Reinforcing structure and construction method for high water level pipe jacking in shoal

Abstract

This invention discloses a reinforced structure and construction method for high-water-level pipe jacking support in sandbars. The structure includes a caisson unit, a pipe roof grouting and water-stopping unit, and a pipe reinforcement unit. The caisson unit comprises a seepage barrier wall, a working well, and a receiving well. Multiple tightly interlocking seepage barriers form a composite curtain of support and water-stopping. The pipe roof grouting and water-stopping unit includes a pre-embedded bundled sleeve, a grouting perforated pipe, and bolts. The pre-embedded bundled sleeve is embedded in the sidewall of the caisson. After the grouting perforated pipe is positioned using a dragging process, high-pressure grouting is performed, and the formed piles interlock to form an annular water-stopping curtain, blocking the surrounding water and soil. The pipe reinforcement unit is located in the borehole channel within the water-stopping curtain and includes a jacking pipe, clamps, wire mesh, and pre-reserved reinforcing bars in the well chamber. The wire mesh is fixed to the clamps to form a skeleton mesh. The pre-reserved reinforcing bars in the well chamber are bent and anchored to the wire mesh. Grouting and curing are performed around the jacking pipe to form a reinforced protective layer. This structure achieves integrated and coordinated protection of the enclosure waterproofing and pipeline reinforcement, effectively improving the stability and impermeability of the pipeline.

Description

Technical Field

[0001] This invention belongs to the field of caisson jacking technology, and more specifically, relates to a reinforced structure for caisson jacking support and construction method in sandbars at high water levels. Background Technology

[0002] Pipe jacking is the mainstream trenchless technology in the field of underground pipeline laying. It has advantages such as minimal disturbance to surface traffic and surrounding buildings, high construction efficiency, and environmental friendliness, and has been widely used in the construction of various underground infrastructure projects such as urban underground pipe networks and integrated pipe corridors. In complex and unfavorable strata such as gravel and high water table soil layers, due to the loose soil particles, uneven gradation, high porosity and high permeability, coupled with the consistently high groundwater level in the area, pipe jacking construction is prone to safety hazards such as soil instability around the borehole, groundwater leakage, sand inrush and borehole collapse. Long-term service of pipelines is also prone to quality problems such as pipe section misalignment, structural deformation and damage, joint leakage, and silt blockage inside the pipe, which seriously restricts the safety of construction and the stability of operation.

[0003] For the aforementioned working conditions, existing technologies mostly adopt solutions that independently set up retaining and waterproofing structures and pipeline reinforcement structures, carrying out ground waterproofing protection and pipeline structural reinforcement construction separately. However, this type of model has many drawbacks: the separate construction of the two types of structures significantly increases on-site procedures, prolongs the construction period, and increases project costs; moreover, the protection systems are independent of each other and cannot work together to bear the load, resulting in insufficient protective effect and adaptability to the strata; at the same time, there are also technical shortcomings such as insufficient targeted sealing of the perimeter of the caisson section pipe jacking hole, limited space for directional drilling and retaining construction, insufficient sealing and durability of pipe section connections, difficulty in densely filling the gaps around the pipe wall, and easy loss and difficulty in solidification of grouting slurry in high water level environments.

[0004] Therefore, there is an urgent need for a reinforced structure for pipe jacking in sandy areas with high water levels. This structure can achieve integrated and coordinated protection of water-stopping and pipeline reinforcement, fully adapt to complex geological conditions of sandy gravel with high water levels, ensure the safe progress of pipe jacking construction, and improve the overall structural stability and impermeability of the pipeline. Summary of the Invention

[0005] To address the problems of existing technologies in high-water-level sand and gravel pipe jacking construction, such as the disconnect between the pipe jacking water-stopping and reinforcement systems, easy collapse of the hole and grout leakage during construction, and easy leakage and deformation during operation, this invention provides a reinforced retaining structure and construction method for high-water-level sandbar pipe jacking to solve these defects.

[0006] To achieve the above objectives, this invention provides a reinforced structure for high-water-level pipe jacking in sandbars, comprising: a caisson unit, including a seepage barrier wall, a working well, and a receiving well; the working well and the receiving well are prefabricated and installed upstream and downstream of the pipeline, respectively, with multiple tightly interlocking seepage barriers constructed around their outer perimeters to form a composite curtain; and a pipe roof grouting and water-stopping unit, including pre-embedded bundled sleeves and grouting perforated pipes; the pre-embedded bundled sleeves are respectively installed at the working openings on the side walls of the working well and the receiving well; the grouting perforated pipes are arranged around the axis of the jacking pipe, with both ends passing through two sets of pre-embedded bundled sleeves, and after high-pressure grouting... The piles formed by the grouting pipes interlock and overlap to form a continuous, closed annular water-stop curtain; and a pipeline reinforcement unit is set in the borehole channel in the middle of the annular water-stop curtain, which includes a jacking pipe, clamps, wire mesh and reserved steel bars in the well chamber; multiple clamps are clamped at intervals along the axis of the jacking pipe to the wall of the jacking pipe; the wire mesh is fixed to the clamps to form an integral skeleton mesh; the reserved steel bars in the well chamber are bent and extended in the direction of the pipeline and then overlapped and anchored with the wire mesh; after grouting and curing the gaps around the jacking pipe, a reinforced protective layer is formed, realizing integrated and coordinated protection of the enclosure water-stop and pipeline reinforcement.

[0007] Furthermore, the pre-embedded bundle sleeve includes a positioning ring plate and a sleeve; the positioning ring plate is a ring-shaped structure with an inner diameter larger than the outer diameter of the top pipe, and multiple sets of through holes are evenly spaced around its circumference; the diameter of the sleeve is adapted to the through holes, and multiple sets of sleeves are inserted into the corresponding through holes and fully welded, so that the middle end of the sleeve is fixedly connected to the ring plate.

[0008] Furthermore, the number of grouting perforated pipe groups is the same as the number of casings, with both ends respectively located in the corresponding casings of two sets of pre-embedded bundle casings; a single grouting perforated pipe includes multiple grouting pipe sections, adjacent grouting pipe sections are sequentially threaded to the casing to form a grouting perforated pipe; a dragging pipe drill rod adapted to the casing diameter is used to drive the dragging pipe drill rod to drill horizontally from the casing on the working well side, accurately pass through the corresponding casing hole on the receiving well side, and then connect the grouting perforated pipe through a converter, using a method of pulling back and lengthening to pull the grouting perforated pipe section by section into place until the end of the grouting perforated pipe at the receiving well end is in place, and the end of the grouting perforated pipe at the receiving well end is sealed with a screw head; after all the grouting perforated pipe dragging operations are completed in sequence, the drill rod and conversion components are removed, and a grouting head is connected to the end of the grouting perforated pipe at the working well end to carry out high-pressure grouting operations, thereby forming an annular water-stopping curtain.

[0009] Furthermore, the clamps are arranged at intervals along the axial direction of the jacking pipe according to a differentiated layout principle to adapt to different pipe section lengths. They include clamp rings, reinforcing parts, guide parts, reinforcing ribs, pulleys, threading holes, and grouting holes.

[0010] Furthermore, the hoop includes two half-hoops, which are spliced ​​together to form a hoop. The hoop is tightly secured to the outer wall of the jacking pipe by bolts or welding, and a rubber pad is attached to its inner side. The reinforcing part is circumferentially fixed to the outer periphery of the hoop and has a T-shaped stiffening structure. The guiding part is circumferentially fixed to the outer periphery of the hoop, located on one side of the pipe jacking direction, and has a conical ring structure. The reinforcing ribs are spaced along the outer periphery of the hoop, with their sides fixedly connected to the reinforcing part and their bottoms fixedly connected to the hoop. The pulleys are rotatably mounted on the lower hoop body of the hoop, and multiple sets are provided. The wire-passing holes are located on the reinforcing part and the guiding part, and are used to pass through and fix the main reinforcement of the steel wire mesh. The grout-passing holes are located on the reinforcing ribs and are elliptical channels.

[0011] Furthermore, the wire mesh is laid on the outer periphery of the jacking pipe, including main reinforcement and ring reinforcement; the main reinforcement passes through the wire-threading hole along the pipeline axis to form an integral longitudinal skeleton; the ring reinforcement is tied to the outside of the main reinforcement with tie wire to form a reinforced mesh; the pre-reserved steel bars in the well chamber are laid at the working opening, and after bending and extending in the direction of the pipeline, they overlap and anchor with the end of the wire mesh on the outer wall of the jacking pipe.

[0012] Furthermore, the seepage prevention wall adopts multiple rows of cement mixing piles, which are formed by overlapping each other to form a composite curtain; both the working well and the receiving well are precast reinforced concrete caisson structures, and the two well chambers are respectively provided with working openings on their side walls. The two sets of working openings are precisely aligned along the jacking pipe axis, and temporary sealing can be set at the working openings to block water and soil.

[0013] Furthermore, the grouting holes of the grouting pipe are arranged at an angle towards the receiving well, with an inclination angle ranging from 30° to 60°.

[0014] Furthermore, the jacking pipe is made of steel pipe sections adapted to the sand and gravel strata. The pipe sections are installed in sections by hoisting and jacking one section at a time. The pipe section joints are spliced ​​using a circumferential full welding process, and the joint positions are equipped with clamps for radial reinforcement to ensure the joint strength and water tightness.

[0015] According to another aspect of the present invention, a construction method for a reinforced structure for pipe jacking support in sandbars at high water levels is also provided, comprising the following steps: S1: Complete on-site measurement and layout, construct 2-5 rings of anti-seepage walls around the working well and receiving well to form a composite curtain that combines support and water-stopping functions; simultaneously precast reinforced concrete caissons, pre-embedded bundle sleeves and reserved reinforcing bars in the well chamber at the working opening, and install temporary sealing to block water and soil. S2: After the strength of the anti-seepage wall and the caisson structure reaches the standard, the caisson sinking and bottom sealing construction will be completed in conjunction with the dewatering operation to form a stable and dry underground working cavity; S3: Hoist the pipe-pulling equipment into the working well, drive the pipe-pulling drill rod to drill horizontally from the casing on the side of the working well, and accurately pass through the corresponding casing hole on the side of the receiving well; after removing the drill bit, connect the grouting pipe through the converter, and splice the pipe sections of the grouting pipe with the sleeve, and use the method of pulling back and lengthening at the same time until all the grouting pipes are in place. S4: The receiving well end is sealed with a screw head at the end of the grouting pipe, and the working well end of the grouting pipe is connected to the grouting head for high-pressure grouting, so that the piles formed by the grouting of each grouting pipe interlock with each other and form a continuous and sealed annular water-stop curtain. S5: Select a suitable pipe jacking drilling rig, drive the drilling rig head to enter from the working well end working port, and drill and excavate in the strata inside the annular water-stop curtain along the pipe jacking axis to form a drilling channel; S6: Remove the temporary seal at the end of the working well, bend the reserved steel bars in the well chamber toward the pipeline; install clamps on the outer wall of the jacking pipe, and fix the wire mesh to the clamps; S7: Segmented jacking of pipe, when approaching the receiving wellhead working port, the corresponding temporary plug is removed, and after the pipe is accurately positioned, the drilling equipment is withdrawn, so that the pre-reserved steel bars and wire mesh in the well chamber are overlapped and anchored. S8: Install sealing plates on the inside of the working ports at both ends, inject micro-expansion fine stone concrete into the gaps around the outer periphery of the jacking pipe through the grouting port, and evenly fill the gaps around the wire mesh. Stop grouting after the venting holes continuously and evenly spew out grout, and cure to form a reinforced protective layer around the pipe. S9: Remove the sealing plate, clean the gaps between components at the work opening, and fill the gaps with high-strength micro-expansion waterproof concrete; construct the cover plate, well cylinder, well cover and other caisson accessories in sequence, and backfill the soil around the well chamber in layers symmetrically to complete the overall construction.

[0016] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. The reinforced structure for pipe jacking of the present invention uses grouting pipes arranged circumferentially around the pipe jacking. After being precisely positioned by pre-embedded bundle sleeves, high-pressure grouting is carried out. The formed multiple grouting piles interlock and overlap to form a continuous and sealed annular water-stop curtain. This can completely block groundwater and loose gravel soil around the pipe jacking. It achieves all-round sealing and water-stopping around the pipe jacking hole, effectively avoiding risks such as hole collapse and sand inrush, groundwater leakage, and ground subsidence during pipe jacking construction, and ensuring the stability of the construction stratum from the source.

[0017] 2. The pipe jacking enclosure reinforcement structure of the present invention, by providing a guide clamp between the pipe jacking and the annular water-stop curtain, forms a continuous internal support system. Internally, it can perform overall shaping and reinforcement of the pipe jacking, and externally, it can effectively offset the high pressure water and soil load of high water level strata, avoiding deformation and cracking failure of the outer water-stop structure under pressure. At the same time, the clamp provides a stable installation node for the wire mesh, ensuring that the thickness of the reinforcement layer around the pipe is uniform and the shape is regular, realizing the coordinated force of the water-stop structure and the pipe reinforcement structure, overcoming the drawbacks of the traditional solution where the two are independent and the protection is disconnected.

[0018] 3. The pipe jacking enclosure reinforcement structure of the present invention uses steel wire mesh as the reinforcing skeleton of the outer reinforcement layer of the pipeline, combined with micro-expansion fine stone concrete integral grouting filling. The tensile reinforcement performance of the steel wire mesh and the compressive strength of the concrete form a composite reinforcement system, which significantly improves the overall load-bearing capacity, integrity and impermeability of the outer enclosure structure of the pipeline. At the same time, the reinforcement layer can restrain pipeline deformation, enhance the integrity of pipe joint interfaces, and also form a protective wrap around the steel jacking pipe, greatly improving the pipeline's corrosion resistance and extending the service life of the project.

[0019] 4. The reinforced structure for pipe jacking of the present invention, through the integrated connection structure at the end of the caisson, reliably fixes both ends of the grouting pipe to the walls of the working well and receiving well through the pre-embedded bundle sleeve. At the same time, the wire mesh and the pre-reserved steel bars in the well chamber are bent and lapped for anchoring, so that the pipe jacking pipeline, the annular water-stop curtain, the reinforced protective layer and the composite curtains at both ends form a complete overall stress system. This completely solves the defects of weak rigidity, poor sealing and easy leakage and damage of the pipe-caisson connection node in traditional pipe jacking projects, and greatly improves the stability and waterproof durability of the node structure.

[0020] 5. The reinforced structure for pipe jacking support of the present invention addresses the challenges of narrow construction space in pipe jacking working shafts and the difficulty of directional laying of grouting pipes using traditional methods. This structure employs a pipe-pulling process to accurately pull and install the grouting pipe between the pre-embedded bundle sleeves at both ends of the caisson. This method is convenient to construct and provides precise positioning, effectively adapting to the construction conditions of narrow well chambers, reducing the construction difficulty of pipe jacking support structures in complex strata, and improving the forming quality and operational efficiency.

[0021] 6. The pipe jacking support reinforcement structure of the present invention organically integrates the external pipe roof grouting and water-stopping technology with the internal pipe reinforcement technology, changing the traditional step-by-step construction mode of water-stopping and reinforcement with system separation. The process is simplified and the structure has strong synergy. It can stably adapt to pipe jacking construction in complex strata with high water levels and gravel. At the same time, it solves many industry pain points such as soil instability, water seepage and grouting during the construction stage, and pipe section misalignment, deformation and leakage, and pipe blockage during the operation stage. It improves the construction quality and operational stability of the entire project cycle from the structural root.

[0022] 7. The pipe jacking support reinforcement structure of the present invention adopts a complete set of construction technology, including pipe roof sealing and water stop, rigid reinforcement of pipeline and overall anchoring of well pipe, to form a special pipe jacking construction system adapted to loose, high-permeability, high-water-pressure complex strata. The process is compact and the technology is highly targeted, which can effectively solve the construction problems such as soil instability, groundwater leakage, sand inrush and hole collapse, and jacking blockage in traditional construction technology, and ensure the efficient, safe and stable progress of pipe jacking construction in the caisson section. It has mature conditions for engineering application. Attached Figure Description

[0023] Figure 1 This is a cross-sectional schematic diagram of a reinforced structure for high-water-level pipe jacking support in a sandbar, as described in an embodiment of the present invention. Figure 2 This is a schematic cross-sectional view of the pipe roof grouting and water-stopping unit in an embodiment of the present invention, wherein Figure a is... Figure 1 Figure 1 is a cross-sectional view along the AA direction, Figure 2 is a cross-sectional view along the BB direction, Figure 3 is a cross-sectional view along the CC direction, and Figure 4 is a schematic diagram of the sectional section of the sealing plate. Figure 3 This is a schematic diagram of the construction of the pipe roof grouting and water-stopping unit in an embodiment of the present invention; Figure 4 This is a schematic diagram of the construction of the pipeline reinforcement unit in an embodiment of the present invention; Figure 5 This is a schematic diagram of the pipe reinforcement unit in an embodiment of the present invention; Figure 6 The following are schematic diagrams of the clamp structure in an embodiment of the present invention, wherein Figure a is a three-dimensional structural view of the clamp, Figure b is a sectional view along the AA direction, Figure c is a sectional view along the BB direction, and Figure d is a sectional view along the CC direction; Figure 7 This is a schematic diagram of the grouting pipe structure in an embodiment of the present invention; Figure 8 This is a schematic diagram of the pre-embedded bundle sleeve in an embodiment of the present invention.

[0024] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-Caijing unit, including: 11-Impervious wall, 12-Working shaft, 13-Receiving shaft; 2-Pipe roof grouting and water-stopping unit, including: 21-Pre-embedded bundle sleeve, 211-Positioning ring plate, 212-Sleeve, 22-Grouting flower pipe, 23-Screw head, 24-Sleeve; 3-Pipe reinforcement unit, including: 31-jacking pipe, 32-clamp, 321-clamp ring, 322-reinforcing part, 323-guide part, 324-reinforcing rib, 325-pulley, 326-threading hole, 327-grouting hole, 33-wire mesh, 331-main reinforcement, 332-ring reinforcement, 333-binding wire, 34-reserved reinforcement in the well chamber; 4-Construction accessories, including: 41-Sealing plate, 42-Grouting port, 43-Grouting head, 44-Temporary plug, 45-Drag pipe drill rod, 46-Converter, 47-Drilling rig head, 48-Exhaust hole; 5-Caison accessories, including: 51-Caison cover, 52-Caison shaft, 53-Caison cover. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0026] like Figure 1-8 As shown, this invention provides a reinforced structure for high-water-level pipe jacking in sandbars, comprising a caisson unit 1, a pipe roof grouting and water-stopping unit 2, and a pipe reinforcement unit 3. The caisson unit 1 includes a seepage barrier wall 11, a working well 12, and a receiving well 13. The working well 12 and the receiving well 13 are prefabricated and installed upstream and downstream of the pipeline, respectively. Multiple tightly interlocking seepage barrier walls 11 are constructed around the outer perimeter of both, forming a composite curtain that combines foundation pit support and water-stopping and seepage prevention functions. After being sunk and sealed, it provides a stable and dry construction space for internal pipe jacking operations. The pipe roof grouting and water-stopping unit 2 includes a pre-embedded bundle sleeve 21, a grouting perforated pipe 22, and a screw head 23. The pre-embedded bundle sleeve 21 is pre-embedded in the middle at the working opening on the side wall of the working well 12 and the receiving well 13. The assembled grouting perforated pipe 22 is pulled into place between the two sets of pre-embedded bundle sleeves 21 using a pipe-pulling process. After high-pressure grouting, the piles formed by the solidification of each grouting perforated pipe 22 interlock and overlap, forming a continuous and sealed annular water-stopping curtain around the jacking pipe, thus achieving the isolation and sealing of the surrounding water and soil. The pipeline reinforcement unit 3 is located within the borehole channel in the middle of the annular water-stop curtain. It includes a jacking pipe 31, clamps 32, wire mesh 33, and pre-reserved reinforcing bars 34 in the well chamber. Multiple clamps 32 are spaced along the axis of the jacking pipe and secured to the wall of the jacking pipe 31. The main reinforcing bars 331 of the wire mesh 33 penetrate the clamps 32 axially and are circumferentially wrapped with ring reinforcing bars 332 to form an integral skeleton mesh. The pre-reserved reinforcing bars 34 in the well chamber are bent and extended towards the pipeline and overlapped with the wire mesh 33 for anchoring. Grouting is performed on the outer periphery of the jacking pipe 31 to form a reinforced protective layer, effectively improving the structural stability, deformation resistance, and impermeability durability of the pipeline. The jacking pipe enclosure reinforcement structure of this invention achieves integrated and synergistic protection of water-stopping enclosure and pipeline reinforcement, fully adapting to complex geological conditions with high water levels in gravel formations, ensuring the safe progress of jacking pipe construction, and improving the overall structural stability and impermeability durability of the pipeline.

[0027] like Figure 1As shown in the embodiment of the present invention, the caisson unit 1 provides stable and dry closed working conditions for pipe roof grouting construction and pipe jacking operations in a gravelly high-water-level soil environment, and includes a seepage-proof wall 11, a working well 12 and a receiving well 13.

[0028] The seepage barrier wall 11 serves as the outer protective structure of the caisson structure. It employs multiple tightly interlocking cement mixing piles, arranged in 2-5 rings around the perimeter of the working well 12 and the receiving well 13. This seepage barrier wall 11 utilizes multiple rows of cement mixing piles, interconnected to form a composite curtain that combines foundation pit support and water-stopping / seepage prevention. It effectively blocks high-level groundwater and loose gravel from seeping into the well, controlling the risk of ground deformation and groundwater intrusion outside the pit, thus creating a stable hydrogeological boundary for caisson sinking and pipe jacking operations. Preferably, dewatering wells are installed diagonally across the area enclosed by the seepage barrier wall 11, allowing for simultaneous dewatering operations with the water-stopping curtain, further lowering the groundwater level in the work area and ensuring dry construction conditions.

[0029] Both the working shaft 12 and the receiving shaft 13 are precast reinforced concrete caisson structures with high rigidity and strong impermeability, capable of withstanding lateral water and soil pressure in gravel strata with high water levels. The working shaft 12 is located upstream of the pipeline and serves as the starting working shaft for pipe jacking construction. The receiving shaft 13 is located downstream of the pipeline and serves as the receiving working shaft for pipe jacking construction. Both shafts have working openings on their side walls, and the two sets of working openings are precisely aligned along the pipe jacking axis. In the early stage of construction, the working opening is used to block water and soil by installing temporary sealing plates 44 to ensure the safety of the caisson sinking operation. During the pipe jacking construction stage, it serves as the passage for the jacking of the pipe 31. Later, it is used to install sealing plates 41 to carry out grouting reinforcement of the outer periphery of the pipeline. The working well 12 can accommodate the hoisting, positioning, and operation of the pipe pulling equipment and the pipe jacking drilling equipment. It is the starting point for the grouting pipe 22 to be pulled back and the pipe jacking 31 to be jacked in sections. The receiving well 13 provides working space for the pipe pulling drill rod 45 to pass through and the drilling head 47 to receive it in the construction accessories 4. Together, they constitute the working benchmarks and structural support at both ends of the entire pipe jacking construction process.

[0030] During the prefabrication construction of working well 12 and receiving well 13, pre-embedded bundle sleeves 21 are pre-embedded at the working openings located in the middle of the side walls of both well chambers, providing a positioning reference for the subsequent installation of grouting pipes 22. Simultaneously, pre-reserved reinforcing bars 34 are provided around the working openings for subsequent overlap and anchoring with the wire mesh 33 of the pipeline reinforcement unit 3, achieving overall force transmission between the well body and the pipeline reinforcement system. During the caisson prefabrication stage, temporary sealing 44 is installed to close the working openings during the caisson sinking and water-stopping structure construction stages, preventing sand and groundwater from entering the well. After the structural strength of the anti-seepage wall 11 piles and the prefabricated caisson reaches the design requirements, dewatering operations are initiated. The caisson sinking construction is carried out following the principle of layered excavation and sinking as excavation progresses, with strict control over the verticality, horizontal deflection angle, and elevation accuracy of the caisson throughout the process. After the caisson is positioned and meets the standards, bottom sealing and bottom slab concrete pouring are carried out. After curing to the design strength, a complete and sealed underground working cavity is formed.

[0031] like Figure 1-4 and Figure 7-8 As shown in this embodiment of the invention, the pipe roof grouting and water-stopping unit 2 is arranged around the jacking pipe 31, relying on the two end caisson units 1 for deployment. The grouting perforated pipe 22 is precisely installed using a pipe-dragging construction process, forming a continuously interlocking annular water-stopping curtain after high-pressure grouting. This achieves comprehensive isolation and sealing of the surrounding soil and water in the high-water-level gravel strata, avoiding risks such as borehole collapse, sand inrush, groundwater leakage, and ground subsidence during pipe jacking construction. The pipe roof grouting and water-stopping unit 2 includes a pre-embedded bundle sleeve 21, a grouting perforated pipe 22, a screw head 23, and a sleeve 24.

[0032] The pre-embedded bushing 21 serves as the positioning and load-bearing component for the grouting perforated pipe 22. It is a prefabricated steel component, pre-embedded and installed at the center of the sidewalls of the working shaft 12 and receiving shaft 13 during the caisson prefabrication stage. This provides precise hole positions and sealing support for the subsequent installation of the grouting perforated pipe. It includes a positioning ring plate 211 and a bushing 212. The positioning ring plate 211 has a ring-shaped structure with multiple sets of through holes evenly spaced circumferentially. The inner diameter of the positioning ring plate 211 is 5-10cm larger than the outer diameter of the jacking pipe 31, reserving an adjustment gap for jacking construction and ensuring sufficient working space. The bushing 212 has a diameter matching the through holes. Multiple sets of bushings 212 are inserted into the corresponding through holes and fully welded, fixing the middle end of the bushing 212 to the ring plate 211. Furthermore, the inner diameter of the bushing 212 is Φ50-Φ75mm, the wall thickness is not less than 3.5mm, and the length is consistent with the thickness of the caisson sidewall. In terms of parameter design, the distance between the sleeve 212 and the inner edge of the positioning ring plate 211 is controlled at 15-30cm, and the net spacing between adjacent sleeves 212 is 10-25cm. By matching the above design parameters, it can be ensured that the interlocking width of the pile body after the subsequent grouting of the grouting pipe 22 is not less than 5cm, ensuring that the annular water-stop curtain is completely sealed and leak-free.

[0033] The number of grouting pipe groups 22 is the same as the number of sleeves 212. Both ends of the pipe are respectively located within the corresponding sleeves 212 of two sets of pre-embedded bundle sleeves 21. The grouting pipe 22 injects concrete grout into the surrounding soil layer through grouting holes on its body, forming concrete piles. Multiple circumferentially arranged concrete piles interlock and overlap, forming a continuous and sealed annular water-stop curtain. Preferably, the grouting pipe 22 uses Φ48.3×3.6 specification scaffolding steel pipe, a material readily available locally and with rigidity and durability suitable for complex underground environments. Furthermore, each grouting pipe 22 comprises multiple grouting pipe sections, each with threaded ends. The threads consist of 2-15 threads, with a pull-out length of not less than 15cm, ensuring the sealing and structural strength of the threaded connection. Adjacent grouting pipe sections are sequentially threaded to sleeves 24, thus forming a spliced ​​structure. A grouting perforation pipe 22 is formed; furthermore, the grouting holes of the grouting perforation pipe 22 are arranged at an angle towards the receiving well 13, with the angle of inclination controlled between 30° and 60°; through the inclined grouting holes, mud can be prevented from entering the pipe through the grouting holes and causing blockage during the pullback of the drill pipe 45, while ensuring that after the grouting slurry is injected from the working well end, it can evenly fill the gaps of the sand and gravel around the grouting perforation pipe 22 from bottom to top and from the inside to the outside, thereby improving the uniformity and density of the grouting consolidation.

[0034] The screw head 23 is a threaded sealing component, which is fixedly installed at the end of the grouting pipe 22 on one side of the receiving well 13. The pipe opening is sealed by threaded connection to prevent grout from overflowing from the receiving well end during grouting, and to ensure stable grouting pressure and grout diffusion effect. The end of the grouting pipe 22 on one side of the working well 12 is equipped with a grouting head 43 for connecting to the external grouting pipeline to carry out high-pressure grouting operations.

[0035] The sleeve 24 is a steel threaded connection sleeve used for connecting adjacent grouting pipe sections, enabling rapid extension of pipe sections and sealing of pipelines, and adapting to the operation mode of pulling pipe construction while simultaneously pulling back and extending the pipe.

[0036] In this embodiment of the invention, the pipe roof grouting and water-stopping unit 2 is laid out and grouting is formed using a pipe-pulling process. During construction, a pipe-pulling drill rod 45 adapted to the diameter of the casing 212 is used to drive the pipe-pulling drill rod 45 to drill horizontally from the casing 212 on the working well side. After accurately penetrating the corresponding hole of the casing 212 on the receiving well side, the grouting perforated pipe 22 is connected through the converter 46. The grouting perforated pipe is pulled into place section by section by pulling back and extending it until the end of the grouting perforated pipe 22 at the receiving well end is in place. The end of the grouting perforated pipe 22 at the receiving well end is sealed with a screw head 23. After all the grouting perforated pipe 22 is pulled out in sequence, the drill rod and the conversion component are removed. Then, a grouting head 43 is connected to the end of the grouting perforated pipe 22 at the working well end to carry out high-pressure grouting.

[0037] During drilling operations, the pre-embedded bundled sleeve 21 is centered and fixed to the side wall of the working opening via the positioning ring plate 211. The sleeve 212 and the positioning ring plate 211 are fully welded and cured to ensure the relative positional accuracy of a single set of holes. The specifications and layout of the pre-embedded bundled sleeves 21 of the working well 12 and the receiving well 13 are completely consistent. During the sinking process of the caisson, the verticality, plane deflection and elevation accuracy are strictly controlled to ensure that the corresponding sleeves 212 at both ends are precisely coaxially aligned along the jacking pipe axis, thus determining the drilling benchmark from the source. At the same time, the length of the sleeve 212 is consistent with the thickness of the caisson sidewall, forming a long distance. The rigid guide channel has an inner diameter that matches the outer diameter of the drag pipe drill pipe 45, ensuring smooth drill pipe insertion and limiting drill pipe inlet sway through the radial constraint of the pipe wall, providing stable initial guidance for the entire drilling process and avoiding deviation during the initial drilling stage. The drag pipe drill pipe 45 is sequentially inserted into the corresponding casing 212 from bottom to top, and real-time correction and calibration are performed throughout the drilling process. The drilling attitude is dynamically adjusted based on the coaxial reference of the casing 212 at both ends to ensure that the drill pipe accurately passes through the corresponding casing 212 hole on the receiving well side, eliminating the cumulative deviation error during the drilling process.

[0038] During grouting operations, the grouting pressure is 0.5-0.8 MPa, the grouting time per hole is 20-30 minutes, the grout diffusion radius is 300-500 mm, and the cement grout water-cement ratio is controlled at 1:1-1:1.5. At the same time, 8%-10% silica fume or fly ash admixture and 3%±0.2% flocculant are added. After grouting, the curing period is no less than 28 days. Finally, the piles formed by the grouting of each grouting pipe interlock and overlap to form a continuous and sealed annular water-stop curtain, which completely blocks the groundwater and loose gravel soil outside the jacking pipe. This provides a stable and leak-proof external protective barrier for the internal jacking construction, effectively solving the technical problems of easy hole collapse, sand inrush, and grout leakage in gravelly high water level strata.

[0039] like Figure 1-6 As shown in the embodiment of the invention, the pipeline reinforcement unit 3 is located in the borehole channel inside the annular water-stop curtain, which can effectively offset the water and soil pressure of the high-water-level strata, prevent the outer water-stop structure from being deformed by pressure, and at the same time improve the structural stability, deformation resistance and impermeability durability of the jacking pipeline. The pipeline reinforcement unit 3 includes a jacking pipe 31, clamps 32, wire mesh 33 and pre-reserved reinforcing bars 34 in the well chamber.

[0040] The jacking pipe 31 is the main load-bearing component of the pipeline. It is made of steel pipe sections adapted to the gravel strata and is laid out in the borehole channel inside the annular water-stop curtain along the jacking pipe axis. It also serves as the installation base for reinforcement components such as clamps 32 and wire mesh 33. The pipe sections are laid out by segmented hoisting and jacking in section by section. The pipe section joints are spliced ​​by circumferential full welding process. The joint positions are equipped with clamps 32 for radial reinforcement to ensure the strength and water tightness of the joint.

[0041] The clamp 32 is made of high-rigidity alloy material and is axially and spacedly fastened to the pipe wall of the jacking pipe 31 to form a continuous internal support system, while providing a stable installation node for the wire mesh 33; the clamp 32 includes a clamp ring 3211, a reinforcing part 322, a guide part 323, a reinforcing rib 324, a pulley 325, a wire threading hole 326, and a grout penetration hole 327. The clamp 321 comprises two half-clamps, which are joined together to form the clamp 3211. The clamp 321 is tightly secured to the outer wall of the jacking pipe 31 by bolts or welding, and has a width of not less than 20cm. Furthermore, a rubber pad is attached to the inner side of the clamp 321 to prevent direct contact between the rigid structure and the jacking pipe 31, thus avoiding damage or scratches to the pipe wall and enhancing contact friction and sealing. The reinforcing part 322 is circumferentially fixed to the outer periphery of the clamp 321; it is a T-shaped stiffening structure that significantly improves the overall bending and compressive stiffness of the clamp 32, offsetting structural deformation caused by external water and soil pressure and jacking load. The guiding part 323 is circumferentially fixed to the outer periphery of the clamp 321, located on one side of the pipe jacking direction; it is a conical ring structure that significantly reduces pipe wall friction during jacking construction. The force provides precise guidance for pipeline jacking, ensuring smooth progress. The reinforcing ribs 324 are spaced along the outer circumference of the clamp ring 321, with their sides fixedly connected to the reinforcing part 322 and their bottom fixedly connected to the clamp ring 321, further strengthening the clamp 32's resistance to jacking deformation and improving overall structural stability. The pulleys 325 are rotatably mounted on the lower clamp body of the clamp ring 3211, with multiple sets, 4-6 evenly distributed within a 60° radius from the bottom of the clamp ring 3211. During jacking, they convert the sliding friction between the pipe wall and the soil in the duct into rolling friction, significantly reducing jacking resistance and minimizing wear on the outer wall of the pipeline, protecting the pipeline's anti-corrosion layer. The wire-penetrating holes 326 are located on the reinforcing part 322 and the guiding part 323, used to thread and fix the main reinforcement 331 of the wire mesh 33. The grout-permeable holes 327 are located on the reinforcing ribs 324, and are elliptical channels, ensuring smooth flow and uniform filling of grout during subsequent grouting of the outer circumference of the pipeline.

[0042] The clamp 32 follows a differentiated layout principle: when the pipe section length is ≤3m, a clamp 32 is installed at the pipe section connection position. An intermediate clamp can be added according to the self-weight of the pipe, and the number of pulleys 325 can be increased to further reduce the jacking resistance; when the pipe section length is >3m, a clamp 32 is installed every 1.5-3m along the axis of the jacking pipe 31; a clamp 32 is installed 30cm away from the pipe head of the first jacking pipe section to ensure the stability and guiding accuracy of the first pipe section jacking.

[0043] The wire mesh 33 serves as the reinforcing framework for the outer reinforcement layer of the pipeline, arranged around the outer perimeter of the jacking pipe 31. It includes main reinforcing bars 331 and ring reinforcing bars 332, both made of high-strength steel wire. The main reinforcing bars 331 and ring reinforcing bars 332 differ in size by 2-6 sizes. The main reinforcing bars 331 pass through the wire-passing holes 326 of the clamps 32 along the pipeline axis, forming an integral longitudinal framework. The ring reinforcing bars 332 are tied to the outside of the main reinforcing bars 331 with binding wire 333 at fixed intervals of 3-5 cm, forming a uniformly meshed and structurally stable reinforced mesh. The two ends of the wire mesh 33 are lapped and anchored to the bent and extended pre-reserved reinforcing bars 34 in the manhole, achieving an effective force transmission connection between the pipeline reinforcement structure and the main structure of the caisson, improving the integrity and anti-disturbance capability of the manhole pipe connection.

[0044] The pre-reserved steel bars 34 in the well chamber are pre-embedded reinforcing bars in the prefabrication stage of the working well 12 and the receiving well 13. They are laid at the working opening. During the construction stage, the pre-reserved steel bars 34 in the well chamber are bent and extended in the direction of the pipeline and overlapped and anchored with the end of the wire mesh 33 on the outer wall of the jacking pipe 31. This makes the pipeline reinforcement system and the caisson structure at both ends form a complete whole-body force system, which solves the defects of weak rigidity, poor sealing and easy leakage and damage of the pipeline and caisson connection node in traditional pipe jacking projects, and greatly improves the stability and waterproof durability of the node structure.

[0045] In this embodiment of the invention, after the jacking pipe 31 is jacked into place, a sealing plate 41 is installed inside the working opening. The sealing plate 41 has multiple sets of through holes, the positions of which correspond to the positions of the grouting pipes 22. A screw head 23 is threaded through the through holes and connected to the grouting pipe 22, thereby locking the sealing plate 41 tightly against the inside of the working opening. The end sealing plate 41 of the receiving well has a grouting port 42 at its top, and the end sealing plate 41 of the working well has a vent hole at its top. High-pressure injection of micro-expansion fine aggregate concrete of at least C25 is carried into the gaps around the jacking pipe 31 through the grouting port 42. The grout evenly fills all gaps around the wire mesh 33. Grouting is stopped when grout continuously and evenly emerges from the vent hole 48 and no air bubbles are discharged. After grouting, curing is carried out for at least 14 days. After the concrete has cured, a completely wrapped and uniformly reinforced protective layer is formed on the outside of the jacking pipe 31. Internally, this system can constrain pipeline deformation, reinforce pipeline structure, and improve anti-seepage and anti-corrosion performance; externally, it can support the outer water-stop curtain and jointly bear water and soil loads, realizing the integrated and coordinated stress bearing of the water-stop structure and pipeline reinforcement structure, while strengthening the integrity and durability of well pipe nodes, and ensuring the long-term stable service of pipelines.

[0046] When constructing the reinforced pipe jacking structure of this invention, construction preparation and on-site measurement and layout are completed first. Two to five tightly interlocking anti-seepage walls 11 are constructed around the working well 12 and receiving well 13 to form a composite curtain that combines support and water-stopping functions. Simultaneously, a reinforced concrete caisson is precast. A pre-embedded bundle sleeve 21 is installed at the caisson working opening, and a pre-reserved steel bar 34 is reserved in the well chamber. After completion, a temporary seal 44 is installed at the working opening to block water and soil. After the anti-seepage wall 11 and the caisson structure reach the strength standard, dewatering is started and the caisson sinking and bottom sealing operations are carried out to form a stable and dry underground working space. Subsequently, a small pipe-pulling device is hoisted into the working well 12, and the pipe-pulling drill rod 45 is driven horizontally through the working well end in a circumferential sequence from bottom to top. After the casing 212 is precisely passed through the corresponding casing 212 at the receiving well end, the drill bit is removed and the grouting perforated pipe 22 is connected via the converter 46. The pipe sections of the grouting perforated pipe 22 are spliced ​​and connected by the sleeve 24. The grouting perforated pipe 22 is pulled into place as a whole by pulling back and extending it. The end of the grouting perforated pipe 22 is sealed with a screw head 23 at the receiving well end. The working well end is connected to the end of the grouting perforated pipe 22 by a connecting grouting head 43, thereby carrying out high-pressure grouting operations. This allows the pile bodies formed by the grouting of each grouting perforated pipe 22 to interlock and overlap, forming a continuous and sealed annular water-stop curtain. After curing for no less than 28 days and meeting the standards, the construction of the pipe roof grouting water-stop unit 2 is completed. After the strength of the water-stop structure meets the requirements, the temporary sealing 44 at the working well end is removed, and the well is opened. The pre-reserved reinforcing bars 34 in the chamber are bent towards the pipeline. A pipe jacking drill with an outer contour of the drill head 47 that matches the size of the clamp 32 is selected. The clamp 32 is installed on the outer wall of the jacking pipe 31. The main reinforcing bars 331 are passed through the corresponding wire holes 326 along the axial direction. The ring reinforcing bars 332 are tied to the outside of the main reinforcing bars 331 with tie wire to form an integral reinforced mesh. Then, the jacking pipe 31 is jacked in sections. When the drill head 47 is close to the working port of the receiving well end, the corresponding temporary plug 44 is removed and the pre-reserved reinforcing bars 34 in the well chamber are bent. The jacking continues until the pipeline is accurately positioned, and then the drill equipment is withdrawn, so that the pre-reserved reinforcing bars 34 in the well chamber and the wire mesh 33 on the outer wall of the jacking pipe 31 can be reliably overlapped and anchored. After the jacking pipe 31 is in place, the sealing plates 41 are installed on the inner side of the working ports at both ends. The sealing plates 41 are connected to the grouting pipe 2 by the screw head 23. Two ends are spirally locked and sealed. Through the grouting port 42 on the upper part of the receiving well end sealing plate 41, high pressure is applied to the gaps around the jacking pipe 31 to inject micro-expansion fine stone concrete of not less than C25. The grout evenly fills all gaps around the wire mesh 33 through the grouting holes 327 of the clamp 32. Grouting is stopped when the vent hole 48 of the working well end sealing plate 41 continuously and evenly emits grout and no air bubbles are discharged. Curing is carried out for no less than 14 days to form a reinforced protective layer around the pipe. Finally, the sealing plate 41 is removed, and the gaps around the grouting pipe 22 and the jacking pipe 31 at the working opening are cleaned. High-strength micro-expansion waterproof concrete is used to fill the gaps and finish the surface. Then, the cover plate 51, well cylinder 52, and well cover 53 of the caisson accessories are constructed in sequence. The soil around the well chamber is backfilled in layers and symmetrically compacted to complete the overall construction operation.

[0047] The reinforced structure for pipe jacking of this invention uses grouting pipes 22 arranged circumferentially around the pipe jacking 31. After being precisely positioned by the pre-embedded bundle sleeve 21, high-pressure grouting is carried out. The formed multiple grouting piles interlock and overlap to form a continuous and sealed annular water-stop curtain. This can completely block groundwater and loose gravel soil around the pipe jacking. It achieves all-round sealing and water-stopping around the hole, effectively avoiding risks such as hole collapse and sand inrush, groundwater leakage, and ground subsidence during pipe jacking construction, and ensuring the stability of the construction stratum from the source.

[0048] The pipe jacking enclosure reinforcement structure of the present invention uses a clamp 32 with guiding function between the pipe jacking 31 and the annular water-stop curtain. The clamp 32 forms a continuous internal support system, which can internally reinforce the pipe jacking 31 as a whole and externally effectively offset the high pressure water and soil load of high water level strata, avoiding the deformation and cracking failure of the outer water-stop structure under pressure. At the same time, the clamp 32 provides a stable installation node for the wire mesh 33, ensuring that the thickness of the reinforcement layer around the pipe is uniform and the shape is regular, realizing the coordinated force of the water-stop structure and the pipe reinforcement structure, overcoming the shortcomings of the traditional solution where the two are independent and the protection is disconnected.

[0049] The pipe jacking enclosure reinforcement structure of the present invention uses steel wire mesh 33 as the reinforcing skeleton of the outer reinforcement layer of the pipeline, combined with micro-expansion fine stone concrete integral grouting filling. The tensile reinforcement performance of steel wire mesh 33 and the compressive strength of concrete form a composite reinforcement system, which significantly improves the overall load-bearing capacity, integrity and impermeability of the outer enclosure structure of the pipeline. At the same time, the reinforcement layer can restrain pipeline deformation, enhance the integrity of pipe joint interfaces, and also form a protective wrap around the steel jacking pipe 31, greatly improving the pipeline's corrosion resistance and extending the service life of the project.

[0050] The reinforced structure for pipe jacking of the present invention, through the integrated connection structure at the end of the caisson, reliably fixes both ends of the grouting pipe 22 to the walls of the working well 12 and the receiving well 13 through the pre-embedded bundle sleeve pipe 21. At the same time, the wire mesh 33 and the pre-reserved steel bars 34 in the well chamber are bent and overlapped for anchoring, so that the pipe jacking pipeline, the annular water-stop curtain, the reinforced protective layer and the composite curtains at both ends form a complete overall stress system. This completely solves the defects of weak rigidity, poor sealing and easy leakage and damage of the pipe-caisson connection node in traditional pipe jacking projects, and greatly improves the stability and waterproof durability of the node structure.

[0051] The reinforced structure for pipe jacking protection of the present invention addresses the challenges of narrow construction space in pipe jacking working shafts and the difficulty of directional laying of grouting pipes using traditional methods. This structure employs a pipe-pulling process to accurately pull and install the grouting perforated pipe 22 between the pre-embedded bundle sleeves 21 at both ends of the caisson. This method is convenient to construct and provides precise positioning, effectively adapting to the construction conditions of narrow well chambers, reducing the construction difficulty of pipe jacking protection structures in complex strata, and improving the forming quality and operational efficiency.

[0052] The pipe jacking support reinforcement structure of this invention organically integrates the external pipe roof grouting and water-stopping technology with the internal pipe reinforcement technology. It changes the traditional step-by-step construction mode of water-stopping and reinforcement with separate systems. The process is simplified and the structure has strong synergy. It can stably adapt to pipe jacking construction in complex strata with high water levels and gravel. At the same time, it solves many industry pain points such as soil instability, water seepage and grout leakage, and jacking blockage during the construction stage, and pipe section misalignment, deformation and leakage, and internal pipe blockage during the operation stage. It improves the construction quality and operational stability of the entire project cycle from the structural root.

[0053] The reinforced structure for pipe jacking of this invention adopts a complete set of construction techniques, including pipe roof sealing and water stoppage, rigid reinforcement of the pipeline, and overall anchoring of the well pipe. This forms a specialized pipe jacking construction system adapted to complex strata with loose soil, high permeability, and high water pressure. The process is tightly linked and highly targeted, which can effectively solve construction problems such as soil instability, groundwater leakage, sand inrush and hole collapse, and jacking blockage in traditional construction techniques. It ensures efficient, safe, and stable progress of pipe jacking construction in the caisson section and has mature conditions for engineering application.

[0054] This invention also provides a construction method for a reinforced structure for pipe jacking support in sandbars at high water levels, comprising the following steps: S1: Complete on-site measurement and layout, construct 2-5 rings of anti-seepage walls 11 around the working well 12 and receiving well 13 to form a composite curtain that combines support and water-stopping functions; simultaneously precast reinforced concrete caissons, pre-embedded bundle sleeves 21 and reserved reinforcing bars 34 in the reserved well chamber at the working opening, and install temporary seals 44 to block water and soil. S2: After the seepage prevention wall 11 and the caisson structure reach the required strength, the caisson sinking and bottom sealing construction will be completed in conjunction with the dewatering operation to form a stable and dry underground working cavity; S3: Hoist the pipe-pulling equipment into the working well 12, drive the pipe-pulling drill rod 45 to drill horizontally from the casing 212 on the side of the working well, and accurately pass through the corresponding casing 212 hole on the side of the receiving well; after removing the drill bit, connect the grouting perforated pipe 22 through the converter 46, and splice the pipe sections of the grouting perforated pipe 22 with the sleeve 24, and use the method of pulling back and lengthening at the same time until all the grouting perforated pipes 22 are in place; S4: The receiving well end is sealed with screw head 23 at the end of the grouting pipe 22, and the working well end of the grouting pipe 22 is connected to the grouting head 43 for high-pressure grouting, so that the piles formed by the grouting of each grouting pipe 22 interlock with each other and form a continuous and sealed annular water-stop curtain. S5: Select a suitable pipe jacking drilling rig, drive the drilling rig head 47 to enter from the working well end working port, and drill and excavate in the strata inside the annular water-stop curtain along the pipe jacking axis to form a drilling channel. S6: Remove the temporary plug 44 at the end of the working well, bend the reserved steel bar 34 in the well chamber toward the pipeline; install clamp 32 on the outer wall of the jacking pipe 31, and fix the wire mesh 33 to the clamp 32. S7: The pipe jacking 31 is segmented and the corresponding temporary plug 44 is removed when it is close to the receiving well end working port. After the pipe is accurately positioned, the drilling equipment is withdrawn, so that the pre-reserved steel bar 34 in the well chamber and the wire mesh 33 are overlapped and anchored. S8: Install sealing plates 41 on the inner side of the working ports at both ends, inject micro-expansion fine stone concrete into the outer periphery of the jacking pipe 31 through the grouting port 42, and evenly fill the gaps around the wire mesh 33. Stop grouting after the venting hole 48 continuously and evenly spews out grout, and cure to form a reinforced protective layer around the pipe. S9: Remove the sealing plate 41, clean the gaps between components at the work opening, and fill the gaps with high-strength micro-expansion waterproof concrete; construct the cover plate 51, well cylinder 52, well cover 53 and other caisson accessories 5 in sequence, and backfill the soil around the well chamber in layers symmetrically to complete the overall construction.

[0055] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A reinforced structure for pipe jacking support in sandbars at high water levels, characterized in that, include: The caisson unit (1) includes a seepage barrier wall (11), a working well (12) and a receiving well (13). The working well (12) and the receiving well (13) are prefabricated and installed at the upstream and downstream positions of the pipeline, respectively. Multiple tightly interlocking seepage barriers (11) are constructed around the outer perimeter of the two to form a composite curtain. The pipe roof grouting water-stopping unit (2) includes a pre-embedded bundle sleeve (21) and a grouting flower pipe (22). The pre-embedded bundle sleeve (21) is respectively installed at the working opening on the side wall of the working well (12) and the receiving well (13). The grouting flower pipe (22) is arranged around the axis of the jacking pipe, and its two ends are respectively inserted on two sets of pre-embedded bundle sleeves (21). After high-pressure grouting, the pile bodies formed by the solidification of each grouting flower pipe (22) interlock and overlap to form a continuous and closed annular water-stopping curtain. The pipeline reinforcement unit (3) is located in the middle of the borehole channel of the annular water-stop curtain. It includes a jacking pipe (31), clamps (32), wire mesh (33) and reserved reinforcing bars (34) in the well chamber. Multiple clamps (32) are clamped at intervals along the axis of the jacking pipe to the wall of the jacking pipe (31). The wire mesh (33) is fixed to the clamps (32) to form an integral skeleton mesh. The reserved reinforcing bars (34) in the well chamber are bent and extended in the direction of the pipeline and then overlapped and anchored with the wire mesh (33). After grouting and curing the gaps around the jacking pipe (31), a reinforced protective layer is formed, realizing the integrated and coordinated protection of water-stopping and pipeline reinforcement.

2. The reinforced structure for high-water-level pipe jacking support in sandbars according to claim 1, characterized in that, The pre-embedded bundle sleeve (21) includes a positioning ring plate (211) and a sleeve (212); the positioning ring plate (211) is a ring-shaped structure with an inner diameter larger than the outer diameter of the top pipe (31), and multiple sets of through holes are evenly spaced around its circumference; the diameter of the sleeve (212) is matched with the through holes, and multiple sets of sleeves (212) are inserted into the corresponding through holes and fully welded, so that the middle end of the sleeve (212) is fixedly connected to the ring plate (211).

3. The reinforced structure for high-water-level pipe jacking support on sandbars according to claim 2, characterized in that, The number of grouting perforated pipes (22) is the same as the number of casings (212), and their two ends are respectively set in the corresponding casings (212) on two sets of pre-embedded bundle casings (21); a single grouting perforated pipe (22) includes multiple grouting pipe sections, and adjacent grouting pipe sections are sequentially threaded to the casing (24) to form a grouting perforated pipe (22); a dragging pipe drill rod (45) adapted to the pipe diameter of the casing (212) is used to drive the dragging pipe drill rod (45) to drill horizontally from the casing (212) on the working well side, and accurately penetrate the corresponding casing on the receiving well side. (212) After the hole is positioned, the grouting pipe (22) is connected to the converter (46). The grouting pipe (22) is pulled into place section by section by pulling back and extending it until the end of the grouting pipe (22) at the receiving well end is in place. The end of the grouting pipe (22) at the receiving well end is sealed with a screw head (23). After all the grouting pipes (22) are pulled in sequence, the drill rod and the conversion component are removed. The grouting head (43) is connected to the end of the grouting pipe (22) at the working well end to carry out high-pressure grouting operation, thereby forming an annular water-stopping curtain.

4. A reinforced structure for high-water-level pipe jacking support on sandbars according to any one of claims 1-3, characterized in that, The clamps (32) are arranged at intervals along the axial direction of the jacking pipe according to the principle of differentiated layout, which can be adapted to different pipe section lengths. They include clamp rings (321), reinforcing parts (322), guiding parts (323), reinforcing ribs (324), pulleys (325), wire threading holes (326) and grouting holes (327).

5. The reinforced structure for high-water-level pipe jacking support in sandbars according to claim 4, characterized in that, The hoop (321) includes two half-hoops, which are spliced ​​together to form the hoop (321); the hoop (321) is tightly fastened to the outer wall of the jacking pipe (31) by bolts or welding, and a rubber pad is pasted on its inner side; the reinforcing part (322) is circumferentially fixed on the outer periphery of the hoop (321), and it is a T-shaped stiffening structure; the guide part (323) is circumferentially fixed on the outer periphery of the hoop (321), located on one side of the pipe jacking direction, and it is a conical ring structure; the reinforcing rib (3 24) The pulleys (325) are arranged at intervals along the outer periphery of the hoop (321), with their sides fixedly connected to the reinforcing part (322) and their bottoms fixedly connected to the hoop (321); the pulleys (325) are rotatably mounted on the lower hoop body of the hoop (321), and are provided in multiple sets; the wire-threading holes (326) are provided on the reinforcing part (322) and the guide part (323), and are used to thread and fix the main reinforcement (331) of the wire mesh (33); the grout-through holes (327) are provided on the reinforcing ribs (324), and are elliptical channels.

6. The reinforced structure for high-water-level pipe jacking support on sandbars according to claim 4, characterized in that, The wire mesh (33) is laid on the outer periphery of the jacking pipe (31) and includes main reinforcement (331) and ring reinforcement (332). The main reinforcement (331) passes through the wire-threading hole (326) along the pipeline axis to form an integral longitudinal skeleton. The ring reinforcement (332) is wrapped and tied to the outside of the main reinforcement (331) with tie wire (333) to form a reinforced mesh. The reserved steel bar (34) in the well chamber is laid at the working opening. After it bends and extends in the direction of the pipeline, it overlaps and anchors with the end of the wire mesh (33) on the outer wall of the jacking pipe (31).

7. A reinforced structure for high-water-level pipe jacking support on sandbars according to any one of claims 1-3, characterized in that, The seepage prevention wall (11) adopts multiple rows of cement mixing piles and is formed by overlapping the piles to form a composite curtain; the working well (12) and the receiving well (13) are both precast reinforced concrete caisson structures. The two well chambers are respectively provided with working openings on their side walls. The two sets of working openings are precisely aligned along the jacking pipe axis. Temporary sealing can be set at the working openings to block water and soil.

8. A reinforced structure for high-water-level pipe jacking support on sandbars according to any one of claims 1-3, characterized in that, The grouting holes of the grouting pipe (22) are arranged at an angle toward the receiving well (13), with an inclination angle ranging from 30° to 60°.

9. A reinforced structure for high-water-level pipe jacking support on sandbars according to any one of claims 1-3, characterized in that, The jacking pipe (31) is made of steel pipe sections adapted to the working conditions of gravel strata. The pipe sections are laid out by segmented hoisting and jacking section by section. The pipe section interfaces are spliced ​​by circumferential full welding process. The interface positions are equipped with clamps (32) for radial reinforcement to ensure the strength and water tightness of the nodes.

10. A construction method for a reinforced retaining structure for pipe jacking in sandbars at high water levels, characterized in that, Includes the following steps: S1: Complete the on-site measurement and layout, construct 2-5 rings of anti-seepage wall (11) around the working well (12) and receiving well (13) to form a composite curtain with both support and water-stopping functions; simultaneously precast reinforced concrete caissons, pre-embed pre-embedded bundle sleeves (21) and pre-reserved reinforcing bars (34) in the working opening, and install temporary seals (44) to block water and soil; S2: After the strength of the anti-seepage wall (11) and the caisson structure reaches the standard, the caisson sinking and bottom sealing construction will be completed in conjunction with the dewatering operation to form a stable and dry underground working cavity; S3: Hoist the towing pipe equipment into the working well (12), drive the towing pipe drill rod (45) to drill horizontally from the casing (212) on the side of the working well, and accurately pass through the corresponding casing (212) hole on the side of the receiving well; after removing the drill bit, connect the grouting flower pipe (22) through the converter (46), and splice the pipe sections of the grouting flower pipe (22) through the sleeve (24), and use the method of pulling back and lengthening at the same time until all the grouting flower pipes (22) are in place; S4: The receiving end is sealed with a screw head (23) at the end of the grouting pipe (22), and the end of the working end of the grouting pipe (22) is connected to the grouting head (43) for high-pressure grouting, so that the piles formed by the grouting of each grouting pipe (22) interlock with each other and form a continuous and closed annular water-stop curtain. S5: Select a suitable pipe jacking drilling rig, drive the drilling rig head (47) to enter from the working well end working port, and drill and excavate in the stratum inside the annular water-stop curtain along the pipe jacking axis to form a drilling channel; S6: Remove the temporary plug (44) at the end of the working well, bend the reserved steel bar (34) in the well chamber toward the pipeline; install clamps (32) on the outer wall of the jacking pipe (31), and fix the wire mesh (33) to the clamps (32); S7: Segmented jacking pipe (31), when approaching the receiving well end working port, remove the corresponding temporary plug (44), after the pipe is accurately positioned, withdraw the drilling equipment, so that the reserved steel bar (34) in the well chamber and the wire mesh (33) are overlapped and anchored. S8: Install sealing plates (41) on the inside of the working ports at both ends, inject micro-expansion fine stone concrete into the gap around the jacking pipe (31) through the grouting port (42), and fill the gap around the wire mesh (33) evenly. Stop grouting after the venting hole (48) continuously and evenly spews out grout, and cure to form a reinforced protective layer around the pipe. S9: Remove the sealing plate (41), clean the gaps in the components at the working opening, and fill the gaps with high-strength micro-expansion waterproof concrete; construct the cover plate (51), well cylinder (52), well cover (53) and other caisson accessories (5) in sequence, and backfill the soil around the well chamber in layers to complete the overall construction.

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