A method of pile foundation construction

Abstract

The present application discloses a kind of pile foundation construction method, comprising the following steps: S1, according to the design position of slope pile foundation, mark the position where steel sheet pile needs to be installed along the both sides of pile position in the straight line range from the top of slope to the bottom of slope;S2, fixed winch equipment at the top of slope, install first movable platform and connect to winch equipment, complete full section steel trestle;S3, place drilling equipment on first movable platform, use winch equipment to make first movable platform drive to planned position on steel trestle, after first movable platform is fixed to steel trestle, use drilling equipment to carry out pile hole construction at pile position;S4, repeat S3 until all pile holes in steel trestle coverage area are drilled, then remove drilling equipment from first movable platform;S5, move or drive hoisting equipment to first movable platform, hoist pile reinforcement cage into all pile holes;S6, pour concrete into pile hole.The present application has the beneficial effect of facilitating mountain slope pile foundation construction.

Description

Technical Field

[0001] This invention relates to the field of pile foundation construction for structures. More specifically, this invention relates to a pile foundation construction method. Background Technology

[0002] With the continuous development of the social economy, the continuous improvement of urbanization, the continuous construction or replacement of roads and bridges, and the continuous promotion of new energy in society, a large number of non-temporary structures have emerged that need to be built on mountains, tidal flats, and permanent slopes, such as wind turbines, photovoltaic equipment platforms, bridge piers, and unconventional residential buildings. These structures have high requirements for their own pile foundations, and temporary pile types such as steel sheet piles can no longer be used. Moreover, since these pile foundations are often located in complex mountainous environments or permanent slopes, the construction process of such structures is much more difficult than construction on flat ground. Especially in pile foundation construction, the conventional method is to first plan several sites and multiple construction roads according to the pile foundation design drawings. This will significantly increase the construction cycle and cost. On hard mountains, large-scale blasting operations are required depending on various conditions. In tidal flats and other areas, a large amount of ground hardening treatment is required. In mountainous areas with dense structures, it may even involve the demolition of surrounding buildings to ensure smooth construction roads. Furthermore, if there are planning requirements, the soil must be backfilled to the pre-construction state after the construction is completed.

[0003] In situations with numerous site constraints and cost requirements, construction sites often rely on a large number of personnel to manually excavate holes on slopes or in areas where construction machinery cannot easily access. After the holes are formed, simple hoisting tools are used to lower the reinforcing cage, followed by concrete pouring for the pile body. This method is inefficient, labor-intensive, and has a long construction period. To address these issues to some extent, when facing complex site constraints such as riverbanks and tidal flats, on-site engineers often use construction platforms to assist in pile foundation construction. However, the platform needs to be continuously erected along with the progress of pile foundation construction. To save labor and shorten the construction period, as exemplified by the invention patent application CN109695237A entitled "A Mobile Pile Foundation Construction Platform," which uses auxiliary piles to allow the supporting platform to be moved and connected to the top of the auxiliary piles along the direction of pile foundation construction, this type of platform can only be used horizontally and is not suitable for mountainous slope terrain. The platform itself has high erection costs and requires high-performance equipment such as drilling rigs. Therefore, it is necessary to design a pile foundation construction method based on a movable pile foundation construction platform suitable for mountainous slopes. Summary of the Invention

[0004] One objective of this invention is to provide a pile foundation construction method that meets the requirements of rapid mechanized construction of bored piles in complex terrains, such as mountain slopes.

[0005] To achieve these objectives and other advantages according to the invention, according to one aspect of the invention, a pile foundation construction method is provided, comprising the following construction steps:

[0006] S1. Based on the designed location of the pile foundation on the slope, conduct a survey and mark the locations where the steel sheet piles need to be installed along both sides of the pile positions within a straight line from the top to the bottom of the slope.

[0007] S2. Fix the winch equipment at the top of the slope, install the first movable platform and connect it to the winch equipment with steel cables to complete the entire steel trestle bridge;

[0008] S3. Move or drive the drilling equipment to the first movable platform, use the winch equipment to drive the first movable platform to the design position on the steel trestle bridge, fix the first movable platform to the steel trestle bridge, and then use the drilling equipment to carry out pile hole construction at the pile position.

[0009] S4. Repeat S3 until all pile holes in the area covered by the steel trestle bridge are drilled, and then unload the drilling equipment from the first movable platform.

[0010] S5. Move or drive the hoisting equipment to the first movable platform and hoist the pile reinforcement cage into all pile holes;

[0011] S6. Pour concrete into the pile hole to complete the pile foundation construction.

[0012] Preferably, the steel trestle bridge includes two parallel and symmetrically arranged rail frames. Each rail frame includes multiple spaced steel sheet piles. The pile bodies of the steel sheet piles are in the slope. The tops of all the steel sheet piles are connected to a steel rail. All sections of the steel rail from the highest point to the lowest point are downhill sections or horizontal sections.

[0013] Preferably, the first movable platform includes a steel frame platform, which is assembled from multiple sets of Bailey bridge beams. A steel plate layer is detachably connected to the Bailey bridge beams. A platform support is detachably connected to the steel frame platform. The platform support is located above the steel trestle bridge and includes two horizontal main support beams parallel to the rail frame. Multiple secondary support beams are detachably connected between the upper surface of the main support beams and the steel frame platform. The bottom surfaces of the multiple secondary support beams are detachably connected to a traction support. The platform support is connected to the traction support and is connected to the winch equipment via a steel cable. The platform support is connected to a hydraulic wheel set, which contacts the lower steel rail.

[0014] Preferably, the steel rail comprises a plurality of spaced steel brackets, with a steel rail beam connecting any two steel brackets. The steel brackets correspond one-to-one with the top of the sheet piles and are detachably connected. The top surface of the steel brackets is flat and flush with the top surfaces of the steel rail beams on both sides without any misalignment or height difference. The vertical surface of the steel brackets near the other side of the steel rail is flush with the vertical surface of the steel rail beam near the other side of the steel rail.

[0015] Preferably, each of the main support beams is located directly above the steel rails on each side. Multiple support bases are detachably connected to the bottom surface of the main support beam, each corresponding to a steel bracket below. A hydraulic jack is located between the bottom surface of the support base and the top surface of the steel bracket, and its height is equal to the net distance between the bottom surface of the support base and the top surface of the steel bracket.

[0016] Preferably, the installation of the first movable platform and its connection to the winch equipment via steel cables, along with the completion of the entire steel trestle bridge, includes the following steps:

[0017] A1. Use a sheet pile driver to construct sheet piles within the cantilever coverage area at the top of the slope. Then install steel brackets on the top of each completed sheet pile and connect steel track beams and rail connecting beams between the steel brackets.

[0018] A2. Using the upper surface of the steel bracket as the base, place each hydraulic jack on each steel bracket and make the top surfaces of each hydraulic jack level. Install the platform support, traction support, steel frame platform, and hydraulic wheel set in sequence. Then connect the traction support and winch equipment with steel cables and move the required steel sheet pile driver to the steel frame platform.

[0019] A3. The winch straightens and loads the steel cable. At this time, the hydraulic wheel set is kept in the rising position and is adjusted in time to keep the support platform level. After removing the hydraulic jacks, the winch is used to lower the steel cable so that the first movable platform slides down to the appropriate position under its own weight. While maintaining the tension of the winch, the lowering of the steel cable is stopped so that the movable platform stops sliding down. The hydraulic jacks are installed between the support base and the steel bracket. After installation, the hydraulic wheel set is retracted so that the platform support sits on the jacks.

[0020] A4. Repeat A1 and A3 to extend towards the bottom of the slope and complete the construction of the steel trestle bridge.

[0021] Preferably, the hoisting of the pile reinforcement cage into all pile holes includes the following steps:

[0022] B1. Lower the first movable platform carrying the lifting equipment to a suitable position, install the hydraulic jacks and then retract the hydraulic wheel assembly, and disconnect the steel cable connection between the movable platform and the winch equipment.

[0023] B2. Install the second movable platform, place the pile reinforcement cage placement frame on it, and connect the winch equipment to the steel cable of the second movable platform;

[0024] B3. Arrange a batch of pile reinforcement cages on the pile reinforcement cage placement rack at the top of the slope;

[0025] B4. Use a winch to lower the second movable platform into the lifting area covered by the lifting equipment on the first movable platform;

[0026] B5. The lifting equipment will lift all the pile reinforcement cages on the second movable platform in sequence and place them into the pile holes within the lifting area. After completion, the second movable platform will be raised to the top of the slope. Repeat steps B3-B4 until all reinforcement cages within the lifting area are completed.

[0027] B6. Repeat B1-B3 until all pile reinforcement cages are completed.

[0028] Preferably, the hydraulic wheel assembly includes two symmetrical single-sided support wheel assemblies connected to the lower surface of the main beam of the support. Each single-sided support wheel assembly includes multiple electric hydraulic cylinders, which are spaced apart and vertically fixed to the bottom surface of the main beam of the support. Each electric hydraulic cylinder has a distribution wheel frame hinged to the end of its hydraulic telescopic rod. The distribution wheel frame is a crank-shaped structure that curves upwards. Two rollers are connected to the surface of the distribution wheel frame facing the near-side steel rail, and the rollers are in contact with the top surface of the steel rail.

[0029] The present invention has at least the following beneficial effects:

[0030] The steel trestle bridge used in this invention, together with the first and second movable platforms, allows various construction machinery to carry out normal pile construction on mountainous or slope terrain, saving construction space, solving the constraints of terrain on pile construction, and greatly reducing the construction period and cost of pile construction projects in mountainous and slope areas.

[0031] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of pile foundation concrete pouring in a pile foundation construction method according to one technical solution of the present invention;

[0033] Figure 2 This is a schematic diagram of a steel trestle bridge construction method for a pile foundation construction in one of the technical solutions of the present invention;

[0034] Figure 3This is a schematic diagram of drilling construction in a pile foundation construction method according to one technical solution of the present invention;

[0035] Figure 4 This is a schematic diagram of the hoisting of the pile reinforcement cage in a pile foundation construction method according to one technical solution of the present invention.

[0036] Figure 5 This is a schematic diagram of the first movable platform in a pile foundation construction method according to one technical solution of the present invention;

[0037] Figure 6 This is an exploded view of the first movable platform in a pile foundation construction method according to a technical solution of the present invention;

[0038] Figure 7 This is a schematic diagram of a platform support and hydraulic wheel assembly for a pile foundation construction method according to one technical solution of the present invention;

[0039] Figure 8 This is a schematic diagram of a steel rail frame and its contact components in a pile foundation construction method according to one technical solution of the present invention; Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can implement it based on the description.

[0041] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0042] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, and the reagents and materials mentioned are commercially available. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to fixed connection or setting, detachable connection or setting, or integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description. They 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, and therefore should not be construed as a limitation of this invention.

[0043] like Figures 1-8 As shown, the present invention provides a pile foundation construction method, comprising the following steps:

[0044] S1. Based on the designed location of the pile foundations on slope 6, survey and mark the locations on both sides of the pile positions within a straight line from the top to the bottom of slope 6. Specifically:

[0045] Before surveying the location of sheet pile 201, it is necessary to use specialized equipment such as theodolites or total stations to accurately pinpoint the location of the cast-in-place piles. In addition to recording the slope of each section along slope 6 during the survey, it is also necessary to combine the previous pile foundation survey report to determine the amount of sheet pile 201 to prepare and select appropriate construction equipment. At this time, the subsequent construction plan should be planned according to the site conditions.

[0046] S2. Fix the winch equipment 3 at the top of the slope 6, install the first movable platform 1 and connect it to the winch equipment 3 with steel cable 31 to complete the entire steel trestle bridge 2. Specifically:

[0047] The first movable platform 1 is made of commercially available materials and has been pre-processed in the factory, requiring only on-site assembly. The first movable platform 1 can be fixed on the steel trestle 2 and can slide down the slope 6 by its own weight or be pulled up the slope 6 by the winch equipment 3. The first movable platform 1 has a hydraulic device to keep the platform surface level at all times. The winch equipment 3 uses two sets of 32-ton winches and multiple 10-ton winches are added to assist in the sliding according to the size of the first movable platform 1. The steel cable 31 of the winch equipment is of grade 48mm or above and is arranged neatly by a forced rope coiler. All steel cable 31 plugs are inserted with cable buckles, and the steel cable 31 is connected to the first movable platform 1 by an anti-detachment hook.

[0048] S3. Move or drive the drilling equipment 42 onto the first movable platform 1, and use the winch equipment 3 to drive the first movable platform 1 onto the steel trestle bridge 2 to the designed position. After fixing the first movable platform 1 onto the steel trestle bridge 2, use the drilling equipment 42 to construct the pile hole 51 at the pile location. Specifically:

[0049] First, the first movable platform 1 is pulled down along the steel trestle bridge 2 by the winch 3 under gravity. The first movable platform 1 is then fixed to the steel trestle bridge 2 at a predetermined position. Next, steel casings are installed in the pile holes within the coverage area of ​​the drilling equipment 42. During drilling, the mud used for wall lining is composed of clay, water, and additives, prepared according to a specific ratio. The mud pit is planned in advance and located at the top of the slope 6 or at the top of the slope 6, connected to the drilling equipment 42 via pipes and a mud pump. During drilling of the pile positions by the drilling device 42, the drill bit should advance slowly and at a uniform speed, while the mud pump is activated for synchronous circulation. Strict control of the drilling dimensions is required during drilling. When drilling to the bottom of the casing, a low-speed drilling strategy is applied. After the drill bit or guide section has fully entered the strata, a fast drilling strategy is switched to.

[0050] S4. Repeat S3 until all pile holes 5 within the coverage area of ​​the steel trestle bridge 2 are drilled. Then, unload the drilling equipment 5 from the first movable platform 1. Specifically:

[0051] After the pile hole 5 is completed, mud sampling and testing should be carried out. If the mud exceeds the standard, it should be dealt with in time. Professional recorders should be assigned to ensure that all data of the hole are true and reliable. The drilling equipment 5 can only be removed after the pile hole 5 of the same batch has passed the acceptance.

[0052] S5. Move or drive the hoisting equipment 43 to the first movable platform 1, and hoist the pile reinforcement cage 51 into all pile holes 5. Specifically:

[0053] When lowering the pile reinforcement cage 51, it should be kept vertical and slowly and gently lowered into the pile hole 5 to avoid collision with the hole wall. If resistance is encountered during lowering, it should not be forced down; the cause should be identified before continuing. After lowering, the positioning bars should be fixed to the steel casing to ensure that there is no deviation during pile grouting.

[0054] S6. Pour concrete into the pile hole to complete the pile foundation construction. Specifically:

[0055] A ground pump 440 is installed at the top of slope 6, and a concrete placing boom 44 is placed on a first movable platform 1. A winch 3 is used to lower the first movable platform 1 to the position specified in the construction plan. Then, a pump pipe 441 is installed on slope 6 to connect the ground pump 440 and the concrete placing boom 44. Concrete is poured from the ground pump 440 through the pump pipe 441 and into the pile holes 5 within the coverage area of ​​the concrete placing boom 44. Commercially available concrete is used, with sand and gravel as the main materials. To ensure the quality of the bored pile construction, it is necessary to control the concrete gradation, workability, and slump. Screening and cleaning are required when necessary. In this project, a rigid grouting pipe with a diameter of 28cm is used for concrete pouring, with the lower end of the pipe embedded in the concrete to a depth >2m. The pouring speed needs to be controlled to reduce the impact on the pile reinforcement cage 51. After all the bored piles are completed, the steel trestle 2 is removed.

[0056] In this technical solution, the first movable platform 1 maintains a horizontal position while being movable. When the first movable platform 1 descends along the steel trestle 2, it relies on its own weight and the load on it to maintain balance and uniform speed through the winch equipment 3. After the first movable platform 1 is lifted to the top of the slope 6 by the winch equipment 3, the mechanical equipment on it can be replaced to complete different procedures in the construction of the cast-in-place piles. During the construction process, the mechanical equipment does not need to be in direct contact with the slope 6, and there is no need to rebuild the platform when changing work areas. This construction method not only solves the problem of difficult and cumbersome construction of cast-in-place piles in complex terrains such as mountain slopes, but also greatly saves the demand for construction machinery and construction sites in complex terrains, reduces labor costs, and all materials of the steel trestle 2 can be disassembled, and the steel sheet piles 201 can be pulled out for reuse. All materials only need to be rented and do not need to be processed by the user, which greatly saves on usage costs.

[0057] In another technical solution, the steel trestle bridge 2 includes two parallel and symmetrically arranged steel rail frames 20. Each steel rail frame 20 includes multiple spaced steel sheet piles 201. The pile body of the steel sheet piles 201 is in the slope. The top of all the steel sheet piles 201 is connected to a steel rail 21. All sections of the steel rail from the highest point to the lowest point are downhill sections or horizontal sections.

[0058] In this technical solution, the sheet pile 201 is a single H-shaped I-beam. The spacing and dimensions of the H-shaped I-beams on a single rail frame 20 need to be determined based on the terrain, geology, and planned load. Alternatively, in addition to H-shaped I-beams, steel pipe sheet piles or Larssen sheet piles can be used for the sheet pile 201. The number of rail frames 20 can also be increased according to actual needs. The steel rail 21 remains downhill or horizontal from the top to the bottom of the slope 6, allowing the first movable platform 1 to slide down from the top to the bottom of the slope 6 using its own weight on the steel trestle 2. The distance between each section of the steel rail 22 and the slope 6 needs to be strictly calculated to avoid structural instability or local plastic damage to the steel trestle 2 during construction.

[0059] In another technical solution, the first movable platform 1 includes a steel frame platform 11, which is assembled from multiple sets of Bailey beams 110. A steel plate layer 111 is detachably connected to the Bailey beam 110. A platform support 12 is detachably connected to the steel frame platform 11. The platform support 12 is located above the steel rail 21 and includes two horizontal main support beams 121 parallel to the rail frame 20. Multiple secondary support beams 122 are detachably connected between the upper surface of the main support beams 121 and the steel frame platform 11. The bottom surfaces of the multiple secondary support beams 122 are detachably connected to a traction support 13. The platform support 12 is connected to the traction support 13 and is connected to the winch equipment 3 via a steel cable 31. The platform support 12 is connected to a hydraulic wheel set 14, which is in contact with the steel rail 21 below.

[0060] In this technical solution, the Bailey beam 110 of the steel frame platform 11 is composed of multiple sets of Bailey trusses arranged in parallel, and the parallel Bailey trusses are connected by at least two Bailey truss beams. The steel plate layer 111 is composed of multiple rectangular steel plates, and the steel plates are directly mechanically connected to the Bailey beams below by bolts or fasteners. A personnel fence 112 is set around the upper surface of the steel plate layer 111. The steel frame platform 11 has minimal deformation when under load and can evenly transfer the load of the steel plate layer 111 downwards through the Bailey beam 110 to the load-bearing components. The secondary support beam 122 of the platform support 12 distributes the load to the main support beam 121. The traction support 13 is connected to multiple secondary support beams 122 and has multiple lifting points to connect the steel cable 31. The hydraulic wheel set 14 can independently bear the platform support 12, the steel frame platform 11 and its load while traveling on the steel track 21. When the first movable platform 1 moves, the hydraulic wheel set 14 can rely on the extension and retraction of its own hydraulic rods to keep the platform support 12 on it always horizontal.

[0061] In another technical solution, the steel rail 21 includes a plurality of spaced steel brackets 211, and a steel rail beam 212 is connected between any two steel brackets 211. The steel brackets 211 correspond one-to-one with the top of the steel sheet piles 201 and are detachably connected. The top surface of the steel brackets 211 is flat and flush with the top surfaces of the steel rail beams 212 on both sides without any misalignment or height difference. The vertical surface of the steel brackets 211 near the other side of the steel rail 21 is flush with the vertical surface of the steel rail beam 212 near the other side of the steel rail 21. Individual steel track beams 212 are batch-processed according to different slopes and required lengths. The steel track beams 212 are H-shaped I-beams with upward-facing planes, reinforced with gusset plates and stiffening ribs; other types of rails can also be used. Steel brackets 211 are connected to the steel track beams 212 by high-strength bolts, and steel brackets 211 are also connected to the steel sheet piles 201 by high-strength bolts. The flat upper surface of the steel track 21 allows the first movable platform 1 to travel smoothly. Multiple rail connecting beams 22 connect the two rail frames 20, perpendicular to the rail frames 20. The rail connecting beam 22 is horizontally positioned, with both ends detachably connected to the steel brackets 211 on both sides. The top surface of the rail connecting beam 22 is lower than the top surface of the connected steel brackets 211. A supporting pulley 220 is fixed on the top surface of the rail connecting beam 22, and each supporting pulley 220 can support a steel cable 31. The supporting pulley 220 is set at the place where the slope of the steel rail 21 changes. Whenever the first movable platform 1 slides down to a more steep area, the steel cable 31 is naturally placed on the supporting pulley 220, and the supporting pulley 220 acts as a fulcrum.

[0062] In another technical solution, the main support beam 121 is located directly above each side of the steel rail 21. The bottom surface of the main support beam 121 is detachably connected to multiple support bases 15, which correspond one-to-one with the steel brackets 211 below. There is a hydraulic jack 16 between the bottom surface of the support base 15 and the top surface of the steel bracket 211, and its height is equal to the net distance between the bottom surface of the support base 15 and the top surface of the steel bracket 211.

[0063] In this technical solution, since the interval between any two adjacent sheet piles 201 is the same, when assembling the first movable platform 1, the multiple support bases 15 connected to the same main beam 121 are also arranged in this manner, and the interval between them is used as the length modulus of the horizontal movement distance of the first movable platform 1. This ensures that when the first movable platform 1 is in any position, all support bases 15 can correspond one-to-one with the nearest steel bracket 211. Each support base 15 has a hydraulic jack 16 between it and its lower steel bracket 211. The top surfaces of all hydraulic jacks 16 are at the same level to ensure that the platform support 12 above them remains horizontal. The hydraulic jacks 16 are only installed when the first movable platform 1 is fixed to the steel rail 21. They are manually disassembled before the first movable platform 1 slides down or is pulled up.

[0064] In another technical solution, installing the first movable platform 1 and connecting it to the winch equipment 3 with steel cable 31 to complete the entire steel trestle bridge 2 includes the following steps:

[0065] A1. Using a sheet pile driver 41, steel sheet piles 201 within the cantilever's coverage area are constructed at the top of slope 6. Then, steel brackets 211 are installed at the top of each completed sheet pile 201, and steel rail beams 212 and rail connecting beams 22 are connected between the steel brackets 211. Specifically:

[0066] According to the construction site environment, first level a construction site in the relatively flat top area of ​​slope 6, transport the required materials to the construction site, use the steel sheet pile driving machine 41 to construct the first few rows of steel sheet piles 201 on the top of slope 6, and manually connect the steel brackets 211, steel rail beams 212, and rail connecting beams 22. In order to ensure rapid construction on site, all connection measures should use high-strength bolts.

[0067] A2. Using the upper surface of the steel bracket 211 as the base, place each hydraulic jack 16 on the steel bracket 211, ensuring that the top surfaces of each hydraulic jack 16 are at the same level. Install the platform support 12, traction support 13, steel frame platform 11, and hydraulic wheel assembly 14 in sequence. Then, connect the traction support 13 and the winch equipment 3 with steel cables to move the required sheet pile driver 41 onto the steel frame platform 11. Specifically:

[0068] When the first movable platform 1 is fixed on the steel trestle bridge 2, the hydraulic jack 16 is always under force. The platform support 12, the traction support 13, and the steel frame platform 11 are all connected by high-strength bolts.

[0069] A3. The winch 3 straightens and applies force to the steel cable 31. At this time, the hydraulic wheel assembly 14 is kept raised and adjusted to ensure the support platform 12 remains level. After removing the hydraulic jacks 16, the winch 3 lowers the steel cable 31, allowing the first movable platform 1 to move to a suitable position under its own weight. While maintaining the tension of the winch 3, the lowering of the steel cable 31 is stopped, preventing the first movable platform 11 from sliding down. The hydraulic jacks 16 are then installed between the support base 15 and the steel bracket 211. After installation, the hydraulic wheel assembly 14 retracts, allowing the platform support 12 to rest on the hydraulic jacks 16. Specifically:

[0070] Before the hydraulic wheel assembly 14 is lifted, all necessary equipment and materials required for subsequent construction must be installed and stacked on the first movable platform 1. Then, the winch 3 is tightened and the length of the steel cable 31 is locked. While the hydraulic wheel assembly 14 is in the lifting state, the load borne by the hydraulic jacks 16 is monitored at all times. When the total load borne by all the hydraulic jacks 16 is zero, the hydraulic jacks 16 are removed. After that, the winch 3 can be operated to move the first movable platform 1. When the first movable platform 1 is moved to the appropriate position, the winch 3 is finely adjusted so that the support base 15 and the steel bracket 211 are aligned one by one. The hydraulic jacks 16 are placed in them. After locking the winch 3, the hydraulic wheel assembly 14 is slowly raised, and the force on the hydraulic wheel assembly 14 is monitored at all times. When the overall load of the hydraulic wheel assembly 14 is 0, the first movable platform 1 can be regarded as fixed to the steel trestle bridge 2. At this time, the steel cable 31 can be removed.

[0071] A4. Repeat A1 and A3 to extend towards the bottom of slope 6 and complete the construction of steel trestle bridge 2, specifically:

[0072] The construction of the steel trestle bridge can be flexibly determined according to traffic conditions and site conditions, either from the top to the bottom of the slope 6 or from the bottom to the top of the slope 6. When the steel trestle bridge 2 is constructed from the bottom to the top of the slope 6, other procedures remain unchanged. Only the process of the first movable platform 1 sliding down under the control of the winch equipment 3 is changed to the process of pulling up under the control of the winch equipment 3.

[0073] In another technical solution, the process of hoisting the pile reinforcement cage 51 into all pile holes 5 includes the following steps:

[0074] B1. Lower the first movable platform 1 carrying the lifting equipment 43 to a suitable position, install the hydraulic jack 16 and then raise the hydraulic wheel assembly 14, and disconnect the steel cable 31 connecting the first movable platform 1 and the winch equipment 3.

[0075] B2. Install the second movable platform 12, place the pile reinforcement cage placement frame 430 on it, and connect the winch equipment 3 to the steel cable 31 of the second movable platform 12. Specifically:

[0076] The second movable platform 12 serves as a material transport function when the first movable platform 1 is fixed. Its platform structure is the same as the first movable platform 2, and its platform can be made larger to better complete the transport task. To ensure safety, under normal circumstances, only one movable platform can be connected to the winch equipment 3 at the same time on the same steel trestle bridge 2, while the other platforms remain fixed. The position of the lifting point on the traction bracket 13 needs to be further designed. When any movable platform is connected to the winch equipment 3, the steel cable 31 will not come into contact with other movable platforms above, regardless of whether the movable platform is pulled up or down.

[0077] B3. At the top of slope 6, using lifting equipment 43, a batch of pile reinforcement cages 51 are arranged on the pile reinforcement cage placement frame 430. Specifically:

[0078] The length of a single pile reinforcement cage 51 is controlled between 4 and 6 meters. In order to allow more pile reinforcement cages 51 to be stacked on the second movable platform 10 within a safe range, the pile reinforcement cage placement frame 430 is a stacking support made of structural steel, which can place multiple layers and rows of pile reinforcement cages 51 at intervals and ensure stability after stacking.

[0079] B4. Using winch 3, lower the second movable platform 10 to the lifting area covered by lifting equipment 43 on the first movable platform 1. Specifically:

[0080] The lifting equipment 43 needs to be selected according to actual needs and the load capacity of the first movable platform 1. It can be a fixed rotating crane or a crawler crane. Before the lifting process, the lifting equipment 43 needs to be fixed in place to the steel frame platform 11. If the lifting load is large, additional fixing fixtures need to be installed in the steel frame platform 11 before connecting the lifting equipment 43 to the fixing fixtures to act as ground anchors when the equipment is working on flat ground.

[0081] B5. The lifting equipment 43 lifts all the pile reinforcement cages 51 on the second movable platform 10 in sequence and puts them into the pile holes 51 within the lifting area. After completion, the second movable platform 10 is raised to the top of the slope 6. Steps B3-B4 are repeated until all reinforcement cages 51 within the lifting area are completed.

[0082] In another technical solution, the hydraulic wheel assembly 14 includes two symmetrical single-sided support wheel assemblies 141 connected to the lower surface of the main beam 12 of the support. Each single-sided support wheel assembly 141 includes multiple electric hydraulic cylinders 1411, which are spaced apart and vertically fixed to the bottom surface of the main beam 121 of the support. The hydraulic telescopic rod 1412 of each electric hydraulic cylinder 1411 is hinged to a distribution wheel frame 142 at its end bearing. The distribution wheel frame 142 is a crank-shaped structure that curves upward. Two traveling wheels 143 are connected to the surface of the distribution wheel frame 142 facing the near-side steel rail 21. The traveling wheels 143 are in contact with the top surface of the steel rail 12.

[0083] In this technical solution, to ensure the platform's load-bearing capacity and stability, the hydraulic wheel assembly 14 adopts a four-cylinder hydraulic support, including four electric hydraulic cylinders 1411, and stroke sensors for the hydraulic telescopic rods 1412 of each electric hydraulic cylinder 1411, multiple tilt sensors, etc. The tilt sensors can be fixed in the steel frame platform 11 to monitor the tilt angle of the steel frame platform 11 in real time, and then adjust the stroke of the hydraulic rods 1412 in a timely manner to control the levelness of the steel frame platform 11. The distribution wheel frame 142, which is hinged to the single-sided support wheel assembly 141, evenly distributes the load on it to each roller 143. The distribution wheel frame 142 evenly distributes the load to the rollers 143 on it to reduce the maximum bending moment on the steel rail 21. The rollers 143 arranged front and rear on a single distribution wheel frame 142 can better adapt to the bending section of the steel rail 21, so that the first movable platform 1 can travel smoothly on the steel trestle bridge 2.

[0084] In this technical solution, according to the load distribution on the first movable platform 1, an inclined hydraulic cylinder 144 can be added between the secondary support beam 122 and any distribution wheel frame 142. The two ends of the inclined hydraulic cylinder 144 are respectively hinged to the bearings of the secondary support beam 122 and the distribution wheel frame 142, so as to satisfy the integrity of the hydraulic wheel set 14 and make the load distribution transmitted by the hydraulic wheel set 14 to the steel trestle bridge 2 uniform.

[0085] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A pile foundation construction method, characterized in that, Includes the following steps: S1. Based on the designed location of the pile foundation on the slope, conduct a survey and mark the locations where the steel sheet piles need to be installed along both sides of the pile positions within a straight line from the top to the bottom of the slope. S2. Fix the winch equipment at the top of the slope, install the first movable platform and connect the first movable platform to the winch equipment with steel cables to complete the entire steel trestle bridge; The steel trestle bridge includes two parallel and symmetrically arranged steel rail frames. Each steel rail frame includes multiple spaced steel sheet piles. The pile bodies of the steel sheet piles are in the slope. The tops of all the steel sheet piles are connected to a steel rail. All sections of the steel rail from the highest point to the lowest point are downhill sections or horizontal sections. The first movable platform includes a steel frame platform, which is assembled from multiple sets of Bailey beams. A steel plate layer is detachably connected to the Bailey beams. A platform support is detachably connected to the bottom of the steel frame platform. The platform support is located above the steel trestle bridge. The platform support includes two horizontal main support beams that are parallel to the steel rail frame. Multiple secondary support beams are detachably connected between the upper surface of the main support beams and the steel frame platform. A traction support is detachably connected to the bottom surface of the multiple secondary support beams. The traction support is connected to the winch equipment via a steel cable. The platform support is connected to a hydraulic wheel set, which contacts the lower steel rail. The steel rail includes multiple spaced steel brackets, with a steel rail beam connecting any two steel brackets. The tops of the steel brackets correspond one-to-one with the tops of the steel sheet piles and are detachably connected. The top surface of the steel bracket is flat and flush with the top surfaces of the steel rail beams on both sides without any misalignment or height difference. The vertical surface of the steel bracket near the other side of the steel rail is flush with the vertical surface of the steel rail beam near the other side of the steel rail. Each of the main beams of the support is located directly above the steel rails on each side. Multiple support bases are detachably connected to the bottom surface of the main beams of the support. Each support base corresponds to a steel bracket below it. There is a hydraulic jack between the bottom surface of the support base and the top surface of the steel bracket. The height of the hydraulic jack is equal to the net distance between the bottom surface of the support base and the top surface of the steel bracket. The completion of the entire steel trestle bridge includes the following steps: A1. Use a sheet pile driver to construct sheet piles within the coverage area of ​​the sheet pile driver cantilever at the top of the slope. Then, install steel brackets on the top of each completed sheet pile and connect steel track beams and rail connecting beams between the steel brackets. A2. Using the upper surface of the steel bracket as the base, place each hydraulic jack on the steel bracket and make the top surfaces of each hydraulic jack level. Install the platform support, traction support, steel frame platform, and hydraulic wheel set in sequence. Then connect the traction support and winch equipment with steel cables and move the required steel sheet pile driver to the steel frame platform. A3. The winch straightens and loads the steel cable. At this time, the hydraulic wheel set is kept in the rising position and is adjusted in time to keep the support platform level. After removing the hydraulic jacks, the winch is used to lower the steel cable so that the first movable platform slides down to the appropriate position under its own weight. While maintaining the tension of the winch, the lowering of the steel cable is stopped so that the first movable platform stops sliding down. The hydraulic jacks are installed between the support base and the steel bracket. After installation, the hydraulic wheel set is retracted so that the platform support sits on the jacks. A4. Repeat A1 and A3 to extend towards the bottom of the slope and complete the construction of the steel trestle bridge; S3. Move or drive the drilling equipment to the first movable platform, use the winch equipment to drive the first movable platform to the design position on the steel trestle bridge, fix the first movable platform to the steel trestle bridge, and then use the drilling equipment to carry out pile hole construction at the pile position. S4. Repeat S3 until all pile holes in the area covered by the steel trestle bridge are drilled, and then unload the drilling equipment from the first movable platform. S5. Move or drive the hoisting equipment to the first movable platform and hoist the pile reinforcement cage into all pile holes; S6. Pour concrete into the pile hole to complete the pile foundation construction.

2. The pile foundation construction method as described in claim 1, characterized in that, The process of hoisting the pile reinforcement cage into all pile holes includes the following steps: B1. Lower the first movable platform carrying the lifting equipment to a suitable position, install the hydraulic jacks and then retract the hydraulic wheel assembly, and disconnect the steel cable connection between the movable platform and the winch equipment. B2. Install the second movable platform, place the pile reinforcement cage placement frame on the second movable platform, and connect the winch equipment to the steel cable of the second movable platform; B3. Arrange a batch of pile reinforcement cages on the pile reinforcement cage placement rack at the top of the slope; B4. Use a winch to lower the second movable platform into the lifting area covered by the lifting equipment on the first movable platform; B5. The lifting equipment will lift all the pile reinforcement cages on the second movable platform in sequence and place them into the pile holes within the lifting area. After completion, the second movable platform will be raised to the top of the slope. Repeat steps B3-B4 until all reinforcement cages within the lifting area are completed. B6. Repeat B1-B3 until all pile reinforcement cages are completed.

3. The pile foundation construction method as described in claim 2, characterized in that, The hydraulic wheel assembly includes two symmetrical single-sided support wheel assemblies connected to the lower surface of the main beam of the support. Each single-sided support wheel assembly includes multiple electric hydraulic cylinders, which are spaced apart and vertically fixed to the bottom surface of the main beam of the support. The hydraulic telescopic rod end of each electric hydraulic cylinder is hinged to a distribution wheel frame, which is a crank-shaped structure that curves upward. Two traveling wheels are connected to the surface of the distribution wheel frame facing the near-side steel rail, and the traveling wheels are in contact with the top surface of the steel rail.

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