CN106351585A - Hole collapse and shrinkage prevention bidirectional spiral extrusion and expansion drilling tool and construction technology thereof - Google Patents

Abstract

The invention discloses a two-way helical extruding and expanding drilling tool for anti-collapse holes and diameter reduction and its construction technology. The bottom end of the drill pipe is connected with a two-way helical extruding and expanding drill bit, the top is provided with a connecting piece, and the drill pipe is provided with a steel casing , The steel casing and the drill pipe are connected by a flange, and a centering bracket is provided on the outer wall of the drill pipe to stabilize the steel casing. The invention is technically feasible, simple in structure, economical and practical. Using this kind of drilling tool to construct the spiral squeezed soil grouting pile, the steel casing is lowered or lifted synchronously with the drill bit, and the side of the pile hole after the extrusion and expansion is completed and before the slurry material is pressed and poured can be timely repaired. Rigid retaining walls are used to prevent hole collapse and diameter shrinkage, and improve the pile quality of spiral squeezed soil piles. It is suitable for various complex strata including silt and soft clay.

Description

A two-way helical extruding and expanding drilling tool with anti-collapse and diameter reduction and its construction technology

technical field

The invention relates to a two-way helical extruding and expanding drilling tool for anti-slump holes and diameter reduction used in the field of pile foundation engineering and its construction technology.

Background technique

In the field of pile foundation engineering, according to the influence of pile formation on the stratum, piles are generally divided into three categories: non-squeezed soil piles, partial soil-squeezed piles and fully-soil-squeezed piles. Because there are many problems in technology, environmental protection and cost of non-squeeze piles (such as bored piles, punched piles, CFA piles, etc.), the pile foundation engineering circle has been committed to developing a kind of pile with high bearing capacity, less pollution to the construction environment, A new type of soil-squeezing pile with good economic benefits. In recent years, China Jingye Engineering Technology Co., Ltd. has successfully developed a completely soil-squeezing spiral soil-squeezing cast-in-place pile. During construction, the specially designed spiral extrusion drill bit/drilling tool squeezes the soil in the original pile hole to the side of the pile hole. The wall does not discharge the ground, which improves the physical and mechanical properties of the soil around the pile, and increases the bearing capacity of the pile foundation. At the same time, there is no pollution, no vibration, and low noise during the entire construction process. At present, its representative patents are as follows:

Application No. 200710063983.3 "Construction method of two-way spiral extruded pile and two-way spiral closed extruded drill bit" invention patent

Application No. 201010172621.X "Adjustable Multi-stage Helical Extrusion Expansion Drilling Tool" Invention Patent

Application No. 201010177548.5 "Bidirectional Helical Squeeze Expansion Drill Bit with Controllable Squeeze Volume" Invention Patent

Application No. 201020169448.3 utility model patent for "extendable two-way helical extrusion drill bit"

However, when using the above-mentioned drill bits/drilling tools in some special formations, such as silt or high water content soft clay formations, or when the pile depth is relatively deep, after the pile hole is squeezed and expanded, the pile before the grouting material is pressed The side wall of the hole is prone to hole collapse or diameter shrinkage, which will cause problems such as mud inclusion in the pile body and excessive sediment at the bottom of the pile, which will reduce the quality of the pile.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a two-way spiral extrusion and expansion that can effectively prevent the anti-collapse hole and diameter reduction during the construction of the spiral extrusion soil grouting pile in a technically feasible, simple in structure, economical and practical manner. Drilling tools and their construction techniques.

The technical solution adopted in the present invention is: a bi-directional helical extruded expansion drilling tool for anti-collapse and diameter reduction, including a hollow drill pipe, a bi-directional helical extruded and expanded drill bit, connectors, a steel casing and a centering bracket;

The bottom end of the hollow drill pipe is connected with a two-way helical extruding drill bit, the top of the hollow drill pipe is provided with a connecting piece, the periphery of the hollow drill pipe is provided with a steel casing, and the outer wall of the hollow drill pipe near the connecting piece is welded with a A ring of flange 1, a ring of flange 2 is welded on the outer wall of the top of the steel casing, and the flange 1 and flange 2 are matched and connected into a whole by bolts; the hollow drill pipe Several centering brackets are welded on the outer wall of the outer wall, and the centering brackets are located under the first flange and the second flange.

As a preference, the material of the steel casing is Q235 steel, and the length of the steel casing is: extending from the outer wall flange of the hollow drill pipe to the top of the bidirectional helical extruding drill bit; the wall thickness of the steel casing is 5-10mm between.

Preferably, the outer diameter of the centering bracket is slightly smaller than the inner diameter of the steel casing, and the inner diameter of the steel casing is equal to the maximum outer diameter of the bidirectional helical expansion drill bit.

Preferably, the pipe wall at the bottom end of the steel casing is made into a blade foot.

The construction technology of using the above-mentioned drilling tool to implement the spiral squeezed soil grouting pile includes the following steps:

1) Put the piling drilling rig equipped with anti-collapse holes and bi-directional helical extruding and expanding drilling tools with reduced diameters in place according to the setting-out position of the pile holes, and prepare the concrete pump and the required pile materials. The pile material is concrete slurry material or cement fly ash crushed stone slurry material and steel cage.

2) Start the piling drilling rig to apply right-handed torque and vertical pressure, and use the two-way helical extrusion drill bit to perform down-rotation extrusion to form holes. During this process, the steel casing descends synchronously with the hollow drill bit, and the extrusion can be completed in time. Finally, the side wall of the upper pile hole is protected to prevent hole collapse and diameter reduction, and the hole is expanded by rotary extrusion until the drill bit reaches the designed hole depth.

3) After the first step of rotary extrusion and expansion is completed, start the pile drilling rig to apply right-handed torque and upward axial pulling force, so that the two-way helical extrusion and expansion drill bit moves upward and rotates to expand the pile hole again. During this process, start the grouting pump, press the grouting material to the pile hole through the hollow channel of the hollow drill pipe, squeeze and expand the grouting material pressure, so that the diameter of the pile hole that has been grouted and grouted meets the design requirements, and the unpressed grouting material The pile hole section will not collapse and shrink under the retaining wall of the steel casing. In the second step, the rotary extrusion and expansion grouting process continues until the hollow drill bit is lifted to the surface.

4) According to the design requirements, according to the known method, insert the prepared reinforcement cage into the grout material of the pile hole, so far the cylindrical spiral squeezed soil grouting pile is formed.

Beneficial effects of the present invention: 1) By adding a steel casing outside the drill pipe, the steel casing is lowered and lifted together with the two-way helical extrusion and expansion drill bit when the drill is run in and lifted, so that after the extrusion and expansion are completed, before pressing the grouting material, the steel casing is lowered and lifted. The rigid retaining wall function of the pile hole wall prevents hole collapse and diameter shrinkage in silt and soft clay strata. 2) By adding a centering bracket on the outer wall of the drill pipe, the steel casing has a supporting and stabilizing effect on the steel casing after the steel casing is placed on the drill pipe, and the steel casing will not swing left and right to disturb the side of the pile hole during drilling and lifting wall soil, and the pile hole has a higher verticality. 3) The pipe wall at the bottom end of the steel casing is made into a sharp blade foot. When the steel casing descends with the drill bit, the sinking resistance can be reduced, and at the same time, the soil or stones adhering to the wall of the pile hole can be cut to make the pile hole The walls are smoother.

Description of drawings

Fig. 1 is a kind of anti-collapse hole of the present invention and the two-way helical extruded expanding drilling tool structure schematic diagram of reducing diameter;

Fig. 2 is a schematic diagram of the connection between the steel casing and the drill rod of a two-way helical extruded and expanded drilling tool for anti-collapse holes and reduced diameters of the present invention;

Fig. 3 is a schematic diagram of the steel casing bottom pipe wall edge foot of a bidirectional helical extruded and expanded drilling tool for anti-collapse holes and diameter reduction in the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1-3, a bi-directional helical expansion drilling tool with anti-collapse hole and reduced diameter includes hollow drill pipe 1, bi-directional helical expansion drill bit 2, connector 3, steel casing 4 and centering bracket 8 ;

The bottom end of the hollow drill pipe 1 is connected with a two-way helical extruding drill bit 2, the top of the hollow drill pipe 1 is provided with a connecting piece 3, the periphery of the hollow drill pipe 1 is provided with a steel casing 4, and the vicinity of the connecting piece 3 is hollow. A ring of flange 1 5 is welded on the outer wall of the drill pipe 1, and a ring of flange 2 6 is welded on the outer wall of the top end of the steel casing 4, and the flange 1 5 is matched with the flange 2 6, It is connected as a whole by bolts 7; several centering brackets 8 are welded on the outer wall of the hollow drill pipe 1, and the centering brackets 8 are located under the first flange 5 and the second flange 6.

The material of the steel casing 4 is Q235 steel, and the length of the steel casing 4 is: extending from the outer wall flange-5 of the hollow drill rod 1 to the top of the two-way helical extruding and expanding drill bit 2; the wall thickness of the steel casing 4 is at Between 5 and 10mm. The outer diameter of the centering bracket 8 is slightly smaller than the inner diameter of the steel casing 4 , and the inner diameter of the steel casing 4 is equal to the maximum outer diameter of the two-way helical expansion drill bit 2 . Described steel casing 4 bottom end tube walls are made blade foot.

Using the present invention to implement the construction technology of spiral squeezed soil grouting pile, comprises the following steps:

1) Put the piling drilling rig equipped with anti-collapse holes and bi-directional helical extruding and expanding drilling tools with reduced diameters in place according to the setting-out position of the pile holes, and prepare the concrete pump and the required pile materials. The pile material is concrete slurry material or cement fly ash crushed stone slurry material and steel cage.

2) Start the piling drilling rig to apply right-handed torque and vertical pressure, and use the two-way helical extrusion drill bit to perform down-rotation extrusion to form holes. During this process, the steel casing descends synchronously with the hollow drill bit, and the extrusion can be completed in time. Finally, the side wall of the upper pile hole is protected to prevent hole collapse and diameter reduction, and the hole is expanded by rotary extrusion until the drill bit reaches the designed hole depth.

3) After the first step of rotary extrusion and expansion is completed, start the pile drilling rig to apply right-handed torque and upward axial pulling force, so that the two-way helical extrusion and expansion drill bit moves upward and rotates to expand the pile hole again. During this process, start the grouting pump, press the grouting material to the pile hole through the hollow channel of the hollow drill pipe, squeeze and expand the grouting material pressure, so that the diameter of the pile hole that has been grouted and grouted meets the design requirements, and the unpressed grouting material The pile hole section will not collapse and shrink under the retaining wall of the steel casing. In the second step, the rotary extrusion and expansion grouting process continues until the hollow drill bit is lifted to the surface.

4) According to the design requirements, according to the known method, insert the prepared reinforcement cage into the grout material of the pile hole, so far the cylindrical spiral squeezed soil grouting pile is formed.

It should be pointed out that those skilled in the art can make some improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention. All components that are not specified in this embodiment can be realized by existing technologies.

Claims (5)

1. A two-way helical extruded expansion drilling tool for anti-collapse holes and reduced diameter, characterized in that: it includes a hollow drill rod, a bidirectional helical extruded and expanded drill bit, a connector, a steel casing and a centering bracket; The bottom end of the hollow drill pipe is connected with a two-way helical extruding drill bit, the top of the hollow drill pipe is provided with a connecting piece, the periphery of the hollow drill pipe is provided with a steel casing, and the outer wall of the hollow drill pipe near the connecting piece is welded with a A ring of flange 1, a ring of flange 2 is welded on the outer wall of the top of the steel casing, and the flange 1 and flange 2 are matched and connected into a whole by bolts; the hollow drill pipe Several centering brackets are welded on the outer wall of the outer wall, and the centering brackets are located under the first flange and the second flange. 2. A bidirectional helical extruded and expanded drilling tool for anti-collapse holes and diameter reduction according to claim 1, characterized in that: the material of the steel casing is Q235 steel, and the length of the steel casing is: from the hollow drill The flange on the outer wall of the rod extends to the top of the two-way helical extruding drill bit; the wall thickness of the steel casing is between 5 and 10 mm. 3. A bi-directional helical extruded and expanded drilling tool for anti-collapse holes and reduced diameter according to claim 1, characterized in that: the outer diameter of the centering bracket is slightly smaller than the inner diameter of the steel casing, and the steel casing The inner diameter is equal to the maximum outer diameter of the two-way helical expansion drill bit. 4. A bi-directional helical extruded and expanded drilling tool for anti-collapse holes and diameter reduction according to claim 1, characterized in that: the pipe wall at the bottom end of the steel casing is made into a blade foot. 5. A construction technique for using the anti-collapse hole described in claim 1, 2, 3 or 4 and the two-way helical extruding and expanding drilling tool of reducing diameter to implement the spiral extruding soil grouting pile, it is characterized in that: comprise the following steps: 1) Put the piling drilling rig equipped with anti-collapse holes and bi-directional helical extrusion and expansion drilling tools with reduced diameters in place according to the position of the pile hole, and prepare the concrete pump and the required pile materials; the pile materials are concrete slurry or cement powder Fly ash crushed stone slurry material and steel cage; 2) Start the pile drilling rig to apply right-handed torque and vertical pressure, and use the two-way helical extrusion drill bit to expand the hole. During this process, the steel casing descends synchronously with the hollow drill bit, and the extrusion can be completed in time. After that, the side wall of the upper pile hole shall be protected to prevent the hole from collapsing and shrinking, and the hole shall be expanded by rotary extrusion until the drill bit reaches the designed hole depth; 3) After the first step of rotary extrusion and expansion is completed, start the pile drilling rig to apply right-handed torque and upward axial pulling force, so that the two-way spiral extrusion drill bit moves upward and rotates again to expand the pile hole. During this process, start the grouting pump, press the grouting material to the pile hole through the hollow channel of the hollow drill pipe, squeeze and expand the grouting material pressure, so that the diameter of the pile hole that has been grouted and grouted meets the design requirements, and the unpressed grouting material The pile hole section will not collapse and shrink under the retaining wall of the steel casing. In the second step, the rotary extrusion grouting process continues until the hollow drill bit is lifted to the surface; 4) According to the design requirements, according to the known method, insert the prepared reinforcement cage into the grout material of the pile hole, so far the cylindrical spiral squeezed soil grouting pile is formed.