CN114991135A - High-pressure grouting prestressed pipe pile and construction method - Google Patents

Abstract

The invention discloses a high-pressure grouting precast tubular pile and a construction method, which are mainly used in the field of pile foundations in constructional engineering, greatly improve the bearing capacity of a pile foundation, and have the advantages of high construction speed and low comprehensive unit price; the pile mainly comprises a tubular pile body, a grouting device and a pile tip; the construction method comprises the following steps: sequentially driving each section of pipe pile into the ground to a designed elevation by using a conventional method through hammering or static pressure, then placing high explosive in a cavity of a pile tip, filling cement mortar in a through hole A, then detonating the high explosive, expanding the bottom of the pipe pile by the exploded high explosive, then installing a grouting device, applying pressure to a grouting piston of the grouting device by using a pile hammer of a pile driver or a jack of a static pressure pile driver, extruding the cement mortar subjected to strong pressure through a plurality of grouting holes again and injecting the cement mortar into soil layers around a plurality of annular grooves to form a final expanded hole cavity, forming a final expanded bottom cavity by the soil layers around the pile tip, finally stabilizing the grouting piston for a period of time, then dismantling the grouting device, and finishing pile foundation construction.

Description

High-pressure grouting prestressed pipe pile and construction method

Technical Field

The invention belongs to the field of pile foundations in constructional engineering, and particularly relates to a prestressed pipe pile and a construction method.

Background

The prestressed pipe pile used in the field of building engineering at present has the advantages of high construction speed and low comprehensive cost, and is widely used, but the prestressed pipe pile has smooth appearance, small friction force with surrounding soil after pile forming, and is not beneficial to compression resistance or pulling resistance, particularly pulling resistance.

Disclosure of Invention

The invention solves the problems, not only improves the pulling-resistant bearing capacity of the prestressed pipe pile foundation, but also greatly improves the compression-resistant bearing capacity of the prestressed pipe pile foundation; the pile mainly comprises a tubular pile body (1), a grouting device (6), a pile feeder (17) and a pile tip (27); the pile body (1) of each section of prestressed pipe pile is reserved with a plurality of ring grooves (3), each ring groove (3) is reserved with a plurality of grouting holes (2), the upper end and the lower end of the pile body (1) of each section of prestressed pipe pile are respectively fixed with an end steel plate (5), each end steel plate (5) is provided with a central hole (26), the hole diameter of the central hole (26) is smaller than that of the through hole A (4), each end steel plate (5) is provided with a plurality of bolt holes B (13), the pile body (1) of each section of prestressed pipe pile is provided with a central through hole A (4), the pile body (1) of the lowest section of prestressed pipe pile is provided with steel plates (14) on the inner wall and the outer wall of the lower part except the structure, the end steel plate (5) at the lower end of the pile body (1) of the lowest section of prestressed pipe pile is fixed with a pile tip (27), and the pile tip (27) consists of a cross rib plate (16) with certain taper and a plurality of conical flaps (15), the expanded end of the cross rib plate (16) is fixed with an end steel plate (5) at the lower end of the pile body (1) of the lowest section of tubular pile, a plurality of conical valves (15) surround the cross rib plate (16) and form a pile head, and the upper ends of the conical valves (15) are hinged with the end steel plate (5); the grouting device (6) mainly comprises a grouting cylinder (7) and a grouting piston (10), wherein a circular ring bottom plate (8) is fixed at the lower end of the grouting cylinder (7), a sealing ring A (11) is fixed at the lower end of the circular ring bottom plate (8), a plurality of bolt holes A (12) are formed in the circular ring bottom plate (8), the positions of the bolt holes A (12) correspond to the positions of bolt holes B (13) of an end steel plate (5) of a tubular pile body (1) one by one, a slurry conveying pipe (9) is fixed on the upper cylindrical wall of the grouting cylinder (7), a check valve is installed on the slurry conveying pipe (9), and the grouting piston (10) slides in the grouting cylinder (7); the pile feeder (17) is cylindrical, a pile feeder top plate (19) is fixed at the upper end of the pile feeder (17), a pile feeder bottom plate (20) is fixed at the lower end of the pile feeder, a through hole B (18) is formed in the center of the pile feeder top plate, a plurality of bolt holes are formed in the pile feeder top plate (19), the positions of the bolt holes correspond to the bolt holes A (12) of the bottom plate (8) of the grouting device (6) one by one, and a sealing ring B (21) is installed at the lower end of the pile feeder bottom plate (20); the construction method of the high-pressure grouting prestressed pipe pile comprises the following steps: sequentially driving the lowest section of prestressed pipe pile and each section of pipe pile into the ground to a designed elevation by hammering or static pressure by a conventional method, firmly welding the joint part of each section of pipe pile and ensuring sealing, then placing high explosive (25) in the cavity of the pile tip (27) of the lowest section of pipe pile and leading a detonating cord out of the pipe pile, then fully filling cement mortar (22) in the through hole A (4) of the pile body (1) of each section of pipe pile, then plugging the central hole (26) of the end steel plate (5) of the pile body (1) of the uppermost section of pipe pile by using a temporary sealing plate, then detonating the high explosive (25), punching a plurality of conical flaps (15) of the pile tip (27) by the downward impact force of the high explosive (25) after detonation, pushing open the bottom cavity (24) by the upward impact force of the plurality of conical flaps (15), and pushing the through hole A (4) of each section of pipe pile body (1) by the upward impact force of the high explosive (25) after detonation, cement mortar (22) is pushed and injected into soil layers around the plurality of annular grooves (3) through the plurality of grouting holes (2) to form a primary expanding cavity (23), after blasting is completed, the cement mortar (22) in partial through holes A (4) collapses into the primary expanding cavity (24) under the action of gravity, then a temporary sealing plate of a central hole (26) of an end steel plate (5) of the uppermost section of tubular pile body (1) is removed, the falling height of the cement mortar (22) in the through hole A (4) of the uppermost section of tubular pile body (1) is measured, the size of the primary expanding cavity (24) can be preliminarily determined, the through hole A (4) of the uppermost section of tubular pile body (1) is filled with cement mortar (22), then a grouting device (6) is installed, a bottom plate (8) of the grouting device (6) is tightly connected with the end steel plate (5) of the uppermost section of tubular pile body (1) to ensure sealing, then conveying cement mortar (22) into a grouting cylinder (7) of a grouting device (6) through a mortar conveying pump and a mortar conveying pipe (9), applying pressure to a grouting piston (10) of the grouting device (6) by using a pile hammer of a pile driver or a jack of a static pressure pile driver, extruding and injecting the cement mortar (22) subjected to strong pressure into a soil layer around the plurality of annular grooves (3) through the plurality of grouting holes (2) again to form a final hole expanding cavity (23), solidifying the cement mortar (22) in the hole expanding cavity (23) and reaching the strength, the root part of the groove is embedded in the annular groove (3), the shear strength of the cement mortar (22) in the expanding cavity (23) is greatly increased, meanwhile, a final bottom expanding cavity (24) is formed in a soil layer around the pile tip (27), the grouting device (6) can be detached after the grouting piston (10) is stabilized for a period of time, and the whole pile foundation construction is finished; if the designed elevation of the pile top of the prestressed pipe pile is below the ground, pile feeding is needed under the condition, after the pile top of the prestressed pipe pile is driven to the ground, the pile feeder (17) is hoisted, the pile top of the prestressed pipe pile is conveyed to the designed elevation by the hammering or static pressure pile feeder (17), and at the moment, the sealing ring B (21) of the bottom plate (20) of the pile feeder at the lower end of the pile feeder (17) is tightly attached to the end steel plate (5) of the pile body (1) of the uppermost section of pipe pile to play a sealing role, and the pile bottom is reamed and grouted by the same method.

Drawings

1-tubular pile body, 2-grouting hole, 3-annular groove, 4-through hole A, 5-end steel plate, 6-grouting device, 7-grouting cylinder, 8-bottom plate, 9-slurry feeding pipe, 10-grouting piston, 11-sealing ring A, 12-bolt hole A, 13-bolt hole B, 14-steel plate, 15-conical valve, 16-cross rib plate, 17-pile feeder, 18-through hole B, 19-pile feeder top plate, 20-pile feeder bottom plate, 21-sealing ring B, 22-cement mortar, 23-expanding cavity, 24-expanding bottom cavity, 25-high explosive, 26-central hole and 27-pile tip.

Fig. 1 is a schematic diagram of the prestressed pipe pile after hole expansion and grouting.

Fig. 2 is an exploded view of the prestressed pipe pile and the grouting device 6.

Fig. 3 is an exploded schematic view of the grouting device 6, the pile feeder 17 and the tubular pile body 1.

Fig. 4 is a top view of the tapered flaps 15 and cross ribs 16 of the stake tip 27.

Detailed Description

Referring to fig. 2, the pressure applied to the surrounding material after detonation of the high explosive charge 25 is equal, as can be seen from the toe diagram of fig. 2: the total stressed area of the multi-block conical valve 15 of the pile tip 27 is far larger than the area of the hole 26 of the end steel plate 5 of the pile body 1 of the lowest section of tubular pile, so that most of the impact force of the high explosive 25 after explosion impacts the multi-block conical valve 15 of the pile tip 27 downwards, the multi-block conical valve 15 is pushed away, and therefore the main effect of the high explosive 25 is as follows: reaming the pile bottom of the prestressed pipe pile; referring to fig. 1, the cross rib plate 16 of the pile tip of the tubular pile plays a role of a steel skeleton after the cement mortar 22 in the bottom expanding cavity 24 reaches the strength; referring to fig. 2, each section of standard section of the prestressed pipe pile widely produced at present is provided with an end steel plate 5, the end steel plate 5 is also provided with a bolt hole B and a central hole 26, each section of standard section is provided with a through hole a4, the prestressed pipe pile of the invention is only provided with an annular groove 3 and a grouting hole 2 on the basis of the standard section of the prestressed pipe pile at present, so the prestressed pipe pile has good adaptability; the steel plates 14 and the end steel plates 5 of the inner wall and the outer wall at the lower part of the tubular pile body 1 of the lowest section of the prestressed tubular pile wrap the concrete wall of the tubular pile, so that the exploded high explosive 25 cannot explode the concrete wall of the tubular pile; referring to fig. 1, if the foundation of the prestressed pipe pile is designed to be a rock-socketed pile, namely, the pile tip of the prestressed pipe pile enters medium weathering rock or slightly weathering rock, the pile foundation is mainly based on the bearing capacity of the pile end, and the friction force of the pile body is assisted, the invention cancels the pile bottom reaming process and reserves the grouting process of the side surface of the pile body, thus increasing the compression bearing capacity of the pile and greatly improving the anti-pulling bearing capacity of the pile; if the foundation of the prestressed pipe pile is designed to be a non-socketed pile, the pile tip of the prestressed pipe pile does not enter medium weathered rock or slightly weathered rock but enters strong weathered rock or cohesive soil, the pile foundation mainly takes the friction force of a pile body, and the bearing capacity of a pile end is assisted.

Claims (2)

1. High-pressure slip casting precast tubular pile, characterized by: the pile mainly comprises a tubular pile body (1), a grouting device (6), a pile feeder (17) and a pile tip (27); the pile body (1) of each section of prestressed pipe pile is reserved with a plurality of ring grooves (3), each ring groove (3) is reserved with a plurality of grouting holes (2), the upper end and the lower end of the pile body (1) of each section of prestressed pipe pile are respectively fixed with an end steel plate (5), each end steel plate (5) is provided with a central hole (26), the hole diameter of the central hole (26) is smaller than that of the through hole A (4), each end steel plate (5) is provided with a plurality of bolt holes B (13), the pile body (1) of each section of prestressed pipe pile is provided with a central through hole A (4), the pile body (1) of the lowest section of prestressed pipe pile is provided with steel plates (14) on the inner wall and the outer wall of the lower part except the structure, the end steel plate (5) at the lower end of the pile body (1) of the lowest section of prestressed pipe pile is fixed with a pile tip (27), and the pile tip (27) consists of a cross rib plate (16) with certain taper and a plurality of conical flaps (15), the expanded end of the cross rib plate (16) is fixed with an end steel plate (5) at the lower end of the pile body (1) of the lowest section of tubular pile, a plurality of conical valves (15) surround the cross rib plate (16) and form a pile head, and the upper ends of the conical valves (15) are hinged with the end steel plate (5); the grouting device (6) mainly comprises a grouting cylinder (7) and a grouting piston (10), wherein a circular ring bottom plate (8) is fixed at the lower end of the grouting cylinder (7), a sealing ring A (11) is fixed at the lower end of the circular ring bottom plate (8), a plurality of bolt holes A (12) are formed in the circular ring bottom plate (8), the positions of the bolt holes A (12) correspond to the positions of bolt holes B (13) of an end steel plate (5) of a tubular pile body (1) one by one, a slurry conveying pipe (9) is fixed on the upper cylinder wall of the grouting cylinder (7), a check valve is installed on the slurry conveying pipe (9), and the grouting piston (10) slides in the grouting cylinder (7); the pile feeder (17) is cylindrical, a pile feeder top plate (19) is fixed at the upper end of the pile feeder, a pile feeder bottom plate (20) is fixed at the lower end of the pile feeder top plate, a through hole B (18) is formed in the center of the pile feeder top plate, a plurality of bolt holes are formed in the pile feeder top plate (19) and correspond to the bolt holes A (12) of the bottom plate (8) of the grouting device (6) in position one by one, and a sealing ring B (21) is installed at the lower end of the pile feeder bottom plate (20).

2. The high-pressure grouting precast tubular pile according to claim 1, wherein the construction method comprises the following steps: sequentially driving the lowest section of prestressed pipe pile and each section of pipe pile into the ground to a designed elevation by hammering or static pressure by a conventional method, firmly welding the joint part of each section of pipe pile and ensuring sealing, then placing high explosive (25) in the cavity of the pile tip (27) of the lowest section of pipe pile and leading a detonating cord out of the pipe pile, then fully filling cement mortar (22) in the through hole A (4) of the pile body (1) of each section of pipe pile, then plugging the central hole (26) of the end steel plate (5) of the pile body (1) of the uppermost section of pipe pile by using a temporary sealing plate, then detonating the high explosive (25), punching a plurality of conical flaps (15) of the pile tip (27) by the downward impact force of the high explosive (25) after detonation, pushing open the bottom cavity (24) by the upward impact force of the plurality of conical flaps (15), and pushing the through hole A (4) of each section of pipe pile body (1) by the upward impact force of the high explosive (25) after detonation, cement mortar (22) is pushed and injected into soil layers around the plurality of annular grooves (3) through the plurality of grouting holes (2) to form a primary expanding cavity (23), after blasting is completed, the cement mortar (22) in partial through holes A (4) collapses into the primary expanding cavity (24) under the action of gravity, then a temporary sealing plate of a central hole (26) of an end steel plate (5) of the uppermost section of tubular pile body (1) is removed, the falling height of the cement mortar (22) in the through hole A (4) of the uppermost section of tubular pile body (1) is measured, the size of the primary expanding cavity (24) can be preliminarily determined, the through hole A (4) of the uppermost section of tubular pile body (1) is filled with cement mortar (22), then a grouting device (6) is installed, a bottom plate (8) of the grouting device (6) is tightly connected with the end steel plate (5) of the uppermost section of tubular pile body (1) to ensure sealing, then conveying cement mortar (22) into a grouting cylinder (7) of a grouting device (6) through a mortar conveying pump and a mortar conveying pipe (9), applying pressure to a grouting piston (10) of the grouting device (6) by using a pile hammer of a pile driver or a jack of a static pressure pile driver, extruding and injecting the cement mortar (22) subjected to strong pressure into a soil layer around the plurality of annular grooves (3) through the plurality of grouting holes (2) again to form a final hole expanding cavity (23), solidifying the cement mortar (22) in the hole expanding cavity (23) and reaching the strength, the root part of the groove is embedded in the annular groove (3), the shear strength of the cement mortar (22) in the expanding cavity (23) is greatly increased, meanwhile, a final bottom expanding cavity (24) is formed in a soil layer around the pile tip (27), the grouting device (6) can be detached after the grouting piston (10) is stabilized for a period of time, and the whole pile foundation construction is finished; if the designed elevation of the pile top of the prestressed pipe pile is below the ground, pile feeding is needed under the condition, after the pile top of the prestressed pipe pile is driven to the ground, the pile feeder (17) is hoisted, the pile top of the prestressed pipe pile is conveyed to the designed elevation by the hammering or static pressure pile feeder (17), and at the moment, the sealing ring B (21) of the bottom plate (20) of the pile feeder at the lower end of the pile feeder (17) is tightly attached to the end steel plate (5) of the pile body (1) of the uppermost section of pipe pile to play a sealing role, and the pile bottom is reamed and grouted by the same method.

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