Construction method of near-water low-pile pile cap under existing bridge influence

Abstract

The application provides a kind of construction method of near water low pile cap under the influence of existing bridge, comprising pumping assembly, the two sides of pumping assembly are symmetrically arranged with extension assembly, the side of extension assembly is connected with first flat plate, extension assembly includes second flat plate and first pipeline, first pipeline is arranged below second flat plate, the method is applicable to construction under the influence of existing bridge, removes bridge abutment, sets up temporary cofferdam in river channel, uses fast cofferdam device to open foundation pit in cofferdam for low pile cap construction, combined with the optimization of drainage channel and drainage device, can keep the whole foundation pit dry, reduce construction difficulty, speed up the cofferdam speed, improve construction efficiency, solve how to construct low pile cap and the problem of difficult drainage of water in foundation pit under the influence of existing bridge fast cofferdam construction.

Description

Technical Field

[0001] This invention relates to the field of river cofferdam construction, and in particular to a method for constructing a low-pile cap near water under the influence of an existing bridge. Background Technology

[0002] Near-water low-pile cap construction refers to the process of constructing low-pile caps in near-water areas using special technical means. A low-pile cap is a type of pile foundation characterized by its relatively low pile height, making it better suited to complex hydrogeological conditions.

[0003] During the construction of low-pile foundations near water, because construction is carried out by water, it is necessary to first construct a cofferdam with sandbags around the river and water area, and then carry out construction within the cofferdam. The sandbag cofferdam construction is slow and requires a lot of time to fill sandbags. During the construction process, there is a large amount of groundwater or river seepage, resulting in a large amount of water accumulation in the foundation pit, which affects the construction progress. At the same time, there is a lot of silt in the foundation pit. The traditional method is to pump out the silt with sewage pumps and then manually dredge the pit before standing in the middle of the pit to work. The foundation pit will continue to seep water in the future. When there is water accumulation, it is inconvenient for construction personnel to work in the foundation pit and poses a great safety hazard. Therefore, there is a need for a device and method that can quickly form a cofferdam, drain the water in the foundation pit in a timely manner, and allow construction personnel to carry out preliminary work in the foundation pit. Summary of the Invention

[0004] The main objective of this invention is to provide a construction method for low-pile foundations near water under the influence of existing bridges, which solves the problems of how to quickly construct low-pile foundations with cofferdams under the influence of existing bridges and the difficulty in draining water from the foundation pit, which hinders the movement of construction personnel.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a construction method for low-pile caps near water under the influence of existing bridges, the method comprising: S1. Draw lines on both sides of the existing bridge abutment to mark the construction area of ​​the cofferdam device, install fixed seats on both sides of the area, and drive fixed piles at selected locations in the river channel. S2. Connect the guide rod between the fixed seat and the fixed pile, and adjust the connecting guide rod to make the guide rod in the optimal state; S3. Insert side baffles between the guide rods and compact them; insert long baffles between the fixed piles and compact them. S4. Fill the inner side of the temporary cofferdam with sand, remove the existing bridge substructure, break the bridge abutment, stack the cofferdam on the water-facing side and lay geomembrane for water-proofing. S5. Backfill and compact the cofferdam, then perform slope spraying and concrete support on the cofferdam, and then excavate the foundation pit and its slope. S6. Backfill the soil at the foundation location to the original ground level to form a high slope. Spray anchor support is carried out on the high slope and the foundation pit slope before the cast-in-place piles are constructed. S7. Set up drainage ditches around the foundation pit, excavate a sump pit at the designated location, and install drainage devices to complete the dewatering of the foundation pit. S8. Roughening the pile heads, inspecting the pile foundation, installing the pile cap reinforcement, installing the cooling system, and erecting the pile cap formwork; S9. After pouring concrete to complete the foundation construction, backfill the foundation pit, dismantle the cofferdam and cofferdam device, and restore the riverbank protection.

[0006] In the preferred embodiment, the drainage device includes a pumping assembly, with extension assemblies symmetrically arranged on both sides of the pumping assembly, and a first plate connected to one side of each extension assembly. The extension component includes a second plate and a first pipe, with the first pipe positioned below the second plate.

[0007] In the preferred embodiment, the pumping assembly includes an annular upper pipe and a lower pipe, with a vertical column between the upper and lower pipes. A sludge pump is located at the center of the lower pipe, and multiple connecting pipes are provided between the sludge pump and the lower pipe. Multiple through holes are opened on the circumference of the lower pipe.

[0008] In the preferred embodiment, multiple handles are evenly distributed on the upper pipe, and the handles are used to push the pumping components to rotate; A fifth pipe is vertically installed on the top of the connecting pipe, and a flexible pipe is installed between the fifth pipe and the first pipe.

[0009] In the preferred embodiment, a third pipe is provided below the first plate, a liftable support top is provided vertically on one side of the third pipe, guide columns are symmetrically provided above the third pipe, a liftable support frame is provided on the guide columns, a fourth pipe is provided above the third pipe facing the sludge pump, a connecting piece is provided between the fourth pipe and the first pipe, and the support frame, guide columns and the first plate are connected by screws. The support top is connected to the second plate by screws, and the first plate is connected to the pumping assembly by a buckle.

[0010] In the preferred embodiment, the first and second flat plates are made of acetal alloy, and both the first and second flat plates have anti-slip knurling on their top surfaces.

[0011] In the preferred embodiment, the inlet and wall of the third pipe are equipped with stainless steel mesh to prevent large particles of gravel from entering the sludge pump. The inlet of the third pipe is also equipped with a filter head.

[0012] In the preferred embodiment, the cofferdam device includes a fixed base and fixed piles. A detachable guide rod is provided between the fixed base and the fixed piles, and a guide rod is also provided between the fixed piles. A detachable long baffle is provided between the guide rods on one side, and a detachable side baffle is provided between the guide rods on the other side.

[0013] In the preferred embodiment, the bottom of the fixed pile is provided with a pointed fixing rod, the fixing seat is provided with a fixing hole, and the guide rod is connected to the fixing seat and the fixed pile by bolts; The top of the long baffle and the side baffle are also provided with hammer surfaces, and grooves are provided on both sides of the hammer surfaces. The grooves are used to engage the guide rods. A rotatable connecting guide rod is also provided between the guide rods along their axial direction. Locking handles are symmetrically provided on both sides of the hammer surfaces.

[0014] In the preferred embodiment, the locking handle is provided with a locking buckle inside, and the locking handle and the locking buckle are connected by threads. The front end of the locking buckle extends into the groove, and the front end of the locking buckle is also provided with a bevel.

[0015] This invention provides a construction method and drainage device for low-pile caps near water under the influence of existing bridges, which has the following beneficial effects: 1. This invention provides a method for constructing low-pile foundations near water under the influence of existing bridges. This method is applicable to construction under the influence of existing bridges. The bridge is removed and the abutments are demolished. A temporary cofferdam is set up in the river channel. A rapid cofferdam device is used to open a foundation pit within the cofferdam for low-pile foundation construction. Combined with the optimization of drainage channels, the entire foundation pit can be kept dry, reducing construction difficulty, speeding up the cofferdam construction, and improving construction efficiency. 2. This invention provides a drainage device that, through a combination of pumping and a flat platform, can effectively reduce water accumulation in the foundation pit and further provide a working platform for construction personnel to carry out operations such as foundation pit slope protection, foundation reinforcement formwork construction, and cast-in-place pile cutting construction, thereby reducing construction difficulty and improving construction efficiency. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is an axonometric view of the cofferdam device of the present invention in a river channel; Figure 2 This is a top view of the cofferdam device of the present invention in the river channel; Figure 3 This is an axonometric view of the cofferdam device of the present invention in another direction within the river channel; Figure 4 This is an isometric view of the cofferdam device of the present invention; Figure 5 This is a cross-sectional view of the guide rod of the present invention; Figure 6 This is a cross-sectional view of the locking handle of the present invention; Figure 7 This is an isometric view of the side baffle of the present invention; Figure 8 This is a schematic diagram of the cofferdam and foundation pit excavation construction of the present invention; Figure 9 This is a schematic diagram of the layout of the drainage device of the present invention; Figure 10 This is a schematic diagram showing the drainage device of the present invention arranged in another direction; Figure 11 This is an isometric view of the drainage device of the present invention; Figure 12 This is a schematic diagram of the drainage device of the present invention from another direction; Figure 13 This is a cross-sectional view of the drainage device of the present invention; Figure 14 This is a partial view of the pumping assembly of the present invention; Figure 15 This is a cross-sectional view of the pipe of the present invention; Figure 16 This is an isometric view of the connecting member of the present invention.

[0017] In the diagram: 1. Bridge abutment; 2. Ground level; 3. Cofferdam; 4. High slope; 5. Foundation pit; 6. Drainage ditch; 7. Cast-in-place pile; 8. Sump pit; 9. Foundation pit slope; 10. Drainage device; 101. Pumping assembly; 102. Extension assembly; 103. First plate; 104. Silt pump; 105. Upper pipeline; 106. Lower pipeline; 107. Connecting pipe; 108. Second plate; 109. First pipeline; 1010. Second pipeline; 1011. Third pipeline; 1012. Support frame; 1013. Fourth pipeline; 1014. Connecting component; Support top. 1015; silt discharge pipe 1016; fifth pipe 1017; flexible pipe 1018; handle 1019; stainless steel mesh 1020; guide column 1021; buckle 1022; cofferdam device 11; fixed seat 1101; guide rod 1102; fixed pile 1103; long baffle 1104; fixed hole 1105; clamping boss 1106; side baffle 1107; hammer face 1108; locking handle 1109; connecting guide rod 1110; locking buckle 1111; clamping groove 1112. Detailed Implementation

[0018] Example 1 like Figure 1-10 As shown, a construction method for near-water low-pile caps under the influence of existing bridges is described, the method comprising: S1. Construction preparation: A hydrological survey of the area was conducted. The survey indicated that the annual variation in groundwater level in this area is approximately 1.50–3.00 m; the highest water level is approximately 0.50 m below the surface. It is recommended that the compacted fill and silty clay layer have a permeability coefficient K1 = 0.50 m / d; and that the compacted fill, sand, and gravel layer have a permeability coefficient K2 = 50 m / d.

[0019] The geological survey revealed that, apart from the approximately 0.30m asphalt concrete surface layer on the main lane of the existing road, the strata revealed within the depth range of this exploration are Quaternary sedimentary layers, and the stratigraphic characteristics are briefly described below.

[0020] Quaternary Holocene Fill Layer (Q4ml) ① Compacted fill: The main components are pebbles, variegated, loose, and wet; the parent rock is mainly quartzite, granite, basalt, etc.; the particle size is 20-50mm, moderately to slightly weathered, round to sub-rounded, with poor sorting and gradation; the pebble content accounts for 50-60% of the total weight, arranged randomly, and most are not in contact; the filling material is mainly sand; it is not uniformly sized soil with poor gradation. This layer is the base layer of the existing road, formed more than 10 years ago. It was compacted during the original road construction and subjected to long-term vehicle loads, so most of it is slightly dense. This layer is continuously layered; the layer thickness is 1.10-3.90m, with an average thickness of 2.70m.

[0021] Quaternary Holocene alluvial deposits (Q4al) ②-1 Silty clay (plastic): Brownish-yellow, predominantly flocculent, followed by honeycomb aggregate structure; no shaking reaction, slightly glossy cut surface, moderate dry strength and toughness; contains iron-manganese spots and calcareous nodules, occasionally with fine cracks. This layer was revealed in about half of the borehole, with a discontinuous layered distribution; the top of the layer is buried at a depth of 1.10–3.90 m, the layer thickness is 0.60–3.20 m, and the average thickness is 1.34 m.

[0022] ②-2 Silty clay (soft plastic): Brownish-gray, flocculent structure; no shaking reaction, slightly glossy cut surface, moderate dry strength and toughness; contains iron and manganese spots; no fishy smell. This layer is only revealed by exploration points ZK13 and ZK31, and is distributed in a lenticular shape; the top of the layer is buried at depths of 2.70 and 3.20 m respectively, and the layer thickness is 1.00 and 1.30 m respectively.

[0023] Quaternary Holocene alluvial-diluvial deposits (Q4al+pl) ③ Fine sand: bluish-gray to gray, loose, moist, single-crystal structure; main components are quartz, mica minerals, etc., uniform-grained soil, poorly graded. This layer is revealed in about 1 / 3 of the boreholes, distributed in lenticular form above or within the pebble layer; the top of the layer is buried at a depth of 2.50–6.60 m; the layer thickness is 0.60–4.70 m, with an average thickness of 1.00 m.

[0024] ④ Pebbles: grayish-yellow, gray, grayish-green, etc.; parent rock composition is quartzite, granite, sandstone, basalt, moderately to slightly weathered; particle size 20-120mm, containing 5-10% boulders, round to sub-rounded; non-uniform granular soil, poorly graded; filling material is mainly medium to fine sand. This layer is continuously distributed; the top of the layer is buried at a depth of 1.80-5.20m, which was not penetrated in this exploration, and the revealed thickness is 4.70-11.20m; according to the pebble content, arrangement, and number of dynamic probe blows, it is divided into four sub-layers according to Article 4.2.3 of the Regional Building Foundation Design Code (DB51 / T5026-2001).

[0025] ④-1 Loose pebbles: The pebbles account for 50-55% of the total weight; the skeletal particles are arranged very randomly, with most of them not in contact, and the N120 blow count is less than 4 blows / 10cm.

[0026] ④-2 Slightly dense pebbles: Pebbles account for 55-60% of the total weight; the skeletal particles are arranged randomly and most of them do not contact each other; N120 blow count is 4-7 blows / 10cm.

[0027] ④-3 Medium-Dense Pebbles: Pebbles account for 60-70% of the total weight; the skeletal particles are interlaced and mostly in contact; N120 blow count is 7-10 blows / 10cm.

[0028] ④-4 Dense pebbles: pebble content greater than 70% of total weight; skeletal particles are interlaced and in close contact; N120 blow count greater than 10 blows / 10cm.

[0029] According to further investigation, the underlying rock strata of the pebble layer are buried at a depth of about 30 to 80 meters and are Cretaceous mudstone and argillaceous sandstone, which will not have a significant impact on the project.

[0030] S2. Draw lines on both sides of the existing bridge abutment to mark the construction area of ​​the cofferdam device 11, install fixed seats 1101 on both sides of the area, and drive fixed piles 1103 at selected locations in the river. Draw lines on the bridge abutment wall to identify the area where the cofferdam needs to be constructed. Place one side of the fixing seat 1101 close to the bridge abutment and fix the fixing seat 1101 to the bridge abutment 1 by passing bolts through the fixing holes 1105. Drive the fixing piles 1103 into the river channel and compact them.

[0031] S3. Connect guide rod 1102 between fixed seat 1101 and fixed pile 1103, and adjust connecting guide rod 1110 to make guide rod 1102 in the best state. One end of the guide rod 1102 is connected to the fixed base 1101, and the other end is connected to the fixed pile 1103. The guide rod 1102 is composed of multiple guide rods 1102 and connecting guide rods 1110. The length of the entire guide rod 1102 can be adjusted by adjusting the connecting guide rods 1110, and the guide rod 1102 can be adjusted to a taut state.

[0032] S4. Insert side baffles 1107 between guide rods 1102 and compact them; insert long baffles 1104 between fixed piles 1103 and compact them. A side baffle 1107 is inserted between the guide rod 1102 on one side, between the fixed seat 1101 and the fixed pile 1103. After the side baffle 1107 is inserted, it is manually compacted to insert the side baffle 1107 into the bottom of the river. The grooves on both sides of the side baffle 1107 lock the guide rod 1102. After the hammer surface 1108 reaches the required construction height, the locking handles 1109 on both sides of the hammer surface 1108 are rotated to make the locking buckle 1111 extend inward. The inclined surface at the front end of the locking buckle 1111 will lock the guide rod 1102. The long baffle 1104 on both sides can be composed of multiple side baffles 1107 spliced ​​together or a single plate. The side baffles 1107 and the long baffles 1104 can be spliced ​​together by having locking protrusions 1106 or locking grooves 1112 on both sides.

[0033] S5. Fill the inner side of the temporary cofferdam with sand, demolish the existing bridge substructure, break bridge abutment 1, and after the complete demolition of the bridge substructure in the river channel, use an excavator to dredge the silt on the right side of the road of this project, remove it to the bedrock at the bottom of the riverbed, stack the cofferdam 3 on the water-facing side and lay geomembrane for water isolation. S6, backfill and compact cofferdam 3, then perform surface-breaking spray concrete support on cofferdam 3, and then excavate foundation pit 5 and foundation pit slope 9. Cofferdam dimensions: 1.5m wide at the crest, 2m high, with a 1:1 slope ratio on the upstream and downstream sides, and a 6m wide base. Cohesive soil should be used for backfilling whenever possible. If this is not possible, natural soil from the site can be used, but it must not contain silt, domestic waste, or similar contaminants. After the sand is loaded, it should be transported to the cofferdam filling location 3 using a loader. During the filling process, construction will begin upstream. A section will be filled as a trial, and observations will be conducted. Once the cofferdam 3 is stable and meets the requirements, filling will continue. The sand filling will follow the construction sequence of "upstream first, then downstream, from the riverbank to the middle of the river," with the closure point of cofferdam 3 located downstream. The top width of the sand and soil cofferdam 3 is 1.5m. When stacking, the slope ratio of the water-facing side and the backwater side is 1:1. The soil pile is stacked from top to bottom in layers at an angle, and the upper and lower layers as well as the inner and outer layers should be staggered, and the stacking should be dense and neat. After the sand and soil cofferdam is reinforced, a layer of impermeable geotextile is laid along the water-facing side as a waterproof layer to effectively control the river water from entering. After the construction of cofferdam 3 is completed, observe the water flow velocity. If necessary, geotextile can be used to isolate the water-facing side of the cofferdam. The geotextile must ensure sufficient overlap length to reduce leakage and prevent the backfill soil within the sand from being eroded away. The riverbed end and the top of the cofferdam should be firmly secured with sand to ensure effective water isolation. To ensure the stability and safety of the cofferdam structure, technical and surveying personnel should be arranged to observe and measure the cofferdam body during and after construction, and reinforcement measures should be taken in a timely manner if any problems are found. After the construction of S7 and cofferdam 3 is completed, in order to facilitate the construction of cast-in-place pile 7, the original abutment demolition area will be backfilled in layers using the soil excavated on site. The relative compaction of the soil will not be less than 85%. After backfilling to the original ground level 2 elevation, rotary drilling cast-in-place pile 7 foundation construction will be carried out. After cofferdam 3 is completed, pumping begins and the cofferdam is inspected for leakage. The first pumping is carried out inside the foundation pit 5. The pumping speed should be slow to allow the cofferdam to gradually withstand water pressure and complete pre-deformation, preventing the cofferdam 3 from collapsing due to excessive pumping. S8. After the water in the weir is pumped out, drainage ditch 6 is set up around the foundation pit 5, water collection pit 8 is dug at the designated location, and silt pump 104 is used to pump out the water to ensure smooth drainage of the foundation pit 5. Install drainage device 10 to complete the dewatering of foundation pit 5. First, roll pumping assembly 101 into foundation pit 5, place pumping assembly 101 in water collection pit 8, lay third pipe 1011 in drainage ditch, place second plate 108 on the upper pipe 105 of pumping assembly 101, connect buckle 1022 below second plate 108 to handle 1019 on upper pipe 105, and connect second plate 108 to support top 1015 with screws. The first pipe 109 and the fifth pipe 1017 below the second plate 108 are connected by a flexible pipe 1018. The connecting piece 1014 is placed between the second platform 108 and the first platform 103. The connecting piece 1014 is tightened to connect one end of the first pipe 109 to one end of the fourth pipe 1013. The first plate 103 is laid flat above the third pipe 1011 and locked to the top of the support frame 1012 and the guide column with screws. The same arrangement is symmetrical on the other side of the pumping assembly 101 to complete the construction of the drainage device 10.

[0034] S9. Roughening the pile heads, inspecting the pile foundation, installing the pile cap reinforcement, installing the cooling system, and erecting the pile cap formwork; S10. Pour concrete to complete the foundation construction, then backfill the foundation pit 5, dismantle the cofferdam 3 and cofferdam device 11, and restore the riverbank protection.

[0035] S11. After pouring concrete to complete the foundation construction, backfill the foundation pit 5, dismantle the cofferdam 3 and cofferdam device 11, restore the riverbank protection, and carry out bank protection construction on the removed loess riverbed substructure. According to the drawings, the bank protection uses 20cm C20 concrete for slope protection. The C20 concrete bank protection foundation is 24.1cm thick, and a 134.1cm thick large stone footing is constructed at the toe of the slope, with a footing width of 50cm. The embankment foundation is placed on a slightly dense pebble layer. The slope of the slope protection and footing is determined according to the actual site conditions; Starting from the downstream, the cofferdam will be dismantled gradually from the top to the bottom. Before the dismantling of cofferdam 3, river dredging work is required. For the concrete debris that has rolled into the river, an excavator will be used to clean it up to the bank, and then a loader will be used to transport it to a muck truck for off-site transport. This will ensure that the bridge can still carry water after dismantling. During the dismantling process, a dedicated person should be assigned to observe the substructure. If any possibility of overturning is found, the work should be stopped immediately and can only continue after reinforcement measures have been taken.

[0036] A drainage device for the construction method of low-pile cap near water under the influence of the above-mentioned existing bridge includes a pumping component 101, with extension components 102 symmetrically arranged on both sides of the pumping component 101, and a first plate 103 connected to one side of the extension component 102. The extension component 102 includes a second plate 108 and a first pipe 109, with the first pipe 109 located below the second plate 108.

[0037] In the preferred embodiment, the pumping assembly 101 includes an annular upper pipe 105 and a lower pipe 106. A vertical column is provided between the upper pipe 105 and the lower pipe 106. A sludge pump 104 is provided at the center of the lower pipe 106. Multiple connecting pipes 107 are provided between the sludge pump 104 and the lower pipe 106. Multiple through holes are opened on the circumference of the lower pipe 106.

[0038] In the preferred embodiment, multiple handles 1019 are evenly distributed on the upper pipe 105, and the handles 1019 are used to push the pumping assembly 101 to rotate. A fifth pipe 1017 is vertically provided on the upper part of the connecting pipe 107, and a flexible pipe 1018 is provided between the fifth pipe 1017 and the first pipe 109.

[0039] In the preferred embodiment, a third pipe 1011 is provided below the first plate 103. A liftable support top 1015 is provided vertically upward on one side of the third pipe 1011. A guide column 1021 is symmetrically provided above the third pipe 1011. A liftable support frame 1012 is provided on the guide column 1021. A fourth pipe 1013 is provided above the third pipe 1011 on the side facing the sludge pump 104.

[0040] In the preferred embodiment, a connecting member 1014 is provided between the fourth pipe 1013 and the first pipe 109.

[0041] In the preferred embodiment, the support frame 1012, the guide column 1021, and the first plate 103 are connected by screws; The support top 1015 is connected to the second plate 108 by screws.

[0042] In the preferred embodiment, the first plate 103 and the second plate 108 are made of acetal steel, and both the first plate 103 and the second plate 108 are provided with anti-slip knurling.

[0043] In the preferred embodiment, the inlet and wall of the third pipe 1011 are equipped with stainless steel mesh to prevent large particles of gravel from entering the sludge pump 104. The inlet of the third pipe 1011 is also equipped with a filter head.

[0044] In the preferred embodiment, the first plate 103 is connected to the pumping assembly 101 via a fastener 1022.

[0045] In a preferred embodiment, the cofferdam device 11 includes a fixed base 1101 and fixed piles 1103. A detachable guide rod 1102 is provided between the fixed base 1101 and the fixed piles 1103. A guide rod 1102 is also provided between the fixed piles 1103. A detachable long baffle 1104 is provided between the guide rods 1102 on one side, and a detachable side baffle 1107 is provided between the guide rods 1102 on the other side.

[0046] In the preferred embodiment, the bottom of the fixed pile 1103 is provided with a pointed and long fixing rod, the fixing seat 1101 is provided with a fixing hole 1105, and the guide rod 1102 is connected to the fixing seat 1101 and the fixed pile 1103 by bolts. The top of the long baffle 1104 and the side baffle 1107 is also provided with a hammer surface 1108. The hammer surface 1108 has grooves on both sides for engaging the guide rod 1102. The guide rod 1102 is also provided with a rotatable connecting guide rod 1110 in the axial direction. Locking handles 1109 are symmetrically provided on both sides of the hammer surface 1108.

[0047] In the preferred embodiment, the locking handle 1109 is provided with a locking buckle 1111 inside. The locking handle 1109 and the locking buckle 1111 are connected by threads. The front end of the locking buckle 1111 extends into the groove. The front end of the locking buckle 1111 is also provided with a bevel.

[0048] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A construction method for low-pile caps near water under the influence of existing bridges, characterized by: The method includes: S1. Draw lines on both sides of the existing bridge abutment to mark the construction area of ​​the cofferdam device (11). The cofferdam device (11) includes a fixed seat (1101) and a fixed pile (1103). A detachable guide rod (1102) is provided between the fixed seat (1101) and the fixed pile (1103). A guide rod (1102) is also provided between the fixed piles (1103). A detachable long baffle (1104) is provided between the guide rods (1102) on one side, and a detachable side baffle (1107) is provided between the guide rods (1102) on the other side. Install the fixed seat (1101) on both sides of the area and drive the fixed pile (1103) into the selected position in the river. S2. Connect a guide rod (1102) between the fixed seat (1101) and the fixed pile (1103), and adjust the connecting guide rod (1110) to make the guide rod (1102) be in the best state; S3. Insert side baffles (1107) between guide rods (1102) and compact them; insert long baffles (1104) between fixed piles (1103) and compact them. S4. Fill the inside of the cofferdam device (11) with sand, remove the existing bridge substructure, break the bridge abutment (1), stack the cofferdam (3) on the water-facing side and lay geomembrane for water-proofing treatment. S5. Backfill and compact the cofferdam (3), then perform slope spraying and concrete support on the cofferdam (3), and then excavate the foundation pit (5) and the foundation pit slope (9). S6. Backfill the soil at the foundation location to the original ground elevation to form a high slope (4). Spray anchor support is carried out on the high slope (4) and the foundation pit slope (9). Then, the cast-in-place piles (7) are constructed. S7. Set up drainage ditches (6) around the foundation pit, excavate a water collection pit (8) at the designated location, and install drainage devices (10) to complete the dewatering of the foundation pit (5); S8. Roughening the pile heads, inspecting the pile foundation, installing the pile cap reinforcement, installing the cooling system, and erecting the pile cap formwork; S9. After pouring concrete to complete the foundation construction, backfill the foundation pit (5), dismantle the cofferdam (3) and cofferdam device (11), and restore the riverbank protection.

2. The construction method for near-water low-pile caps under the influence of existing bridges according to claim 1, characterized in that: The drainage device (10) includes a pumping assembly (101), with extension assemblies (102) symmetrically arranged on both sides of the pumping assembly (101), and a first plate (103) connected to one side of the extension assembly (102). The extension component (102) includes a second plate (108) and a first pipe (109), the first pipe (109) being disposed below the second plate (108).

3. The construction method for near-water low-pile caps under the influence of existing bridges according to claim 2, characterized in that: The pumping assembly (101) includes an annular upper pipe (105) and a lower pipe (106). A vertical column is provided between the upper pipe (105) and the lower pipe (106). A sludge pump (104) is provided at the center of the lower pipe (106). Multiple connecting pipes (107) are provided between the sludge pump (104) and the lower pipe (106). Multiple through holes are opened on the circumference of the lower pipe (106).

4. The construction method for a low-pile cap near water under the influence of an existing bridge according to claim 2, characterized in that: Multiple handles (1019) are evenly distributed on the upper pipe (105), and the handles (1019) are used to push the pumping assembly (101) to rotate; A fifth pipe (1017) is vertically provided on the upper part of the connecting pipe (107), and a flexible pipe (1018) is provided between the fifth pipe (1017) and the first pipe (109).

5. The construction method for a low-pile cap near water under the influence of an existing bridge according to claim 2, characterized in that: Below the first plate (103), there is a third pipe (1011). On one side of the third pipe (1011), there is a vertically adjustable support top (1015). Above the third pipe (1011), there are symmetrical guide columns (1021). On the guide columns (1021), there is an adjustable support frame (1012). Above the third pipe (1011), on the side facing the sludge pump (104), there is a fourth pipe (1013). The fourth pipe (1013) and the first pipe (109) are connected by a connecting piece (1014). The support frame (1012), the guide column (1021) and the first plate (103) are connected by screws. The support top (1015) is connected to the second plate (108) by screws, and the first plate (103) is connected to the pumping assembly (101) by a buckle (1022).

6. The construction method for a low-pile cap near water under the influence of an existing bridge according to claim 5, characterized in that: The first plate (103) and the second plate (108) are made of acetal steel, and the top of the first plate (103) and the second plate (108) are provided with anti-slip knurling.

7. The construction method for a low-pile cap near water under the influence of an existing bridge according to claim 5, characterized in that: The inlet and wall of the third pipe (1011) are equipped with stainless steel mesh to prevent large particles of gravel from entering the sludge pump (104). The inlet of the third pipe (1011) is also equipped with a filter head.

8. The construction method for a low-pile cap near water under the influence of an existing bridge according to claim 7, characterized in that: The bottom of the fixed pile (1103) is provided with a pointed fixed rod, the fixed seat (1101) is provided with a fixed hole (1105), and the guide rod (1102) is connected to the fixed seat (1101) and the fixed pile (1103) by bolts; The top of the long baffle (1104) and the side baffle (1107) is also provided with a hammer surface (1108). The hammer surface (1108) is provided with grooves on both sides for engaging the guide rod (1102). A rotatable connecting guide rod (1110) is also provided between the guide rods (1102) in the axial direction. Locking handles (1109) are symmetrically provided on both sides of the hammer surface (1108).

9. The construction method for a low-pile cap near water under the influence of an existing bridge according to claim 8, characterized in that: The locking handle (1109) has a locking buckle (1111) inside. The locking handle (1109) and the locking buckle (1111) are connected by threads. The front end of the locking buckle (1111) extends into the groove. The front end of the locking buckle (1111) also has a bevel.

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