CN117823050A - Graded reaming and hard rock center coring hob drilling method for large-diameter pile filling layer - Google Patents

Abstract

The invention relates to the technical field of large-diameter pile construction, and discloses a large-diameter pile rock filling layer grading reaming and hard rock center coring hob drilling method, which comprises the steps of pre-perforating in a soil layer section to form a pre-perforating section, wherein the soil layer section comprises a soil filling layer, a rock filling layer and a clay layer from top to bottom; a steel sleeve is put into the pre-opening section, and the bottom of the steel sleeve extends into the clay layer; performing downward grading reaming and rotary digging through the pre-perforated section to form soil layer holes, wherein the soil layer holes extend to the top of the hard rock section; coring and drilling the hard rock section to form a central hole, wherein an outer ring rock section is formed at the periphery of the central hole; adopting a hydraulic reverse circulation drilling machine to drill downwards along the axial direction of the central hole, wherein the bottom of the drill rod is provided with a full-section hob bit to form a rock section hole, and the soil layer hole is communicated with the rock section hole up and down to form a pile hole; the full face hob drill bit grinds and breaks the outer ring rock section to form rock scraps, in the process, internal mud in the pile hole carries the rock scraps to be discharged to the outside of the pile hole, and external mud after precipitation treatment is discharged to the pile hole.

Description

Graded reaming and hard rock center coring hob drilling method for large-diameter pile filling layer

Technical Field

The invention relates to the technical field of large-diameter pile construction 1, in particular to a large-diameter pile stone filling layer grading reaming and hard rock center coring hob drilling method.

Background

In recent years, along with the rapid development of economy, super high-rise buildings continuously emerge, the designed cast-in-place pile engineering pile diameter is larger and larger, the rock entering requirement is deeper and deeper, the performance requirement on construction equipment is higher and higher, the construction equipment is influenced and limited by complex condition factors such as surrounding environment of a site, stratum and the like, and single pile equipment and technology are difficult to meet the actual construction needs.

The project pile foundation engineering of Shenzhen city front sea T102-0306 land is located in the nineteen units of the front sea Ma Bay, and the total occupied area is 35268m ² The foundation pit excavates the deepest 21m. The design diameter phi of the core tube foundation engineering piles is 3.0m, the total number of piles is 72, the effective pile length is about 20-40 m, the pile end bearing layer is breeze granite, the breeze rock is more than or equal to 0.8m, and the pore-forming hole depth is about 40-60m. The stratum of the project site mainly comprises filling soil, filling stone, silt, powdery clay, gravel sand, gravel clay and granite from top to bottom, the thickness of the filling soil and the filling stone in the upper soil layer is about 9m, the filling stone mainly comprises breeze granite block stone, the diameter of the block stone is 10-30 cm, the maximum diameter of the block stone is more than 50cm, and the content of the block stone is more than 50%; the silt is in a flowing plastic shape, and the averageA thickness of about 2m; crushing and fissure development of the rock mass in the process of downstroke, wherein the saturated uniaxial compressive strength is 37.8MPa at the maximum, the average layer thickness is 12.0m, and the maximum thickness is 20.5m; the breeze rock mass is complete and hard, and the saturated uniaxial compressive strength is up to 104.1MPa.

The large-diameter cast-in-place pile is used for constructing the upper soil layer, is deep in filling and stone, adopts a conventional hole protection barrel buried 3-6 m long, is easy to leak and collapse holes at the bottom, and has large upper stone filling layer thickness, large content and large block size, thereby bringing great difficulty to normal drilling of rotary digging. Meanwhile, the hard rock fracture development adopts rotary drilling and grading reaming to drill so as to easily cause eccentric holes, the subsequent reaming can further lead to hole inclination, the drilling deviation correction difficulty is high, the time is long, and the drilling noise of the rock is out of standard. In addition, the hard rock section has high strength, low drilling efficiency and high cost.

Disclosure of Invention

The invention aims to provide a grading reaming and hard rock center coring hob drilling method for a large-diameter pile filled rock layer, and aims to solve the problems of slurry leakage and hole collapse of a filled soil layer, a filled rock layer and a clay layer in the prior art.

The invention discloses a method for realizing grading reaming of a large-diameter pile filling layer and coring and hob drilling of a hard rock center, which comprises the following construction steps:

1) Pre-perforating in a soil layer section of a construction site by using a rotary drilling rig to form a pre-perforating section, wherein the soil layer section sequentially comprises a filling layer, a filling stone layer and a clay layer along the direction from top to bottom;

2) A steel sleeve is put into the pre-opening section, the lower part of the steel sleeve penetrates through the bottom of the pre-opening section and extends downwards, the bottom of the steel sleeve extends into the clay layer, and the upper part of the steel sleeve surrounds the periphery of the pre-opening section;

3) The rotary drilling rig is used for performing downward grading reaming rotary drilling through a pre-drilling section, a soil layer hole is formed in the soil layer section, and the bottom of the soil layer hole extends to the top of the hard rock section;

4) Drilling through a soil layer hole by utilizing a roller cone barrel, and performing core drilling on a hard rock section until the elevation of the pile bottom is designed to form a central hole, wherein an outer ring rock section is formed on the periphery of the central hole;

5) The hydraulic reverse circulation drilling machine is used for downwards drilling along the axial direction of the central hole, the hydraulic reverse circulation drilling machine is provided with a drill rod, the bottom of the drill rod is provided with a full-face hob drill bit, the full-face hob drill bit downwards drills to the elevation of the designed pile bottom along the axial direction of the central hole to form a rock section hole, and the soil layer hole is communicated with the rock section hole from top to bottom to form a pile hole;

the full-face hob drill bit grinds and breaks the outer ring rock section to form rock scraps, and in the process of drilling in the hard rock stratum, internal slurry in the pile hole carries the rock scraps to be discharged to the outside of the pile hole, and external slurry after precipitation treatment is discharged to the pile hole.

Optionally, in the construction step 1), the rotary drilling rig adopts a pre-opening drill bucket to precess in the soil layer to form a pre-opening section; the outer diameter of the pre-opened drilling bucket is larger than the diameter of the pile hole.

Optionally, in the construction step 1), the pre-opened section passes through the earth filling layer and the stone filling layer, and the bottom of the pre-opened section extends into the clay layer.

Optionally, in the construction step 3), the rotary drilling rig uses a small-diameter drilling bucket to drill through a pre-drilling section in a rotary manner, and after a small-diameter hole which is formed in the soil layer section and is drilled to the top of the hard rock section in a rotary manner, the rotary drilling rig uses a large-diameter drilling bucket to drill through the pre-drilling section in a rotary manner, and the small-diameter hole is reamed to form the soil layer hole.

Optionally, in the construction step 5), a balancing weight is formed on the full face hob drill bit, and the balancing weight is circumferentially arranged along the circumference of the drill rod.

Optionally, in the step 5), an abrasive surface is formed at the bottom of the full-section hob drill, a plurality of ball tooth hobs arranged in a rolling manner are arranged on the abrasive surface, the ball tooth hobs are circumferentially arranged at intervals along the circumferential direction of the abrasive surface, the ball tooth hobs are arranged in a staggered manner along the radial direction of the abrasive surface, and when the full-section hob drill rotates, the circumferential track of the ball tooth hobs covers the whole abrasive surface;

in the construction step 5), in the process of drilling the full-section hob drill bit in the hard rock stratum, a plurality of spherical tooth hobs synchronously rotate along with the full-section hob drill bit, and the spherical tooth hobs synchronously roll on a grinding surface to grind and crush the outer ring rock section to form rock scraps.

Optionally, in the step 5), a plurality of mounting blocks are disposed on the grinding surface, the plurality of mounting blocks are circumferentially arranged along the circumferential direction of the grinding surface at intervals, and the plurality of mounting blocks are arranged in a staggered manner along the radial direction of the grinding surface; the installation block is provided with a tilting shaft which is arranged in an upward tilting way along the direction from the center of the grinding surface to the periphery;

the spherical tooth hob is in a frustum shape, the spherical tooth hob is provided with a big head end and a small head end, and a plurality of spherical convex teeth are convexly arranged on the periphery of the spherical tooth hob; the gear hob is rotatably sleeved on the inclined shaft, and is obliquely arranged upwards along the direction from the big end to the small end of the gear hob, and a grinding interval is arranged between the periphery of the gear hob and the mounting block;

in the construction step 5), in the process of drilling the full-face hob drill bit in the hard rock stratum, a plurality of the spherical tooth hobs synchronously rotate along with the full-face hob drill bit, the spherical tooth hobs synchronously roll on a grinding surface, and the outer ring rock segments are ground and crushed by utilizing convex teeth on the periphery of the spherical tooth hobs to form rock fragments.

Optionally, an air pipe is arranged on the drill rod, a slurry discharging pipe is arranged in the drill rod, and an air outlet and a slurry sucking port are formed in the bottom of the full-section hob drill bit; the upper end of the air pipe is communicated with the air compressor, and the lower end of the air pipe is communicated with the air outlet; the lower end of the pulp discharging pipe is communicated with the pulp sucking port, and the upper end of the pulp discharging pipe is communicated with the sedimentation tank;

in the construction step 5), in the process of drilling the full-section hob drill bit in a hard rock stratum, the air compressor injects high-pressure air through an air pipe, the high-pressure air is sprayed downwards through an air outlet, a negative pressure area is formed below the slurry suction port, and internal slurry in the negative pressure area carries rock debris and is discharged into a settling tank through the slurry suction port and a slurry discharge pipe;

and the internal slurry carrying rock scraps in the settling tank is filtered through settling to form external slurry, and the external slurry is injected into the pile hole through the grouting pipe.

Optionally, the settling tank comprises a primary separation bin, a secondary settling bin and a tertiary settling bin, wherein an upper filter plate which is obliquely arranged downwards is arranged at the top of the primary separation bin, a suction pump is arranged at the top of the upper filter plate, the suction pump is connected with a suction pipe which is arranged in a downward extending way, and the suction pipe is communicated with the upper end of the pulp discharging pipe;

the secondary sedimentation bin is positioned below the upper layer filter plate, the secondary sedimentation bin is adjacently arranged with the tertiary sedimentation bin, the top of the secondary sedimentation bin is provided with an overflow notch communicated with the tertiary sedimentation bin, the upper part of the tertiary sedimentation bin is provided with an overflow port, and the overflow port grouting pipe is communicated;

in the construction step 5), after the internal slurry carrying the rock debris moves upwards through the suction pipe, the internal slurry flows downwards in a tilting manner along the upper filter plate, the internal slurry falls into the secondary sedimentation bin from top to bottom, the rock debris is discharged downwards in a tilting manner along the upper filter plate, the internal slurry is sedimented in the secondary sedimentation bin and overflows into the tertiary sedimentation bin through the overflow notch, the internal slurry is sedimented in the tertiary sedimentation bin to form external slurry, and the external slurry is discharged into the grouting pipe through the overflow port.

Optionally, in the construction step 5), an upper layer filter hole is formed in the upper layer filter plate, a lower layer filter plate is arranged below the upper layer filter plate, a lower layer filter hole is formed in the lower layer filter plate, and the diameter of the lower layer filter hole is smaller than that of the upper layer filter hole; the upper end of the lower filter plate is butted with the lower end of the upper filter plate, and the lower end of the lower filter plate is obliquely arranged downwards;

the upper filter holes are arranged at the lower part of the upper filter plate along the downward inclined direction of the upper filter plate, the lower filter holes are arranged at the lower part of the lower filter plate along the downward inclined direction of the lower filter plate, and the upper filter holes and the lower filter holes are arranged in a vertically staggered manner;

in the construction step 5, the internal slurry carrying the rock debris flows downwards obliquely along the upper filter plate, when the internal slurry flows to the lower part of the upper filter plate, the internal slurry falls on the lower filter plate through the upper filter hole, the internal slurry flows downwards obliquely along the lower filter plate, and when the internal slurry flows to the lower part of the lower filter plate, the internal slurry falls in the secondary sedimentation bin through the lower filter hole.

Compared with the prior art, the large-diameter pile rock filling layer grading reaming and hard rock center coring hob drilling method provided by the invention has the advantages that the soil layer section is perforated in advance, then the steel sleeve is put down, the soil filling layer, the rock filling layer and other easy-to-collapse hole strata are blocked by the steel sleeve, the hole wall stability in the drilling process is ensured, the drilling speed of the deep rock filling layer is improved by adopting a downward grading reaming rotary drilling mode, meanwhile, the small-diameter cone drum drilling coring is adopted to reach the design elevation during the hard rock section primary drilling, the formed center hole effectively releases rock stress, the broken rock section of the follow-up full-section rotary drilling is reduced, the vibration is small, the noise is avoided, and the influence on the surrounding environment is small; in addition, the hydraulic reverse circulation drilling machine is adopted for construction of hard rock, the large torque provided by the equipment is utilized to drive the full-section hob drill bit to form holes, the comprehensive hole forming efficiency is greatly improved, meanwhile, the slag discharging and hole cleaning effects are good, and the requirement of hole bottom sediment is met. The steel sleeve is adopted to protect the wall of the bad easy-collapse stratum at the upper part, so that slurry leakage and hole collapse are avoided, the pore forming is regular, and the verticality is effectively controlled.

Drawings

FIG. 1 is a schematic flow chart of a large-diameter pile rock-filling layer grading reaming and hard rock center coring hob drilling method provided by the invention;

FIG. 2 is a schematic construction diagram of step 1) provided by the present invention;

FIG. 3 is a schematic construction diagram of step 2) provided by the present invention;

FIG. 4 is a schematic construction diagram of step 3) provided by the present invention;

FIG. 5 is a schematic construction diagram of step 3) provided by the present invention;

FIG. 6 is a schematic flow chart of step 4) provided by the present invention;

FIG. 7 is a schematic flow chart of step 5) provided by the present invention;

FIG. 8 is a schematic flow chart of step 5) provided by the present invention;

FIG. 9 is a partial schematic view of the bottom of the full face hob bit provided by the present invention;

FIG. 10 is an exploded view of the settling tank provided by the present invention;

FIG. 11 is a schematic cross-sectional view of a primary separation cartridge provided by the present invention.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

The implementation of the present invention will be described in detail below with reference to specific embodiments.

The same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the present invention, it should be understood that, if there is an azimuth or positional relationship indicated by terms such as "upper", "lower", "left", "right", etc., based on the azimuth or positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, but it is not indicated or implied that the apparatus or element referred to must have a specific azimuth, be constructed and operated in a specific azimuth, and thus terms describing the positional relationship in the drawings are merely illustrative and should not be construed as limitations of the present patent, and specific meanings of the terms described above may be understood by those skilled in the art according to specific circumstances.

Referring to fig. 1-11, a preferred embodiment of the present invention is provided.

The invention provides a large-diameter pile filling layer grading reaming and hard rock center coring hob drilling method, which comprises the following construction steps:

1) Pre-perforating 100 in a soil layer section of a construction site by using a rotary drilling rig to form a pre-perforating section, wherein the soil layer section sequentially comprises a filling layer 11, a filling layer 12 and a clay layer 13 along the direction from top to bottom;

2) A steel sleeve 110 is put into the pre-opening section, the lower part of the steel sleeve 110 penetrates through the bottom of the pre-opening section and extends downwards, the bottom of the steel sleeve 110 extends into the clay layer 13, and the upper part of the steel sleeve 110 surrounds the periphery of the pre-opening section;

3) The rotary drilling rig performs graded reaming and rotary drilling downwards through the pre-drilling section, a soil layer hole 300 is formed in the soil layer section, and the bottom of the soil layer hole 300 extends to the top of the hard rock section 20;

4) A roller cone barrel drill 410 penetrates through the soil layer hole 300, core drilling is carried out on the hard rock section 20 until the pile bottom elevation is designed, a central hole 400 is formed, and an outer ring rock section is formed on the periphery of the central hole 400;

5) The hydraulic reverse circulation drilling machine is adopted to drill downwards along the axial direction of the central hole 400, the hydraulic reverse circulation drilling machine is provided with a drill rod 420, the bottom of the drill rod 420 is provided with a full-face hob bit, the full-face hob bit drills downwards along the axial direction of the central hole 400 to the designed pile bottom elevation, a rock section hole 500 is formed, and the soil layer hole 300 is communicated with the rock section hole 500 up and down to form a pile hole;

the full-section hob bit grinds and breaks the outer ring rock section to form rock scraps, in the process that the full-section hob bit drills in the hard rock stratum, internal slurry in the pile hole carries the rock scraps to be discharged to the outside of the pile hole, and external slurry after precipitation treatment is discharged to the pile hole.

According to the method for grading reaming of the large-diameter pile rock-filling layer 12 and coring and hobbing cutter drilling of the hard rock center, the soil layer section adopts the mode of pre-perforating 100, then lowering the steel sleeve 110, and then downwards grading reaming and rotary drilling, so that the drilling speed of the deep rock-filling layer 12 is improved, meanwhile, when the hard rock section 20 is initially drilled, the small-diameter cone barrel drill 410 is adopted to drill and core to the designed elevation, the formed center hole 400 effectively releases rock stress, and the rock breaking section of the follow-up full-section rotary drilling is reduced; in addition, the hydraulic reverse circulation drilling machine is adopted for construction of hard rock, the large torque provided by the equipment is utilized to drive the full-section hob drill bit to form holes, the comprehensive hole forming efficiency is greatly improved, meanwhile, the slag discharging and hole cleaning effects are good, and the requirement of hole bottom sediment is met. The long steel sleeve 110 is adopted to protect the wall of the bad easy-collapse stratum at the upper part, so that slurry leakage and hole collapse are avoided, the hole forming shape is regular, and the verticality is effectively controlled.

The rotary drilling rig and the hydraulic reverse circulation drilling rig are adopted to drill the hole, compared with the traditional construction method of the rotary drilling rig, the rock entering drilling time is greatly shortened, compared with the construction method of the hydraulic reverse circulation drilling rig alone, the central hole 400 of the rotary drilling rig can be used for coring and then determining the elevation of a final hole in advance, and repeated confirmation of rock judgment of a bearing stratum during subsequent large-section rotary drilling is avoided; in addition, as the deep hard rock section 20 is drilled by hydraulic rotary drilling, the hydraulic drilling is noiseless, the 24-hour drilling construction can be carried out, the pore-forming time is effectively shortened, and the comprehensive cost is economic.

In the construction step 1), a rotary drilling rig adopts a pre-opening drilling bucket to precess in a soil layer to form a pre-opening section; the outer diameter of the pre-opened drilling bucket is larger than the diameter of the pile hole. In this way, the steel bushing 110 is facilitated to be lowered.

In this embodiment, in the construction step 1), the pre-perforated section passes through the earth-filled layer 11 and the rock-filled layer 12, and the bottom of the pre-perforated section extends into the clay layer 13. In this way, the steel bushing 110 is facilitated to be lowered.

In the construction step 3), the rotary drilling rig adopts the small-diameter drilling bucket 210 to drill through the pre-perforating section in a rotary manner, and after a small-diameter hole which is dug to the top of the hard rock section 20 in a rotary manner is formed in the soil layer section, the rotary drilling rig adopts the large-diameter drilling bucket 310 to drill through the pre-perforating section in a rotary manner, and the small-diameter hole is reamed to form the soil layer hole 300. Thus, the drilling speed is improved by adopting secondary reaming drilling.

Specifically, in the construction step 5), the weight 421 is formed on the full face hob drill, and the weight 421 is circumferentially arranged along the circumference of the drill pipe 420. Thus, the weight 421 provides vertical pressure, improving grinding efficiency.

In the construction step 5), an abrasive surface is formed at the bottom of the full-face hob drill, a plurality of ball tooth hobs 422 are arranged on the abrasive surface in a rolling way, the ball tooth hobs 422 are arranged in a surrounding way along the circumferential direction of the abrasive surface at intervals, the ball tooth hobs 422 are arranged in a staggered way along the radial direction of the abrasive surface, and when the full-face hob drill rotates, the circumferential track of the ball tooth hobs 422 covers the whole abrasive surface;

in the construction step 5), in the process of drilling the full face hob drill bit in the hard rock stratum, the plurality of spherical tooth hobs 422 synchronously rotate along with the full face hob drill bit, and the spherical tooth hobs 422 synchronously roll on the grinding surface to grind and crush the outer ring rock section to form rock scraps. In this way, the button hob 422 is guaranteed to grind hard rock completely under the entire grinding surface during rotation of the drill pipe 420.

Specifically, in the construction step 5), the grinding surface is provided with a plurality of mounting blocks 423, the plurality of mounting blocks 423 are circumferentially arranged along the circumferential direction of the grinding surface at intervals, and the plurality of mounting blocks 423 are arranged in a staggered manner along the radial direction of the grinding surface; the mounting block 423 is provided with a tilt shaft 424, and the tilt shaft 424 is arranged obliquely upward along the direction from the center to the periphery of the grinding surface;

the hob 422 is in a frustum shape, the hob 422 is provided with a big head end 4221 and a small head end 4220, and a plurality of spherical convex teeth are convexly arranged on the periphery of the hob 422; the hob 422 is rotationally sleeved on the inclined shaft 424, the hob 422 is obliquely arranged upwards along the direction from the big end 4221 to the small end 4220 of the hob 422, and a grinding interval is arranged between the periphery of the hob 422 and the mounting block 423;

in the construction step 5), in the process of drilling the full face hob bit in the hard rock stratum, the plurality of spherical tooth hobs 422 synchronously rotate along with the full face hob bit, the spherical tooth hobs 422 synchronously roll on the grinding surface, and the outer ring rock section is ground and crushed by utilizing convex teeth on the periphery of the spherical tooth hobs 422 to form rock fragments. In this way, the inclined shaft 424 is arranged in an inclined manner, and the hob 422 can rotate around the inclined shaft 424, so that the hob 422 can grind peripheral hard rock at multiple angles, and meanwhile, the hob has an upward inclined angle, so that grinding force is increased, and the rock stratum can be better crushed by the teeth, so that grinding efficiency is improved. In addition, due to the design of the big head end 4221 and the small head end 4220, the ball tooth hob 422 can be stressed more uniformly when rotating, and local stress concentration is reduced, so that the service life of the ball tooth hob 422 is prolonged, and the ball tooth hob 422 can be well crushed into hard rock of an outer ring rock section through the arrangement.

An air pipe 610 is arranged on the drill rod 420, a slurry discharging pipe 710 is arranged in the drill rod 420, and the bottom of the full-face hob drill bit is provided with an air outlet and a slurry sucking port; the upper end of the air pipe 610 is communicated with the air compressor 600, and the lower end of the air pipe 610 is communicated with the air outlet; the lower end of the slurry discharging pipe 710 is communicated with the slurry sucking port, and the upper end of the slurry discharging pipe 710 is communicated with the sedimentation tank 700;

in the construction step 5), in the process of drilling the full-section hob drill bit in the hard rock stratum, high-pressure air is injected into the air compressor 600 through the air pipe 610, the high-pressure air is sprayed downwards through the air outlet, a negative pressure area is formed below the slurry suction port, rock debris is carried by slurry in the negative pressure area, and the slurry is discharged into the sedimentation tank 700 through the slurry suction port and the slurry discharge pipe 710;

the internal mud carrying the cuttings in the settling tank 700 is filtered by settling to form an external mud, which is injected into the pile hole through the grouting pipe 720. Thus, the slag discharging and hole cleaning effects are good, and the sediment at the bottom of the hole is ensured to meet the requirements. The slurry can be recycled, and the overall construction is environment-friendly.

Specifically, the grinding surface is annular, the grinding surface surrounds and forms a middle surface, the middle surface is positioned in the middle of the bottom surface of the drill rod, a slurry suction port is formed in the middle surface, rock scraps in the hole move towards the slurry suction port in the circumferential direction in the grinding process of the spherical tooth hob, and the hole cleaning efficiency is improved.

The sedimentation tank 700 comprises a primary separation bin 730, a secondary sedimentation bin 740 and a tertiary sedimentation bin 750, wherein the top of the primary separation bin 730 is provided with an upper filter plate 731 which is arranged obliquely downwards, the top of the upper filter plate 731 is provided with a suction pump, and the suction pump is connected with a suction pipe which is arranged in a downward extending way and is communicated with the upper end of the pulp discharge pipe 710;

the secondary sedimentation bin 740 is positioned below the upper layer filter plate 731, the secondary sedimentation bin 740 is adjacently arranged with the tertiary sedimentation bin 750, the top of the secondary sedimentation bin 740 is provided with an overflow notch 741 communicated with the tertiary sedimentation bin 750, the upper part of the tertiary sedimentation bin 750 is provided with an overflow port 751, and the overflow port 751 is communicated with the grouting pipe 720;

in the construction step 5), after the internal slurry carrying the rock debris moves upwards through the suction pipe, the internal slurry flows downwards in a tilting manner along the upper filter plate 731, the internal slurry falls into the secondary sedimentation bin 740 from top to bottom, the rock debris is discharged downwards in a tilting manner along the upper filter plate 731, the internal slurry is sedimented in the secondary sedimentation bin 740 and overflows into the tertiary sedimentation bin 750 through the overflow notch 741, the internal slurry is sedimented in the tertiary sedimentation bin 750 to form external slurry, and the external slurry is discharged into the grouting pipe 720 through the overflow port 751. In this way, the upper filter plate 731 is used to isolate the large rock debris on the upper filter plate 731, so that the rock debris flows downwards in an inclined manner, the internal slurry falls into the second-stage sedimentation bin 740 below the upper filter plate 731 from top to bottom, the upper part of the internal slurry in the second-stage sedimentation bin 740 flows to the third-stage sedimentation bin 750 through the overflow notch 741, the rock debris is sedimented at the lower part of the internal slurry, and finally the internal slurry in the third-stage sedimentation bin 750 flows into the grouting pipe 720 through the overflow notch 751, so that the rock debris is removed by sedimentation.

In the present embodiment, in the construction step 5), the upper filter plate 731 has an upper filter hole 7310 therein, the lower filter plate 732 is disposed below the upper filter plate 731, the lower filter plate 732 is disposed with a lower filter hole 7320 therein, and the diameter of the lower filter hole 7320 is smaller than the diameter of the upper filter hole 7310; the upper end of the lower filter plate 732 is butted with the lower end of the upper filter plate 731, and the lower end of the lower filter plate 732 is arranged obliquely downwards;

along the downward inclination direction of the upper filter plate 731, the upper filter holes 7310 are arranged at the lower part of the upper filter plate 731, along the downward inclination direction of the lower filter plate 732, the lower filter holes 7320 are arranged at the lower part of the lower filter plate 732, and the upper filter holes 7310 and the lower filter holes 7320 are arranged in a vertically staggered manner;

in the construction step 5, the internal slurry carrying the rock debris flows obliquely downward along the upper filter plate 731, and when the internal slurry flows to the lower portion of the upper filter plate 731, the internal slurry falls onto the lower filter plate 732 through the upper filter holes 7310, and when the internal slurry flows to the lower portion of the lower filter plate 732, the internal slurry falls into the secondary sedimentation bin 740 through the lower filter holes 7320. In this way, cuttings falling into the secondary settling bin 740 are reduced, avoiding excessive storage of cuttings by the secondary settling bin 740, resulting in flow through overflow notch 741 into the tertiary settling bin 750.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.

Claims (10)

1. The method for grading reaming of the large-diameter pile filling layer and coring hob drilling of the hard rock center is characterized by comprising the following construction steps:

1) Pre-perforating in a soil layer section of a construction site by using a rotary drilling rig to form a pre-perforating section, wherein the soil layer section sequentially comprises a filling layer, a filling stone layer and a clay layer along the direction from top to bottom;

2) A steel sleeve is put into the pre-opening section, the lower part of the steel sleeve penetrates through the bottom of the pre-opening section and extends downwards, the bottom of the steel sleeve extends into the clay layer, and the upper part of the steel sleeve surrounds the periphery of the pre-opening section;

3) The rotary drilling rig is used for performing downward grading reaming rotary drilling through a pre-drilling section, a soil layer hole is formed in the soil layer section, and the bottom of the soil layer hole extends to the top of the hard rock section;

4) Drilling through a soil layer hole by utilizing a roller cone barrel, and performing core drilling on a hard rock section until the elevation of the pile bottom is designed to form a central hole, wherein an outer ring rock section is formed on the periphery of the central hole;

5) The hydraulic reverse circulation drilling machine is used for downwards drilling along the axial direction of the central hole, the hydraulic reverse circulation drilling machine is provided with a drill rod, the bottom of the drill rod is provided with a full-face hob drill bit, the full-face hob drill bit downwards drills to the elevation of the designed pile bottom along the axial direction of the central hole to form a rock section hole, and the soil layer hole is communicated with the rock section hole from top to bottom to form a pile hole;

the full-face hob drill bit grinds and breaks the outer ring rock section to form rock scraps, and in the process of drilling in the hard rock stratum, internal slurry in the pile hole carries the rock scraps to be discharged to the outside of the pile hole, and external slurry after precipitation treatment is discharged to the pile hole.

2. The method for grading reaming of a large-diameter pile filling layer and coring and hobbing cutter drilling of a hard rock center as claimed in claim 1, wherein in the construction step 1), the rotary drilling rig adopts a pre-opening drill bucket to precess in a soil layer to form a pre-opening section; the outer diameter of the pre-opened drilling bucket is larger than the diameter of the pile hole.

3. The method for grading reaming of a large-diameter pile-filled rock layer and coring and hobbing cutter drilling of a hard rock center as set forth in claim 1, wherein in the construction step 1), the pre-opened section passes through the filled rock layer and the filled rock layer, and the bottom of the pre-opened section extends into the clay layer.

4. The method for grading reaming of a large-diameter pile filling layer and coring and hobbing cutter drilling of a hard rock center as claimed in claim 1, wherein in the construction step 3), the rotary drilling machine adopts a small-diameter drilling bucket to drill through a pre-perforating section in a rotary manner, and after a small-diameter hole which is formed in a soil layer section in a rotary manner and is drilled to the top of the hard rock section in a rotary manner is formed in the soil layer section, the rotary drilling machine adopts a large-diameter drilling bucket to drill through the pre-perforating section in a rotary manner, so that the small-diameter hole is reamed to form the soil layer hole.

5. The method for grading reaming of a large-diameter pile filling layer and coring of hard rock center as claimed in claim 1, wherein in the construction step 5), weights are formed on the full face hob drill, and the weights are circumferentially arranged along the circumference of the drill rod.

6. The method for grading reaming of a large-diameter pile filling layer and coring of hard rock in a center, as set forth in claim 1, characterized in that in the step 5), a grinding surface is formed at the bottom of the full-face hob drill, a plurality of ball tooth hobs are arranged on the grinding surface in a rolling manner, the ball tooth hobs are arranged circumferentially and circumferentially along the grinding surface at intervals, the ball tooth hobs are arranged in a staggered manner along the radial direction of the grinding surface, and when the full-face hob drill rotates, the circumferential track of the ball tooth hobs covers the whole grinding surface;

in the construction step 5), in the process of drilling the full-section hob drill bit in the hard rock stratum, a plurality of spherical tooth hobs synchronously rotate along with the full-section hob drill bit, and the spherical tooth hobs synchronously roll on a grinding surface to grind and crush the outer ring rock section to form rock scraps.

7. The method for grading reaming of a large-diameter pile filling layer and coring and hobbing cutter drilling of a hard rock center as claimed in claim 6, wherein in the construction step 5), a plurality of mounting blocks are arranged on the grinding surface, the plurality of mounting blocks are circumferentially arranged at intervals along the circumferential direction of the grinding surface, and the plurality of mounting blocks are arranged in a staggered manner along the radial direction of the grinding surface; the installation block is provided with a tilting shaft which is arranged in an upward tilting way along the direction from the center of the grinding surface to the periphery;

the spherical tooth hob is in a frustum shape, the spherical tooth hob is provided with a big head end and a small head end, and a plurality of spherical convex teeth are convexly arranged on the periphery of the spherical tooth hob; the gear hob is rotatably sleeved on the inclined shaft, and is obliquely arranged upwards along the direction from the big end to the small end of the gear hob, and a grinding interval is arranged between the periphery of the gear hob and the mounting block;

in the construction step 5), in the process of drilling the full-face hob drill bit in the hard rock stratum, a plurality of the spherical tooth hobs synchronously rotate along with the full-face hob drill bit, the spherical tooth hobs synchronously roll on a grinding surface, and the outer ring rock segments are ground and crushed by utilizing convex teeth on the periphery of the spherical tooth hobs to form rock fragments.

8. The method for grading reaming of a large-diameter pile filling layer and coring and hobbing cutter drilling of a hard rock center as claimed in any one of claims 1 to 7, wherein an air pipe is arranged on the drill rod, a slurry discharging pipe is arranged in the drill rod, and an air outlet and a slurry sucking port are arranged at the bottom of the full-section hobbing cutter drill bit; the upper end of the air pipe is communicated with the air compressor, and the lower end of the air pipe is communicated with the air outlet; the lower end of the pulp discharging pipe is communicated with the pulp sucking port, and the upper end of the pulp discharging pipe is communicated with the sedimentation tank;

in the construction step 5), in the process of drilling the full-section hob drill bit in a hard rock stratum, the air compressor injects high-pressure air through an air pipe, the high-pressure air is sprayed downwards through an air outlet, a negative pressure area is formed below the slurry suction port, and internal slurry in the negative pressure area carries rock debris and is discharged into a settling tank through the slurry suction port and a slurry discharge pipe;

and the internal slurry carrying rock scraps in the settling tank is filtered through settling to form external slurry, and the external slurry is injected into the pile hole through the grouting pipe.

9. The method for grading reaming of a large-diameter pile filling layer and coring and hobbing cutter drilling of a hard rock center as claimed in claim 8, wherein the sedimentation tank comprises a primary separation bin, a secondary sedimentation bin and a tertiary sedimentation bin, the top of the primary separation bin is provided with an upper filter plate which is arranged obliquely downwards, the top of the upper filter plate is provided with a suction pump, the suction pump is connected with a suction pipe which is arranged in a downward extending way, and the suction pipe is communicated with the upper end of a slurry discharging pipe;

the secondary sedimentation bin is positioned below the upper layer filter plate, the secondary sedimentation bin is adjacently arranged with the tertiary sedimentation bin, the top of the secondary sedimentation bin is provided with an overflow notch communicated with the tertiary sedimentation bin, the upper part of the tertiary sedimentation bin is provided with an overflow port, and the overflow port grouting pipe is communicated;

in the construction step 5), after the internal slurry carrying the rock debris moves upwards through the suction pipe, the internal slurry flows downwards in a tilting manner along the upper filter plate, the internal slurry falls into the secondary sedimentation bin from top to bottom, the rock debris is discharged downwards in a tilting manner along the upper filter plate, the internal slurry is sedimented in the secondary sedimentation bin and overflows into the tertiary sedimentation bin through the overflow notch, the internal slurry is sedimented in the tertiary sedimentation bin to form external slurry, and the external slurry is discharged into the grouting pipe through the overflow port.

10. The method for grading reaming of a large-diameter pile filling layer and coring and hobbing cutter drilling of a hard rock center as claimed in claim 9, wherein in the construction step 5), an upper layer filter hole is formed in the upper layer filter plate, a lower layer filter plate is arranged below the upper layer filter plate, a lower layer filter hole is formed in the lower layer filter plate, and the diameter of the lower layer filter hole is smaller than that of the upper layer filter hole; the upper end of the lower filter plate is butted with the lower end of the upper filter plate, and the lower end of the lower filter plate is obliquely arranged downwards;

the upper filter holes are arranged at the lower part of the upper filter plate along the downward inclined direction of the upper filter plate, the lower filter holes are arranged at the lower part of the lower filter plate along the downward inclined direction of the lower filter plate, and the upper filter holes and the lower filter holes are arranged in a vertically staggered manner;

in the construction step 5, the internal slurry carrying the rock debris flows downwards obliquely along the upper filter plate, when the internal slurry flows to the lower part of the upper filter plate, the internal slurry falls on the lower filter plate through the upper filter hole, the internal slurry flows downwards obliquely along the lower filter plate, and when the internal slurry flows to the lower part of the lower filter plate, the internal slurry falls in the secondary sedimentation bin through the lower filter hole.