D-shaped simply supported beam support structure in high groundwater area and construction method thereof

Abstract

This invention relates to a construction method and support structure for D-type temporary beams in areas with high groundwater levels. The method includes manual excavation, H-beam insertion, grouting reinforcement, rebar cage fabrication and installation, anchorage connection, concrete pouring, and curing. The advantages of this invention are: after manually excavating to areas below the groundwater level where construction is difficult, H-beam insertion and pile bottom grouting are performed directly. Only a small amount of water needs to be pumped out of the hole, eliminating the need for large-scale, high-intensity dewatering operations. This avoids uneven settlement of the railway subgrade caused by dewatering, fundamentally eliminating the safety hazards of dewatering operations to railway operating lines and meeting the control requirements for construction near operating lines. The H-beams bear vertical loads and resist buoyancy, the grouting reinforcement strengthens the bearing capacity of the soil at the pile bottom and prevents the H-beams from sinking, and the reinforced concrete pile body ensures the overall stability of the pile. These three elements work together to adapt to the load and buoyancy effects in areas with high groundwater levels.

Description

Technical Field

[0001] This invention relates to the field of jacking frame bridge technology, and in particular to a D-type temporary beam support structure and its construction method in areas with high groundwater levels. Background Technology

[0002] Jacking-up frame bridges are a core construction technique for the renovation of existing railway lines and urban underpass railway projects. Their key advantage is that construction can be completed without interrupting railway operations, ensuring uninterrupted flow of the main railway artery. D-type construction beams, as crucial temporary support structures in jacking-up frame bridge construction, are erected on both sides and beneath the railway subgrade via support piles to bear the beams and construction loads. Their stability directly affects railway operational safety and the quality of the jacking-up construction.

[0003] Because the D-type temporary beam support piles are located adjacent to the railway operating line, the industry generally adopts manual excavation of bored piles to avoid disturbance and damage to the railway subgrade caused by large-scale excavation by heavy machinery. However, in areas with high groundwater levels, the groundwater level is usually located within the design depth range of the bored piles. After manually excavating to the groundwater level, water will quickly accumulate in the hole, making it impossible to carry out excavation work normally. In existing technologies, the main way to solve this problem is large-area, high-intensity dewatering operations, which use deep well dewatering, lightweight wellpoint dewatering, etc., to lower the groundwater level in the construction area below the bottom of the piles before manual excavation.

[0004] However, this construction method has significant technical defects and safety hazards: 1. High-intensity dewatering operations will cause a rapid decrease in the moisture content of the soil around the construction area. Soil consolidation and shrinkage can easily lead to uneven settlement of the railway subgrade, which can cause deformation of the railway track in severe cases, directly threatening the operational safety of the railway line; 2. Dewatering operations require the installation of a large number of dewatering wells and supporting equipment, resulting in a long construction period, high project investment, and continuous monitoring of water level and subgrade settlement during the dewatering process, which significantly increases construction management costs; 3. Dewatering operations have high requirements for geological conditions. In highly permeable strata such as sandy soil and silty clay, the dewatering effect is not good, and it is still difficult to avoid the problem of water accumulation in the borehole, affecting the efficiency of borehole construction; 4. Traditional concrete manually excavated bored piles have insufficient anti-buoyancy performance and bearing capacity in areas with high groundwater levels. They are prone to problems such as pile floating, settlement and deformation due to groundwater buoyancy, which reduces the support stability of the D-type temporary beam.

[0005] Some existing technologies attempt to use precast piles to replace manually excavated piles. However, precast pile construction requires large piling machinery, which easily causes strong vibrations and disturbances to the railway subgrade, failing to meet the vibration control requirements for construction near operational lines and thus limiting its application in areas surrounding operational lines. Therefore, there is an urgent need to develop a D-type temporary beam support construction method and structure that requires no high-intensity dewatering, minimizes construction disturbance, and provides high support stability, in order to solve the technical challenges of D-type temporary beam support construction near operational lines in areas with high groundwater levels. Summary of the Invention

[0006] This invention provides a construction method and support structure for D-type temporary beams in areas with high groundwater levels, which can solve the problems of existing technologies such as the need for high-intensity dewatering, the tendency to cause uneven settlement of railway subgrades, and the insufficient anti-buoyancy and bearing capacity of traditional support piles.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a construction method for D-type temporary beam support in areas with high groundwater levels, comprising the following steps: Manual excavation was used to dig holes to areas below the groundwater level where construction was difficult. The H-beam is driven vertically into the bottom of the bored pile to the test depth, and an anchorage section is reserved at the upper end of the H-beam for connection with the reinforcing cage. High-pressure grouting is performed on the bottom and sides of the H-beam to form a grouting reinforced body. After the grouting body reaches the design strength, the soil after grouting the bottom and sides of the H-beam forms the H-beam driven section pile foundation with the H-beam. Tie the reinforcing cage according to the design specifications, hoist the reinforcing cage into the bored pile, and ensure that the distance between the reinforcing cage and the hole wall is uniform. The anchorage section of the H-beam is fixedly connected to the reinforcing cage; Concrete is poured into the bored pile and vibrated to compact it until it reaches the design elevation of the pile top. The concrete and the reinforcing cage form a concrete section pile foundation. After the concrete pile foundation has been poured, it is kept moist and cured to allow the concrete to reach its design strength.

[0008] Preferably, the manual excavation step further includes temporary protection of the hole wall during the excavation process to prevent the hole wall from collapsing.

[0009] Preferably, the temporary protection of the borehole wall adopts a steel casing or concrete casing, and the depth of the casing is synchronized with the depth of manual excavation.

[0010] Preferably, the perimeter of the combined section of the H-beam is not less than the perimeter of the concrete pile foundation.

[0011] Preferably, before the H-beam insertion step, the H-beam is subjected to a bearing capacity test under the same conditions, and the test bearing capacity should not be less than the theoretical calculation value; the reserved length of the anchorage section is 1.5 to 2.0 times the diameter of the concrete pile foundation.

[0012] Preferably, the diameter of the H-beam driven section pile foundation is 300-500 mm larger than the diameter of the concrete section pile foundation.

[0013] Preferably, the anchorage section of the H-beam is fixedly connected to the reinforcing cage by welding or mechanical connection, and an anchorage connecting bar is provided between the anchorage section of the H-beam and the reinforcing cage. The anchorage connecting bar tightens the anchorage section of the H-beam and the longitudinal bars of the reinforcing cage, thereby strengthening the connection strength between the two and ensuring effective force transmission.

[0014] The present invention also provides a D-type temporary beam support structure for areas with high groundwater levels, comprising concrete section pile foundations and H-shaped steel driven section pile foundations arranged sequentially from top to bottom; The concrete section pile foundation is a solid pile formed by concrete pouring, and a steel cage is installed inside the concrete section pile foundation; The H-beam driven into the pile foundation consists of an H-beam inside and a grouting reinforced body formed by high-pressure grouting into the soil at the bottom and sides of the H-beam. The top of the H-beam extends into the concrete pile foundation to form an anchorage section, which is fixedly connected to the reinforcing cage.

[0015] Preferably, the perimeter of the combined section of the H-beam is not less than the perimeter of the concrete pile foundation.

[0016] Preferably, the diameter of the H-beam driven section pile foundation is 300-500 mm larger than the diameter of the concrete section pile foundation.

[0017] Compared with the prior art, the beneficial effects of the present invention are: No need for high-intensity dewatering, ensuring railway operation safety: After manually excavating holes to areas below the groundwater level where construction is difficult, H-beams are directly inserted and pile bottom grouting is performed. Only a small amount of water needs to be pumped out of the holes. This eliminates the need for large-scale, high-intensity dewatering operations, avoiding uneven settlement of the railway subgrade caused by dewatering. It fundamentally eliminates the safety hazards of dewatering operations to the operation of railway operating lines and meets the control requirements for construction near operating lines.

[0018] A composite support structure is formed to improve load-bearing and anti-buoyancy performance: This invention adopts a combined support pile structure of "H-beam steel + grouting reinforcement + reinforced concrete". The H-beam steel bears the vertical load and anti-buoyancy tension, the grouting reinforcement strengthens the bearing capacity of the soil at the pile bottom and prevents the H-beam steel from sinking, and the reinforced concrete pile body ensures the overall stability of the pile body. The three work together, and compared with the traditional concrete manually excavated pile, the load-bearing capacity is significantly improved and the anti-buoyancy performance is significantly enhanced, making it suitable for the load and buoyancy effects in areas with high groundwater levels.

[0019] With minimal construction disturbance, it is suitable for construction near operating lines: The core construction process involves manual excavation and static pressure / light hammer installation of H-beams. There is no large-scale excavation with heavy machinery or strong vibration construction, resulting in minimal disturbance to the railway subgrade. It meets the vibration control standards for construction near operating lines and can simultaneously ensure normal railway operation during the construction process.

[0020] The construction process is closely linked, reducing project investment: The construction process of this invention is simple and highly interconnected, eliminating the need to deploy a large number of dewatering devices, thus reducing the equipment, labor, and management costs of dewatering operations. The project investment is significantly lower than that of the traditional dewatering + manual excavation process. At the same time, the construction cycle is shortened, effectively improving the efficiency of D-type temporary beam support construction in areas with high groundwater levels.

[0021] Highly adaptable and scalable: The construction method and structure of this invention can be adjusted according to different geological conditions (sandy soil, silty clay, clay) to adjust the H-steel type, grouting parameters and concrete grade, adapting to the construction needs of areas with different high groundwater levels. Moreover, the construction equipment is conventional engineering equipment, which is convenient to operate and easy to promote and apply in the industry. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the jacking frame bridge and support system for crossing a railway according to the present invention; Figure 2 This is a schematic diagram of the vertical cross-sectional structure of the present invention; Figure 3 This is a schematic diagram of the horizontal cross-sectional structure at the anchoring section of the present invention; Figure 4 This is a schematic diagram of the structure of the anchorage connection bar of the present invention; In the diagram: 1. H-beam; 2. Grouting reinforcement body; 3. Concrete section pile foundation; 4. Anchorage section; 5. Existing jacking pit slab slope; 6. Top surface of railway track; 7. D-beam temporary beam; 8. Jacking frame bridge main body; 9. Reinforcing cage; 10. Anchorage connection bar. Detailed Implementation

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solution of this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] like Figures 1 to 3 As shown, the present invention provides a construction method for D-type temporary beam support in areas with high groundwater levels, comprising the following steps: Manual excavation: Excavating to areas below the groundwater level where construction is difficult using manual excavation methods; H-beam insertion: H-beam 1 is vertically driven into the test depth of the bottom of the bored pile, and an anchorage section 4 is reserved at the upper end of H-beam 1 to connect with the reinforcing cage 9. Grouting reinforcement: High-pressure grouting is performed on the bottom and sides of H-beam 1 to form grouting reinforcement body 2. After the grouting body reaches the design strength, the soil after grouting the bottom and sides of H-beam 1 and H-beam 1 form H-beam driven section pile foundation. Reinforcing cage fabrication and installation: Tie the reinforcing cage 9 according to the design specifications, hoist the reinforcing cage 9 into the bored pile, and ensure that the distance between the reinforcing cage 9 and the hole wall is uniform. Anchorage section connection: The anchorage section 4 of the H-beam 1 is fixedly connected to the reinforcing cage 9; Concrete pouring: Pour concrete into the bored pile and vibrate it until it reaches the design elevation of the pile top. The concrete and the reinforcing cage form the concrete section pile foundation 3. Curing and shaping: Moisturize and cure the concrete pile foundation 3 after pouring to make the concrete reach the design strength.

[0025] Specifically, before construction, preparations should be made, including: accurately laying out and locating the construction points of the D-type temporary beam support piles in areas with high groundwater levels; using a total station to determine the pile center and axis; clearing obstacles from the construction site; verifying underground pipelines, geological stratification, and hydrogeological conditions in the construction area; and clarifying key parameters such as the groundwater level and stratum lithology. Simultaneously, prepare equipment for manual excavation (digging shovel, winch, ventilation equipment), pile drivers, customized H-beams, high-pressure grouting equipment, pile foundation reinforcement cage processing equipment, and anti-seepage concrete pouring equipment, and debug and calibrate all equipment. For example, using a total station to lay out and locate the support pile points, determining the center of the four support piles, clearing the construction site, verifying that the strata in the construction area are gravelly soil, the groundwater level is 3m deep, and there are no underground pipelines; preparing manual excavation winches, small static pressure pile drivers, H-beams, high-pressure grouting pumps, reinforcement cage processing equipment, and concrete pouring chutes, and debugging the equipment to normal working condition.

[0026] Manual excavation: Excavation is carried out manually along the center of the pile location. During excavation, the excavation diameter is strictly controlled to be consistent with the designed pile diameter. Temporary protection is applied to the borehole wall every 1.0-1.5m. The protection method is selected based on the geological conditions, using either steel casing or concrete wall protection. The steel casing is made of 8-10mm thick rolled steel plate with a diameter not less than the designed pile diameter, and it is advanced synchronously with the excavation depth. The concrete wall thickness is not less than 100mm, and it is poured on-site and compacted by vibration. The next layer of excavation is carried out only after the wall reaches the designed strength. Excavation is stopped when the groundwater level is below which construction becomes difficult (the rate of water accumulation in the borehole exceeds the pumping rate, making manual excavation impossible). The water level in the borehole and the stability of the borehole wall are monitored in real time to prevent the borehole wall from collapsing.

[0027] H-beam driving: Move the pile driver directly above the pile location, adjust the machine body to keep it level, and vertically hoist the selected H-beam into the bored pile; start the pile driver and use static pressure or light hammer to drive the H-beam vertically into the designed depth at the bottom of the pile. During the driving process, monitor the verticality of the H-beam in real time to ensure that the verticality deviation is not greater than 0.5%; reserve an anchoring section at the upper end of the H-beam for connection with the pile foundation reinforcement cage.

[0028] Grouting reinforcement: Lower the grouting pipe along the wall of the bored pile to the bottom of the pile, with the lower end of the grouting pipe 50-100mm away from the soil at the bottom of the pile. Connect the upper end of the grouting pipe to the high-pressure grouting pump. Perform high-pressure grouting, slowly raising the grouting pipe during the grouting process to ensure that the soil at the bottom of the pile and within a 300-500mm radius around it is penetrated and consolidated by cement grout. After the grouting volume reaches the design value and the grouting pressure stabilizes, stop grouting and cure for 24 hours until the grout reaches the design strength, forming a grouting reinforcement body at the bottom of the pile, thereby fixing the lower end of the H-beam and strengthening the soil at the bottom of the pile.

[0029] Reinforcing cage fabrication and installation: The pile foundation reinforcing cage is fabricated on the construction site according to the design specifications. The main reinforcing bars are made of threaded steel, and the stirrups are made of round steel. The cage is formed by binding or welding. The diameter of the reinforcing cage is slightly smaller than the inner diameter of the bored pile to ensure a uniform protective layer thickness between the reinforcing cage and the borehole wall. The reinforcing cage is vertically hoisted into the bored pile. During the hoisting process, the reinforcing cage is prevented from colliding with the borehole wall and H-beams. After positioning, the reinforcing cage is fixed with positioning bars.

[0030] Anchorage section connection: The anchorage section of the H-beam is connected and reinforced to the pile foundation reinforcement cage. 25mm diameter threaded steel bars are used as anchorage connection bars. One end of the anchorage connection bar is fully welded to the flange of the H-beam, with a welding length of not less than 10 times the diameter of the steel bar. The other end is fully welded to the main reinforcement bar of the pile foundation reinforcement cage. The anchorage connection bars are evenly arranged along the circumference of the H-beam at 500mm intervals to ensure the connection strength between the H-beam and the pile foundation reinforcement cage, achieving effective force transfer between the two.

[0031] Treatment of water accumulation in the borehole: Lower the suction pipe of the water pump to the bottom of the bored pile, start the water pump to pump the water in the borehole to the designated drainage system outside the borehole. During the pumping process, observe the water accumulation in the borehole in real time. Stop the pumping operation when there is no obvious water accumulation in the borehole and the water accumulation rate is less than 0.1 m³ / h.

[0032] Concrete pouring: Pour impermeable concrete into the bored pile. The concrete strength grade shall not be lower than C35 and the impermeability grade shall not be lower than P8. Use a tremie pipe to transport the concrete to the bottom of the hole to prevent concrete segregation. The lower end of the tremie pipe shall be no more than 2m above the bottom of the hole or the surface of the poured concrete. Continue pouring the concrete until it reaches the design elevation of the pile top.

[0033] Curing and shaping: After the concrete is poured, the top of the pile should be covered and kept moist for curing for no less than 7 days. During the curing process, the pile should be protected from external impact. After the concrete reaches 100% of the design strength, the construction of the composite support pile can be completed, and the subsequent erection and connection of the D-type temporary beam can be carried out.

[0034] The invention also provides a D-type temporary beam support structure for areas with high groundwater levels, comprising concrete pile foundations and H-beam driven pile foundations arranged sequentially from top to bottom.

[0035] The concrete section pile foundation is a solid pile formed by concrete pouring, and a steel reinforcement cage is installed inside the concrete section pile foundation.

[0036] The H-beam driven into the pile foundation consists of an H-beam inside and a grouting reinforced body formed by high-pressure grouting into the soil at the bottom and sides of the H-beam. The top of the H-beam extends into the concrete pile foundation to form an anchorage section, which is fixedly connected to the reinforcing cage.

[0037] It includes a composite support pile, which is a steel-concrete composite structure and is the core vertical support component of the D-type temporary beam. Its upper end is connected to the lower chord of the D-type temporary beam by welding, and its lower end is anchored in the grouting and solidified body at the bottom of the pile and in the stratum. From top to bottom, it consists of concrete section pile foundation and H-shaped steel driven section pile foundation. H-beam driven pile foundation: The grouting reinforcement body is formed by cement grouting and consolidation with the soil around the pile bottom. The diameter of the grouting reinforcement body is 300-500mm larger than the diameter of the concrete pile foundation. The bottom is arc-shaped to enhance the contact area with the stratum and the pull-out resistance. The lower end of the H-beam is embedded in the grouting reinforcement body to a depth of not less than 800mm to achieve a firm bond between the H-beam and the grouting reinforcement body. Concrete pile foundation: This is a solid pile formed by pouring impermeable concrete with a strength grade of C35 and an impermeability grade of P8. A reinforcing cage is installed inside the pile, serving as the main reinforcing framework supporting the pile and bearing tensile and compressive loads. H-beams are vertically inserted into the reinforcing cage, and their anchorage sections are fixed to the cage via anchorage bars. These anchorage bars are evenly distributed circumferentially along the H-beams, achieving an integrated connection between the H-beams and the reinforcing cage, ensuring effective load transfer between them. The outer side of the concrete pile section is the wall of a manually excavated bored pile hole. A protective layer, either a steel casing or a concrete wall, is installed between the hole wall and the concrete pile. Cement mortar is filled between the steel casing and the concrete pile to ensure a tight fit.

[0038] In order to prevent the hole wall from collapsing during manual excavation, ensure the safety of underground operations, guarantee the quality of pile hole formation, and ensure the safe operation of railways, the manual excavation operation steps preferably include temporary protection of the hole wall during the excavation process to prevent the hole wall from collapsing.

[0039] Specifically, by implementing temporary borehole wall protection simultaneously during excavation, soil instability and collapse can be effectively prevented, protecting the safety of underground workers, ensuring that the borehole size and verticality meet design requirements, avoiding rework, project delays, and increased costs caused by borehole collapse, and providing a stable and reliable working space for subsequent H-beam driving, grouting, and concrete pouring. Borehole wall protection is carried out simultaneously throughout the manual excavation operation, with protective measures following the excavation progress until reaching a difficult location below the groundwater level, ensuring effective protection of the borehole wall throughout the excavated section.

[0040] In order to achieve the purpose of clearly defining the form of borehole wall protection and ensuring that the protection covers the entire excavation section to prevent borehole collapse and water seepage, preferably, the temporary borehole wall protection adopts steel casing or concrete wall protection, and the depth of the wall protection is synchronized with the depth of manual excavation.

[0041] Specifically, two standardized protection methods, steel casing or concrete wall protection, are adopted to adapt to different geological conditions. They are synchronized with the excavation depth throughout the process, and can completely seal the borehole wall, block groundwater, and restrain soil deformation. This fundamentally avoids problems such as borehole wall collapse, diameter reduction, and water inrush, ensuring the safety of underground operations and the quality of pile hole formation. It provides stable and reliable working conditions for subsequent H-beam driving, grouting, and concrete pouring, while also meeting the safety control requirements for construction near operating lines.

[0042] The steel casing protection is made of 8-10mm thick steel plate rolled up. The diameter of the casing is not less than the designed pile diameter. It is lowered synchronously with the excavation depth during the manual excavation process, and the hole wall is sealed throughout the process. It can quickly prevent soil deformation and groundwater infiltration. It is suitable for soft soil, sandy soil, high permeability and other easily collapsed strata, and can continuously ensure the stability of the hole wall and the safety of underground operations.

[0043] The concrete retaining wall is a concrete structure cast in sections on site. Each section is cast every 1.0 to 1.5 meters, with a thickness of not less than 100 mm and compacted by vibration. The next layer is excavated only after the retaining wall reaches the design strength. The depth of the retaining wall is synchronized with the depth of the borehole. It is suitable for working conditions with good strata stability, such as clay and silty clay. It is reliable in forming and durable in protection, and can effectively prevent borehole collapse and diameter reduction.

[0044] In order to ensure that the cross-sectional stiffness of the H-beam 1 matches the stress of the upper pile foundation, preferably, the perimeter of the combined cross-section of the H-beam 1 is not less than the perimeter of the concrete pile foundation 3.

[0045] Specifically, it is stipulated that the perimeter of the combined section of H-beam 1 should not be less than the perimeter of the concrete pile foundation 3. This ensures that H-beam 1 has sufficient vertical bearing capacity and anti-buoyancy capacity, avoiding local buckling and deformation failure due to insufficient cross-section. It also ensures that the stiffness of H-beam 1 and concrete pile foundation 3 are coordinated and the overall stress is uniform, significantly improving the bearing capacity and anti-buoyancy performance of the composite pile. The perimeter of the concrete pile foundation is calculated based on the design pile diameter. When selecting the type of H-beam 1, ensure that the perimeter of its combined section is greater than or equal to this value to ensure that the section parameters meet the stress requirements.

[0046] In order to verify the bearing capacity of H-beam 1 and ensure reliable force transmission of the anchorage section, preferably, before the step of inserting H-beam 1, the bearing capacity of H-beam 1 under the same conditions is tested, and the test bearing capacity should not be less than the theoretical calculation value; the reserved length of the anchorage section 4 is 1.5 to 2.0 times the diameter of the concrete section pile foundation 3.

[0047] Specifically, conducting a bearing capacity test before construction allows for early verification of the performance of H-beam 1, preventing insufficient bearing capacity later due to material defects. The anchorage section 4 is set at 1.5 to 2.0 times the pile diameter to ensure a firm connection between H-beam 1 and the reinforcing cage 9, resisting pull-out and dynamic loads, achieving efficient force transmission, and improving the overall safety of the support system. A bearing capacity test under the same conditions is conducted before driving in H-beam 1, and the test bearing capacity is not lower than the theoretical calculation value. The reserved length of the upper anchorage section 4 of H-beam 1 is 1.5 to 2.0 times the diameter of the concrete pile foundation 3.

[0048] In order to expand the reinforcement range of the pile bottom and improve the anti-buoyancy and end bearing capacity, preferably, the diameter of the H-beam driven section of the pile foundation is 300-500mm larger than the diameter of the concrete section of the pile foundation.

[0049] Specifically, making the diameter of the H-beam driven section of the pile foundation 300-500mm larger than that of the concrete section increases the contact area between the grouting solid and the soil, significantly improving the pile bottom bearing capacity and resistance to uplift and buoyancy. This effectively counteracts the buoyancy effect of high groundwater levels, preventing pile floating and uneven settlement, and is suitable for the stress environment of high-water areas. During design and construction, the diameter of the H-beam driven section of the pile foundation should be controlled to be 300-500mm larger than the diameter of the upper concrete section, and the grouting area should cover the expanded section of soil.

[0050] To strengthen the connection between the H-beam 1 and the reinforcing cage and ensure effective force transmission, preferably, the anchorage section 4 of the H-beam 1 is fixedly connected to the reinforcing cage 9 by welding or mechanical connection. An anchorage connecting bar 10 is provided between the anchorage section 4 of the H-beam 1 and the reinforcing cage 9. The anchorage connecting bar 10 tightens the anchorage section 4 of the H-beam 1 and the longitudinal bars of the reinforcing cage 9, strengthening the connection between the two and ensuring effective force transmission.

[0051] Specifically, employing welding or mechanical connections and adding anchoring reinforcement bars can significantly improve the strength of the connection nodes, resisting repeated vertical loads, buoyancy, and railway dynamic loads, preventing connection failure and pile separation, ensuring the coordinated work of H-beam 1, reinforcing cage 9, and concrete, and maintaining the long-term stability of the support structure. The anchoring section 4 of H-beam 1 and the reinforcing cage 9 are connected by welding or mechanical means, and the longitudinal reinforcement of the anchoring section 4 and the reinforcing cage 9 is tightened with anchoring reinforcement bars 10. The reinforcement bars are evenly distributed circumferentially to ensure a tight and secure connection.

[0052] The above are merely preferred embodiments of the present invention and are 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 construction method for supporting D-type temporary beams in areas with high groundwater levels, characterized in that, Includes the following steps: Manual excavation was used to dig holes to areas below the groundwater level where construction was difficult. The H-beam is driven vertically into the bottom of the bored pile to the test depth, and an anchorage section is reserved at the upper end of the H-beam for connection with the reinforcing cage. High-pressure grouting is performed on the bottom and sides of the H-beam to form a grouting reinforced body. After the grouting body reaches the design strength, the soil after grouting the bottom and sides of the H-beam forms the H-beam driven section pile foundation with the H-beam. Tie the reinforcing cage according to the design specifications, hoist the reinforcing cage into the bored pile, and ensure that the distance between the reinforcing cage and the hole wall is uniform. The anchorage section of the H-beam is fixedly connected to the reinforcing cage; Concrete is poured into the bored pile and vibrated to compact it until it reaches the design elevation of the pile top. The concrete and the reinforcing cage form a concrete section pile foundation. After the concrete pile foundation has been poured, it is kept moist and cured to allow the concrete to reach its design strength.

2. The construction method for D-type temporary beam support in areas with high groundwater levels according to claim 1, characterized in that: The manual excavation process also includes temporary protection of the borehole wall during excavation to prevent it from collapsing.

3. The construction method for D-type temporary beam support in areas with high groundwater levels according to claim 2, characterized in that: The temporary protection of the borehole wall is provided by steel casing or concrete wall protection, and the depth of the wall protection is synchronized with the depth of manual excavation.

4. The construction method for D-type temporary beam support in areas with high groundwater levels according to claim 1, characterized in that: The perimeter of the combined section of the H-beam is not less than the perimeter of the concrete pile foundation.

5. The construction method for D-type temporary beam support in areas with high groundwater levels according to claim 4, characterized in that: Before the H-beam insertion step, the H-beam is subjected to a bearing capacity test under the same conditions, and the test bearing capacity should not be less than the theoretical calculation value; the reserved length of the anchorage section is 1.5 to 2.0 times the diameter of the concrete pile foundation.

6. The construction method for D-type temporary beam support in areas with high groundwater levels according to claim 1, characterized in that: The diameter of the H-beam driven pile foundation is 300-500 mm larger than the diameter of the concrete pile foundation.

7. The construction method for D-type temporary beam support in areas with high groundwater levels according to claim 1, characterized in that: The anchorage section of the H-beam is fixedly connected to the reinforcing cage by welding or mechanical connection. An anchorage connecting bar is provided between the anchorage section of the H-beam and the reinforcing cage. The anchorage connecting bar tightens the anchorage section of the H-beam and the longitudinal bars of the reinforcing cage, strengthens the connection between the two, and ensures effective force transmission.

8. A type D-beam support structure for areas with high groundwater levels, characterized in that: This includes concrete pile foundations and H-beam driven pile foundations arranged sequentially from top to bottom; The concrete section pile foundation is a solid pile formed by concrete pouring, and a steel cage is installed inside the concrete section pile foundation; The H-beam driven into the pile foundation consists of an H-beam inside and a grouting reinforced body formed by high-pressure grouting into the soil at the bottom and sides of the H-beam. The top of the H-beam extends into the concrete pile foundation to form an anchorage section, which is fixedly connected to the reinforcing cage.

9. The D-type temporary beam support structure for areas with high groundwater levels according to claim 8, characterized in that: The perimeter of the combined section of the H-beam is not less than the perimeter of the concrete pile foundation.

10. The D-type temporary beam support structure for areas with high groundwater levels according to claim 8, characterized in that: The diameter of the H-beam driven pile foundation is 300-500 mm larger than the diameter of the concrete pile foundation.

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