CN-117230785-B - Split combined type hanging casing and use method thereof

CN117230785BCN 117230785 BCN117230785 BCN 117230785BCN-117230785-B

Abstract

The invention belongs to the technical field of pile foundation construction pile casings, and discloses a split combined type suspension pile casing and a use method thereof. The split combined type suspension pile casing converts the side friction stress of the conventional landfill extrusion type pile casing and the bottom side stress of the pile casing into the stress of a pressure-bearing steel plate on the ground of an orifice, and simultaneously increases the vertical pressure-bearing stress area to convert the pile casing bearing large pressure into the pressure stress on the ground, and particularly comprises the pressure-bearing steel plate, the pile casing and the pressure-bearing seat. Aiming at the conditions of ultra-deep large-diameter pile foundation construction, particularly the conditions of high bearing capacity of the pile casing, lower bearing capacity of the foundation and high bearing capacity of the pile casing, the invention designs and improves the conventional embedded extrusion type pile casing lower setting installation technology, and effectively solves the problems of low pile casing settlement, easy deflection, multiple working efficiency of pile casing lower setting installation procedures, high bearing pressure and friction resistance of the side surface of the pile casing, easy damage and deformation, low recycling rate and the like of the foundation under the condition of high bearing capacity of the embedded extrusion type pile casing.

Inventors

WU YANG
WANG JUN
LIU YUAN
WU QIWEI
Lian Changcheng
MA YUHENG
ZHANG HAIXIAO

Assignees

中国水电基础局有限公司

Dates

Publication Date: 20260505
Application Date: 20231028

Claims (4)

1. The application method of the split combined type suspension pile casing is characterized in that the split combined type suspension pile casing is provided with: The pressure-bearing steel plate (1) is designed to be separated from the protective cylinder (2) and is fixed with the ground through a pressure-bearing steel plate fixing bolt (4) arranged on the pressure-bearing steel plate (1) and used for bearing the pressure stress, the interior of the pressure-bearing steel plate (1) is of an empty circle structure, and the protective cylinder (2) penetrates through the empty circle; the top of the protective cylinder (2) is welded with the pressure-bearing seat (3) by a full seam; The pressure-bearing seat (3) is fixed with the pressure-bearing steel plate (1) through a pressure-bearing seat fixing bolt (5); The application method converts the side friction resistance stress of the embedded extrusion type pile casing and the bottom side stress of the pile casing into the stress of a pressure-bearing steel plate (1) on the ground of an orifice, and simultaneously increases the vertical pressure-bearing stress area to convert the pile casing bearing large pressure into the pressure stress to the ground, and specifically comprises the following steps: S1, preparing a split combined suspension pile casing; S2, excavating a pile casing pit, namely excavating the pile casing pit, measuring, positioning and lofting the center of a pile foundation, checking the perpendicularity of a hole site and a guide rod, reaming and excavating, wherein the excavation depth is a preset depth set below the pile casing and is increased by more than 0.5m, so as to form a reserved pile casing pit, and the reaming aperture exceeds the outer wall of the pile casing and is more than 30mm in vertical distance; s3, installing a protective cylinder in a lower mode; s4, pulling and recovering the protective cylinder; The lower setting installation of a protective barrel specifically comprises: step 1, paving leveling sand for leveling, namely paving 30mm fine sand on the periphery of a pile casing pit so as to level a pressure-bearing steel plate (1); Step 2, spraying a release agent for reducing drag and damage, namely spraying the release agent on the inner side and the outer side of the pressure-bearing steel plate (1) and the protective cylinder in advance; Step 3, hoisting the pressure-bearing steel plates (1) in place and leveling, symmetrically penetrating through hanging holes on two sides of each pressure-bearing steel plate (1) by adopting two steel wire ropes, hanging 4 sleeve openings of the steel wire ropes on a lifting hook of a conventional automobile crane, hoisting the pressure-bearing steel plates (1) in place and centering and leveling, leveling by adopting fine sand and a thin steel gasket, and fixing after leveling; Step 4, hoisting the pile casing in-place leveling, namely symmetrically penetrating hanging holes on two sides of the top of the pile casing by adopting steel wire ropes and hanging the steel wire ropes on an automobile crane hook, slowly hoisting the pile casing and transporting the pile casing to the upper surface of a pile hole for alignment and downward setting, correcting hole positions after bearing seats (3) on two sides of the top of the pile casing fall on a bearing steel plate (1), correcting verticality of the pile casing by a long horizontal ruler and a thin rigid gasket, and adding a thin steel gasket on the bottom surface of the bearing seat (3) on one side with lower elevation of the top surface of the pile casing until the elevation of the top surface of the pile casing is consistent, and fixing the pile casing after leveling; And 5, pile foundation hole forming, namely starting a rotary drilling rig for hole forming construction, and simultaneously supplying slurry from a slurry supply through hole (6) of the protection cylinder to ensure that the top surface of the slurry of the protection wall is kept unchanged during hole forming.
2. The use method of the split combined type hanging pile casing according to claim 1, wherein the pressure-bearing steel plate (1) is provided with a pressure-bearing steel plate hanging hole (7), and the pile casing (2) is provided with a slurry supply through hole (6) and a pile casing hanging hole (8).
3. The use method of the split combined type suspension pile casing according to claim 2, wherein the periphery of the pressure-bearing steel plate (1) is of a square structure, the thickness of the pressure-bearing steel plate (1) is not less than 40mm, and the diameter of an empty circle is the same as the diameter of a pile hole; The pile casing (2) is made of steel with the length of 6m-7m and the thickness of not less than 20 mm.
4. The method of using a split combined hanging casing according to claim 1, wherein in step S4, the recovery of the casing comprises opening the bearing seat fixing pin (5), lifting and flushing the transfer casing (2), opening the bearing steel plate fixing pin (4), cleaning and lifting the transfer bearing steel plate (1).

Description

Split combined type hanging casing and use method thereof Technical Field The invention belongs to the technical field of pile foundation construction pile casings, and particularly relates to a split combined type suspension pile casing and a use method thereof. Background The technology for the conventional orifice pile casing adopted in pile foundation construction is characterized by comprising the steps of measuring and positioning, excavating a pile casing pit, leveling and tamping the bottom of the pit foundation, laying a cushion layer, hoisting the pile casing in place, leveling and fixing, symmetrically filling and tamping soil mass around the pile casing in a layered mode, excavating a slurry supply ditch, cleaning soil materials around the pile casing opening and pore-forming construction. In the process flow, the excavation of the pile casing pit mainly comprises two modes, namely excavating equipment such as an excavator, reaming and excavating by using a rotary drilling machine hole making equipment, filling sand gravel, soil materials and other granules on the periphery of the pile casing, and compacting by extrusion. In addition, part of the projects are arranged under the soft foundation by adopting hydraulic vibration pliers aiming at the small-mouth casing, and the method is applicable to the condition that the casing is used under the condition of smaller bearing. The conventional landfill extrusion type pile casing technology has a plurality of defects, and particularly aims at the problems that the technology is complex, the work efficiency is low, the pile casing bearing capacity is difficult to reach the standard, the pile casing is easy to deflect and deform, the repeated utilization rate is low and the like under the condition that the pile casing needs to bear a high-pressure carrier during construction of a large-diameter deep pile foundation. Aiming at the high vertical precision and bearing capacity project of the large-pile-diameter deep pile foundation, the prior landfill extrusion type pile casing technology is adopted to protect, guide and bear the gravity of the orifice object, and the following defects and shortcomings exist: ① The orifice is not protected in place, the earth surface near the orifice has much muddy water, the construction environment is dirty and messy, and the on-site civilized construction does not reach the standard; ② The pile casing is easy to generate uneven settlement (the pile casing landfill stress is uneven, the strength of the pile casing bottom contact surface is low or uneven), thereby causing the pile casing deflection; ③ The length of the pile casing is generally short (generally about 2 m), the guiding performance is poor, and the vertical precision of the pile foundation is difficult to ensure; ④ The conventional pile casing has small bearing capacity, is difficult to bear the gravity when other objects such as a reinforcement cage with large weight, a guide pipe and the like are arranged below the orifice, and is easy to deflect. ⑤ When the pile casing with larger bearing pressure is arranged under the pile casing, the pile casing substrate (especially the soft soil foundation) needs to be tamped or cushioned so as to increase the bearing capacity of the foundation and prevent the pile casing from sedimentation deformation. Namely, the problems of small bearing capacity of the foundation and small bearing capacity of the pile casing exist. After the pile casing is arranged, the surrounding soil body needs to be filled and compacted to squeeze the pile casing, to increase the side friction of the casing, thereby increasing the bearing capacity of the top surface of the protective cylinder. The area of the side surface of the bottom of the pile casing is small, the bearing capacity of the top surface of the pile casing is mainly supported by the friction force of the outer side wall of the pile casing, and the pile casing is easy to settle and incline when the top surface of the pile casing bears the heavy weight of the carrier. ⑥ Because the conventional pile casing is pressed by landfill to improve the bearing capacity, the outer side of the pile casing is often filled with the concrete to be compacted and pressed tightly, and after concrete pouring is finished, when the pile casing is pulled up and recovered, the pile casing is difficult to pull up or deform due to larger friction resistance, and particularly, the utilization rate of the long pile casing exceeding 5m is extremely low ⑦ The conventional buried pile casing is provided with a complex installation process, low speed, high cost, easy settlement and deflection of the pile casing and difficult guarantee of engineering quality safety, and the conventional pile casing is provided with an installation process flow of site compaction leveling, measurement positioning, excavation of pile casing pits, leveling and tamping or bedding layers at the bottoms of pit foundation bases, ho