CN114876377A

CN114876377A - Large-diameter full-section squeezing-expanding cast-in-place pile equipment and construction process

Info

Publication number: CN114876377A
Application number: CN202210547127.XA
Authority: CN
Inventors: 马志华; 李东森; 孙双福; 刘小江; 乔志军; 岳安华; 付威; 权力; 刘兰芳; 王�华; 郭琦; 程玉彬; 张明月; 吴若飞; 郝学刚; 戴沛冰
Original assignee: First Engineering Bureau Of Henan Water Conservancy
Current assignee: First Engineering Bureau Of Henan Water Conservancy
Priority date: 2022-05-20
Filing date: 2022-05-20
Publication date: 2022-08-09
Anticipated expiration: 2042-05-20
Also published as: CN114876377B

Abstract

The invention discloses large-diameter full-section extrusion-expansion cast-in-place pile equipment which comprises a rotary drilling rig, wherein the bottom of a drill rod of the rotary drilling rig is connected with an extrusion-expansion drill bit and a rotary drilling bit, the extrusion-expansion drill bit is provided with a shell, the whole shell is in a circular truncated cone shape with a large upper part and a small lower part, and the shell of the extrusion-expansion drill bit is in rotating fit with the drill rod through a first rotating fit structure; a plurality of extruding and expanding vertical holes are uniformly formed in the side wall of the shell of the extruding and expanding drill bit along the circumferential direction, and the extruding and expanding vertical holes extend downwards from the top of the side wall of the shell of the extruding and expanding drill bit to the bottom end of the side wall of the shell; the shell is internally provided with a squeezing and expanding mechanism corresponding to the squeezing and expanding vertical holes. The invention also discloses a corresponding construction process, wherein the rotary drilling bit and the extruding and expanding bit are connected together to perform vertical full-section extruding and expanding hole forming; the squeezing and expanding are separated from the rotating action, so the required torque is greatly reduced, and the strength requirement on equipment materials is also greatly reduced.

Description

Large-diameter full-section squeezing-expanding cast-in-place pile equipment and construction process

Technical Field

The invention relates to the field of foundation engineering construction, in particular to large-diameter full-section extrusion-expansion cast-in-place pile equipment and a construction process.

Background

The cast-in-place piles can be divided into a large number of soil-squeezing piles (such as immersed tube cast-in-place piles and spiral soil-squeezing cast-in-place piles), a small number of soil-squeezing piles (such as squeezed branch plate cast-in-place piles) and non-soil-squeezing piles (such as manually digging, drilling and punching, grabbing and digging holes) according to the influence degree of the holes on the soil.

The construction process of the concrete cast-in-place pile with the non-soil-squeezing pore-forming hole by rotary drilling is widely applied to basic engineering, but the quality problems of hole collapse, necking down, pile breaking and the like are easy to occur in compressible rock stratum such as filling, clay powder soil, loess and the like, particularly when the underground water is buried to a shallow depth. The wall protection slurry is a technical means for preventing the hole collapse in the prior art, but has great pollution to soil.

The spiral soil-squeezing filling pile utilizes a spiral soil-squeezing pore-forming technology, soil is not required to be produced, a mud retaining wall is not required, soil squeezing and hole expanding are carried out in the circumferential direction, common quality problems of the bored filling pile such as hole collapse and necking are really avoided, and the bearing capacity of the foundation is increased. The drill bit of the soil-squeezing cast-in-place pile process is similar to a screw and rotates downwards to squeeze into the soil body, and the soil body with the vertical full length of the drilled hole is squeezed into the soil body outside the drilled hole, so that the process belongs to a large amount of soil-squeezing processes. Because the key technology (spiral soil extrusion) of the spiral soil extrusion pile is stress in the 360-degree (circumferential) direction, the spiral soil extrusion pile needs large torque and is limited by the existing equipment, and the spiral soil extrusion pile is not suitable for a concrete cast-in-place pile with the diameter larger than 800 mm. When the diameter of the drilled hole is larger than 800 mm, the torque of the spiral soil squeezing device cannot be achieved (the device does not rotate at all when squeezing soil). Even if torque is achieved, the device is very vulnerable to damage under the action of large torque. In fact, the large torque contribution has also resulted in equipment that is prone to seizing (i.e., stalling) when the borehole diameter approaches 800 mm. The current situation results in that the existing large-amount soil-squeezing cast-in-place pile technology cannot be applied to large-diameter drilling construction.

A small amount of soil-squeezing piles (such as squeezed branch-disk filling piles) are suitable for drilling construction of large-diameter filling piles, and in the prior art, a rotary drilling bit is used for rotary drilling, and then soil squeezing and hole expanding operation (referred to as squeezed expansion for short) is carried out on local (referring to local cross sections in the vertical direction instead of vertical full-length full-cross sections) parts. The soil is locally squeezed, and the soil which is rotationally lifted outside the hole does not need to be squeezed, so the method belongs to a small amount of soil squeezing technology. According to the construction mode, not only is additional power equipment required to be added, but also the time difference between rotary drilling operation and squeezing and expanding operation is large, so that mud is required to protect the wall of a drilled hole which is already rotary drilled, hole collapse is prevented, the working procedures are increased by using the mud to protect the wall, the construction efficiency is reduced, the construction cost is improved, and pollution is caused.

Disclosure of Invention

The invention aims to provide large-diameter full-section extruding and expanding cast-in-place pile equipment, which greatly reduces torque required during extruding and expanding operation and provides basic conditions for rotary excavating and extruding and expanding integrated operation of a large-diameter cast-in-place pile hole.

In order to achieve the purpose, the large-diameter full-section extrusion-expansion cast-in-place pile equipment comprises a rotary drilling rig, wherein the rotary drilling rig is provided with a drill rod, the bottom end of the drill rod is connected with a rotary drilling bit, an extrusion-expansion drill bit is mounted on the drill rod above the rotary drilling bit and is provided with a shell, the whole shell is in a circular truncated cone shape with a large upper part and a small lower part, and the shell of the extrusion-expansion drill bit is in rotating fit with the drill rod through a first rotating fit structure;

a plurality of extruding and expanding vertical holes are uniformly formed in the side wall of the shell of the extruding and expanding drill bit along the circumferential direction, and the extruding and expanding vertical holes extend downwards from the top of the side wall of the shell of the extruding and expanding drill bit to the bottom end of the side wall of the shell;

the shell is internally provided with an extruding and expanding mechanism corresponding to the extruding and expanding vertical holes, and the extruding and expanding mechanism is in rotating fit with the drill rod through a second rotating fit structure;

the extruding and expanding mechanism comprises a plurality of strip-shaped soil extruding plates which are in one-to-one correspondence with the plurality of extruding and expanding vertical holes, and the inclination angles of the soil extruding plates and the generatrix of the truncated cone-shaped shell are the same; the soil squeezing plate periodically extends out of the squeezing and expanding vertical hole and is periodically collected into the shell under the driving of the drill rod, and the soil squeezing plate squeezes a soil body to expand the hole when extending out of the squeezing and expanding vertical hole;

the squeezing and expanding mechanism is connected with the drill rod through a clutch mechanism, and the clutch mechanism is structurally matched with the squeezing and expanding mechanism, so that when the squeezing and expanding mechanism is driven by the drill rod, the soil squeezing plate is positioned in the squeezing and expanding vertical hole and drives the shell to rotate, and when the soil squeezing plate extends out of the squeezing and expanding vertical hole, the squeezing and expanding mechanism is separated from the drill rod for transmission; in the single transmission process of the squeezing and expanding mechanism and the drill rod, the rotation angle of the soil squeezing plate driving the shell is the same as the angle of a central angle alpha occupied by the soil squeezing plate in the circumferential direction of the shell.

The first rotating fit structure is: the top end of the shell is provided with a top plate, and the lower part of the shell is provided with a bottom plate higher than the bottom end of the shell;

the top plate is downwards supported on the outer ring of the upper support bearing, and the inner ring of the upper support bearing is fixedly connected to the drill rod;

the bottom plate is downwards supported on the outer ring of the lower support bearing, and the inner ring of the lower support bearing is fixedly connected to the drill rod;

the second rotating fit structure is as follows: the top of the squeezing and expanding mechanism is connected with an upper connecting cylinder, the upper connecting cylinder is fixedly connected with an outer ring of a first supporting bearing, an inner ring of the first supporting bearing is fixedly connected to the drill rod, and the squeezing and expanding mechanism and the first supporting bearing are both lower than the top plate; the bottom of the squeezing and expanding mechanism is connected with a lower connecting cylinder, the lower connecting cylinder is fixedly connected with an outer ring of a second supporting bearing, an inner ring of the second supporting bearing is fixedly connected to the drill rod, and the bottom end of the squeezing and expanding mechanism and the second supporting bearing are both lower than the bottom plate and higher than the bottom end of the shell; the bottom plate and the vertical extruding and expanding holes are provided with a plurality of notches which are used for radial expansion of the extruding and expanding mechanism in a one-to-one correspondence mode, and the notches are communicated with the vertical extruding and expanding holes.

Four squeezing-expanding vertical holes are uniformly distributed along the circumferential direction of the side wall of the shell;

the squeezing and expanding mechanism also comprises an upper squeezing and expanding device connected with the top of the soil squeezing plate and a lower squeezing and expanding device connected with the bottom of the soil squeezing plate; the upper extruding and expanding device and the lower extruding and expanding device are respectively provided with four sets of soil extruding plates in one-to-one correspondence;

the four cams are fixedly connected to the drill rod and are of an axisymmetric structure and a centrosymmetric structure;

the four-top cam is provided with four vertexes which are uniformly distributed in the circumferential direction of the four-top cam, namely an A vertex, a B vertex, a C vertex and a D vertex; the center of the four cams is O point, AO = CO, BO = DO, and AO > BO; the vertex A and the vertex C are called long vertices, and the vertex B and the vertex D are called short vertices; the long vertexes and the short vertexes are alternately and uniformly distributed in the circumferential direction;

two cams are arranged at intervals up and down on the four top cams;

the upper extruding and expanding device and the lower extruding and expanding device have the same structure, each upper extruding and expanding device corresponds to one four-top cam, and each lower extruding and expanding device corresponds to one four-top cam; the upper extruding and expanding device and the lower extruding and expanding device are collectively called as extruding and expanding devices,

the radial direction of the drill rod is taken as the radial direction, and the structure of the squeezing and expanding device is as follows:

the soil squeezing device comprises a cross rod, wherein the radial outer end of the cross rod is connected with a soil squeezing plate; the cross rod penetrates through the hanging ring in a sliding mode, and the radial outer end part of the cross rod is supported on the hanging ring in a sliding mode; the upper connecting cylinder and the lower connecting cylinder are called as connecting cylinders in a unified mode, and the radial inner end of the cross rod penetrates through the connecting cylinders and is in movable jacking fit with the four cams;

the first support bearing and the second support bearing are collectively called as squeezing support bearings; the upper connecting cylinder and the lower connecting cylinder are collectively called as vertical connecting cylinders, the radial outer end of the outer ring of the extruding and expanding support bearing is upwards connected with the vertical connecting cylinders, and the inner end parts of the cross rods penetrate through the vertical connecting cylinders and are supported on the vertical connecting cylinders in a sliding manner; the four cams are positioned in the vertical connecting cylinder;

in the rotation of the four-top cam, the cross rod is positioned at the extending limit position when contacting with the long top point, and is positioned at the retracting limit position when contacting with the short top point; the cross rod is in a state of being supported on the hanging ring in a sliding mode and being in movable compression joint with the vertical connecting cylinder in the stroke range;

a clamping block is arranged at the bottom of the cross rod downwards, and a tension spring is connected between the clamping block and the vertical connecting cylinder;

the lifting ring of the upper extruding and expanding device is upwards fixedly connected with the top plate, and the lifting ring of the lower extruding and expanding device is upwards fixedly connected with the bottom plate;

the tension spring applies centripetal recovery tension to the soil squeezing plate through the clamping block and the cross rod in work, when the four cams rotate to the long top to be connected with the cross rod, the corresponding cross rod is pushed outwards to the extended limit position, and at the moment, the corresponding soil squeezing plate radially extends out of the shell; when the radial inner ends of the four cross rods are simultaneously positioned at the midpoint position between two adjacent vertexes of the four cams, the four soil squeezing plates are all positioned in the corresponding squeezing vertical holes, and the outer surfaces of the soil squeezing plates are all parallel and level to the outer surface of the shell;

when the four cams rotate to the short vertices to meet the cross bars, the corresponding cross bars are pulled inward to the retracted extreme position with the corresponding soil squeezing plates inside the housing.

The top of the rotary drilling bit is fixedly connected with a gear ring, and a gap between adjacent teeth in the gear ring is called as a transmission gap; the transmission gap is matched with the clamping block; a fixture block of the lower extruding and expanding device passes through the transmission gap when performing radial telescopic motion along with the cross rod, and the fixture block and the gear ring are in a transmission state when passing through the transmission gap and rotate together with the gear ring under the drive of the gear ring;

the clamping blocks pass through the transmission gaps outwards or inwards along the radial direction, simultaneously the soil squeezing plates synchronously pass through the squeezing expanded vertical holes outwards or inwards, at the moment, the soil squeezing plates and the shell are in a transmission state, and the clamping blocks drive the shell to synchronously rotate through the cross rods and the soil squeezing plates; the clamping block is separated from the transmission state with the gear ring after leaving the transmission gap.

The invention also discloses a construction process which is carried out by adopting the large-diameter full-section extruding-expanding cast-in-place pile equipment, is suitable for the drilling construction of the concrete cast-in-place pile and is carried out according to the following steps:

the first step is to measure the positioning;

measuring and paying off according to the designed pile position, installing a pile casing, and positioning a rotary drilling rig;

the second step is drill bit installation;

determining the radial compression amount of the hole wall to be M cm under a specific geological condition through a test; determining the structural parameters of the squeezing and expanding drill bit according to the matching of the M value and the preset hole diameter X;

the diameter of the rotary drilling bit is larger than or equal to the diameter of the bottom of the shell of the squeezing and expanding bit, and the diameter of the rotary drilling bit is smaller than the diameter of the top of the shell of the squeezing and expanding bit;

after the rotary drilling rig is in place, splicing the rotary drilling bit, the squeezing and expanding bit and the drill rod together and sinking into the protective cylinder;

thirdly, rotary excavating, extruding and expanding to form holes;

starting a drilling machine, driving a rotary drilling bit to carry out earth digging operation by a drill rod, continuously rotating a four-top cam under the driving of the drill rod, driving a cross rod to reciprocate in the horizontal direction by the four-top cam and a tension spring together, and enabling a clamping block to reciprocate along with the cross rod;

in the reciprocating motion, when the fixture block does not pass through the transmission gap, the squeezing and expanding drill bit is in a rotating intermittent state, and when the fixture block passes through the transmission gap, the squeezing and expanding drill bit is in a rotating state;

the radial inner ends of four cross rods of the squeezing and expanding device are simultaneously positioned at four vertexes of the four cams or at a position between two adjacent vertexes; when the radial inner ends of the four cross rods are simultaneously positioned at the midpoint position between two adjacent vertexes of the four cams, the four soil squeezing plates are all positioned in the corresponding squeezing-expanding vertical holes; the soil squeezing plates distributed at 180 degrees are called a pair of soil squeezing plates, and the four soil squeezing plates form two pairs of soil squeezing plates; with the rotation of the four cams, when one pair of the soil squeezing plates passes through the squeezing and expanding vertical hole from inside to outside, the other pair of the soil squeezing plates simultaneously passes through the squeezing and expanding vertical hole from outside to inside; after the pair of soil squeezing plates pass through the squeezing and expanding vertical hole from inside to outside, the hole wall of the squeezing and drilling hole of the pair of soil squeezing plates is squeezed and expanded;

the squeezing and expanding drill bit continuously and alternately performs squeezing and expanding and rotating actions along with the rotation of the drill rod, a gap with the sum of circumferential angles larger and larger is formed between the casing of the squeezing and expanding drill bit and the hole wall of the drill hole until an annular gap is formed between the casing of the squeezing and expanding drill bit and the hole wall of the drill hole, and at the moment, under the pressing action of the drill rod and the self-weight action of the squeezing and expanding drill bit and the rotary drilling bit, the squeezing and expanding drill bit falls to the hole wall of the drill hole along with the rotary drilling bit to support the squeezing and expanding drill bit;

during the third step, when the rotary drilling bit is full of soil, operating the drilling machine to carry out the lifting and drilling operation, and carrying out the third step again after unloading;

continuing to execute the third step until the hole is drilled to the designed depth;

the fourth step is wall protection by clean water;

one end of a water outlet of the water pipe is conveyed to the bottom of the drilled hole, and water is poured to protect the wall;

and fifthly, putting a reinforcement cage in the drilled hole, and pouring concrete to complete all the working procedures.

The radial compression amount of the hole wall is M cm, the length of the soil extrusion plate radially extending out of the casing of the extrusion-expansion drill bit is N cm, N is a real number, and N is one third to one seventh of M.

The invention has the following advantages:

the torque required by the conventional spiral soil squeezing is large because the soil squeezing equipment rotates and squeezes soil in the 360-degree (circumferential) direction at the same time, so that the soil squeezing area is large, and the shearing force on a soil body during rotation greatly increases the torque requirement.

The invention is stressed on two 180-degree lines, most of the two lines are not stressed in the circumferential direction at the same time, soil squeezing is only carried out at two local positions distributed at 180 degrees, the soil squeezing area at a single moment is greatly reduced compared with the prior art, the soil squeezing is not rotated (the soil squeezing plate extends out of the squeezing vertical hole, so that the squeezing mechanism is separated from the drill rod for transmission when the soil body is squeezed and expanded), and no shearing force is applied to the soil body, so that the required torque is greatly reduced, and the strength requirement on equipment materials is also greatly reduced.

The existing small amount of soil-extruding piles (such as extruded branch-plate filling piles) complete the radial extrusion amount at the same position at one time, so that the soil body is easy to be sheared and damaged, and larger stress resilience is easy to occur after the completion of the radial extrusion amount, thereby causing hole collapse.

The squeezing and expanding drill bit of the prior squeezing and expanding branch plate filling pile is of a structure capable of radially extending and contracting and extends into the hole in a contraction state; after the soil is stretched into the hole, the soil is radially expanded and sequentially squeezed in the circumferential direction.

The casing of the extruding and expanding drill bit is designed to be in a circular truncated cone shape with a large upper part and a small lower part, a foundation is provided for finishing radial extrusion amount for multiple times (N is one third to one seventh of M), and the amount of one part is extruded each time, and after each extrusion, an annular gap is formed between the casing of the extruding and expanding drill bit and a soil body, so that the extruding and expanding drill bit pair can automatically fall down; the casing is in a circular truncated cone shape with a large upper part and a small lower part, so that the casing can be automatically supported by soil. In the process of extruding soil for multiple times (to complete the total radial extrusion amount) at the same position, the stress rebound after the previous extrusion can be eliminated during the next extrusion, the stress rebound degree after the radial extrusion amount is completely completed is greatly reduced, the soil body cannot be sheared and damaged under the stress rebound effect, and thus hole collapse is avoided.

When the method is used for constructing the large-diameter (more than 800 mm in diameter) drill hole, the rotary drilling operation and the squeezing and expanding operation are carried out synchronously, so that the mud retaining wall is not needed, the working procedures are reduced, the construction efficiency is improved, the construction cost is reduced, the pollution caused by the mud retaining wall is avoided, and the method is green and environment-friendly.

The torque required by the squeezing and expanding process is greatly reduced, so that the drilling rod can be shared with the rotary drilling bit, and additional power is not required.

Through the clutch structure formed by the gear ring and the fixture block and matched in order, the invention realizes the regular intermittent rotation of the extruding and expanding drill bit while the rotary drilling drill bit rotates continuously, and provides basic conditions for carrying out multiple soil extruding actions in different angles in the circumferential direction and preventing the soil extruding plate from rotating during soil extruding. Because the gear ring and the clamping block are disengaged from the transmission fit when the soil-squeezing plate squeezes soil in the radial direction, the soil-squeezing plate does not rotate when squeezing soil, and the torque required when squeezing soil is greatly reduced.

The angle of rotation of the soil squeezing plate driving the shell is the same as the angle of a central angle of the soil squeezing plate occupied in the circumferential direction of the shell, so that the soil squeezing plate rotates along with the drill rod every time and then reaches the adjacent position of the previous soil squeezing plate, and the hole expanding position of the soil squeezing plate can gradually cover the circumferential surface of the whole drilling hole through continuous operation.

The first rotary engagement structure allows the housing to rotate relative to the drill rod. The second rotating fit structure can rotate relative to the drill rod by using the squeezing and expanding mechanism.

The soil squeezing plates and the squeezing and expanding vertical holes are arranged in pairs at 180 degrees, so that stress balance can be realized, and when soil is squeezed at 180 degrees, reaction forces from the soil can be mutually offset when the soil squeezing plates at two sides squeeze the soil; the number of the soil squeezing plates is six or other even numbers, but the more the number is, the more the structure is complex (the more the complex and the higher the cost is), the torque required for squeezing the soil is necessarily increased after the total area of the soil is increased, and the four squeezing-expanding vertical holes and the four soil squeezing plates are preferably arranged in a comprehensive consideration.

The extrusion expanding device of the invention positions the specific position of each cross rod by the combined action of the tension spring and the four cams. The four cams are in an axisymmetrical structure and are also in a centrosymmetric structure, so that the radial motion states of the two cross rods and the soil squeezing plate which are distributed at 180 degrees are always consistent. Two soil squeezing plates distributed at 180 degrees are used as a pair of soil squeezing plates, and the four soil squeezing plates form two pairs of soil squeezing plates. The long vertexes and the short vertexes are alternately and uniformly distributed in the circumferential direction, so that only one pair of soil squeezing plates extend out of the shell in opposite directions at the same time to squeeze soil, the two pairs of soil squeezing plates alternately extend out of the shell to squeeze soil, and the two pairs of soil squeezing plates are alternately retracted into the shell. When the soil is pressed, the two soil squeezing plates which are distributed at 180 degrees extend out simultaneously, the reaction force from the soil body is offset by the cross rod and the four cams, and the structural stress is better.

The soil squeezing plate not only has the soil squeezing function, but also has the transmission function of driving the shell to rotate; the clamping block not only has the functions of installing the tension spring and enabling the cross rod to contract centripetally, but also has the transmission function of rotating under the driving of the gear ring. When the clamping block leaves the transmission gap, the squeezing and expanding drill bit does not rotate, and the working conditions that the rotary drilling bit continuously rotates under the driving of the drill rod and the squeezing and expanding drill bit rotates in the gap are formed. The intermittent rotation period of the squeezing and expanding drill bit is the time for squeezing and expanding the soil of the soil squeezing plate.

The casing of the extrusion-expansion drill bit is designed into a truncated cone shape with a large top and a small bottom to form a pore diameter gradual change section before and after hole expansion, after the hole expansion position of a soil body extruded by the soil extrusion plate gradually covers the circumferential surface of the whole drilled hole, when the soil extrusion plate is flush with the casing (the soil extrusion plate is positioned in the extrusion-expansion vertical hole), the casing and the pore diameter gradual change section form a gap, at the moment, the rotary drilling bit and the extrusion-expansion drill bit integrally fall by dead weight, and the fall stops when the gap disappears due to the large top and the small bottom of the pore diameter of the gradual change section, and the next-stage extrusion-expansion work is continued.

The soil squeezing plates are required not to rotate when the soil body is squeezed radially, and only by rotating, the four soil squeezing plates can gradually complete squeezing and reaming of the circumferential side wall of the drilled hole in the circumferential direction by 360 degrees without dead angles; the intermittent rotation of the squeezing and expanding drill bit meets the requirements of the two points, the operation that the existing operation of extruding soil by 360 degrees at one time is converted into the operation that only a small part of hole wall is extruded at one time is converted, and a foundation is provided for greatly reducing the torque of a drill rod during soil extrusion.

The transmission function can be realized only by adjusting the structural matching relation among the soil squeezing plate, the squeezing vertical hole of the shell, the cross rod, the clamping block and the gear ring according to the transmission purpose, and a new structure is not required to be arranged, so that the whole structure is more compact, the cost is lower, and the maintenance is more convenient.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic cross-sectional structure diagram of a squeezing bit and a rotary drilling bit;

FIG. 3 is a horizontal cross-sectional view at the crossbar of FIG. 2;

FIG. 4 is a schematic diagram of a four-lobe cam configuration;

fig. 5 is a schematic top view of the base plate.

Detailed Description

As shown in fig. 1 to 5, the large-diameter full-section extruding-expanding bored concrete pile equipment comprises a rotary drilling rig 1, wherein the rotary drilling rig 1 is used for constructing a bored concrete pile hole 2.

The rotary drilling rig 1 is provided with a drill rod 3, the bottom end of the drill rod 3 is connected with a rotary drilling bit 4, a squeezing and expanding drill bit 5 is installed on the drill rod 3 above the rotary drilling bit 4, and the squeezing and expanding drill bit 5 is vertically adjacent to the rotary drilling bit 4. The squeezing and expanding drill bit 5 is provided with a shell 6, the whole shell 6 is in a circular truncated cone shape with a large upper part and a small lower part, the diameter of the bottom of the squeezing and expanding drill bit 5 is smaller than or equal to that of the rotary drilling bit 4, and the diameter of the top of the rotary drilling bit 4 is larger than that of the rotary drilling bit 4;

the shell 6 of the squeezing and expanding drill bit 5 is made of a steel plate and is in running fit with the drill rod 3 through a first running fit structure;

four squeezing and expanding vertical holes 7 are uniformly formed in the side wall of the shell 6 of the squeezing and expanding drill bit 5 along the circumferential direction, and the squeezing and expanding vertical holes 7 extend downwards from the top of the side wall of the shell 6 of the squeezing and expanding drill bit 5 to the bottom end of the side wall of the shell 6;

a squeezing and expanding mechanism corresponding to the four squeezing and expanding vertical holes 7 is arranged in the shell 6, and the squeezing and expanding mechanism is in rotating fit with the drill rod 3 through a second rotating fit structure;

the extruding and expanding mechanism comprises four long-strip-shaped soil extruding plates 8 which correspond to the four extruding and expanding vertical holes 7 one by one, and the inclination angles of the soil extruding plates 8 and the generatrix of the circular truncated cone-shaped shell 6 are the same; the soil squeezing plate 8 periodically extends out of the squeezing vertical hole 7 and is periodically collected into the shell 6 under the driving of the drill rod 3, and the soil body is squeezed to be reamed when the soil squeezing plate 8 extends out of the squeezing vertical hole 7;

the squeezing and expanding mechanism is connected with the drill rod 3 through a clutch mechanism, and the clutch mechanism is matched with the squeezing and expanding mechanism in structure, so that when the squeezing and expanding mechanism is transmitted with the drill rod 3, the soil squeezing plate 8 is positioned in the squeezing and expanding vertical hole 7 and drives the shell 6 to rotate, and when the soil squeezing plate 8 extends out of the squeezing and expanding vertical hole 7, the squeezing and expanding mechanism is separated from the drill rod for transmission; in the single transmission process of the squeezing and expanding mechanism and the drill rod 3, the angle of the soil squeezing plate 8 driving the shell 6 to rotate is the same as the angle of a central angle alpha occupied by the soil squeezing plate 8 in the circumferential direction of the shell 6;

the angle of the soil squeezing plate 8 driving the shell 6 to rotate is the same as the angle of the central angle of the soil squeezing plate 8 occupied in the circumferential direction of the shell 6, so that after the soil squeezing plate 8 rotates along with the drill rod 3 every time, the adjacent position of the soil squeezing plate 8 before comes, and through continuous operation, the position of the soil squeezing plate 8 squeezing the soil body for reaming gradually covers the circumferential surface of the whole drilled hole. The soil-squeezing process of each soil-squeezing plate 8 (two pairs are performed alternately) will be specifically analyzed after the structure of the four cams is described below.

The first rotating fit structure is: the top end of the shell 6 is provided with a top plate 9, and the lower part of the shell 6 is provided with a bottom plate 10 higher than the bottom end of the shell 6;

the top plate 9 is downwards supported on the outer ring of the upper support bearing 11, and the inner ring of the upper support bearing 11 is fixedly connected to the drill rod 3;

the bottom plate 10 is downwards supported on the outer ring of the lower support bearing 12, and the inner ring of the lower support bearing 12 is fixedly connected to the drill rod 3;

the second rotating fit structure is: the top of the squeezing and expanding mechanism is connected with an upper connecting cylinder 13, the upper connecting cylinder 13 is fixedly connected with the outer ring of a first supporting bearing 14, the inner ring of the first supporting bearing 14 is fixedly connected on the drill rod 3, and the squeezing and expanding mechanism and the first supporting bearing 14 are both lower than the top plate 9; the bottom of the squeezing and expanding mechanism is connected with a lower connecting cylinder 15, the lower connecting cylinder 15 is fixedly connected with an outer ring of a second supporting bearing 16, an inner ring of the second supporting bearing 16 is fixedly connected to the drill rod 3, and the bottom end of the squeezing and expanding mechanism and the second supporting bearing 16 are both lower than the bottom plate 10 and higher than the bottom end of the shell 6; four notches 17 for radial expansion of the extruding and expanding mechanism are arranged on the bottom plate 10 in one-to-one correspondence with the extruding and expanding vertical holes 7, and the notches 17 are communicated with the extruding and expanding vertical holes 7. In the present invention, each support bearing is preferably a thrust bearing, and a sleeve may be used instead of the support bearing. The drill rod passes through a central bore 18 in the base plate 10. The gap 17 is arranged on the bottom plate, so that the bottom end of the squeezing and expanding mechanism can be lower than the bottom plate, and a transmission matching structure for interval transmission is arranged between the squeezing and expanding mechanism and the rotary drilling bit; meanwhile, as the squeezing and expanding mechanism and the first supporting bearing 14 are lower than the top plate 9, no gap is required to be arranged on the top plate 9, and soil leakage caused by the gap arranged on the top plate is prevented; the bottom plate is shielded by the top plate, the side wall of the shell is arranged in the circumferential direction to expand and squeeze the enclosure of the soil plate, and the rotary digging drill bit is arranged below the bottom plate, so that the gap can not cause soil to enter the shell; the trace soil entering the shell does not influence the normal work.

The first rotary engagement arrangement allows the housing 6 to rotate relative to the drill rod 3. The second running fit may be rotatable relative to the drill pipe 3 using a crowd mechanism.

Four squeezing-expanding vertical holes 7 are uniformly distributed along the circumferential direction of the side wall of the shell 6, the four squeezing-expanding vertical holes are determined by the design of four cams, 180-degree paired arrangement can realize stress balance, and when soil is squeezed at 180 degrees, reaction forces from the soil can be mutually offset when soil is squeezed by the soil squeezing plates 8 at two sides; the number of the soil squeezing plates is six or other even numbers, but the more the number is, the more the structure is complex (the more the complex and the higher the cost is), the torque required for squeezing the soil is inevitably increased after the total area of the soil squeezing each time is increased, and four squeezing and expanding vertical holes 7 and four soil squeezing plates 8 are preferably arranged in comprehensive consideration;

the squeezing and expanding mechanism also comprises an upper squeezing and expanding device connected with the top of the soil squeezing plate 8 and a lower squeezing and expanding device connected with the bottom of the soil squeezing plate 8; four sets of upper extruding and expanding devices and four sets of lower extruding and expanding devices are respectively arranged in one-to-one correspondence with the soil extruding plates 8;

the four-top cam 19 is fixedly connected to the drill rod 3, and the four-top cam 19 is of an axisymmetric structure and is also of a centrosymmetric structure;

the four-top cam 19 is provided with four vertexes which are uniformly distributed in the circumferential direction of the four-top cam 19 and sequentially comprise an A vertex, a B vertex, a C vertex and a D vertex; the center of the four-top cam is O point, AO = CO, BO = DO, namely the distance between two top points distributed in 180 degrees and the center of the four-top cam is the same, and AO is greater than BO; the vertex A and the vertex C are called long vertices, and the vertex B and the vertex D are called short vertices; the long vertexes and the short vertexes are alternately and uniformly distributed in the circumferential direction; two cams 19 are arranged at intervals up and down;

the upper extruding and expanding device and the lower extruding and expanding device have the same structure, each upper extruding and expanding device corresponds to one four-top cam 19, and each lower extruding and expanding device corresponds to one four-top cam 19; the upper extruding and expanding device and the lower extruding and expanding device are collectively called as extruding and expanding devices,

the radial direction of the drill rod 3 is taken as the radial direction, and the structure of the squeezing and expanding device is as follows:

comprises a cross rod 20, the radial outer end of the cross rod 20 is connected with the soil squeezing plate 8; the cross bar 20 penetrates through the hanging ring 21 in a sliding mode, and the radial outer end portion of the cross bar is supported on the hanging ring 21 in a sliding mode; the upper connecting cylinder 13 and the lower connecting cylinder 15 are collectively called as connecting cylinders, and the radial inner ends of the cross rods 20 penetrate through the connecting cylinders and are movably matched with the four-top cams 19 in a jacking and pressing mode;

the first support bearing 14 and the second support bearing 16 are collectively referred to as a crowd-spread support bearing; the upper connecting cylinder 13 and the lower connecting cylinder 15 are collectively referred to as a vertical connecting cylinder 22;

the radial outer end of the outer ring of the squeezing support bearing is upwards connected with the vertical connecting cylinder 22, and the inner end part of the cross rod 20 penetrates through the vertical connecting cylinder 22 and is supported on the vertical connecting cylinder 22 in a sliding manner; the four cams 19 are positioned in the vertical connecting cylinder 22;

during the rotation of the four-top cam 19, the crossbar 20 is in the extended extreme position when in contact with the long top point, and the crossbar 20 is in the retracted extreme position when in contact with the short top point; the cross bar 20 is supported on the hanging ring 21 in a sliding way and is movably pressed on the vertical connecting cylinder 22 in the stroke range;

a clamping block 23 is fixedly connected to the bottom of the cross rod 20 downwards, and a tension spring 24 is connected between the clamping block 23 and the vertical connecting cylinder 22;

the hanging ring 21 of the upper squeezing device is upwards fixedly connected with the top plate 9, and the hanging ring 21 of the lower squeezing device is upwards fixedly connected with the bottom plate 10;

the tension spring 24 applies centripetal recovery tension to the soil squeezing plate 8 through the fixture block 23 and the cross rod 20 in work, so that the radial inner end of the cross rod 20 is always connected with the four cams 19; when the four cams 19 are rotated to the point where the long apexes meet the crossbars 20, the respective crossbars 20 are pushed outwardly to the extended limit positions at which the respective soil-engaging plates 8 extend radially out of the housing 6; when the four cams 19 are rotated to the short apex to meet the crossbars 20, the respective crossbars 20 are drawn inwardly to the retracted extreme position with the respective soil squeezing plates 8 inside the housing 6.

The upper squeezing devices share a vertical connecting cylinder 22, and the lower squeezing devices share a vertical connecting cylinder 22.

By adopting the squeezing device of the invention, the specific position of each cross rod 20 is positioned by the combined action of the tension spring and the four-top cam 19. The four cams 19 are in an axisymmetrical structure and a centrosymmetric structure, so that the radial motion states of the two cross rods 20 and the soil squeezing plates 8 which are distributed at 180 degrees are always consistent. Two soil squeezing plates 8 distributed at 180 degrees are used as a pair of soil squeezing plates 8, and the four soil squeezing plates 8 form two pairs of soil squeezing plates 8. The long vertexes and the short vertexes are alternately and uniformly distributed in the circumferential direction, so that only one pair of soil squeezing plates 8 extend out of the shell 6 in opposite directions at the same time to squeeze soil, the two pairs of soil squeezing plates 8 alternately extend out of the shell 6 to squeeze soil, and the two pairs of soil squeezing plates are alternately withdrawn into the shell 6. When the soil is pressed, the two soil squeezing plates 8 distributed at 180 degrees extend out simultaneously, the reaction force from the soil body is counteracted by the cross rod 20 and the four cams 19, and the structural stress is better.

The top of the rotary drilling bit 4 is fixedly connected with a gear ring 25, and a gap between adjacent teeth in the gear ring 25 is called as a transmission gap; the transmission clearance is matched with the clamping block 23; when the fixture block 23 of the lower squeezing device does radial telescopic motion along with the cross rod 20, the fixture block 23 passes through the transmission gap, is in a transmission state with the gear ring 25 when passing through the transmission gap, and rotates along with the gear ring 25 under the drive of the gear ring 25;

the clamping blocks 23 of the lower squeezing and expanding device pass through the transmission gaps outwards or inwards along the radial direction, meanwhile, the soil squeezing plates 8 synchronously outwards or inwards pass through the squeezing and expanding vertical holes 7, at the moment, the soil squeezing plates 8 and the shell 6 are in a transmission state, and the clamping blocks 23 of the lower squeezing and expanding device drive the shell 6 to synchronously rotate through the cross rods 20 and the soil squeezing plates 8;

after the clamping block 23 of the lower squeezing device leaves the transmission gap, the clamping block is separated from the gear ring 25 in a transmission state.

The soil squeezing plate 8 has the soil squeezing function and the transmission function of driving the shell 6 to rotate; the block 23 not only has the function of mounting the tension spring 24 to enable the cross rod 20 to centripetally contract, but also has the transmission function of rotating under the driving of the gear ring 25. When the transmission structure determines that the fixture block 23 passes through the transmission gap, the squeezing and expanding drill bit 5 rotates under the driving of the rotary drilling bit 4, and when the fixture block 23 leaves the transmission gap, the squeezing and expanding drill bit 5 does not rotate, so that the working conditions that the rotary drilling bit 4 continuously rotates under the driving of the drill rod 3 and the squeezing and expanding drill bit 5 rotates in the gap are formed. The intermittent period of the rotation of the squeezing and expanding drill bit 5 is the time for the squeezing and expanding of the soil by the soil squeezing plate 8.

The soil squeezing plates 8 are required to be not rotated when the soil is squeezed radially, and only by rotating, the four soil squeezing plates 8 can gradually complete squeezing and reaming of the circumferential side wall of the drilled hole in the circumferential direction for 360 degrees without dead angles; the intermittent rotation of the squeezing and expanding drill bit 5 meets the requirements of the two points, the operation that the existing operation of squeezing soil by 360 degrees at one time is converted into the operation that only a small part of hole walls are squeezed at one time, and a foundation is provided for greatly reducing the torque of the drill rod 3 during soil squeezing.

The transmission function can be realized only by adjusting the structural matching relation among the soil squeezing plate 8, the squeezing vertical hole 7 of the shell 6, the cross rod 20, the fixture block 23 and the gear ring 25 according to the transmission purpose, and a new structure is not required to be arranged, so that the whole structure is more compact, the cost is lower, and the maintenance is more convenient. The gearing action described above is independent of the speed at which the ring gear 25 rotates.

The invention also discloses a construction process adopting the large-diameter full-section squeezing-expanding bored concrete pile equipment, which is suitable for drilling construction of concrete bored concrete piles in compressible rock strata such as filling soil, clay, silt, loess and the like or underground water-containing strata, and is carried out according to the following steps:

the first step is to measure the positioning;

measuring and setting out according to the designed pile position, installing a pile casing, and positioning the rotary drilling rig 1;

the second step is drill bit installation;

determining the radial compression of the hole wall to be M cm under specific geological conditions through tests (namely testing soil compaction after drilling); determining the structural parameters of the squeezing and expanding drill bit 5 according to the matching of the M value and the preset hole diameter X (the unit is centimeter); including the top diameter DS and the bottom diameter DX of the casing 6 of the reamed drill bit 5, M, X, DS and DX are all in centimeters and are all positive and real numbers. The diameter DS of the top of the shell 6 of the squeezing and expanding drill bit 5 is equal to the preset hole diameter X, and the diameter DX of the bottom of the shell 6 of the squeezing and expanding drill bit 5 is X-2M;

the diameter of the rotary drilling bit 4 is larger than or equal to the bottom diameter of the shell 6 of the squeezing and expanding bit 5, and the diameter of the rotary drilling bit 4 is smaller than the top diameter of the shell 6 of the squeezing and expanding bit 5;

after the rotary drilling rig 1 is in place, splicing a rotary drilling bit 4, an extrusion drilling bit 5 and a drill rod 3 together and sinking into a protective cylinder;

thirdly, rotary excavating, extruding and expanding to form holes;

the drilling machine is started, the drill rod 3 drives the rotary drilling bit 4 to carry out earth digging operation, the four-top cam 19 is driven by the drill rod 3 to rotate ceaselessly, the four-top cam 19 and the tension spring 24 jointly drive the cross rod 20 to reciprocate in the horizontal direction, and the fixture block 23 reciprocates along with the cross rod 20;

in the reciprocating motion, when the fixture block 23 does not pass through the transmission gap, the squeezing and expanding drill bit 5 is in a rotation intermittent (pause) state, and when the fixture block 23 passes through the transmission gap, the squeezing and expanding drill bit 5 is in a rotation state;

the radial inner ends of four cross rods 20 of the squeezing device are simultaneously positioned at four vertexes of the four-top cam 19 or at a position between two adjacent vertexes; when the radial inner ends of the four cross rods 20 are simultaneously positioned at the midpoint 26 between two adjacent vertexes of the four-top cam 19, the four soil squeezing plates 8 are all positioned in the corresponding squeezing vertical holes 7, and the outer surfaces of the soil squeezing plates 8 are all flush with the outer surface of the shell 6; the soil squeezing plates 8 distributed at 180 degrees are called a pair of soil squeezing plates 8, and the four soil squeezing plates 8 form two pairs of soil squeezing plates 8; with the rotation of the four cams 19, when one pair of soil squeezing plates 8 passes through the squeezing vertical holes 7 from inside to outside, the other pair of soil squeezing plates 8 simultaneously passes through the squeezing vertical holes 7 from outside to inside (at this time, each cross rod 20 is contacted with the corresponding middle point 26); after the pair of soil squeezing plates 8 pass through the squeezing and expanding vertical hole 7 from inside to outside, the hole walls of the holes drilled by the pair of soil squeezing plates 8 are squeezed to carry out soil squeezing and expanding;

with the rotation of the drill rod 3, the squeezing and expanding drill bit 5 continuously and alternately performs (at the time of rotation interval) squeezing and expanding and rotating actions, a gap with the sum of circumferential angles larger and larger is formed between the shell 6 of the squeezing and expanding drill bit 5 and the hole wall of the drill hole until an annular gap is formed between the shell 6 of the squeezing and expanding drill bit 5 and the hole wall of the drill hole, and at the moment, under the pressing action of the drill rod 3 and the self-weight action of the squeezing and expanding drill bit 5 and the rotary drilling bit 4, the squeezing and expanding drill bit 5 falls to the hole wall of the drill hole along with the rotary drilling bit 4 to support the squeezing and expanding drill bit 5;

during the third step, when the hopper of the rotary drilling bit 4 is filled with soil, the drilling machine is operated to carry out the lifting and drilling operation, and the third step is carried out again after the discharging operation;

the fourth step is wall protection by clean water;

and a fifth step of placing a reinforcement cage in the drilled hole and pouring concrete to complete all the working procedures.

And in the fifth step, the steel reinforcement cage and the concrete pouring construction are carried out according to the current construction specification, which is not repeated.

The radial compression amount of the hole wall is M centimeters, the length of the soil extrusion plate 8 radially extending out of the casing 6 of the extrusion and expansion drill bit 5 is N centimeters, N is a real number, and N is one third to one seventh of M, preferably one fifth.

N is one third to one seventh of M, which has two advantages. On the one hand, the soil mass compression amount of the soil extrusion plate 8 to the hole wall of the drill hole is greatly reduced when being compared with N = M, so that the working size of the four cams 19 during single extrusion is greatly reduced when being compared with N = M, the torque is reduced, the requirement on the material strength is reduced, and the requirement on the power of the drilling machine is reduced. On the other hand, the distance that the reaming bit 5 falls after completing one hole expansion is greatly reduced compared with the distance that the reaming bit falls after completing one hole expansion, and the impact force on the equipment during the falling is greatly reduced.

Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.

Claims

1. Crowded bored concrete pile equipment that expands of full section of major diameter, including digging the rig soon, dig the rig soon and have the drilling rod, the bottom of drilling rod is connected with and digs the drill bit soon, installs crowded drill bit that expands on digging the drilling rod of drill bit top soon, and crowded drill bit that expands has the casing, and the casing is whole to be big-end-up's round platform shape, its characterized in that:

the shell of the squeezing and expanding drill bit is in rotating fit with the drill rod through a first rotating fit structure;

the squeezing and expanding mechanism is connected with the drill rod through a clutch mechanism, and the clutch mechanism is matched with the squeezing and expanding mechanism in structure, so that when the squeezing and expanding mechanism is driven by the drill rod, the soil squeezing plate is positioned in the squeezing and expanding vertical hole and drives the shell to rotate; when the soil squeezing plate extends out of the squeezing vertical hole, the squeezing mechanism is separated from the transmission of the drill rod; in the single transmission process of the squeezing and expanding mechanism and the drill rod, the rotation angle of the soil squeezing plate driving the shell is the same as the angle of a central angle alpha occupied by the soil squeezing plate in the circumferential direction of the shell.

2. The large-diameter full-section extruded and expanded cast-in-place pile equipment as claimed in claim 1, wherein: the first rotating fit structure is: the top end of the shell is provided with a top plate, and the lower part of the shell is provided with a bottom plate higher than the bottom end of the shell;

the second rotating fit structure is: the top of the squeezing and expanding mechanism is connected with an upper connecting cylinder, the upper connecting cylinder is fixedly connected with an outer ring of a first supporting bearing, an inner ring of the first supporting bearing is fixedly connected to the drill rod, and the squeezing and expanding mechanism and the first supporting bearing are both lower than the top plate; the bottom of the squeezing and expanding mechanism is connected with a lower connecting cylinder, the lower connecting cylinder is fixedly connected with an outer ring of a second supporting bearing, an inner ring of the second supporting bearing is fixedly connected to the drill rod, and the bottom end of the squeezing and expanding mechanism and the second supporting bearing are both lower than the bottom plate and higher than the bottom end of the shell; the bottom plate and the extruding and expanding vertical holes are provided with a plurality of gaps for radial expansion of the extruding and expanding mechanism in one-to-one correspondence, and the gaps are communicated with the extruding and expanding vertical holes.

3. The large-diameter full-section extruded and expanded cast-in-place pile equipment as claimed in claim 2, wherein: four squeezing-expanding vertical holes are uniformly distributed along the circumferential direction of the side wall of the shell;

two cams are arranged at intervals up and down on the four top cams;

when the four cams rotate to the short top point to be connected with the cross bars, the corresponding cross bars are pulled inwards to the limit position of recovery, and the corresponding soil squeezing plates are positioned inside the shell.

4. The large-diameter full-section extruded and expanded cast-in-place pile equipment as claimed in claim 3, wherein:

5. The construction process of the large-diameter full-section extruded and expanded cast-in-place pile equipment in claim 4 is suitable for drilling construction of the concrete cast-in-place pile, and is characterized by comprising the following steps of:

the first step is to measure the positioning;

the second step is drill bit installation;

thirdly, performing rotary digging, extruding and expanding to form a hole;

the fourth step is wall protection by clean water;

6. The construction process according to claim 5, wherein: