Pore-forming device and pore-forming method for concrete drilling cast-in-place threaded pile
Technical Field
The invention relates to the field of cast-in-situ bored piles in pile foundation engineering, in particular to a pore-forming device and a pore-forming method for a concrete cast-in-situ bored threaded pile.
Background
The cast-in-situ bored pile in the pile foundation engineering is divided into an end bearing pile and a friction pile according to the stress characteristics, and the bearing capacity of the end bearing pile mainly comes from the resistance of a solid soil layer or bedrock at the pile end; the bearing capacity of the friction pile mainly comes from the side friction between the pile body and the soil. After the cast-in-situ bored pile is formed into a hole, the hole wall is extruded to form a thread shape, so that the side friction between the pile and the soil is improved, and the bearing capacity of the friction pile can be improved. The current concrete screw pile is mainly a precast pile, and is extruded into a soil body by applying torque on a pile body, the torque which can be borne by the pile body is limited by the strength of concrete, and the pile diameter and the pile length are relatively small.
Disclosure of Invention
The invention aims to provide a hole forming device and a hole forming method for a concrete drilling and pouring threaded pile, so as to solve the problems.
In order to achieve the purpose, the invention adopts the following technical scheme:
a pore-forming device for a concrete drilling cast-in-place threaded pile comprises a middle core rod, a sleeve rod threaded wall driving device, a middle core rod threaded wall and a middle core rod threaded wall driving device; the sleeve rod is sleeved on the central core rod and can axially slide along the central core rod; the sleeve rod thread wall is arranged on the outer side of the sleeve rod, and the sleeve rod thread wall are connected through a sleeve rod thread wall driving device; the middle core rod thread wall is arranged on the outer side of the middle core rod, and the middle core rod thread wall and the middle core rod are connected through a middle core rod thread wall driving device; the sleeve rod thread wall and the middle core rod thread wall can be enclosed into a complete thread column.
Furthermore, the loop bar threaded wall driving device comprises four loop bar bidirectional hydraulic oil cylinders which are equally divided into two groups and symmetrically arranged on two sides of the loop bar, and output ends of the loop bar bidirectional hydraulic oil cylinders are connected to the loop bar threaded wall.
Furthermore, the output directions of the two loop bar bidirectional hydraulic oil cylinders on the same side are intersected; two ends of the loop bar bidirectional hydraulic oil cylinder are respectively hinged with the loop bar and the loop bar thread wall.
Furthermore, the driving device for the threaded wall of the center core rod comprises four center core rod bidirectional hydraulic cylinders, the four center core rod bidirectional hydraulic cylinders are divided into two groups and symmetrically arranged on two sides of the center core rod, and the output ends of the center core rod bidirectional hydraulic cylinders are connected to the threaded wall of the center core rod.
Furthermore, the output directions of the two-way hydraulic oil cylinders of the two center core rods on the same side are intersected; two ends of the two-way hydraulic cylinder of the central core rod are respectively hinged with the threaded wall of the central core rod and the threaded wall of the central core rod.
Furthermore, two symmetrical axial grooves are formed in the side wall of the loop bar, and a limiting cap is arranged at one end of the loop bar.
Furthermore, the middle part of the central core rod is provided with a limiting block matched with the limiting cap.
Furthermore, the sleeve rod thread wall and the middle core rod thread wall are both two thread walls with the same structure, and when the limiting cap is contacted with the limiting block, the two sleeve rod thread walls and the two middle core rod thread walls enclose a complete thread column.
Further, the thread of the threaded post surface is a continuous thread.
Further, a hole forming method of the concrete bored screw pile comprises the following steps:
lifting the sleeve rod to make the thread wall of the sleeve rod and the thread wall of the central core rod staggered up and down;
the bidirectional hydraulic cylinder is contracted to enable the threaded wall of the sleeve rod and the threaded wall of the central core rod to be in a folded state;
after a conventional straight-wall cast-in-place pile hole is formed, the device is put to the bottom of the hole or a set depth position, and the inner diameter of the selected device is the same as the aperture of the conventional cast-in-place pile hole;
extending the two-way hydraulic oil cylinder on the middle core rod to ensure that the threaded wall of the middle core rod is unfolded under the action of the upper and lower guide grooves and the hydraulic oil cylinder;
lowering the sleeve rod to the bottom to expand the threaded wall of the sleeve rod under the action of the upper and lower guide grooves and the hydraulic oil cylinder to form an integral structure together with the threaded wall of the central core rod;
the pile is rotated and lifted upwards along the thread direction, and the rotation and lifting speed is ensured to ensure that the threads formed on the hole wall and the soil body around the pile do not generate vertical relative displacement;
when the pile rotates and is lifted to the hole opening or the set height, the sleeve rod thread wall is firstly folded and lifted, then the central core rod thread wall is folded, and finally the pile hole is lifted, so that the hole forming work of the concrete cast-in-situ bored pile is completed.
Compared with the prior art, the invention has the following technical effects:
the loop bar can move up and down on the central core bar, the loop bar thread wall is connected with the loop bar through the bidirectional hydraulic oil cylinder, the central core bar thread wall is connected with the central core bar through the bidirectional hydraulic oil cylinder, and the folding and the extension of the thread wall are realized through the expansion of the hydraulic oil cylinder and the restriction of the guide grooves on the central core bar and the loop bar. In the construction process of the cast-in-situ bored pile, after the conventional straight-wall cast-in-situ bored pile is formed into a hole, the device is adopted to be lifted to the hole opening from the bottom of the pile hole in a rotating mode, a thread-shaped structure is formed on the hole wall, and the side friction between the pile and the soil is increased, so that the bearing capacity of a pile foundation is improved on the premise that the pile diameter is not changed, or the pile diameter or the pile length can be reduced when the requirement of the bearing capacity is met, and the purpose of saving the construction cost is achieved.
Drawings
FIG. 1 is a general schematic of the present invention;
FIG. 2 is an isometric view of a loop bar
FIG. 3 is a perspective view of a mandrel
FIG. 4 is a combination view of a loop bar and a center bar
FIG. 5 is an isometric view of a threaded wall of a loop bar
FIG. 6 is an isometric view of the threaded wall of the core rod
FIG. 7 is a schematic representation of a process: complete folding of the device
FIG. 8 in use: center pin threaded wall extension
FIG. 9 shows the device about to fully extend during use
Figure 10 full extension of the device during use
Wherein: 1, a central core rod; 2, sleeving a rod; 3, a sleeve rod thread wall; 4, a loop bar bidirectional hydraulic oil cylinder; 5 a core rod threaded wall; 6, a two-way hydraulic oil cylinder of the central core rod; 11, a limiting cap; 21 a limiting block.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
referring to fig. 1 to 9, an object of the present invention is to provide a hole forming device and a hole forming method for a concrete bored and cast-in-place screw pile, which can improve bearing capacity without changing pile diameter and pile length, or can reduce pile diameter and pile length reasonably while satisfying the requirement of bearing capacity, thereby saving construction cost.
The invention adopts the following technical scheme: the pore-forming device comprises a central core rod, a loop bar thread wall, a central core rod thread wall, an underwater bidirectional hydraulic oil cylinder and other main components, wherein the loop bar can move up and down on the central core rod, the loop bar thread wall is connected with the loop bar through the bidirectional hydraulic oil cylinder, the central core rod thread wall is connected with the central core rod through the bidirectional hydraulic oil cylinder, and the gathering and the extension of the thread wall are realized through the extension and the contraction of the hydraulic oil cylinder and the restriction of guide grooves on the central core rod and the loop bar.
The invention relates to a hole forming device and a method for a concrete bored pile, which are shown in figure 1, in the construction process, on the basis of the hole forming of a conventional bored pile, the device is folded, put to the bottom of a hole, extended at the bottom of the hole, rotated and lifted to a pile mouth or a set height, the hole wall of a cylindrical surface is extruded into a thread shape, in the process, the rotation and lifting speed are required to ensure that screw threads formed on the hole wall and the soil body around the pile do not generate vertical relative displacement, and after the hole is lifted out of an orifice by rotation, a steel reinforcement cage is put down to pour concrete or the concrete is directly poured to form the concrete threaded pile.
The method of use of the present invention is described in further detail below:
in the concrete drilling and pouring process of the screw pile, the concrete method using the device is as follows:
firstly, lifting a sleeve rod of the device to enable the thread wall of the sleeve rod and the thread wall of the central core rod to be staggered up and down;
contracting the bidirectional hydraulic cylinder to enable the sleeve rod thread wall and the central core rod thread wall to be in a furled state;
thirdly, after the conventional straight-wall cast-in-place pile hole is formed, the device is put down to the bottom of the hole or a set depth, and the inner diameter of the selected device is the same as the aperture of the conventional cast-in-place pile; the inner diameter of the device is selected to be the diameter of the cylinder formed after the threads are removed.
Fourthly, stretching the two-way hydraulic oil cylinder on the middle core rod to enable the threaded wall of the middle core rod to be unfolded under the action of the upper and lower guide grooves and the hydraulic oil cylinder;
lowering the sleeve rod to the bottom to expand the threaded wall of the sleeve rod under the action of the upper and lower guide grooves and the hydraulic oil cylinder to form an integral structure together with the threaded wall of the middle core rod;
sixthly, the pile head rotates upwards along the direction of the thread and is lifted, and the rotation and lifting speed ensures that the thread formed on the hole wall and the soil body around the pile do not generate vertical relative displacement;
and seventhly, when the pile is rotated and lifted to an orifice or a set height, the threaded wall of the sleeve rod is firstly folded, the sleeve rod is lifted, then the threaded wall of the central core rod is folded, and finally the pile hole is lifted out, so that the hole forming work of the concrete drilling and pouring threaded pile is completed.