Construction structure for controlling filling coefficient of cast-in-place pile

Abstract

The utility model discloses a construction structure for controlling the filling coefficient of a cast-in-place pile. When a soft backfill soil layer is drilled, a pile casing is erected, hole collapse is prevented during drilling, the bottom of the pile casing is filled with a clay layer, the perpendicularity of the pile casing is guaranteed, mud loss and displacement of the pile casing are prevented, and the stability of the pile casing is improved. A steel reinforcement cage is placed in a drilled hole after the drilled hole is formed, the outer side of the steel reinforcement cage is coated with a layer of iron sheet, a cushion block used for controlling the distance between the stirrup and the iron sheet is arranged on the stirrup of the steel reinforcement cage, and the iron sheet serves as an outer formwork for pouring when concrete is poured, so that the pile forming quality can be improved, and the problems of bulging of a pile body and the like are solved; the filling coefficient of concrete is greatly reduced, so that the construction cost is controlled, and the construction quality is stabilized.

Description

Technical Field

[0001] The utility model relates to the field of cast-in-place piles, in particular to a construction structure for controlling the filling coefficient of cast-in-place piles. Background Art

[0002] Reclamation projects, as the name suggests, involve transporting inland rocks, rubble, and spoil to planned reclamation areas for backfilling, expanding the land area through artificial construction. Reclamation areas have complex geological conditions, and the backfill layer is still loose to slightly dense, not yet fully consolidated under its own weight. The structure exhibits significant unevenness in softness and hardness, making it unstable and unsuitable for use as a foundation bearing layer without treatment. Therefore, building foundations in reclamation areas require pile foundations, with rock serving as the bearing layer. Furthermore, the presence of large-sized rock in the artificial backfill layer hinders precast pile construction, so cast-in-place piles are often used.

[0003] Since the backfill layer in the reclamation area has not completed its self-weight consolidation and the stratum is unstable, the hole collapse is prone to occur during the drilling process of the rotary bored pile. As a result, when the pile body concrete is poured, the concrete is over-cubic and the overall filling coefficient is too large, which increases the construction cost. In addition, the pile body bulges or forms a mushroom head, which interferes with the pile foundation test results and has a great impact on the project quality. Utility Model Content

[0004] The purpose of the utility model is to provide a construction structure for controlling the filling coefficient of bored piles, so as to solve the technical problems such as low stability of backfill soil layer, easy collapse of holes, excessive filling coefficient of concrete during bored pile casting, resulting in bulging of pile body, affecting pile quality, interfering with pile foundation detection results, and affecting project quality.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] The utility model provides a construction structure for controlling the filling coefficient of bored piles, comprising a backfill soil layer, a drill hole being provided in the backfill soil layer, a casing and a steel cage being provided in the drill hole, and the top end of the steel cage being connected to a crane via a traction rope; the casing is provided on the inner side surface of the upper part of the drill hole, the upper end of the casing extends out of the drill hole, and a clay layer is provided on the lower end; the steel cage is provided on the inner side surface of the casing and is arranged throughout the drill hole, an iron sheet layer is provided around the outer side surface of the steel cage, and a spacer is provided between the steel cage and the iron sheet layer for controlling the spacing between the steel cage and the iron sheet layer; the steel cage comprises longitudinal bars and stirrups spaced apart in the length direction of the longitudinal bars; the spacer comprises a plurality of groups of spacers, and the plurality of groups of spacers are spaced apart in the length direction of the steel cage; at least four spacers are provided in a single group, and the four spacers are all fixed on the same stirrup and are evenly distributed on the outer side of the stirrup.

[0007] Preferably, wooden strips are tied to the outer side surface of the top of the casing to prevent the casing from sliding down.

[0008] Preferably, the iron sheet layer is a cylindrical shape formed by rolling rectangular iron sheets, and rivets are provided at intervals on the overlapping edges to fix the iron sheet layer into shape.

[0009] Preferably, the thickness of the iron sheet layer is 0.4 mm.

[0010] Preferably, the distance between the iron sheet layer and the steel cage is 70 mm.

[0011] Preferably, the pad is made of plastic or concrete and is fixed by tying with steel wire and stirrups.

[0012] Preferably, the side surface of the pad close to the iron sheet is a smooth convex arc surface, which is used to fit the curvature of the inner side surface of the iron sheet layer.

[0013] Preferably, the side of the pad close to the iron sheet is coated with polytetrafluoroethylene powder to reduce friction.

[0014] The beneficial effects of the present invention are as follows:

[0015] The utility model provides a construction structure for controlling the filling coefficient of bored piles. When drilling a hole in a soft backfill soil layer, a casing is supported to prevent the hole from collapsing during drilling. A clay layer is filled at the bottom of the casing to ensure the verticality of the casing, prevent mud loss and displacement, and improve the stability of the casing. After the hole is drilled, a steel cage is placed in the drilled hole, and a layer of iron sheet is provided on the outer side of the steel cage. Pads for controlling the distance between the stirrups and the iron sheet are provided on the stirrups of the steel cage. When pouring concrete, the iron sheet serves as an external template for pouring, which can improve the quality of the pile, avoid problems such as bulging of the pile body, greatly reduce the filling coefficient of the concrete, thereby controlling the construction cost and stabilizing the construction quality.

[0016] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The main purpose and other advantages of the present invention can be achieved and obtained through the solutions specifically pointed out in the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described in detail below with reference to the accompanying drawings.

[0018] Figure 1 It is a cross-sectional view of the present utility model.

[0019] Figure 2 yes Figure 1 Cross-sectional view of AA.

[0020] Figure numerals: 1-backfill soil layer, 2-drill hole, 3-casing, 4-reinforcement cage, 41-longitudinal reinforcement, 42-hoops, 5-traction rope, 6-crane, 7-clay layer, 8-iron layer, 9-pad, 10-wooden square, 11-rivet. DETAILED DESCRIPTION

[0021] The technical solutions of the present invention are described in detail below through examples. The following examples are merely exemplary and can only be used to explain and illustrate the technical solutions of the present invention, and cannot be interpreted as limiting the technical solutions of the present invention.

[0022] Reference Figure 1-2 The utility model provides a construction structure for controlling the filling coefficient of bored piles, including a backfill soil layer 1, a borehole 2 is provided in the backfill soil layer 1, a casing 3 and a steel cage 4 are provided in the borehole 2, and the top of the steel cage 4 is connected to a crane 6 through a traction rope 5; the casing 3 is provided on the inner side surface of the upper part of the borehole 2, the upper end of the casing 3 extends out of the borehole 2, and a clay layer 7 is provided at the lower end, and a wooden beam 10 is tied to the outer side surface of the top of the casing 3 to prevent the casing 3 from sliding down; the steel cage 4 is provided on the inner side surface of the casing 3 and is arranged throughout the borehole 2, and an iron sheet 8 is provided around the outer side surface of the steel cage 4, the thickness of the iron sheet 8 is 0.4 mm, and the iron sheet 8 is a cylindrical shape formed by rolling rectangular iron sheets, and rivets 11 are provided at intervals on the overlapping edges to fix the iron sheet 8 into shape; the steel A pad 9 is provided between the reinforcement cage 4 and the iron layer 8 to control the spacing between the reinforcement cage 4 and the iron layer 8, and the spacing is controlled to 70 mm. The pad 9 is made of plastic or concrete and is fixed by binding with the stirrup 42 by steel wire. The side of the pad 9 close to the iron layer 8 is a smooth convex arc surface, which is used to fit the curvature of the inner side of the iron layer 8, or a layer of polytetrafluoroethylene powder is applied on the side of the pad 9 close to the iron layer 8 to reduce friction; the reinforcement cage 4 includes longitudinal reinforcement 41 and stirrups 42 spaced apart in the longitudinal direction of the longitudinal reinforcement 41; the pad 9 includes multiple groups, and the multiple groups of pads 9 are spaced apart in the longitudinal direction of the reinforcement cage 4; a single group of pads 9 is provided with at least four, and the four pads 9 are all fixed on the same stirrup 42 and are evenly distributed on the outer side of the stirrup 42.

[0023] Furthermore, before drilling hole 2, a casing 3 should be buried at the determined pile position. The length of casing 3 should be 6 to 8 meters, ensuring that the bottom of casing 3 is seated in the backfill layer 1. Accurately fix the position of borehole 2, isolate ground water, stabilize the soil at the hole mouth, and protect the hole wall from collapse, so as to facilitate the drilling of hole 2. Use steel casing 3, the diameter of which should be larger than the diameter of the drill bit. The top elevation of casing 3 should be 10 to 20 cm above the construction surface, and the casing wall should be perpendicular to the horizontal plane. When positioning casing 3, first verify the pile position. Then, with the pile position as the center, determine mutually perpendicular cross control pile lines and use cross bolt points for control. Then, dig the hole for casing 3, hoist casing 3 into place, and fill the voids around casing 3 with clay and tamp it down. Simultaneously, use cross lines to align the center of casing 3 and the center of the pile position, ensuring that the deviation between the center of casing 3 and the center of the pile is less than 2 cm. After the casing 3 is fixed in the correct position, it is backfilled and compacted in layers with clay layers 7 to ensure its verticality and prevent mud loss and displacement of the casing 3. If the bottom soil layer of the casing 3 is not clay, it should be deepened or replaced with soil. After backfilling and compacting the clay layer with a thickness of 300 to 500 mm at the bottom of the pit, the casing 3 can be placed to prevent leakage and collapse at the bottom of the casing 3.

[0024] After the drilling rig has bored a hole, the pile length is measured. Rebar is cut based on the pile length and design requirements. After cutting, the reinforcement is tied according to the design drawings. The design requirement for the net protective layer thickness of the pile stirrups 42 is 70mm, requiring 70mm thick spacers 9. These spacers 9 are then tied to the stirrups 42. Iron sheets with a thickness of 0.4mm are cut to determine the length of the iron sheet 8 wrapping around the steel cage 4. The overlap length of the iron sheet 8 is 50mm, and the overlap is secured with rivets 11, with rivets 11 spaced 500mm apart.

[0025] Furthermore, the steel cage 4 is hoisted into the hole in sections using a construction method. After the steel cage 4 is hoisted to 0.3m to 0.5m from the ground, it should be checked whether the steel cage 4 is stable. The main hook is then lifted. According to the distance between the tail of the steel cage 4 and the ground, the crane 6 auxiliary hook is commanded to cooperate in lifting the hook at any time. Slowly make the steel cage 4 perpendicular to the ground. Command the crane 6 to lift the cage into the hole and position it. The crane 6 should move smoothly. The traction rope 5 should be pulled on the steel cage 4. Do not force it into the hole when lowering it. The upper and lower sections of the steel cage 4 are welded on the same straight line. After all the joints are welded, they can be sunk into the hole. After the steel cage 4 enters the hole, the iron layer 8 is hoisted again so that the inner side of the iron layer 8 is against the pad 9 and slides down to the bottom of the iron layer 8 and reaches the bottom of the drill hole 2, until the iron layer 8 completely covers the steel cage 4.

[0026] Furthermore, when pouring concrete, the concrete surface in the hole must rise evenly, with a rate of at least 3m / h. During the concrete pouring process, the actual concrete surface elevation must be measured with a hammer at all times. The concrete rise height, the relative position of the lower end of the conduit and the concrete, and the amount of concrete poured must be calculated and recorded promptly. During the pouring process, the depth of the conduit embedded in the concrete must be controlled between 2.0 and 6.0m. Once the concrete reaches a point above the design elevation, add another 0.5 to 1m.

[0027] The above description is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in the present invention should be included in the protection scope of the present invention.

Claims

1. A construction structure for controlling the filling coefficient of a bored pile, characterized by: The invention comprises a backfill soil layer (1), a borehole (2) is provided in the backfill soil layer (1), a casing (3) and a steel cage (4) are provided in the borehole (2), and the top of the steel cage (4) is connected to a crane (6) via a traction rope (5); A casing (3) is arranged on the inner side surface of the upper part of the borehole (2), the upper end of the casing (3) extends out of the borehole (2), and a clay layer (7) is arranged on the lower end; a steel cage (4) is arranged on the inner side surface of the casing (3) and is arranged throughout the borehole (2), an iron layer (8) is arranged around the outer side surface of the steel cage (4), and a spacer (9) is arranged between the steel cage (4) and the iron layer (8) for controlling the spacing between the steel cage (4) and the iron layer (8); The steel cage (4) includes longitudinal bars (41) and stirrups (42) spaced apart along the longitudinal direction of the longitudinal bars (41); The pads (9) include multiple groups, and the multiple groups of pads (9) are spaced apart in the longitudinal direction of the steel cage (4); a single group of pads (9) is provided with at least four pads (9), and the four pads (9) are all fixed on the same stirrup (42) and are evenly distributed on the outer side of the stirrup (42).

2. A construction structure for controlling the filling coefficient of a bored pile according to claim 1, characterized in that: A wooden beam (10) is tied to the outer side surface of the top of the casing (3) to prevent the casing (3) from sliding downward.

3. A construction structure for controlling the filling coefficient of a bored pile according to claim 1, characterized in that: The iron sheet layer (8) is a cylindrical shape formed by rolling a rectangular iron sheet, and rivets (11) are arranged at intervals on the overlapping edges to fix the iron sheet layer (8) into shape.

4. A construction structure for controlling the filling coefficient of a bored pile as claimed in claim 3, characterized in that: The thickness of the iron sheet layer (8) is 0.4 mm.

5. A construction structure for controlling the filling coefficient of bored piles as claimed in claim 1, characterized in that: The distance between the iron sheet layer (8) and the steel cage (4) is 70 mm.

6. A construction structure for controlling the filling coefficient of a bored pile according to claim 1, characterized in that: The pad (9) is made of plastic or concrete and is fixed by tying steel wire and stirrups (42).

7. A construction structure for controlling the filling coefficient of a bored pile according to claim 6, characterized in that: The side surface of the pad (9) close to the iron sheet layer (8) is a smooth convex arc surface, which is used to fit the curvature of the inner side surface of the iron sheet layer (8).

8. A construction structure for controlling the filling coefficient of a bored pile according to claim 6, characterized in that: The side of the pad (9) close to the iron layer (8) is coated with polytetrafluoroethylene powder to reduce friction.

Images