Composite pile group foundation for rock-embedded bridges of unequal heights suitable for soft foundation and its construction method

Abstract

The present invention discloses a composite pile group foundation for rock-embedded bridges of unequal heights suitable for soft foundations and a construction method thereof, and relates to the technical field of bridge construction. The present invention comprises a cap, the bottom end of which is evenly fixed with pile foundations, a first shear wall is fixed between the tops of a plurality of pile foundations at the same end, a second shear wall is fixed between a plurality of first shear walls at the same side, and a grouting reinforcement groove is formed between the second shear walls at two adjacent ends. Through the coordination of the pile foundation, the shear wall and the cap, the composite pile group foundation for rock-embedded bridges of unequal heights fully utilizes the mechanical properties of the foundation bearing layer, and the rock-embedded depth of the pile foundation is reasonably set according to the soil strength of the bearing layer. At the same time, through the coordination of a plurality of pile foundations and the shear wall, better vertical and horizontal bearing capacity can be provided, and the rock-embedded depth of the pile foundation and the shear wall can be reasonably set according to the characteristics of the rock strata of the bearing layer.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge construction, and in particular relates to a composite pile group foundation for rock-embedded bridges of unequal heights suitable for soft foundations and a construction method thereof. Background Art

[0002] Pile group foundation is the main foundation form of buildings in my country's bridge engineering construction field. The bridge foundation composed of multiple piles is used to bear the bridge load and transmit it to the foundation. When a single pile cannot meet the upper load requirements, multiple piles must be used to transfer the upper load. The piles are connected by caps to carry the load.

[0003] The geological environment in which bridge pile groups are located is often complex and changeable. For river-crossing and sea-crossing bridge foundations, the pile groups are subject to complex loads, such as waves, strong earthquakes, and ship collisions. Under the action of ship collisions, river-crossing and sea-crossing pile groups may be subjected to strong impacts, which can significantly affect the safety performance of the bridge pile group foundation structure and even cause overall instability or local damage to the bridge structure, posing a huge threat to the bridge pile group foundation.

[0004] In a patent application number CN201810280897.6 for a composite foundation for bridges suitable for deep water and strong earthquake conditions, the foundation is a new type of composite foundation consisting of piles, suction caisson foundations, pressureless caisson foundations, and reinforced cushions. Piles are used to reinforce the foundation, and a graded reinforced cushion is laid on top to act as a seismic isolation layer. Multiple suction caisson foundations are arranged in a circular ring around the pressureless caisson foundation. The pressureless caisson foundation is placed directly on top of the reinforced cushion and is not connected to the piles, suction caisson foundations, or reinforced cushions. This solves the problem in actual engineering applications where, during an earthquake, if there is a large displacement between the caisson foundation and the underlying composite foundation, the caisson foundation will shift beyond the boundary of the pile foundation reinforcement range, causing the entire foundation to overturn and be damaged due to uneven bearing capacity of the foundation. Furthermore, while the seismic isolation cushion effectively prevents the transmission of seismic forces, it also weakens the foundation's ability to resist horizontal loads, which are primarily borne by the friction between the caisson and the gravel cushion. Under common loads such as wind, waves, and currents, the foundation can remain generally stable. However, under strong winds and long-term scouring conditions, the foundation may experience significant displacement. Furthermore, under deep water or earthquake conditions, the gravel cushion layer is likely to liquefy due to vibration, which may also lead to the destruction of the entire foundation, thereby threatening the overall safety of the bridge.

[0005] Patent application number CN202110695731.2 describes a bridge seismic isolation structure suitable for pile group foundations. The structure includes a bridge pier with a cap fixedly cast at the bottom. A bearing steel plate corresponding to the pile foundation at the base of the cap is embedded within the cap. An outer steel casing with its mouth facing downward is fixed to the bottom of the bearing steel plate. The outer steel casing extends beyond the base of the cap and covers the top of the pile foundation. An inner steel casing, encasing the pile foundation, is fixed to the top of the pile foundation. The inner steel casing is a bottomless cylinder with a radial gap between the sidewalls of the inner and outer steel casings. The outer diameter of the inner steel casing is equal to the outer diameter of the pile foundation, and the radial gap between the inner and outer steel casings is 3-5 cm. This solves the problem that currently common bridge seismic isolation systems are mainly divided into two categories: ductile and isolation systems. Common ductile seismic isolation systems are implemented by installing plastic hinges at the base or top of the pier. The seismic isolation and earthquake resistance system mainly consumes earthquake energy by installing seismic isolation bearings or other energy-absorbing devices, thereby reducing the effect of earthquakes. Commonly used seismic isolation systems are generally implemented by installing seismic isolation bearings or other seismic isolation devices between the upper and lower parts, which cannot be integrated with the bridge structure. In the design of the bridge substructure, the pedestal and pile foundation are often designed as a consolidation system, that is, the pedestal and the pile top are cast together with concrete to achieve a rigid connection, which is not convenient for the installation of seismic isolation devices.

[0006] Currently, bridge pile foundations are composed of multiple single piles that are not connected to each other. They mainly bear the vertical loads of the bridge superstructure and have poor bearing capacity for horizontal loads. Therefore, they are not effective in bridge structures with complex load environments or large live loads.

[0007] Therefore, a composite pile group foundation for rock-embedded bridges of unequal heights suitable for soft foundations and a construction method thereof were designed to provide another solution to the above technical problems. Summary of the Invention

[0008] The object of the present invention is to provide a rock-embedded composite pile foundation for bridges of unequal heights suitable for soft foundations and a construction method thereof. Through the cooperation of pile foundations, shear walls and pedestals, the composite pile foundation for bridges of unequal heights can be used as bridge anchor foundations, bridge cable tower foundations and other bridge construction foundations based on pile foundations. The rock-embedded composite pile foundation for bridges of unequal heights fully utilizes the mechanical properties of the foundation bearing layer, and the rock embedding depth of the pile foundation is reasonably set according to the soil strength of the bearing layer. While reducing the project cost, the settlement and deformation of the soil can be well controlled to meet the design requirements of the bridge foundation. At the same time, through the cooperation of multiple pile foundations and shear walls, better vertical and horizontal bearing capacity can be provided. Moreover, according to the characteristics of the rock stratum of the bearing layer, the rock embedding depth of the pile foundation and the shear wall can be reasonably set, and the shear wall does not need to be rock embedded. In this way, while ensuring the resistance of the bridge structure to horizontal forces, the project cost is also reduced and the construction period is shortened.

[0009] To solve the above technical problems, the present invention is achieved through the following technical solutions:

[0010] The present invention is a composite pile foundation for rock-embedded bridges of unequal heights suitable for soft foundations, comprising a cap, pile foundations being evenly distributed and fixed at the bottom end of the cap, a first shear wall being fixed between the tops of a plurality of the pile foundations located at the same end, a second shear wall being fixed between a plurality of the first shear walls located on the same side, and a grouting reinforcement groove being formed between the second shear walls at adjacent ends.

[0011] Furthermore, C40 concrete is used for pouring the foundation.

[0012] Furthermore, a connecting mechanism for positioning is installed between two adjacent platforms, and the connecting mechanism includes a positioning fixing plate, a connecting positioning column, an assembly plate and a limit positioning plate. The limiting positioning plates are fixed at both ends of the positioning fixing plate, and the limiting positioning plates are slidingly connected to the platforms. The inner part of the limiting positioning plate away from one end of the positioning fixing plate is slidingly connected with a connecting positioning column, and the connecting positioning column is slidingly connected to the platform, and the outer side of the limiting positioning plate is slidingly connected with an assembly plate.

[0013] Furthermore, a limit assembly for positioning is installed on the limit positioning plate, and the limit assembly includes a displacement positioning block, a limit sliding plate and a return spring. A positioning cavity is opened inside the limit positioning plate, and the top and bottom ends of the positioning cavity are both slidably connected to the limit sliding plate. A return spring is fixed between the two limit sliding plates, and displacement positioning blocks are evenly fixed on the top of the limit sliding plate, and the displacement positioning blocks and the limit positioning plates, as well as the assembly plate and the displacement positioning blocks are all slidably connected.

[0014] Furthermore, an inclined surface is provided at one end of the top of the displacement positioning block away from the positioning fixing plate, and a first communicating flow hole is provided inside the displacement positioning block and the limiting sliding plate.

[0015] Furthermore, a first circulation groove is provided inside the top of the positioning and fixing plate, a second circulation groove is provided inside the positioning and fixing plate and at the bottom of the first circulation groove, and the first circulation groove and the second circulation groove are connected, and both ends of the second circulation groove pass through the limiting positioning plate, and the second circulation holes are evenly distributed on the end of the limiting positioning plate away from the positioning and fixing plate.

[0016] A construction method for a composite pile group foundation of a rock-embedded bridge of unequal height on soft soil, for any of the above items, comprising the following steps:

[0017] S1: Clean and level the site, and accurately locate the coordinates of each pile foundation and shear wall;

[0018] S2: When constructing the pile foundation, first locate the center of the pile and use the rotary drilling reverse circulation process;

[0019] S3: Construction of the first shear wall. The first shear wall is grooved with a milling machine. After the groove is formed, the steel cage is lowered and concrete is poured. The shear wall and the pile foundation are connected by bite-locking.

[0020] S4: Second shear wall construction: The second shear wall is slotted using a slot milling machine. After the slot is formed, the steel cage is lowered and concrete is poured. Each slot section is connected with a rigid joint;

[0021] S5: Grouting reinforcement construction, the soil in the four formed compartments is subjected to foundation grouting reinforcement treatment;

[0022] S6: After the grouting construction is completed, the foundation pile construction work is carried out, and the profiled channel steel is supported around the pile group foundation. After the concrete pouring is completed, the concrete is cured.

[0023] Furthermore, after the hole is formed, the steel cage is lowered and concrete is poured.

[0024] Furthermore, the verticality deviation of the pile body is <1%.

[0025] Further, A. install the assembly plate on the outer side of the limit positioning plate, and position the assembly plate by means of a displacement positioning block;

[0026] B. Place the limiting positioning plate into the inner side of the corresponding platform;

[0027] C. Pour concrete into the first flow channel.

[0028] The present invention has the following beneficial effects:

[0029] 1. The present invention can be used as the foundation of bridge anchorages, bridge pylons and other bridge structures based on pile foundations through the coordination of pile foundations, shear walls and pedestals. The composite pile group foundation of bridges with unequal heights embedded in rock fully utilizes the mechanical properties of the foundation bearing stratum. The rock embedding depth of the pile foundation is reasonably set according to the soil strength of the bearing stratum. While reducing the project cost, the settlement and deformation of the soil can be well controlled to meet the design requirements of the bridge foundation. At the same time, through the coordination of multiple pile foundations and shear walls, better vertical and horizontal bearing capacity can be provided. Moreover, according to the characteristics of the rock stratum of the bearing stratum, the rock embedding depth of the pile foundation and the shear wall can be reasonably set, and the shear wall does not need to be embedded in rock. In this way, while ensuring the resistance of the bridge structure to horizontal forces, the project cost is also reduced and the construction period is shortened.

[0030] 2. The present invention can locate the position between two pedestals that need to be connected through the coordination of the positioning fixing plate, the connecting positioning column, the mounting hole and the assembly plate, and can fix the limiting positioning plate inside the pedestal by injecting concrete from the inside of the first flow groove.

[0031] 3. The present invention cooperates with the displacement positioning block, the limiting sliding plate and the reset spring. When in use, the displacement positioning block can be moved after being reset by the lifting and lowering of the displacement positioning block and the rebound after compression of the reset spring, thereby fixing the position of the assembly plate installed on the outside of the limiting positioning plate. At the same time, concrete can flow through the first flow hole, thereby fixing the assembly plate and the displacement positioning block.

[0032] 4. The present invention cooperates with the first circulation groove, the second circulation groove and the second circulation hole to allow concrete to enter the interior of the limiting positioning plate through the interior of the first circulation groove, and then enter the interior of the first circulation hole and the second circulation hole from the interior of the limiting positioning plate, thereby fixing the interior of the limiting positioning plate, between the assembly plate and the displacement positioning block, and between the limiting positioning plate and the base to prevent detachment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 This is a structural schematic diagram of a composite pile group foundation for rock-embedded bridges of unequal heights suitable for soft foundations according to the present invention;

[0035] Figure 2 This is a structural schematic diagram of a rock-embedded composite pile group foundation for bridges of unequal heights suitable for soft foundations according to the present invention;

[0036] Figure 3 This is a front view of a composite pile group foundation of a rock-embedded bridge of unequal heights suitable for soft foundations according to the present invention;

[0037] Figure 4 This is a side view of a composite pile group foundation for rock-embedded bridges of unequal heights suitable for soft foundations according to the present invention;

[0038] Figure 5 A top view of a composite pile group foundation of a rock-embedded bridge of unequal height suitable for soft foundation according to the present invention;

[0039] Figure 6 This is a schematic diagram of the internal structure of the connection between the cap and the positioning fixing plate of a composite pile group foundation of a rock-embedded bridge of unequal height suitable for soft foundation according to the present invention;

[0040] Figure 7 This is a schematic structural diagram of a positioning and fixing plate for a composite pile group foundation of a rock-embedded bridge of unequal heights suitable for soft foundations according to the present invention;

[0041] Figure 8 This is a structural schematic diagram of a limiting positioning plate for a composite pile group foundation of a rock-embedded bridge of unequal heights suitable for soft foundations according to the present invention;

[0042] Figure 9 This is a schematic diagram of the internal structure of a limiting positioning plate for a composite pile group foundation of a rock-embedded bridge of unequal heights suitable for soft foundations according to the present invention;

[0043] Figure 10 This is a schematic diagram of the internal structure of a positioning and fixing plate for a composite pile group foundation of a rock-embedded bridge of unequal heights suitable for soft foundations according to the present invention;

[0044] Figure 11 The present invention is a structural schematic diagram of a displacement positioning block for a composite pile group foundation of a rock-embedded bridge of unequal heights suitable for soft foundation.

[0045] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0046] 1. Cap; 2. Pile foundation; 3. First shear wall; 4. Second shear wall; 5. Grouting reinforcement groove; 6. First circulation hole; 7. Positioning and fixing plate; 8. Connecting positioning column; 9. First sliding mounting hole; 10. Assembly plate; 11. Limiting positioning plate; 12. First circulation groove; 13. Second sliding mounting hole; 14. Displacement positioning block; 15. Limiting sliding plate; 16. Second circulation groove; 17. Limiting slide groove; 18. Second circulation hole; 19. Return spring. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0048] Example 1:

[0049] See also Figure 1-Figure 5 As shown, the present invention is a composite pile group foundation suitable for rock-embedded bridges of unequal heights on soft foundations, comprising a cap 1, pile foundations 2 evenly fixed at the bottom end of the cap 1, a first shear wall 3 fixed between the tops of multiple pile foundations 2 located at the same end, a second shear wall 4 fixed between multiple first shear walls 3 located on the same side, and the second shear wall 4 is located at the center, and a grouting reinforcement groove 5 is formed between the second shear walls 4 at adjacent ends;

[0050] The composite pile group foundation of the bridge is suitable for soft soil foundations and is embedded in moderately weathered rock strata with a diameter twice that of the pile. The composite pile group foundation of the bridge forms a first shear wall 3 of unequal height along the bridge direction. The first shear wall 3 connects the large-diameter pile foundations along the bridge direction in sequence to form a first shear wall 3 capable of resisting horizontal forces.

[0051] The cap 1 is a reinforced concrete cap, and the pile foundation is a large-diameter pile foundation. During construction, a rotary drilling rig with reverse circulation was used for drilling, and the pile foundation diameter is 3m. To fully utilize the mechanical properties of the foundation's bearing stratum, the rock embedment depth of the pile foundation was set at 5m based on the position of the bearing stratum to ensure the foundation's load-bearing performance and deformation resistance requirements. The first shear wall 3 was milled using a slot milling machine to form a second-phase slot section, which overlaps the large-diameter pile foundation. To fully utilize the mechanical properties of the foundation's bearing stratum and ensure the load-bearing and deformation resistance requirements of the pile group foundation, the first shear wall 3 is set to a length of 15m, with unequal heights along the bridge. The main function of the first shear wall 3 is to sequentially connect the pile foundations along the bridge, forming a shear wall capable of resisting horizontal forces. The second shear wall 4 was milled using a slot milling machine to form a second-phase slot section. The second shear wall 4 is set to a length of 15m. The five groups of shear walls along the bridge are connected. The main function of the second shear wall 4 is to connect the five groups of shear walls along the bridge into a load-bearing whole, ensuring the coordinated load and deformation stability of the entire foundation; the scope of the grouting reinforcement groove 5 is the four compartments separated by the first shear wall 3 and the second shear wall 4. The soil within the lower 10m range of the four compartments is subjected to foundation grouting reinforcement treatment. By reinforcing the surface soil of the stratum, the deformation of the soil inside the pile group foundation is controlled to ensure the bearing performance of the pile group foundation.

[0052] Cap 1 is 33m long, 28.7m wide, and 5m high. Piles are connected by cap 1, which carries the load and serves as the load-transmitting structure of the bridge pile foundation, transferring the bridge load to the foundation. C40 concrete was used to cast cap 1 to ensure its structural strength.

[0053] This allows for a total of five sets of second shear walls 4, consisting of six pile foundations along the longitudinal direction and a first shear wall 3 milled by a slotting machine. These shear walls are not at the same height as the pile foundations. Across the bridge, two long shear walls are milled by a slotting machine. The second shear walls 4 are not at the same height as the pile foundations, forming four large compartments that are reinforced with grouting. The rock-embedded composite pile foundation for bridges of unequal heights fully utilizes the mechanical properties of the foundation's bearing stratum. The rock-embedded depth of the pile foundation is appropriately set based on the soil strength of the bearing stratum. This reduces construction costs while effectively controlling soil settlement and deformation, making it a novel foundation structure for bridges or other buildings.

[0054] Example 2:

[0055] See also Figures 6-11 As shown, the difference from the first embodiment is that:

[0056] A connecting mechanism for positioning is installed between two adjacent platforms 1, and the connecting mechanism includes a positioning fixing plate 7, a connecting positioning column 8 and a limiting positioning plate 11. The limiting positioning plates 11 are fixed at both ends of the positioning fixing plate 7, and the limiting positioning plates 11 are slidably connected to the platform 1, and a certain gap is left between the limiting positioning plates 11 and the inside of the platform 1. The limiting positioning plate 11 is slidably connected to the connecting positioning column 8 at one end away from the positioning fixing plate 7, and the connecting positioning column 8 is slidably connected to the platform 1. A second sliding mounting hole 13 is provided inside the limiting positioning plate 11, and the connection between the positioning column 8 and the limiting positioning plate 11 is provided. The connection between the support 1 and the support 1 is slidably connected through the second sliding mounting hole 13, so that the connection positioning column 8 can easily enter the interior of the second sliding mounting hole 13. A first sliding mounting hole 9 is opened in the interior of the support 1 and at a position corresponding to the second sliding mounting hole 13. The connection positioning column 8 and the support 1 are slidably connected through the first sliding mounting hole 9, so that the connection positioning column 8 can easily enter the interior of the first sliding mounting hole 9, and then enter the interior of the second sliding mounting hole 13 after the connection positioning column 8 enters from the top, and the connection positioning column 8 can only be detached from the top through the sliding connection;

[0057] The connecting positioning column 8 is inserted into the first sliding installation hole 9 on the support platform 1 through a sliding connection, and then into the second sliding installation hole 13, thereby preventing the limiting positioning plate 11 from separating from the support platform 1 and positioning the position of the limiting positioning plate 11;

[0058] A limiting assembly for positioning is installed on the limiting positioning plate 11, and the limiting assembly includes a displacement positioning block 14, a limiting sliding plate 15 and a return spring 19. A positioning cavity is opened inside the limiting positioning plate 11, and the top and bottom ends of the positioning cavity are slidably connected to the limiting sliding plate 15, so that the limiting sliding plate 15 can slide inside the positioning cavity under the extrusion of external force. A return spring 19 is fixed between the two limiting sliding plates 15, so that the limiting sliding plate 15 can be reset and moved by the rebound of the return spring 19 after being squeezed. The top and bottom of the limiting sliding plate 15 are evenly fixed with displacement positioning blocks 14. The displacement positioning block 14 is slidably connected to the limit positioning plate 11, so that the displacement positioning block 14 can be lifted and slid inside the limit positioning plate 11. A limit slot 17 is provided inside the limit positioning plate 11, and the bottom end of the limit slot 17 is connected to the positioning cavity. The displacement positioning block 14 is slidably connected to the limit positioning plate 11 through the limit slot 17. An inclined surface is provided on the top of the displacement positioning block 14 away from the positioning fixing plate 7. A first flow hole 6 is provided in communication with the displacement positioning block 14 and the limit sliding plate 15, so that objects can enter the interior of the displacement positioning block 14 through the first flow hole 6 and then flow out.

[0059] The outer side of the limiting positioning plate 11 is slidably connected to the assembly plate 10, and the assembly plate 10 is slidably connected to the displacement positioning block 14, so that the position of the assembly plate 10 slidably mounted on the outer side of the limiting positioning plate 11 can be fixed by the rise of the displacement positioning block 14 after it is lowered, so that multiple assembly plates 10 can be installed as needed to increase the thickness of the positioning and fixing plate 7, and concrete can be allowed to enter the inner side of the assembly plate 10 through the first flow hole 6, and then the assembly plate 10 can be fixed to the outer side of the limiting positioning plate 11 according to the solidification of the concrete;

[0060] When in use, the assembly plate 10 that needs to be added is installed on the outside of the limit positioning plate 11 through the sliding connection with the limit positioning plate 11, and then the displacement positioning block 14 is pressed to make the displacement positioning block 14 move downward inside the limit positioning plate 11. The downward movement of the displacement positioning block 14 drives the limit sliding plate 15 to move downward, and the downward movement of the limit sliding plate 15 drives the return spring 19 to be compressed, and then the assembly plate 10 is slid so that the assembly plate 10 moves outside the limit positioning plate 11 and enters the outside of the corresponding displacement positioning block 14, and makes the assembly plate 10 fit with the positioning fixing plate 7, and at the same time releases the displacement positioning block 14. The extrusion force drives the limiting sliding plate 15 to reset and rise through the rebound of the return spring 19 after compression. The reset movement of the limiting sliding plate 15 drives the displacement positioning block 14 to enter the corresponding assembly plate 10, thereby positioning the position of the assembly plate 10, and then the limiting positioning plate 11 is installed between the two supporting platforms 1 through a sliding connection. At the same time, there is a certain gap between the limiting positioning plate 11 and the inner side of the supporting platform 1; after the connecting positioning column 8 is inserted into the first sliding mounting hole 9 on the supporting platform 1 through a sliding connection, it enters the second sliding mounting hole 13, thereby preventing the limiting positioning plate 11 from separating from the supporting platform 1 and positioning the position of the limiting positioning plate 11;

[0061] A first flow groove 12 is provided inside the top of the positioning and fixing plate 7, and a second flow groove 16 is provided inside the positioning and fixing plate 7 and at the bottom end of the first flow groove 12, and the first flow groove 12 and the second flow groove 16 are connected, so that the concrete entering the first flow groove 12 can directly enter the second flow groove 16, and the two ends of the second flow groove 16 pass through the limiting positioning plate 11, so that the concrete entering the second flow groove 16 can enter the positioning cavity on the limiting positioning plate 11, and the limiting positioning plate 11 is evenly provided with second flow holes 18 on the end away from the positioning and fixing plate 7, and the second flow holes 18 are located between the two adjacent second sliding mounting holes 13, so that the concrete can enter the inner side of the base 1 through the second flow holes 18, and then the limiting positioning plate 11 and the base 1 are fixed by cooling;

[0062] After the limiting positioning plate 11 is installed inside the pedestal 1, concrete is injected into the first circulation groove 12, so that the concrete enters the second circulation groove 16 through the first circulation groove 12, and then enters the positioning cavity through the second circulation groove 16. When the positioning cavity is filled, the concrete enters the gap between the limiting positioning plate 11 and the pedestal 1 bracket through the second circulation hole 18, fixing the limiting positioning plate 11 inside the pedestal 1, and some concrete enters the assembly plate 10 through the first circulation hole 6, fixing the assembly plate 10 and the limiting positioning plate 11 more firmly to prevent the two pedestals 1 from separating.

[0063] The working principle of this embodiment is as follows:

[0064] The return spring 19 is compressed, and then the sliding assembly plate 10 is slid, so that the assembly plate 10 moves outside the limit positioning plate 11 and enters the outer side of the corresponding displacement positioning block 14, and makes the assembly plate 10 fit with the positioning fixing plate 7. At the same time, the squeezing force on the displacement positioning block 14 is released, and the rebound after compression of the return spring 19 drives the limit sliding plate 15 to return to the upper position, and the return movement of the limit sliding plate 15 drives the displacement positioning block 14 to enter the corresponding assembly plate 10, thereby positioning the assembly plate 10. Then the limit positioning plate 11 is installed between the two supporting platforms 1 through the sliding connection, and at the same time, the limit positioning plate 11 has a certain gap with the inner side of the supporting platform 1.

[0065] After the connecting positioning column 8 is slidably connected into the first sliding mounting hole 9 on the base 1, it enters the second sliding mounting hole 13, thereby preventing the limit positioning plate 11 from separating from the base 1, and positioning the position of the limit positioning plate 11, and then injecting concrete into the first flow groove 12, so that the concrete enters the second flow groove 16 through the first flow groove 12, and then enters the positioning cavity through the second flow groove 16. When the positioning cavity is filled, the concrete enters the gap between the limit positioning plate 11 and the base 1 bracket through the second flow hole 18, fixing the limit positioning plate 11 to the inside of the base 1, and some concrete enters the inside of the assembly plate 10 through the first flow hole 6, fixing the assembly plate 10 and the limit positioning plate 11 more firmly, and preventing the two bases 1 from separating.

[0066] Example 3:

[0067] Based on the above embodiment 1, the construction method is disclosed, and the steps are as follows:

[0068] Step 1: site cleaning and leveling, the site is 50m long and 50m wide, and the position coordinates of each pile foundation and shear wall are accurately located;

[0069] Step 2: Pile foundation construction. First, a total station is used to locate the center of the pile. A rotary drilling rig with reverse circulation is used. After the hole is drilled, a steel cage is lowered and C30 concrete is poured. The verticality of the pile is strictly controlled, with a verticality deviation of <1%.

[0070] Step 3: Construction of the first shear wall 3. The first shear wall 3 is grooved with a milling machine. The vertical deviation of the groove shall not be greater than 1 / 400 of the wall height. After the groove is formed, the steel cage is lowered and concrete is poured. The shear wall and the pile foundation are connected by bite.

[0071] Step 4: Construction of the second shear wall 4. The second shear wall 4 is grooved with a slot milling machine. The vertical deviation of the groove shall not be greater than 1 / 400 of the wall height. After the groove is formed, the steel cage is lowered and concrete is poured. Each groove section is connected with a rigid joint;

[0072] Step 5: Grouting reinforcement construction, the soil in the four formed compartments is subjected to foundation grouting reinforcement treatment, and the soil reinforcement depth is within 10m of the lower part of the compartment.

[0073] Step 6: Construction of the cap. After the grouting is completed, the construction of cap 1 is carried out. Channel steel is set around the pile group foundation. The cushion elevation is strictly controlled during pouring. After the concrete pouring is completed, the concrete is cured.

[0074] Example 4:

[0075] Based on the above embodiment 2, the construction method is disclosed:

[0076] A. Install the assembly plate 10 on the outside of the limiting positioning plate 11 and position the assembly plate 10 using the displacement positioning block 14;

[0077] B. Place the limiting positioning plate 11 into the inner side of the corresponding support platform 1;

[0078] C. Concrete is injected into the first flow groove 12, and the space between the limiting positioning plate 11 and the base 1, between the limiting positioning plate 11 and the assembly plate 10, and the interior of the limiting positioning plate 11 are fixedly connected after cooling to increase firmness during use.

[0079] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0080] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. The preferred embodiments do not describe all details in detail, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A composite pile group foundation for rock-embedded bridges of unequal heights suitable for soft foundations, characterized by: It comprises a capping platform (1), wherein pile foundations (2) are evenly distributed and fixed at the bottom end of the capping platform (1), a first shear wall (3) is fixed between the tops of a plurality of the pile foundations (2) located at the same end, a second shear wall (4) is fixed between a plurality of the first shear walls (3) located at the same side, and a grouting reinforcement groove (5) is formed between the second shear walls (4) at two adjacent ends; A connection mechanism for positioning is installed between two adjacent platforms (1), the connection mechanism comprising a positioning fixing plate (7), a connecting positioning column (8), an assembly plate (10) and a limiting positioning plate (11), both ends of the positioning fixing plate (7) are fixed with a limiting positioning plate (11), and the limiting positioning plate (11) is slidably connected to the platform (1), the inner part of the limiting positioning plate (11) away from the end of the positioning fixing plate (7) is slidably connected with a connecting positioning column (8), and the connecting positioning column (8) is slidably connected to the platform (1), and the outer side of the limiting positioning plate (11) is slidably connected with the assembly plate (10); A limiting assembly for positioning is installed on the limiting positioning plate (11), and the limiting assembly comprises a displacement positioning block (14), a limiting sliding plate (15) and a return spring (19). A positioning cavity is provided inside the limiting positioning plate (11), and the top and bottom ends of the positioning cavity are both slidably connected to the limiting sliding plate (15). A return spring (19) is fixed between the two limiting sliding plates (15). Displacement positioning blocks (14) are evenly fixed on the top of the limiting sliding plate (15), and the displacement positioning blocks (14) and the limiting positioning plate (11), as well as the assembly plate (10) and the displacement positioning blocks (14) are all slidably connected.

2. The composite pile group foundation of rock-embedded bridges of unequal heights suitable for soft foundation according to claim 1, characterized in that: The cap (1) is cast using C40 concrete.

3. The composite pile group foundation of rock-embedded bridges of unequal heights suitable for soft foundation according to claim 1, characterized in that: An inclined surface is provided at one end of the top of the displacement positioning block (14) away from the positioning fixing plate (7), and a first flow hole (6) communicating with the displacement positioning block (14) and the limiting sliding plate (15) is provided inside.

4. The composite pile group foundation of rock-embedded bridges of unequal heights suitable for soft foundation according to claim 1, characterized in that: A first flow groove (12) is provided inside the top of the positioning fixing plate (7), a second flow groove (16) is provided inside the positioning fixing plate (7) and located at the bottom of the first flow groove (12), and the first flow groove (12) and the second flow groove (16) are connected, and both ends of the second flow groove (16) pass through the limiting positioning plate (11), and second flow holes (18) are evenly distributed on one end of the limiting positioning plate (11) away from the positioning fixing plate (7).

5. A construction method for a composite pile group foundation of a rock-embedded bridge of unequal heights applicable to soft foundation, used for the composite pile group foundation of a rock-embedded bridge of unequal heights applicable to soft foundation according to any one of claims 1 to 4, characterized in that: Here are the steps: S1: Clean and level the site, and accurately locate the position coordinates of each pile foundation and shear wall; S2: When constructing the pile foundation, first locate the center of the pile and use the rotary drilling reverse circulation process; S3: Construction of the first shear wall (3). The first shear wall (3) is grooved by a groove milling machine. After the groove is formed, a steel cage is lowered and concrete is poured. The shear wall and the pile foundation are connected by a bite-locking method. S4: Construction of the second shear wall (4). The second shear wall (4) is slotted using a slot milling machine. After the slot is formed, a steel cage is lowered and concrete is poured. Each slot section is connected using a rigid joint. S5: Grouting reinforcement construction, the soil in the formed (4) compartments is subjected to foundation grouting reinforcement treatment; S6: Construction of the cap After the grouting construction is completed, the construction of the cap (1) is carried out. Channel steel is set around the pile group foundation. After the concrete pouring is completed, the concrete is cured.

6. The construction method of a composite pile group foundation of a rock-embedded bridge of unequal height applicable to soft foundation according to claim 5, characterized in that: After the hole is drilled, the steel cage is lowered and concrete is poured.

7. The construction method of a composite pile group foundation of a rock-embedded bridge of unequal height applicable to soft foundation according to claim 5, characterized in that: The verticality deviation of the pile body is <1%.

8. The construction method of a composite pile group foundation of a rock-embedded bridge of unequal height applicable to soft foundation according to claim 5, characterized in that: A. Install the assembly plate (10) on the outer side of the limit positioning plate (11), and position the assembly plate (10) by means of a displacement positioning block (14); B. Place the limiting positioning plate (11) into the inner side of the corresponding support platform (1); C. Inject concrete into the first flow channel (12).

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