation piles or additional shaft excavation from the ground. It does not interrupt ground traffic or damage underground pipelines, greatly shortens the construction period and reduces the project cost, perfectly meeting the stringent requirements of underground excavation in the core urban area.

[0031] (6) The present invention can be directly extended to parallel rectangular pipe jacking projects with larger cross sections and close distances. As long as the prestressing parameters and the arrangement of transverse prestressing tie rods are adjusted, it can adapt to different cross-sectional dimensions, different net distances and complex geological conditions, such as two-way underground expressways, subway stations, and double-compartment integrated pipe corridors, etc., and has significant economic and social benefits. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0033] Figure 2 For the present invention Figure 1 Side profile of the middle soil section;

[0034] Figure 3 This is a partially enlarged detailed view of a single connection node of the present invention;

[0035] Figure 4 This is a flowchart illustrating the construction process of this invention.

[0036] In the diagram: 1. Left rectangular pipe section; 2. Right rectangular pipe section; 3. Middle soil; 4. Transverse prestressed tie rod; 5. Guide steel sleeve; 6. Water-stop flange; 7. Anchor; 8. Anchor plate; 9. Sealing ring. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] like Figure 1-4 As shown, the present invention provides a technical solution: a large-section, closely spaced, parallel rectangular jacking pipe structure, including a left-line rectangular pipe section 1 and a right-line rectangular pipe section 2. Both the left-line rectangular pipe section 1 and the right-line rectangular pipe section 2 are precast reinforced concrete components, manufactured in a factory. There is an intermediate soil body 3 between the left-line rectangular pipe section 1 and the right-line rectangular pipe section 2.

[0039] Guide steel sleeves 5 are pre-embedded in the corresponding side walls of the left rectangular pipe section 1 and the right rectangular pipe section 2. The transverse prestressed tie rods 4 are inserted in the guide steel sleeves 5. During the jacking stage of the left rectangular pipe section 1 and the right rectangular pipe section 2, the two ends of the guide steel sleeves 5 are temporarily sealed with crushable high-strength concrete plugs. After the jacking is in place, the guide steel sleeves 5 are precisely positioned using a pipeline robot or a horizontal drilling rig, the sealing plugs are broken, and the transverse prestressed tie rods 4 are installed.

[0040] Several transverse prestressed tie rods 4 that penetrate the intermediate soil 3 are connected between the right inner wall of the left rectangular tube section 1 and the left inner wall of the right rectangular tube section 2. The two ends of the transverse prestressed tie rods 4 are anchored to the inner walls of the left rectangular tube section 1 and the right rectangular tube section 2. By applying prestress, the left rectangular tube section 1, the intermediate soil 3, and the right rectangular tube section 2 are pressed together to form an integral structure.

[0041] The transverse prestressed tie rod 4 is made of finely rolled threaded steel bar or unbonded steel strand, and the tensioning prestress value of the transverse prestressed tie rod 4 is 50-100kN. The two ends of the transverse prestressed tie rod 4 are locked with anchors 7. Anchor plates 8 are set between the anchors 7 and the guide steel sheath 5, the left rectangular tube section 1 and the right rectangular tube section 2. Multiple sealing rings 9 are set between the anchor plates 8 and the guide steel sheath 5, the left rectangular tube section 1 and the right rectangular tube section 2. The anchors 7 are grouted and sealed to form a permanent anti-corrosion structure.

[0042] The guide steel sleeve 5 is pre-embedded in a matrix pattern every 1.0-2.0 meters along the longitudinal direction of the left rectangular pipe section 1 and the right rectangular pipe section 2. A water-stop flange 6 is provided in the middle of the outer wall of the guide steel sleeve 5. The water-stop flange 6 is welded to prevent water from outside the pipe section from seeping in along the outer wall of the guide steel sleeve 5.

[0043] Construction steps overview:

[0044] S1. Based on the net distance between the left rectangular pipe section 1 and the right rectangular pipe section 2, design the specifications of the transverse prestressed tie rod 4, and accurately embed the guide steel sleeve 5 in the prefabrication yard.

[0045] S2. The left rectangular pipe section 1 is jacked through first. At this point, the guide steel sleeve 5 pre-embedded on its right side wall becomes the precise starting point of the duct.

[0046] S3. Right-line rectangular pipe section 2 is jacked in, and the pipe section's posture is accurately measured after it is in place.

[0047] S4. Using a micro-horizontal directional drill, drill from inside the left rectangular pipe section 1 through the guide steel sleeve 5 to the right, passing through the intermediate soil 3, and directly through to the corresponding guide steel sleeve 5 of the right rectangular pipe section 2. The accuracy of this process is controlled by a guiding instrument to ensure precise docking.

[0048] S5. Insert the transverse prestressed tie rods 4, install the anchors 7, and apply transverse prestress one by one or in stages. The tensioning sequence is from the middle to both sides and from top to bottom, so that the soil in the middle 3 is uniformly compacted;

[0049] S6. Check the anchoring force and seal the anchor.

[0050] Example 1

[0051] This embodiment takes a city main road underpass project as the background. The project uses the large cross section close distance left and right parallel rectangular pipe jacking method to build a two-way four-lane underground expressway.

[0052] 1) Basic project parameters:

[0053] The cross-sections of the left-line rectangular pipe section 1 and the right-line rectangular pipe section 2 are 10.5m wide and 7.2m high, which are typical large-section rectangular cross-sections.

[0054] Left rectangular tube section 1 and right rectangular tube section 2: reinforced concrete structure, wall thickness 0.6m, single section length 1.5m, concrete strength C50;

[0055] The net distance between the left rectangular pipe section 1 and the right rectangular pipe section 2 is only 2.8m, which is much smaller than the tunnel diameter, making it an extremely close parallel project.

[0056] Soil cover thickness: The soil cover above the top plate of the left rectangular pipe section 1 and the right rectangular pipe section 2 is about 7.0m.

[0057] 2) Detailed structural composition:

[0058] The large-section, closely spaced, parallel rectangular jacking pipe transverse prestressed soil-clamping connection structure consists of a left rectangular pipe section 1, a right rectangular pipe section 2, intermediate soil 3, transverse prestressed tie rod 4, guide steel sleeve 5, water-stop flange 6, anchor 7, anchor plate 8, and sealing ring 9.

[0059] 3) Pipe section prefabrication and embedded parts:

[0060] During the prefabrication of pipe sections, matrix-distributed guide steel sleeves 5 are precisely pre-embedded on the right side wall of the left rectangular pipe section 1, i.e., the side adjacent to the middle soil 3, and on the left side wall of the right rectangular pipe section 2.

[0061] Longitudinal spacing: One row is set in the middle of each pipe section, that is, one row every 1.5m;

[0062] Vertical arrangement: Each column is equipped with 3 guide steel sleeves 5, with a vertical row spacing of 1.8m; the top row is 1.2m away from the inner wall of the top plate of the left line rectangular pipe section 1 and the right line rectangular pipe section 2, and the bottom row is 1.2m away from the inner wall of the bottom plate, maintaining symmetry;

[0063] Guide steel sleeve 5 specifications: Q345B seamless steel pipe, inner diameter 80mm, wall thickness 6mm, length is 0.6m, the same as the left line rectangular pipe section 1 and the right line rectangular pipe section 2, the inner and outer walls of the left line rectangular pipe section 1 and the right line rectangular pipe section 2 are flush;

[0064] Water-stopping structure: Two annular water-stopping flanges 6 are welded in the middle of the outer wall of the guide steel sleeve 5. The water-stopping flanges 6 are 40mm wide and 6mm thick, and are in the shape of a closed ring to block the seepage channel of water and soil outside the left rectangular pipe section 1 and the right rectangular pipe section 2 along the outer surface of the guide steel sleeve 5.

[0065] Temporary sealing: Both ends of the guide steel sleeve 5 are filled with C60 high-strength non-shrink concrete plugs with a thickness of 30mm. The end face is flush with the wall of the left line rectangular pipe section 1 and the right line rectangular pipe section 2. It can withstand the mud and water pressure during the jacking process, but it can be easily broken during subsequent horizontal drilling.

[0066] 4) Construction steps:

[0067] S1. The left rectangular pipe section 1 is jacked first. The left rectangular pipe section 1 is jacked from the starting well using an earth pressure balance rectangular pipe jacking machine. The pipe sections with pre-embedded guide steel sleeves 5 are jacked up one by one until the receiving well is connected. During the jacking process, the attitude is precisely controlled by the shield machine's articulation device and grouting system. After the connection is completed, all the guide steel sleeves 5 on the right side wall of the left rectangular pipe section 1 constitute the precise positioning reference holes for subsequent drilling.

[0068] S2, the right-line rectangular tube section is subsequently jacked in.

[0069] The right-line rectangular pipe section was constructed using the same jacking method. By strictly setting the soil chamber pressure to within 105% of the original lateral pressure of the stratum, and simultaneously grouting volume and jacking speed to approximately 20 mm / min, the disturbance to the intermediate soil 3 and the already constructed left-line rectangular pipe section 1 was minimized. After jacking into place, a three-dimensional laser scanner was used to measure the actual hole position deviation of all corresponding guide steel sleeves 5 of the left-line rectangular pipe section 1 and the right-line rectangular pipe section 2. In this embodiment, the docking deviation was controlled within ±20 mm.

[0070] S3. Horizontal directional drilling: Inside the left rectangular pipe section 1, a compact horizontal directional drilling rig is set up at the position of each row of guide steel sleeves 5. The drill rod carries a 90mm diameter guide drill bit and probe. Starting from inside the guide steel sleeve 5 of the left rectangular pipe section 1, the inner concrete seal is first broken. Then, clean water is used as the circulating medium and the drilling speed is 60rpm to slowly drill through the middle soil 3. Then, the seal of the guide steel sleeve 5 of the right rectangular pipe section 2 is broken. Finally, the hole is penetrated. The guide instrument receiving screen displays the position of the drill bit in real time. The operator continuously adjusts the drill bit inclination and orientation to ensure that the drill bit accurately passes through the center of the corresponding guide steel sleeve 5 of the right rectangular pipe section 2, and completes all the drilling one by one.

[0071] S4. Insert the transverse prestressed tie rod 4 and install the anchor 7. The transverse prestressed tie rod 4 is made of PSB830 grade high-strength precision-rolled threaded steel bar with a diameter of 32mm. The design tension of a single rod is determined to be 80kN. Insert the transverse prestressed tie rod 4 from the outside of the guide steel sleeve 5 of the right line rectangular pipe section 2, pass through the intermediate soil 3 and then pass out from the guide steel sleeve 5 of the left line rectangular pipe section 1. Steel anchor plates 8 with dimensions of 250mm×250mm×25mm are inserted into both ends in sequence. Rubber O-rings 9 are provided on the contact surfaces of the anchor plates 8 with the left line rectangular pipe section 1 and the right line rectangular pipe section 2. The fixed end anchor 7 is installed on the right line rectangular pipe section 2 side and the tensioning end anchor 7 is installed on the left line rectangular pipe section 1 side.

[0072] S5. Apply transverse prestress and use a through-hole jack to tension the left rectangular pipe section 1. Strictly follow the order of "from the middle to the two wings, symmetrical alternating loading": first tension the transverse prestressing tie rod 4 in the middle row, then tension the upper and lower rows. In the same row, tension symmetrically from the middle column to both ends, loading at three levels of 20kN, 50kN, and 80kN, holding each level for 1 minute, and finally locking at 80kN. During tensioning, a dial gauge is placed at the corresponding position of the right rectangular pipe section 2 to monitor the displacement of the side wall of the right rectangular pipe section 2, ensuring that it does not exceed 0.1mm. Through the application of prestress, the middle soil 3 is uniformly compacted and is in a triaxial compression state. The left rectangular pipe section 1 and the right rectangular pipe section 2 are combined with the middle soil 3 into a huge "H"-shaped composite section.

[0073] S6. Sealing, corrosion protection, and finishing: After tensioning, cut off the excess exposed section of the transverse prestressed tie rod 4, leaving 50mm of the anchor 7 outside, install a steel protective cover, inject non-shrink cement-based grout inside the cover to completely cover the anchor 7, and after the grout has solidified, apply a layer of epoxy resin waterproof coating to form a permanent anti-corrosion layer. Finally, use high-strength mortar to locally smooth the inner wall of the left rectangular pipe section 1 and the right rectangular pipe section 2 in the anchoring area to restore the surface flatness.

[0074] 5) Implementation Results:

[0075] Through finite element numerical simulation and on-site construction monitoring, this embodiment achieved the following results: the lateral bending moment of inertia of the composite structure increased to 23 times that of the independent double-hole structure; the maximum ground settlement was reduced by 47% compared to the unconnected condition; the plastic zone inside the intermediate soil 3 completely disappeared; its minimum principal stress was always compressive stress; and the relative displacement between the left-line rectangular pipe section 1 and the right-line rectangular pipe section 2 caused by the vibration of the subsequent operating train was reduced to less than 0.3 mm. The structure fully meets the durability requirements.

[0076] Example 2

[0077] This embodiment is basically the same as Embodiment 1, except that the transverse prestressed tie rod 4 adopts an unbonded steel strand system to adapt to the requirements of greater tensile force and long-distance crossing.

[0078] Project background: The rectangular cross-sections of the left-line rectangular pipe section 1 and the right-line rectangular pipe section 2 are 12.0m wide and 8.0m high, with a net distance of 3.2m and a soil cover of 10m.

[0079] Prestressed system: Two 1×7-Φs15.2, 1860MPa grade unbonded steel strands are inserted into each hole, and the inner diameter of the corresponding guide steel sheath 5 is enlarged to 100mm, and the total design tension is increased to 120kN;

[0080] Anchor 7: A two-hole clamp-type flat anchor is adopted. During tensioning, a front-clamp jack is used to pre-tighten each anchor before the entire anchor is tensioned synchronously to the design force to ensure that the two bundles of steel strands are subjected to uniform force.

[0081] Tensioning procedure: 0→10%σcon→50%σcon→100%σcon, anchor after holding the load for 5 minutes. Due to the relatively large loss due to the slack of the steel strands, a supplementary tensioning is arranged within 24 hours to reach 105% of the design force to completely eliminate the prestress loss.

[0082] Other construction: The wall thickness of the pre-embedded guide steel sleeve 5 is increased to 8mm, and the temporary sealing plug is made of C80 high-strength concrete. The remaining steps are completely consistent with those in Example 1. This scheme still achieves a stable connection under the conditions of higher water pressure and thicker intermediate soil 3.

[0083] Example 3

[0084] Based on Example 1, this embodiment optimizes the tensioning process to address the characteristics of the intermediate soil 3, which is a saturated fine sand layer and prone to large compressive deformation.

[0085] Distinguishing feature: Employs a two-stage re-tensioning process.

[0086] In the first stage, after the right-line rectangular pipe section 2 is jacked up and the duct is completed, the cable is immediately threaded and 50% of the design prestress, i.e. 40kN, is applied to partially restore the stress lost by the intermediate soil 3 due to construction disturbance and achieve early restraint.

[0087] In the second stage, after the grouting layer reaches a certain strength (7 days) and the stratum deformation is basically stable, the tensioning is carried out to 100% of the design prestress (80kN). The prestress value is monitored on the 28th day. If the loss exceeds 5%, the tensioning is carried out again.

[0088] Long-term structural protection: A pressure sensor is added under the anchor plate 8 and connected to the permanent monitoring system for pipe jacking. This allows for real-time monitoring of prestress changes and enables maintenance throughout the entire life cycle.

[0089] This invention breaks through the mindset of separate operations for closely spaced parallel tunnels. For the first time, it proposes to apply tensile prestress by pre-embedded ducts in the sidewalls of the left-line rectangular tube section 1 and the right-line rectangular tube section 2, and to couple the intermediate soil 3 as a "core" with the double rectangular left-line rectangular tube section 1 and the right-line rectangular tube section 2 into a composite whole. By utilizing the geometric advantages of the straight rectangular sidewalls, which are conducive to load bearing and anchoring, the unfavorable physical state of the thin interlayer soil is transformed into a favorable factor for improving the overall stiffness of the cross section through active lateral pressure. The bearing capacity of the intermediate soil 3 under triaxial compression is greatly improved.

[0090] Existing pipe jacking connections are mostly longitudinal joints or transverse connecting channels in open-cut methods. This invention differs from conventional passive reinforcement methods such as pipe jacking and soil grouting. It achieves precise transverse tensioning across the soil by pre-embedding guide steel sleeves 5 for pipe jacking construction, forming a combined structure throughout the entire life cycle. This is an active, structural-level permanent connection.

[0091] The prestress applied by this invention binds the left rectangular pipe section 1, the right rectangular pipe section 2, and the intermediate soil 3 into a wide and flat "H"-shaped component, which dramatically increases the moment of inertia. This solves the persistent problems of soil instability, later tunnel relative displacement, and structural cracking once and for all. The prefabrication precision, micro-directional drilling, and prestressing tensioning relied upon are all mature technologies, with only innovative system integration. No additional ground reinforcement is required, which greatly shortens the construction period, reduces costs, and has little impact on ground traffic. It can be directly used in all large-section, close-distance rectangular pipe jacking projects such as urban underground expressway double-line tunnels, double-compartment integrated pipe corridors, and subway station main bodies, with broad industrialization prospects.

[0092] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0093] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A large-section, closely spaced, parallel rectangular pipe jacking structure, comprising a left-line rectangular pipe section (1) and a right-line rectangular pipe section (2), wherein there is an intermediate soil mass (3) between the left-line rectangular pipe section (1) and the right-line rectangular pipe section (2), characterized in that: Several transverse prestressed tie rods (4) that penetrate the intermediate soil (3) are connected between the right inner wall of the left rectangular tube section (1) and the left inner wall of the right rectangular tube section (2). The transverse prestressed tie rod (4) is anchored at both ends to the inner wall of the left rectangular pipe section (1) and the right rectangular pipe section (2). By applying prestress, the left rectangular pipe section (1), the middle soil (3), and the right rectangular pipe section (2) are pressed together to form an integral structure.

2. The large-section, closely spaced, horizontally parallel rectangular jacking pipe structure according to claim 1, characterized in that: Guide steel sleeves (5) are pre-embedded in the corresponding side walls of the left rectangular tube section (1) and the right rectangular tube section (2), and the transverse prestressed tie rod (4) passes through the guide steel sleeves (5).

3. The large-section, closely spaced, horizontally parallel rectangular jacking pipe structure according to claim 2, characterized in that: The guide steel sheath (5) is pre-embedded in a matrix pattern every 1.0-2.0 meters along the longitudinal direction of the left rectangular pipe section (1) and the right rectangular pipe section (2).

4. A large-section, closely spaced, horizontally parallel rectangular jacking pipe structure according to claim 3, characterized in that: The guide steel sleeve (5) has a water-stop flange (6) in the middle of its outer wall.

5. A large-section, closely spaced, horizontally parallel rectangular jacking pipe structure according to claim 1, characterized in that: The transverse prestressed tie rod (4) is a finely rolled threaded steel bar or an unbonded steel strand, and the tensioning prestress value of the transverse prestressed tie rod (4) is 50-100kN.

6. A large-section, closely spaced, horizontally parallel rectangular jacking pipe structure according to claim 5, characterized in that: The two ends of the transverse prestressed tie rod (4) are locked with anchors (7).

7. A large-section, closely spaced, horizontally parallel rectangular jacking pipe structure according to claim 6, characterized in that: An anchor plate (8) is provided between the anchor (7) and the guide steel sleeve (5), the left rectangular tube section (1) and the right rectangular tube section (2), and multiple sealing rings (9) are provided between the anchor plate (8) and the guide steel sleeve (5), the left rectangular tube section (1) and the right rectangular tube section (2).

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