Permanent and temporary combined sheet pile type retaining wall and construction method thereof

Abstract

The invention relates to a permanent and temporary combined sheet pile type retaining wall and a construction method thereof. The retaining wall is provided with a face plate located on the waterside and a plurality of cast-in-place piles, the cast-in-place piles are located on the backwater side of the face plate and distributed at intervals in the extending direction of the face plate, connecting steel bars are arranged between the face plate and the cast-in-place piles, and the two sides of the connecting steel bars are anchored to the face plate and the cast-in-place piles respectively. A top beam, a wave wall, a hat stone and the like can be sequentially arranged on the panel and the cast-in-place pile according to actual requirements. During construction, the cast-in-place piles are firstly drilled and poured, the cast-in-place piles serve as a temporary supporting system to implement excavation and foundation cleaning needed by the face plate and the face plate foundation, and after the face plate foundation and the face plate are poured, the cast-in-place piles are reserved to serve as a permanent supporting system. According to the construction method, the land occupation requirement of construction can be obviously reduced, and construction of the river retaining wall on the occasion without enough slope conditions is facilitated.

Description

Technical Field

[0001] The invention relates to a permanent-temporary combined sheet pile type retaining wall and a construction method thereof. Background Art

[0002] At present, the construction methods of river retaining walls mostly adopt concrete retaining walls, mortar-stone masonry retaining walls, reinforced concrete retaining walls, etc., which are relatively common. When constructing the above retaining walls, a certain width of excavation and slope surface is required. Support forms such as soil nail anchor spraying support, support piles, and steel sheet piles can be used. After the construction of the main structure is completed, some temporary support measures such as anchor spraying support, part of the pile top, and steel sheet piles need to be removed before subsequent construction. For example, Chinese patent document CN114263212A discloses a single-side formwork support system for an inclined retaining wall, comprising more than two supporting mechanisms, the supporting mechanisms comprising a steel formwork, a telescopic rod, a vertical tension bolt, an oblique tension bolt, a connecting piece and an adjustable bottom bracket; there is more than one vertical tension bolt, and there is more than one oblique tension bolt; the steel formwork, the vertical tension bolt and the oblique tension bolt are respectively fixed to the concrete cushion layer, each oblique tension bolt is welded to more than one vertical tension bolt, each oblique tension bolt is fixed to the steel formwork, the upper end of each vertical tension bolt is connected to the telescopic rod, one end of the telescopic rod is connected to the top of the steel formwork through the connecting piece, the adjustable bottom bracket is fixed to the other end of the telescopic rod, the adjustable bottom bracket is against the soil slope surface, and the steel formworks of multiple supporting mechanisms are connected to each other. The present invention has a simple structure and a short construction time. Chinese patent document CN219508638U discloses a retaining wall support device, which relates to the field of retaining wall support technology, and includes a retaining plate abutting against the slope, adjacent retaining plates are connected by connecting pieces, a bottom plate is provided at the bottom of the retaining plate, a plug-in rod is provided at the bottom of the bottom plate, and a support assembly for pressing the retaining plate against the slope wall is connected to the retaining plate. The present application has the advantages of quickly assembling a retaining wall support structure, ensuring the stability of the excavation or filling slope, and effectively improving the construction efficiency. Chinese patent document CN113417301A discloses a slope support construction method combined with a main structure of a building, comprising the following steps: leveling a site, excavating a construction working surface of a bottom plate of a retaining wall, building a bottom plate, a wall body and a cap of the retaining wall, performing a first backfill, reserving a first platform on the top of the retaining wall, building foundation pipe piles of the main structure of the building, performing a second backfill, reserving a second platform, constructing the main foundation pipe piles, the cap and the overhead structure columns of this platform, performing a third backfill, reserving a third platform, constructing the main foundation pipe piles, the cap and the overhead structure columns of this platform, performing a final backfill, and leveling, constructing the main foundation pipe piles, completing the slope support, and by flexibly adopting a combination of vertical support and slope support of different heights, and utilizing the overhead main structure of the building to perform graded slope release, the vertical support height is reduced, the risk of super-high retaining walls is reduced, the amount of earth backfill is reduced, and the project cost is saved. These technologies have unique characteristics and are suitable for their respective occasions. However, if the river bank is very close to the road and cannot meet the slope requirements, the above-mentioned excavation + support construction method cannot meet the requirements for river retaining wall construction. Summary of the invention

[0003] The purpose of the present invention is to reduce the construction land requirement and facilitate the construction of river retaining walls in situations where sufficient slope conditions are not available.

[0004] The technical solution of the present invention is: a permanent and temporary combined sheet pile retaining wall, which is provided with a panel located on the water side, and is also provided with a plurality of cast-in-place piles (bored cast-in-place piles). The cast-in-place piles are located on the water-repellent side of the panel and are distributed at intervals (alternately) along the extension direction of the panel (the extension direction of the wall surface). Connecting steel bars are provided between the panel and the cast-in-place piles, and the two sides of the connecting steel bars are anchored to the panel and the cast-in-place piles respectively.

[0005] Usually, the depth of the cast-in-place piles is much greater than the depth of the panel, which can be determined based on engineering requirements and geological conditions.

[0006] Furthermore, the panel adopts a reinforced concrete structure, and a panel steel mesh (including longitudinal and transverse steel bars) is arranged inside.

[0007] Furthermore, the bored pile is a reinforced concrete bored pile, which is provided with a bored pile reinforcement cage (including longitudinal reinforcement and stirrups, etc.).

[0008] Preferably, the backwater side of the panel is fixed together with the water-near side of the cast-in-place pile (the cast-in-place pile at the corresponding position).

[0009] Preferably, connecting steel bars are provided between the panel and the cast-in-place piles (the cast-in-place piles at the corresponding positions), one side of the connecting steel bars (the panel side) passes through the panel steel mesh inside the panel, and the other side (the cast-in-place pile side) passes through the cast-in-place pile steel cage inside the cast-in-place pile.

[0010] Furthermore, a panel foundation is provided below the panel.

[0011] Preferably, the panel foundation is a reinforced concrete foundation or a concrete foundation, which is cast integrally with the panel.

[0012] Furthermore, a cap beam is arranged on the panel and the cast-in-place pile.

[0013] Furthermore, the crown beam is a reinforced concrete structure.

[0014] Furthermore, the top of the panel and the cast-in-place piles are fixed together with the bottom of the cap beam.

[0015] Preferably, the longitudinal reinforcements of the cast-in-place piles and the panels extend into the cap beam.

[0016] Furthermore, a wave-breaking wall is provided on the top of the crown beam.

[0017] Preferably, the wave-breaking wall is a reinforced concrete structure and is cast integrally with the cap beam.

[0018] Preferably, a crown beam panel layer is provided on the water-facing side (near the water) of the crown beam, and the crown beam panel layer is cast integrally with the panel.

[0019] Furthermore, the water-facing surfaces of the cap beam panel and the panel are aligned to form a same smooth surface (usually a vertical surface).

[0020] Preferably, a portion of the cap beam reinforcement is located within the cap beam panel.

[0021] Furthermore, a cap stone is provided on the crown beam. The construction method for any permanent-temporary combined sheet pile retaining wall disclosed in the present invention firstly drills holes and casts cast-in-place piles, uses cast-in-place piles as a temporary support system to implement the excavation and foundation clearing required for the panels and panel foundations, and after casting the panel foundations and panels, retains the cast-in-place piles as a permanent support system.

[0022] Based on cast-in-place pile support, there is no need for slope during the construction of panels and panel foundations, and it is also possible not to set up / no need to set up other support systems.

[0023] Preferably, reinforcement bars are planted on the bored piles as connecting reinforcement bars between the bored piles and the panels, the exposed parts of the connecting reinforcement bars are connected and fixed to the panel mesh bars, and then the concrete pouring of the panel foundation and the panel is carried out.

[0024] Preferably, after the excavation required for the panel and panel foundation is implemented, the water-side surface of the bored pile (the corresponding part of the corresponding bored pile) is exposed, which serves as the interface of the casting space of the panel and panel foundation at the corresponding part. Therefore, after the casting of the panel and panel foundation is completed, the corresponding part of the water-side of the bored pile is consolidated together with the panel and panel foundation.

[0025] The beneficial effects of the present invention are as follows: the present invention adopts cast-in-place pile support as a temporary and permanent support system, installs steel mesh between piles and on pile surfaces and pours concrete to form a river retaining wall (panel) structure, does not require slope excavation, and does not require the installation of other support systems. Therefore, the construction scope is small, the impact on the surrounding area is small, and the construction efficiency is high. The present invention is particularly suitable for the construction of river retaining walls that do not have slope conditions, and is also suitable for the construction of similar retaining walls or other similar walls in other occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the retaining wall structure involved in the present invention; Figure 2 It is a schematic diagram of reinforcement arrangement of support piles of a retaining wall involved in the present invention; Figure 3 It is a schematic diagram of the reinforcement of the retaining wall involved in the present invention; Figure 4 It is a top view schematic diagram of the reinforcement of the retaining wall involved in the present invention; Figure 5 It is a schematic diagram of the integral reinforcement of the crown beam and the wave-breaking wall involved in the present invention; Figure 6 The invention relates to a construction flow chart. DETAILED DESCRIPTION

[0027] See also Figure 1-Figure 6 The retaining wall involved in the present invention is mainly composed of a panel 30 and cast-in-place piles 20. The number of cast-in-place piles is several and they are distributed at certain intervals on the backwater side of the panel, serving as a temporary support system during construction and a permanent support system for the retaining wall. Before excavation is implemented (the surface can be cleared first), holes are drilled on the river bank 10 according to the positions where the cast-in-place piles should be located, cast the cast-in-place piles, and then excavation and foundation clearing of the retaining wall are implemented relying on the supporting effect of the cast-in-place piles.

[0028] The panel is connected to the cast-in-place piles, a unified crown beam 40 is arranged on the upper part, a wave-breaking wall 50 is arranged on the crown beam, and a cap stone 60 or other structures can be arranged on the wave-breaking wall according to actual needs.

[0029] The panel is located on the water side of the river bank and can be a vertical facade. A panel foundation 70 is set at the bottom of the panel. The panel and the panel foundation can be regarded as a whole, and steel bars are arranged and concrete is poured uniformly.

[0030] According to actual needs, a seepage pipe 16 passing through the panel and a drainage pipe 17 passing through the wave-breaking wall are provided.

[0031] According to actual needs, a walkway or other ground structures 12 and protective structures can be set up on the top surface of the river bank on the back side of the wave-breaking wall.

[0032] The steel cage used for cast-in-place piles is mainly composed of a number of vertically arranged longitudinal bars 24 and spiral steel bars (or stirrups) 25. A number of tension bars 26 may also be provided. A number of positioning bars 27 are provided on the outer side (circumferential surface) of the steel cage to achieve positioning in the hole.

[0033] The longitudinal reinforcement of the cast-in-place pile reinforcement cage should extend into the crown beam (the casting space of the crown beam) to form the reinforcement in the corresponding direction in the crown beam, which is not only convenient for construction, but also conducive to improving the connection strength between the crown beam and the cast-in-place pile.

[0034] For the same reason, the longitudinal reinforcement 34 of the face plate should also extend into the crown beam (crown beam face plate layer).

[0035] The connecting steel bars 38 can be arranged in layers, and the number of connecting steel bars for the same cast-in-place pile can be two at a time, and the angle β between the two connecting steel bars can be 60°, and they are arranged symmetrically. The number of layers / interlayer spacing of the connecting steel bars depends on actual needs.

[0036] The crown beam and the wave-breaking wall can be integrally reinforced and cast, and the corresponding steel bars 43 in the crown beam and the corresponding steel bars 53 in the wave-breaking wall extend to the common area of ​​the crown beam and the wave-breaking wall to improve the overall structural strength.

[0037] The position and height of each part can be set according to the existing ground line 11 and other topographical features and geological conditions.

[0038] The general construction process of the present invention is: surface clearing → cast-in-place pile construction → concrete panel construction → crown beam and wave-breaking wall construction.

[0039] by Figure 1 The embodiments involved are taken as examples, specifically including: 1) Clearance According to the actual on-site exploration situation, clear the tree roots, weeds, garbage, waste residue, flood alluvial materials and other obstacles in the excavation area.

[0040] 2) Cast-in-place pile construction i) Construction preparation Pile position measurement: According to the general plan and pile position plan, the surveying personnel will lay out the lines, first measure the axis position, mark the axis position with wooden stakes, verify that it is correct, measure the position of each pile according to the pile position plan, and insert 30-50cm steel bars as marks. The steel bar heads are buried underground and marked clearly to prevent the pile driver from moving or colliding with the concrete transport vehicle. The allowable deviation of the pile position is 1 / 6d in the vertical direction of the axis and 1 / 4d along the axis.

[0041] Buried casing: adjust the length of the casing according to the height of the groundwater level, and make it with 5mm steel plate. Weld a reinforcing rib on the upper and lower sections and the outer side of the middle part of the casing to increase rigidity. The inner diameter of the casing is 0.2m larger than the designed pile diameter. Set a 20cm×40cm overflow hole 20cm below the top of the casing. After the casing is made, draw a cross line according to the pile position mark, drive a wooden stake to mark the center line of the pile, and then manually dig a pit to bury the casing. After the casing is buried, check the center point again. The deviation between the center of the casing and the center of the pile position is ≤50mm. The bottom of the casing is treated with cement mortar, and clay is layered and rammed within 60cm around it to the top of the casing.

[0042] Drilling rig in place: Before bored pile foundation construction, the site should be leveled, debris removed, soft soil replaced, compacted, and the drilling rig kept stable during construction. The drilling rig base should not be placed directly on unsolid fill to avoid uneven settlement. For steep slopes, dig the slope first and then proceed with construction.

[0043] Pile position layout: drive the drilling rig to the hole to be constructed, adjust the mast angle, operate the winch, align the center of the drill bit with the center of the drill hole, and put it into the hole, adjust the verticality parameters of the drilling rig to make the drill rod vertical, and slightly lift the drill tool to ensure that the drill bit floats freely in the hole.

[0044] ii) Drilling and hole cleaning Drilling: The drilling rig is in place, and the drilling rig aligns the center line of the drill bit with the center of the pile hole, with the error controlled within 2cm. Start the mud pump and the drilling rig to start drilling. When drilling, first use low gear and slow speed to drill 1m below the casing, and then adjust to normal speed. During the drilling process, different types of drill bits are selected according to different geological conditions. In soil or brecciated strata, the drill bit uses a spiral earth drill or a rotary bucket. During the drilling process, slag samples are often extracted and checked with the design geology, and attention is paid to stratum changes so as to adjust the rotation speed and drilling pressure for different strata in time. During the drilling process, the hole position, hole depth, hole shape, hole diameter, inclination and various indicators of the mud are checked and adjusted in time. The mud consistency in the hole should be appropriate and the water level should be stable. Water and clay should be added in time to maintain the water head difference in the hole to prevent the hole from collapsing. According to the changes in the stratum, the corresponding drilling method and mud consistency are adopted.

[0045] Hole cleaning: The hole is cleaned by pumping method. The sediment is sucked out by a mud pump and mud is added to the hole in time. Only when the design and specification requirements are met can the next construction process be carried out.

[0046] iii) Lifting of steel cage After the drilling hole is qualified in the hole cleaning inspection, the steel cage is hoisted into the hole with a truck crane, and the lifting point is set at the reinforcing stirrups. The steel cage is hoisted in sections. After the first section of the steel cage is placed in the hole, the steel section is inserted under the reinforcing hoop of the steel cage, and the steel cage is temporarily supported on the hole mouth. Then the second section is lowered, and the hole mouth is butt-jointed. When butt-jointing, the upper and lower main bars are aligned to ensure that the upper and lower axes of the steel cage are consistent, the main bars are staggered, and the steel bars are connected with straight threads. When hoisting the steel cage into the hole, align it with the hole position and place it gently and slowly. If there is any resistance, stop lowering it, find out the cause and deal with it. After all the steel cages are in the hole, the placement position should be checked and recorded according to the design and specification requirements. If it meets the requirements and is qualified after inspection by the supervising engineer, the next process can be carried out.

[0047] iv) Catheter lowering The conduit adopts a special spiral thread conduit with an inner diameter of 300mm, a middle section length of 2.7m, a bottom section length of 3.8-4m, and non-standard sections of 0.5m, 1m, and 1.5m. The conduit should be made strong, with a smooth inner wall, straight, and without local bumps. The conduit should be lowered vertically and gently to avoid colliding with the steel cage. When lowering, the number of sections lowered should be recorded. After lowering to the bottom of the hole, the theoretical length should be compared with the actual length to see if they match. After the conduit is completely lowered to the bottom of the hole and checked for correctness, gently lift the conduit to control the bottom opening to be 0.25-0.4m away from the bottom of the hole and located in the center of the borehole.

[0048] v) Underwater Concreting After acceptance, concrete pouring is carried out, and the discharge port extends into the previously poured concrete by at least 2m to prevent mud and water from rushing into the pipe, and shall not exceed 6m. The elevation of the concrete surface layer in the hole is measured frequently, and the corresponding position of the discharge port of the conduit and the concrete surface is adjusted in time, and it is always closely monitored. The conduit is filled in a state without water entering. The bottom of the pipe is 2m below the top surface of the concrete at any time. The concrete delivered to the pile is operated continuously at one time. Before the initial setting, any contaminated concrete is removed from the top of the pile. Concrete should be poured continuously until the top surface of the poured concrete is higher than the cut-off height specified in the drawings or determined by the supervising engineer (generally 0.5~1.0m), and then the pouring can be stopped to ensure that all the concrete below the cut-off surface meets the strength standard.

[0049] 3) Concrete panel construction Construction sequence: tie the reinforcement of the panel foundation part and set up the formwork → pour the foundation concrete → plant the reinforcement of the bored piles → tie the panel steel bars and embed the drainage pipes → set up the panel formwork → pour the panel concrete.

[0050] According to the design requirements, before pouring the concrete panel, the reinforcement is planted on the cast-in-place piles and connected and fixed with the panel mesh reinforcement, with a diameter of 16mm and a spacing of 400mm. The retaining wall drainage pipe is buried, using a PVC pipe with an inner diameter of 75mm, a single length of 850mm, and a spacing of 1.50m in a plum blossom shape. The panel foundation is excavated and cleared, the soil on the cast-in-place piles is cleaned, and the foundation and panel reinforcement are tied. After the tying is completed, the side template of the bottom plate is supported to pour the bottom plate concrete, and then the panel template is supported and the concrete is poured.

[0051] The surface of the steel bar is straight and free of cracks and oil stains. The number of joints, lap length and welding quality of the same cross section of the stressed steel bar meet the requirements of the technical specifications. The spacing, length, protective layer thickness, and position of the bent steel bar of the steel bar are controlled within the error range specified in the technical specifications. When tying the steel bars of the support beams and cross beams, pay attention to the connection with the bored piles and pre-buried bars of the columns. The tying and materials of the steel bars meet the design requirements, and avoid soil contamination during the transportation and tying of the steel bars.

[0052] The foundation formwork is made of wood, and the panel formwork is made of steel. The formwork is made and installed according to the design requirements. After the formwork is installed, the position, verticality and stability of the formwork are checked. If the formwork is deformed or damaged during use, it should be repaired in time.

[0053] 4) Construction of crown beam and wave-breaking wall Construction sequence: tying up the crown beam and wave-breaking wall reinforcement bars → supporting the crown beam and wave-breaking wall formwork → pouring concrete.

[0054] The surface of the steel bar is straight and free of cracks and oil stains. The number of joints, lap length and welding quality of the same cross section of the stressed steel bar meet the requirements of the technical specifications. The spacing, length, protective layer thickness, and position of the bent steel bar of the steel bar are controlled within the error range specified in the technical specifications. When tying the steel bars of the support beams and cross beams, pay attention to the connection with the bored piles and pre-buried bars of the columns. The tying and materials of the steel bars meet the design requirements, and avoid soil contamination during the transportation and tying of the steel bars.

[0055] The crown beam and wave-breaking wall formwork adopts wooden formwork. The formwork is made and installed according to the design requirements, and the formwork is checked after it is installed in place.

[0056] Concrete pouring is carried out by a concrete mixer truck to the construction site and the concrete is placed in the hopper. After the hopper is lifted to the construction site by a crane, the hopper switch is turned on to allow the concrete to enter the warehouse; or the concrete is directly placed in the chute by a concrete mixer truck to allow the concrete to enter the warehouse. Concrete is poured in horizontal sections and compacted with an inserted vibrator.

[0057] Unless otherwise specified or when one preferred or optional technical means is a further limitation of another technical means, the preferred and optional technical means disclosed in the present invention can be arbitrarily combined to form several different specific implementation methods.

Claims

1. A permanent and temporary sheet pile retaining wall, provided with a panel located on the water side, characterized in that A plurality of cast-in-place piles are also provided, which are located on the backwater side of the panel and are spaced apart along the extension direction of the panel. Connecting steel bars are provided between the panel and the cast-in-place piles, and the two sides of the connecting steel bars are anchored to the panel and the cast-in-place piles respectively.

2. The permanent and temporary combined sheet pile retaining wall according to claim 1 is characterized in that The panel adopts reinforced concrete structure with panel steel mesh inside, and the bored piles are reinforced concrete bored piles with bored pile steel cage inside.

3. The permanent and temporary combined sheet pile retaining wall according to claim 1 is characterized in that The backwater side of the panel is consolidated with the water-nearside side of the cast-in-place pile.

4. The permanent and temporary combined sheet pile retaining wall according to claim 1 is characterized in that Connecting steel bars are arranged between the panel and the cast-in-place piles, one side of the connecting steel bars passes through the panel steel mesh in the panel, and the other side passes through the cast-in-place pile steel cage in the cast-in-place pile.

5. The permanent and temporary combined sheet pile retaining wall according to claim 1 is characterized in that A panel foundation is provided below the panel, and the panel foundation is a reinforced concrete foundation or a concrete foundation, which is cast integrally with the panel.

6. The permanent and temporary combined sheet pile retaining wall according to claim 1 is characterized in that A cap beam is arranged on the panel and the cast-in-place pile, and the cap beam is a reinforced concrete structure.

7. The permanent and temporary combined sheet pile retaining wall according to claim 6 is characterized in that The longitudinal reinforcement of the cast-in-place piles and panels extends into the cap beam.

8. A construction method for a permanent and temporary combined sheet pile retaining wall as claimed in any one of claims 1 to 7, characterized in that First, drill holes and cast cast-in-place piles, and use the cast-in-place piles as a temporary support system to implement the excavation and foundation clearing required for the panels and panel foundations. After casting the panel foundation and panels, retain the cast-in-place piles as a permanent support system.

9. The construction method of the permanent and temporary combined sheet pile retaining wall according to claim 8, characterized in that Rebars are planted on the bored piles as connecting reinforcements between the bored piles and the panels. The exposed parts of the connecting reinforcements are connected and fixed to the panel mesh bars, and then the concrete pouring of the panel foundation and the panel is carried out.

10. The construction method of the permanent and temporary combined sheet pile retaining wall according to claim 9, characterized in that After the excavation required for the panel and panel foundation is implemented, the surface of the water side of the cast-in-place pile is exposed, which serves as the interface of the casting space of the panel and panel foundation at the corresponding position.

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