CN110374500B

CN110374500B - Grouped drilling and pile planting construction method

Info

Publication number: CN110374500B
Application number: CN201910638955.2A
Authority: CN
Inventors: 吴国明; 李星; 李俊
Original assignee: Shanghai Guangda Foundation Engineering Co ltd
Current assignee: Shanghai Guangda Foundation Engineering Co ltd
Priority date: 2019-07-16
Filing date: 2019-07-16
Publication date: 2020-08-18
Anticipated expiration: 2039-07-16
Also published as: CN110374500A

Abstract

A grouped drilling pile planting construction method comprises the following steps: 1) preparation before construction; 2) installing two groups of power head assemblies; 3) a first group of power head assemblies and drill rods, spiral drill rods and drilling tools thereof drill and cut; 4) a second group of power head assemblies and drill rods, spiral drill rods and drilling tools thereof are drilled and cut; 5) the second group of power head assembly and the multiple sections of drill rods, spiral drill rods and drilling tools thereof carry out guniting and stirring operations; 6) lifting and disassembling a drill rod and a drilling tool; 7) and (5) implanting the precast pile. The invention can ensure that two groups of power head assemblies arranged on the long guide rail of the upright post of the walking pile frame sequentially drill, stir and ream, improve the surface finish degree of the hole wall, achieve the accurate butt joint between the drill rods fixedly arranged on the two groups of power head assemblies through the transverse moving and fine adjustment of the walking pile frame, avoid the frequent butt joint and disassembly between the drill rods and the drilling tool, reduce the operation intensity of operators, improve the operation efficiency of drilling and pile planting, effectively ensure the pile planting construction quality and greatly reduce the equipment purchase cost.

Description

Grouped drilling and pile planting construction method

Technical Field

The invention relates to a grouped drilling pile planting construction method for planting a precast pile into a stratum after drilling, hole forming, grouting and stirring.

Background

In the continuous development process of urban construction, land resources are less and less, and house buildings are developed to high floors, so that the requirements of high floors and super high-rise buildings on the bearing capacity of pile foundations are higher and higher, the requirements on the buildings for preventing settlement and deformation are higher and higher, and the requirements of the buildings on uplift resistance and horizontal resistance are higher and higher. In order to meet the requirements of bearing capacity and deformation control, deep and long pile foundations are often adopted in the prior art, the performance requirements of pulling resistance, horizontal force resistance and the like cannot be met in hammering type or static pressure type pipe pile construction, and bored piles (embedded type) are basically adopted for foundations with dynamic load requirements of high-rise buildings, super high-rise buildings, roadbeds and the like, but the bored piles are high in manufacturing cost, unstable in quality, long in single-pile construction time, and polluted in environment due to slurry discharge, and do not accord with the environmental protection idea.

As the country greatly promotes the building industrialization and green construction, higher requirements are put forward for construction enterprises. Various newly-built commercial buildings, civil buildings and industrial plants gradually adopt fabricated buildings, so that the proportion of the fabricated buildings is improved. Therefore, the static drilling root planting pile construction technology integrating drilling, deep layer stirring, head expanding and various pile foundation prefabrication technologies is rapidly popularized and developed, the construction technology has the characteristics of industrial prefabrication of pile materials, energy conservation, environmental protection and material conservation and consumption reduction, can replace the drilling filling pile under certain conditions, has the function of a non-soil-squeezing pile penetrating through various rock-soil layers, large diameter and high bearing capacity, greatly reduces the slurry discharge amount, saves water and land, and protects the environment; the single-pile construction efficiency is improved by 4-5 times; social resources are saved; the bearing capacity of the single-side concrete is improved by 2-3 times, raw materials are saved, and resources are fully utilized. The static drilling rooted pile construction technology leads a new direction of green construction in the field of pile foundation construction, and effectively solves the environmental damage influence caused by pile driving noise, pile driving hammer air pollution and pile driving and soil squeezing caused by precast pile construction; on the other hand, the construction process of the cast-in-situ bored pile with large bearing capacity in urban areas can be replaced, and the quality defects of hole shrinkage, pile body mud inclusion, excessive hole bottom sediment and the like caused by hole congestion of the cast-in-situ bored pile are overcome; the pile materials are prefabricated in factories, the quality is guaranteed, and the waste of field materials is avoided; meanwhile, the method has good adaptability to rock-soil layers, has small influence on soil squeezing effect, greatly reduces the discharge amount of slurry, solves the problem of difficult slurry discharge land in urban areas, and saves land. The application development of the precast pile is facilitated, the development of the green pile foundation technology is complied with, and the application field of the precast pile is further expanded. Therefore, the static drilling root-planting pile technology has obvious benefits from the technical and economic aspects, accords with the sustainable development concept, and has good popularization prospect.

In the prior art, a single-shaft stirring drilling machine is generally arranged on a pile frame upright post, a drill rod and the drilling tool cut soil downwards to drill holes, and water or bentonite mixed liquid is injected while drilling the holes, and meanwhile, an arc-shaped wall protection block on the drill rod can correct and protect the wall of a pre-drilled hole body until the drill rod reaches the position near a bearing stratum required by design. In the whole process of drilling and pore-forming, because of the height of an upright column of a matched pile frame, the structural type of an upright column guide rail and the bearing capacity of the pile frame, the connection of a drill rod and a drill bit can not be completed at one time and the drill rod and the drill bit are installed on the upright column of the pile frame, only the length of the drill rod is continuously connected by an operator along with the increase of the drilling depth, and the connection of the drill rod generally requires the steps of disassembling a drill rod joint pin shaft, lifting a power head, disconnecting an upper drill rod (drilling tool) and a lower drill rod (drilling tool), flushing a male joint and a female joint of the upper drill rod (drilling tool) and the lower drill rod (drilling tool) by a high-pressure water gun, hoisting the drill rod by a crane, aligning and locking a lower joint of the hoisting drill rod and an earth-entering drill rod joint, descending the; after the drilling depth is reached, cement slurry is injected into the pile end through a drill rod and a drill bit inner cavity pipeline, and the pile end cement slurry is repeatedly stirred up and down to keep the uniformity of the pile end cement slurry; when all drill rods and drill bits are lifted out of the earth, an operator can only operate the winch to lift the power head to sequentially lift each drill rod, pull out the pin shafts at the male and female joints of the upper and lower drill rods (drilling tools) and pull out the adjacent two drill rods or drilling tools after the drilling tools are separated. And repeating the steps to extract all drill rods or drill tools. Therefore, operators spend much time on connecting and disconnecting the drill rods in the two stages of drilling down and pulling out, and the pile planting construction efficiency is seriously influenced; in addition, because the grouting and stirring construction is carried out in the pre-drilling hole, certain time and progress requirements are met, the pile planting quality of the precast pile can be influenced by excessive frequent drilling rod and drilling tool connection procedures, and the technical performance of the implanted pile is further reduced. Therefore, it is necessary to develop a pile-planting construction apparatus which can effectively improve the pile-planting efficiency and reduce the steps of joining and detaching between drill rods and drilling tools in the construction process.

Disclosure of Invention

The invention mainly aims to overcome the defects of the existing pile planting machine, and provides a grouped drilling pile planting construction method which achieves accurate butt joint between drill rods fixedly arranged at the lower ends of two groups of power head assemblies arranged on an upright guide rail of a pile frame through transverse moving and fine adjustment of a walking pile frame, realizes sequential drilling, grouting, stirring and prefabricated pile implantation of the two groups of power head assemblies, avoids frequent butt joint and disassembly between the drill rods and drilling tools, reduces the operation intensity of operators, improves the operation efficiency of drilling pile planting, further ensures the pile planting construction quality, and greatly reduces the equipment purchase cost.

In order to achieve the above purpose, the solution adopted by the invention is as follows:

a grouped drilling pile planting construction method comprises the following steps: 1) preparation before construction, a) cleaning a construction site, keeping a road surface smooth, and ensuring safety of a construction area without low-altitude high-voltage wires; b) adjusting and determining longitudinal and transverse directions by using a theodolite, and using the theodolite as a reference for walking and shifting of a pile frame chassis of the walking pile frame; c) assembling a walking pile frame, namely hoisting and arranging two transverse walks and two longitudinal walks of a walking mechanism in front of a pile planting station along the transverse direction and the longitudinal direction determined by a theodolite respectively by utilizing hoisting equipment, arranging a jacking mechanism below a pile frame chassis, and fixedly installing the upper ends of a front jacking oil cylinder, a rear jacking oil cylinder, a left jacking oil cylinder and a right jacking oil cylinder below the front part and the rear part and the left part and the right part of the pile frame chassis respectively, and fixedly installing the lower ends of the front jacking oil cylinder, the rear jacking oil cylinder, the left jacking oil cylinder and the right jacking oil cylinder on the two transverse walks and the two longitudinal walks of the walking mechanism respectively to finish the installation; the front part of the pile frame chassis is provided with a vertical column formed by butting a plurality of sections of vertical column barrels with two pairs of guide rails, a top pulley yoke and two inclined support rods; the upright post of the walking pile frame is positioned right ahead of the pile frame chassis; the two inclined support rods are symmetrically arranged at the left side and the right side of the upright post, one end of each inclined support rod is hinged to the support at the back of the upright post barrel in the middle of the upright post, and the other end of each inclined support rod is hinged to the supports at the left rear part and the right rear part of the pile frame chassis; the left side and the right side of the upright post cylinder are arranged along the vertical direction of the upright post cylinder in a V-shaped symmetrical mode, and a pair of left long guide rails and right long guide rails are respectively formed on the left side and the right side of the upright post after being connected with each other; the top pulley yoke is fixedly arranged at the upper end part of a section of upright post cylinder at the top end of the upright post, and the front end of the top pulley yoke is provided with two pulley blocks which are arranged in a V-shaped symmetrical mode; 2) installing two groups of power head assemblies, a) respectively enabling steel wire ropes led out from two groups of hoisting mechanisms on a pile frame chassis of the walking pile frame to pass through two pulley blocks of a pulley yoke at the top of the walking pile frame and then to bypass a hoisting pulley of each group of power head assemblies, and properly connecting the two groups of power head assemblies; b) two groups of power head assemblies are respectively arranged on two pairs of long guide rails of an upright post of a walking pile frame through back guide blocks on a rack of the power head assemblies, two groups of hoisting mechanisms on a pile frame chassis of the walking pile frame are operated to respectively hoist the two groups of power head assemblies to different heights along the two pairs of long guide rails of the upright post, wherein a plurality of sections of drill rods with stirring blades and arc surface protection blocks, a spiral drill rod with spiral blades and a drilling tool are fixedly arranged after a connecting disc is arranged at the lower end of a hollow output shaft of a first group of power head assemblies, and a plurality of sections of drill rods with stirring blades and arc surface protection blocks are fixedly arranged after a connecting disc is arranged at the; c) supporting frames are respectively installed below the two pairs of long guide rails of the upright post, and each supporting frame is respectively and fixedly installed on the two pairs of long guide rails through a pair of guide plates at the rear end of each supporting frame; d) the upright post travelling mechanism is controlled to move along the transverse direction of the pile planting station for fine adjustment, so that the rotating centers of a first group of power head assemblies and drill rods thereof, spiral drill rods and drilling tools which are arranged on a pair of left long guide rails are aligned to the center of the pile planting station; e) connecting cables and grouting pipelines of the two power head assemblies with a control system and a background grouting system respectively, wherein a grouting pipe is communicated with the grouting pipeline of an inner cavity of the grouting pipe through a rotary joint at the upper end of a hollow output shaft to perform a no-load operation test, so that the construction requirements are met; 3) and a control system is operated, a vertical motor of the first power head assembly is started to rotate in the forward direction, a hoisting mechanism of the walking pile frame is operated to enable the power head assembly to move downwards along a pair of left long guide rails of the stand column, so that a plurality of sections of drill rods with stirring blades and arc surface protection blocks, the spiral drill rods with spiral blades and the drilling tools are driven to rotate in the forward direction and drill downwards into a cutting soil layer, and the drilling depth L1 is finished. The cutting wings of the drilling tool at the lowest end are used for drilling, the helical blades of the helical drill rod are convenient for dumping and stirring, the stirring blades arranged on the outer wall of the drill rod are convenient for fully stirring soil, and the cambered surface protection blocks arranged on the outer wall of the drill rod are used for extruding and protecting the formed holes, so that smooth and compact hole walls can be formed; the support frames fixedly arranged on the left long guide rails at the lower ends of the stand columns guide and support the drilling tool, the spiral drill rod and the drill rod, and drilling precision and pore-forming quality are effectively guaranteed. After drilling and digging operations are completed when a plurality of sections of drill rods, spiral drill rods and drilling tools all enter the stratum, the vertical motor is turned off, the power head assembly stops running, an operator enters a pile planting station to detach a locking pin shaft at the joint of a male joint of the uppermost drill rod section exposed out of the ground and a female joint of the connected drill rod section at the output end connecting disc of the hollow output shaft, a first group of power head assemblies are lifted along a pair of left long guide rails of the upright column to be completely separated from the drill rod section, and a travelling mechanism of the pile frame is operated to travel leftwards for a distance of H along the transverse direction of the pile planting station; 4) and when the second group of power head assembly and the plurality of sections of drill rods fixedly arranged on the second group of power head assembly reach a pile planting station, the second group of power head assembly is put down along a pair of long guide rails on the right side of the upright column, so that the female joint of the section of drill rod at the lowest end of the plurality of sections of drill rods fixedly arranged at the lower end of the second group of power head assembly is aligned to the male joint of the section of drill rod exposed out of the stratum, and the second group of power head assembly is locked by a pin shaft after being inserted in. And operating the control system, starting the vertical motor of the second group of power head assembly to rotate in the forward direction, operating the hoisting mechanism of the pile frame to release a steel wire rope to enable the power head assembly to move downwards along the pair of right long guide rails of the upright column, thereby driving a plurality of sections of drill rods with stirring blades and cambered surface protection blocks, spiral drill rods with spiral blades and drilling tools to rotate in the forward direction and continuously drill downwards into a cut soil layer to finish the drilling depth L2, and thus, the total drilling depth reaches L1+ L2. The cutting wings of the drilling tool at the lowest end are used for drilling, the helical blades of the helical drill rod are convenient for soil discharging and stirring, the stirring blades arranged on the outer wall of the drill rod are convenient for fully stirring soil, and the cambered surface protection blocks arranged on the outer wall of the drill rod are used for extruding and protecting the formed holes, so that smooth and compact hole walls can be formed. The support frames fixedly arranged on the pair of right long guide rails at the lower ends of the stand columns guide and support the drilling tool, the spiral drill rod and the drill rod, and drilling precision and pore-forming quality are effectively guaranteed. Operating the second group of power head assemblies and the drill rods, the spiral drill rods and the drilling tools which are fixedly arranged on the second group of power head assemblies to continuously drill and cut along a pair of right long guide rails of the stand column until the depth of the soil bearing stratum which meets the design requirement is reached; 5) the second group of power head assembly and the multiple sections of drill rods, the spiral drill rod and the drilling tool carry out guniting and stirring operation, a hoisting mechanism of the walking pile frame is operated to discharge a steel wire rope, the second group of power head assembly and the multiple sections of drill rods, the spiral drill rod and the drilling tool are lifted along a pair of right long guide rails of the stand column, a preparation and supply slurry system equipped at the background is operated at the same time, solidified cement slurry is injected into inner cavities of the hollow output shaft, the multiple sections of drill rods, the spiral drill rod and the drilling tool through a grouting pipeline, and finally, grouting holes are formed by a grouting hole arranged at the lower end part of the drilling tool for rotary grouting, so that the solidified cement slurry is injected into the forming holes and fully stirred with original soil in the process of lifting the multiple sections of drill rods, the spiral drill rods and the drilling tool; 6) lifting and disassembling multiple sections of drill rods, spiral drill rods and drilling tools, a) operating a second group of power head assemblies to move upwards along a pair of right long guide rails of the stand column, when the second group of power head assemblies move upwards to a limited position of the guide rails, disassembling a female joint of one drill rod connected with the lower end of the second group of power head assemblies and a locking pin shaft at the joint of a male joint of the uppermost drill rod in the multiple sections of drill rods connected with the lower end of the second group of power head assemblies, lifting all the extracted multiple sections of drill rods by using a crane, disassembling the female joint of the endmost drill rod in the extracted multiple sections of drill rods and the locking pin shaft at the joint of the male joint of the one drill rod exposed out of the ground, and lifting the multiple sections of drill rods; b) operating a second group of power head assemblies to descend along a pair of right long guide rails of the stand column, aligning a female joint of a section of drill rod connected with the lower end of the second group of power head assemblies with a male joint of a section of drill rod exposed out of the ground, and locking the second group of power head assemblies by using a pin shaft; operating the hoisting mechanism to discharge a steel wire rope to lift a second group of power head assemblies, lifting the rest of the multiple sections of drill rods, spiral drill rods and drilling tools left in the stratum to the ground, dismounting all the drill rods, spiral drill rods and drilling tools, dismounting locking pin shafts at the connecting positions of connecting discs at the lower ends of the second group of power head assemblies and male joints of the uppermost drill rod in the multiple sections of drill rods connected below the second group of power head assemblies, separating the multiple sections of drill rods from the second group of power head assemblies, and then using a crane to hoist the multiple sections of drill rods, spiral drill rods and drilling tools to a stacking position; 7) implanting a precast pile, namely a) installing a pile feeding cap at a connecting disc of a second group of power head assemblies, and hoisting the precast pile to be implanted into a pile implanting hole by using a crane, wherein the precast pile sinks into the pile implanting hole by means of dead weight; b) operating the second group of power head assembly to move downwards along a pair of right long guide rails of the upright post of the walking pile frame, so that the pile feeding cap is sleeved on the pile head of the precast pile after moving downwards along with the second group of power head assembly; b) and continuously operating a hoisting mechanism of the walking pile frame to enable the second group of power head assemblies and the pile feeding caps connected with the second group of power head assemblies to descend, pressing the precast pile into a drilled hole by means of the self weight of the precast pile and the weight of the second group of power head assemblies to finally reach the designed elevation, and forming an integrated pile planting body foundation by the precast pile, the pile end and the soil body around the pile after the pile end and the solidified cement paste around the pile are hardened.

Preferably, in step 3), the vertical motors in the two groups of power head assemblies are both started and controlled by 8-pole variable frequency motors and external frequency converters, so that stepless regulation and control of the rotating speed and torque of the hollow output shaft, the multiple sections of drill rods, the spiral drill rod and the drilling tool are realized.

Preferably, in step 5), the rotation speed of the second group of power head assemblies, the multiple sections of drill rods, the auger rods and the drilling tool which are fixedly mounted on the second group of power head assemblies, which are lifted and stirred during grouting, is controlled and adjusted through an external frequency converter so as to meet the technical requirements of the injection and stirring speed of the cured cement slurry required in unit time.

Preferably, in step 7), the gap between the inner diameter of the bushing arranged in the guide through hole of the support frame and the outer diameter of the embedded precast pile is 4.00-6.00 mm, so that good guide is ensured when the precast pile is embedded into the hole.

Drawings

The grouped drilling pile planting construction method of the invention is further described with reference to the accompanying drawings and embodiments:

FIG. 1 is a schematic structural diagram of a grouped drilling and pile planting system according to the present invention;

FIG. 2 is a left side view of the powerhead assembly, drill string, auger string and drill section of FIG. 1;

FIG. 3 is a sectional view taken along line A-A of FIG. 1;

FIG. 4 is a top view of FIG. 1;

FIG. 5 is a schematic diagram of the mechanism of the drill rod in the grouped drilling and pile planting system according to the present invention;

FIG. 6 is a top view of FIG. 5;

FIG. 7 is a schematic illustration of the two sets of powerhead assemblies of the present invention in place;

FIG. 8 is a schematic view of a first group of the power head assemblies and their drill rods, agitator drill rods, and drilling tools in a downhole cutting operation according to the present invention;

FIG. 9 is a schematic view of the second power head assembly completing the drill pipe, drill pipe agitator and drill tool connection operation after the pile carriage has traversed its path in the present invention;

FIG. 10 is a schematic illustration of a second group of power head assemblies of the present invention and their drill rods, agitator drill rods and drilling tools for downhole cutting, grouting and blending operations.

Detailed Description

As shown in fig. 1-6, a grouped drilling, drilling and pile planting system comprises two groups of power head assemblies 1, 1', a plurality of sections of drill rods 3 with stirring blades 31 and arc surface protection blocks 32, spiral drill rods 7 with spiral blades 71, a drilling tool 4 with cutting wings 42, two support frames, a walking pile frame 5 and a control system comprising a drilling machine control system, a pile frame control system and a grouting control system, wherein each group of power head assemblies 1 comprises a lifting pulley 11, a frame 12 with a back guide block 121, a vertical motor and a reduction gearbox 122 and a grouting pipeline, and the reduction gearbox 122 is provided with a hollow output shaft 124; the arc-shaped protection block 32 comprises an arc-shaped plate 321, an inserting plate 322 and a socket 323; the walking pile frame 5 comprises a main machine chassis 51 with at least two groups of hoisting mechanisms, a jacking mechanism 56 with a front and rear jacking oil cylinder 561,561 'and a left and right jacking oil cylinder 562,562', a walking mechanism 55 with two transverse walks 551,551 'and two longitudinal walks 552,552', an upright post 52 formed by butting upright post cylinders 521 with two pairs of guide rails 522, 522 ', a top pulley frame 53 and two inclined support rods 54, 54'; the follow-up cradle 8 comprises a cradle body 82 with a guide hole 821, a cradle guide block 81 located at the rear end of the cradle body, and an inner bushing 83; the support frame 6 includes a frame body 62 having a guide through hole 621, a pair of guide plates 61 and a bush 63 at the rear of the frame body; wherein:

the upright column 52 of the walking pile frame 5 is positioned right in front of the host chassis 51; the two inclined support rods 54 and 54' are symmetrically arranged at the left side and the right side of the upright column 52, one end of each inclined support rod is hinged to a support at the back of the upright column barrel 521 at the upper end in the upright column 52, and the other end of each inclined support rod is hinged to supports at the left rear part and the right rear part of the host chassis 51; the two pairs of guide rails 522, 522' of the upright cylinder 521 are arranged on the left and right sides of the upright cylinder in a V-shaped symmetrical mode along the vertical direction of the upright cylinder, and after being connected with each other, two pairs of long guide rails are respectively formed on the left and right sides of the upright 52; the top pulley yoke 53 is fixedly arranged at the upper end part of a section of the upright post barrel 521 at the top end of the upright post 52, and the front end of the top pulley yoke is provided with two pulley blocks 531,531' which are arranged in a V-shaped symmetrical manner; the jacking mechanism 56 is arranged below the pile frame chassis 51, the upper ends of a front and a rear jacking oil cylinder 561,561 'and a left and a right jacking oil cylinder 562,562' of the jacking mechanism are fixedly arranged below the front and the rear parts and below the left and the right parts of the pile frame chassis 51 respectively, and the lower ends of the front and the rear jacking oil cylinders 561,561 'and the left and the right jacking oil cylinders 562,562' are fixedly arranged on two transverse steps 551,551 'and two longitudinal steps 552,552' of the walking mechanism 55 respectively.

The two groups of power head assemblies 1 and 1' are respectively arranged on two pairs of long guide rails of the upright post 52 of the pile frame 5 through back guide blocks 121 on the machine frame 12, and the center distance between the hollow output shafts 224 of the reduction gearbox 122 of the two groups of power head assemblies in the left-right direction of the cross section of the upright post 52 is H; the steel wire ropes led out from the two groups of hoisting mechanisms of the host chassis 51 respectively pass through the two pulley blocks 531,531 ' of the pulley yoke 53 at the top of the walking pile frame 5 and then bypass the hoisting pulleys 11 of each group of power head assemblies 1,1 ', so that each group of power head assemblies 1,1 ' can respectively carry out hoisting and descending motions on the two pairs of long guide rails of the upright post 52.

The hollow output shafts 124 of the reduction gearbox 122 of the two groups of power head assemblies 1 and 1' are respectively installed in a way of vertically penetrating through the box body of the reduction gearbox 12, and the upper ends of the hollow output shafts are fixedly provided with rotary joints and then are connected with a grouting pipeline; wherein, the lower end of the hollow output shaft 224 of one power head assembly 1 is provided with a connecting disc and then is sequentially and fixedly provided with a plurality of drill rods 3, a spiral drill rod 7 and a drilling tool 4, and the lower end of the hollow output shaft 224 of the other power head assembly 1' is provided with a connecting disc and then is fixedly provided with a plurality of drill rods 3; the vertical motor of each group of power head assembly 1 adopts a starting control mode of an 8-pole variable frequency motor and an external frequency converter, so that the regulation control of the output rotating speed and the output torque of the hollow output shaft 124 is realized, and the stepless regulation and control of the rotating speed and the torque of the multi-section drill rod 3, the spiral drill rod 7 and the drilling tool 4 are realized. According to the starting control mode, the 8-pole variable frequency motor is adopted, so that the high-speed or low-speed long-time stability of the motor is ensured, the effective heat dissipation is realized, and the drilling and digging operation requirements of low speed and large torque are met. The external frequency converter can realize the soft start of the motor, avoid the occurrence of heavy current when the motor is started, realize the stepless adjustment control of high-precision rotating speed and torque in a larger range of the motor, adapt to the changes of different stratum structures and complex stratums, effectively ensure the smooth drilling, digging, stirring and pile planting construction process, and further improve the drilling and digging operation efficiency.

Three arc surface protection blocks 32 of the drill rod 3 are arranged above the outer wall of the drill rod body 30 in a radial symmetrical mode, and the stirring blades 31 are arranged on the outer wall of the drill rod body 30 in a mode of being positioned below the wall protection ring 32; the inner wall of each arc protection block 32 is provided with a socket 323, each insertion plate 322 is radially and symmetrically arranged on the outer wall of the drill rod body 30 of the drill rod 3, and each arc protection block 32 is locked on the socket 323 through the insertion plate 322 thereof by a pin shaft. Like this, at two sets of unit head assemblies, drilling rod, stirring drilling rod and drilling tool during creep into and promote the stirring downwards, this cambered surface protects the piece and can extrude and protect the wall to the pore-forming inner wall, forms smooth inseparable internal wall of hole, is convenient for guarantee the construction quality of planting a pile. If the abrasion of the cambered surface protection block exceeds the specified limit size, the cambered surface protection block can be conveniently replaced by disassembling the pin shaft, the maintenance cost of a user is effectively reduced, and the construction efficiency of the drilling machine is improved.

The guide through hole 621 of the support frame 6 is positioned at the front end of the frame body 62, a bush 63 is arranged in the guide through hole, and the bush 63 consists of two symmetrical semicircular or three symmetrical arc-shaped inner bushes; when the abrasion of the inner hole of the bushing exceeds the specified limit size in the using process, each arc-shaped inner bushing can be conveniently detached and replaced by a new arc-shaped inner bushing, and the construction cost is effectively reduced. The two support frames 6 are respectively fixedly mounted on two pairs of long guide rails of the upright 52 through guide plates 61 thereof.

The multiple sections of drill rods 3, the spiral drill rods 7 and the drilling tools 4 connected with the lower end of one power head assembly 1 in the two groups of power head assemblies and the multiple sections of drill rods 3 connected with the other power head assembly 1 respectively penetrate through the inner walls of the bushes 63 arranged in the front end guide through holes 621 of the supporting frames 5 to drill and cut the stratum. The fit clearance between the maximum rotating diameter of the stirring blade 31 of the multi-section drill rod 3 and the cutting wing 42 of the drilling tool 4 and the inner diameter of the bush 63 arranged in the front end guide hole 821 of the follow-up guard 8 and the guide through hole 62 of the support frame 6 is 8.00-12.00 mm. Therefore, when two groups of power head assemblies and a plurality of sections of drill rods, spiral drill rods and drilling tools of the power head assemblies drill downwards, drilling, grouting and stirring stability of the power head assemblies are ensured due to double guiding and supporting of the follow-up protective frame 8 and the supporting frame 6, and construction quality of drilling and pile planting is improved.

The drilling machine control system of the control system controls the operation of two groups of power head assemblies 1, 1', a plurality of sections of drill rods 3, a spiral drill rod 7 and a drilling tool 4, the pile frame control system controls the operation/movement of at least two groups of hoisting mechanisms, a jacking mechanism 56 and a walking mechanism 55 of a walking pile frame 6, and the grouting control system controls the operation of a background slurry preparation and supply system; the operation system displays and controls operation parameters, technical parameters and construction parameters in the drilling and pile planting construction, and realizes storage and printout of related construction parameters. The control system adopts an intelligent control technology to display the actual construction data of the drilling machine and the operation condition of the grouting system through the control console, can record and store the data of the drilling and grouting processes, print data tables and graphic curves, and can provide the analysis basis for the whole drilling and pile planting construction process for users. The display parameters of the manipulation system include: the rotating speed, the working temperature and the rotating direction of a vertical motor in a power head assembly, the rotating speed, the steering direction and the torque of a drilling tool/a drill rod, the drilling (stirring) depth, the working pressure, the flow and the hydraulic oil temperature of a walking pile frame hydraulic system, the inclination of the walking pile frame and the drawing force of the pile frame, the pressure of a grouting pump, the instantaneous cement slurry amount, the total slurry amount, the actual total slurry amount and the total water injection amount of a slurry supply system, the longitudinal/transverse moving speed of a pile frame chassis, the pile forming mark after pile planting and the like.

Referring to fig. 1 to 10, the construction method provided by the present invention includes the following steps:

step 1: preparation before construction

a) Cleaning a construction site, keeping a road surface smooth, and ensuring the safety of a construction area without low-altitude high-voltage wires;

b) the theodolite is used for adjusting and determining the longitudinal direction and the transverse direction to be used as the reference of the walking displacement of the pile frame chassis 51 of the walking pile frame 5;

c) assembling the walking pile frame 5, hoisting two transverse walking tracks 551,551 'and two longitudinal walking tracks 552,552' of the walking mechanism 55 respectively along the transverse direction and the longitudinal direction determined by the theodolite and arranging the two transverse walking tracks 551,551 'and the two longitudinal walking tracks 552,552' in front of a pile planting station by utilizing hoisting equipment, arranging the jacking mechanism 56 below the pile frame chassis 51, fixedly installing the upper ends of a front jacking oil cylinder 561,561 'and a rear jacking oil cylinder 562,562' of the jacking mechanism and the upper ends of a left jacking oil cylinder 562,562 'and a right jacking oil cylinder 562,562' of the jacking mechanism respectively under the front part, the rear jacking oil cylinder 561,561 'and the left jacking oil cylinder 562,562' of the jacking mechanism and the lower ends of the two transverse walking tracks 551,551 'and the two longitudinal walking tracks 552,552' of the; the front part of the pile frame chassis 51 is provided with a vertical column 52 formed by butting a plurality of sections of vertical column barrel 521 with two pairs of guide rails 522 and 522 ', a top pulley frame 53 and two inclined support rods 54 and 54'; the upright post 52 of the walking pile frame 5 is positioned right in front of the pile frame chassis 51; the two inclined supporting rods 54, 54' are symmetrically arranged at the left side and the right side of the upright post 52, one end of each inclined supporting rod is respectively hinged on a support at the back of a section of upright post barrel 521 near the upper end in the upright post 52, and the other end of each inclined supporting rod is respectively hinged on supports at the left rear part and the right rear part of the pile frame chassis 51; the two pairs of guide rails 522, 522' of the upright cylinder 521 are arranged at the left and right sides of the upright in a V-shaped symmetrical mode along the vertical direction of the upright, and after being connected with each other, a pair of left long guide rails and right long guide rails are respectively formed at the left and right sides of the upright 52; the top pulley bracket 53 is fixedly arranged at the upper end part of a section of the upright post barrel 521 at the top end of the upright post 52, and the front end of the top pulley bracket is provided with two pulley blocks 531,531' which are arranged in a V-shaped symmetrical mode.

Step 2: installing two groups of power head assemblies 1, 1'

a) Respectively enabling steel wire ropes led out from two groups of hoisting mechanisms on a pile frame chassis 51 of the walking pile frame 5 to pass through two pulley blocks 531,531 ' of a pulley yoke 53 at the top of the walking pile frame 5 and then to bypass a hoisting pulley 11 of each group of power head assemblies 1 and 1 ', and connecting the two groups of power head assemblies 1 and 1 ';

b) two groups of power head assemblies 1 and 1 'are respectively arranged on two long guide rails of an upright post 52 of a walking pile frame 5 through a back guide block 121 on a frame 12 of the power head assemblies, two groups of hoisting mechanisms on a pile frame chassis 51 of the walking pile frame 5 are operated to respectively hoist the two groups of power head assemblies 1 and 1' to different heights along two pairs of long guide rails of the upright post 52, wherein a plurality of sections of drill rods 3 with stirring blades 31 and arc surface protection blocks 32, a plurality of sections of spiral drill rods 7 with spiral blades 71 and a plurality of sections of drill rods 4 are fixedly arranged after a connecting disc is arranged at the lower end of a hollow output shaft 224 of a first group of power head assemblies 1;

c) support frames are respectively arranged below the two pairs of long guide rails of the upright column 52, and each support frame 6 is respectively and fixedly arranged on the two pairs of long guide rails through a pair of guide plates 64 at the rear end of the support frame;

d) the travelling mechanism of the stand column 52 is controlled to move along the transverse direction of the pile planting station for fine adjustment, so that the rotating centers of the first group of power head assemblies 1, the drill rods 3, the spiral drill rods 7 and the drilling tools 4 which are arranged on a pair of left long guide rails of the stand column are aligned to the center of the pile planting station;

e) cables and grouting pipelines of the two power head assemblies 1 and 1' are respectively connected with the control system and the back-stage grouting supply system, wherein a grouting pipe is communicated with the grouting pipeline of the inner cavity of the grouting pipe through a rotary joint at the upper end of the hollow output shaft 124, and no-load operation test is carried out, so that the construction requirements are met.

And step 3: first group of power head assembly 1, drill rod 3, spiral drill rod 7 and drilling tool 4 of first group of power head assembly

And operating the control system, starting the vertical motors of the first group of power head assemblies 1 to rotate in the forward direction, operating the hoisting mechanism of the pile frame 5 to enable the power head assemblies to descend along the pair of left long guide rails of the upright post 52, and driving the plurality of sections of drill rods 3 with the stirring blades 31 and the retaining rings 32, the spiral drill rods 7 with the spiral blades 71 and the drilling tools 4 to rotate in the forward direction and drill the cut soil layer downwards, so that the drilling depth L1 is completed. The cutting wings of the drilling tool 4 at the lowest end are used for drilling, the helical blades 71 of the helical drill rod 7 are convenient for soil dumping and stirring, the stirring blades 31 arranged on the outer wall of the drill rod 3 are convenient for fully stirring soil, and the wall protection ring 32 arranged on the outer wall of the drill rod 3 is used for extruding and protecting to form holes, so that smooth and compact hole walls can be formed; the support frame 6 fixedly arranged on a pair of left long guide rails at the lower end of the upright column 52 guides and supports the drilling tool 4, the spiral drill rod 7 and the drill rod 3, so that the drilling precision and the pore-forming quality are effectively ensured. After drilling and digging operations are completed when all the multiple sections of drill rods 3, the spiral drill rod 7 and the drilling tool 4 enter the stratum, the vertical motor is turned off, the power head assembly stops running, an operator enters a pile planting station to detach a locking pin shaft at the joint of a male joint of the uppermost drill rod section 3 exposed out of the ground and a female joint of the drill rod section 3 connected with an output end connecting disc of the hollow output shaft 124, the first group of power head assembly 1 is lifted along a pair of left long guide rails of the upright column 52 to be completely separated from the drill rod section 3, and a travelling mechanism of the pile frame 5 is operated to travel leftwards along the transverse direction of the pile planting station for a distance of H; the vertical motors in the two power head assemblies 1 and 1' adopt a starting control mode of an 8-pole variable frequency motor and an external frequency converter, and stepless regulation and control of the rotating speed and the torque of the hollow output shaft 124, the multi-section drill rod 3, the spiral drill rod 7 and the drilling tool 4 are realized.

And 4, step 4: second group of power head assembly 1' and drilling rod 3, spiral drilling rod 7 and drilling tool 4 thereof for drilling and cutting

When the second group of power head assembly 1 ' and the plurality of sections of drill rods 3 fixedly mounted on the second group of power head assembly 1 ' reach a pile planting station, the second group of power head assembly 1 ' is put down along a pair of right long guide rails of the upright column 52, so that the female joint of the lowermost section of drill rod 3 in the plurality of sections of drill rods fixedly mounted at the lower end of the second group of power head assembly is aligned to the male joint of the section of drill rod 3 exposed out of the stratum, and the second group of power head assembly. And operating the control system, starting the vertical motor of the second group of power head assembly 1' to rotate in the forward direction, operating the hoisting mechanism of the pile frame 5 to discharge a steel wire rope to enable the power head assembly to descend along a pair of right long guide rails of the upright post 5, thereby driving the multiple sections of the drill rod 3 with the stirring blades 31 and the retaining ring 32, the spiral drill rod 7 with the spiral blades 71 and the drilling tool 4 with the expansion wings 41 to rotate in the forward direction and continuously drill the cut soil layer downwards, and completing the drilling depth L2, so that the total drilling depth reaches L1+ L2. The cutting wings of the drilling tool 4 at the lowest end are used for drilling, the helical blades 71 of the helical drill rod 7 are convenient for dumping and stirring, the stirring blades 31 arranged on the outer wall of the drill rod 3 are convenient for fully stirring soil, and the wall protection ring 32 arranged on the outer wall of the drill rod 3) is extruded to protect the formed hole, so that the smooth and compact hole wall is favorably formed. The support frame 6 fixedly arranged on a pair of right long guide rails at the lower end of the upright column 52 guides and supports the drilling tool 4, the spiral drill rod 7 and the drill rod 3, so that the drilling precision and the pore-forming quality are effectively ensured. And operating the second group of power head assemblies 1' and the drill rods 3, the spiral drill rods 7 and the drilling tool 4 which are fixedly arranged on the second group of power head assemblies to continuously drill and cut along a pair of long right guide rails of the upright post 52 until the depth of the soil bearing stratum required by the design is reached.

And 5: the second group of power head assembly 1' and the multiple sections of drill rods 3, the spiral drill rod 7 and the drilling tool 4 thereof carry out stirring and guniting operation

A hoisting mechanism of the walking pile frame 5 is operated to release a steel wire rope, a second group of power head assemblies 1' and a plurality of sections of drill rods 3, a spiral drill rod 7 and a drilling tool 4 of the second group are lifted along a pair of right long guide rails of the upright column 52, a slurry preparation and supply system equipped at the background is operated at the same time, solidified cement slurry is injected into inner cavities of the hollow output shaft 124, the plurality of sections of drill rods 3, the spiral drill rod 7 and the drilling tool 4 through a grouting pipeline, and finally grouting holes formed by grouting holes arranged at the lower end part of the drilling tool 4 are used for rotary grouting, so that the solidified cement slurry is injected into the holes to be fully stirred with original soil in the process of lifting the plurality of sections of drill rods 3, the spiral drill rod 7 and the drilling tool 4, the hole body is uniform. The rotation speed of the second group of power head assembly 1' and the plurality of sections of drill rods 3, the spiral drill rod 7 and the drilling tool 4 for lifting and grouting stirring is controlled and adjusted through an external frequency converter so as to meet the technical requirements of the injection and stirring speed of the solidified cement slurry required in unit time.

Step 6, lifting and disassembling the sections of the drill pipe 3, the spiral drill pipe 7 and the drilling tool

a) Operating a second group of power head assemblies 1 ' to move upwards along a pair of right long guide rails of the upright column 52, when the second group of power head assemblies 1 ' move upwards to a limited position of the guide rails, detaching a female joint of a section of drill rod 3 connected with the lower end of the second group of power head assemblies 1 ' and a locking pin shaft at the joint of a male joint of the uppermost section of drill rod 3 in a plurality of sections of drill rods 3 connected with the lower end of the second group of power head assemblies, using a crane to hang all pulled sections of drill rods 3, detaching the female joint of the section of drill rod 3 at the tail end in the pulled sections of drill rods 3 and the locking pin shaft at the joint of the male joint of the section of drill rod 3 exposed out of the ground, and using the crane to hoist and;

b) operating the second group of power head assemblies 1' to descend along a pair of right long guide rails of the upright column 52, aligning a female joint of a section of drill rod 3 connected with the lower end of the second group of power head assemblies with a male joint of a section of drill rod 3 exposed out of the ground, and locking the second group of power head assemblies by using a pin shaft; and operating the hoisting mechanism to release the steel wire rope to lift the second group of power head assembly 1 ', lifting the rest of the multiple drill rods 3, the spiral drill rods 7 and the drilling tools 4 left in the stratum to the ground, detaching all the drill rods 3, the spiral drill rods 7 and the drilling tools 4, detaching the locking pin shaft at the male joint connection part of the connection disc at the lower end of the second group of power head assembly 1 ' and the topmost drill rod 3 in the multiple drill rods 3 connected below the connection disc, separating the multiple drill rods 3 from the second group of power head assembly 1 ', and then hoisting the detached multiple drill rods 3, spiral drill rods 7 and drilling tools 4 to a stockpile by using a crane.

Step 7, implantation of precast pile

a) A pile feeding cap is arranged at the lower end of the connecting disc of the second group of power head assembly 1', a precast pile to be implanted is hoisted into a pile planting hole by a crane, and the precast pile is sunk into the pile planting hole by the dead weight; the gap between the inner diameter of the bush 63 arranged in the guide through hole 621 of the support frame 6 and the outer diameter of the implanted precast pile is 4.00-6.00 mm, so that the precast pile is ensured to be well guided when being implanted into a hole, and the precision requirement of the implanted pile is met;

b) operating the second group of power head assembly 1 'to descend along a pair of right long guide rails of the upright column 52 of the walking pile frame 5, so that the pile feeding cap is sleeved on the pile head of the precast pile after descending along the second group of power head assembly 1';

c) and (3) continuously operating a hoisting mechanism of the walking pile frame 5 to enable the second group of power head assemblies and the pile feeding caps connected with the second group of power head assemblies to descend, pressing the precast pile into a drilled hole by virtue of the self weight of the precast pile and the weight of the second group of power head assemblies 1' to finally reach the designed elevation, and forming an integrated pile planting body foundation by the precast pile, the pile end and the soil mass around the pile after the pile end and the pile periphery are hardened by the solidified cement paste.

The grouped drilling and pile planting construction method of the invention leads two groups of power head assemblies arranged on the upright guide rail of the walking pile frame to sequentially drill, grout, stir and implant the precast pile through the control system, the walking pile frame uses a theodolite as a reference to transversely move and finely adjust along a pile planting station, ensures the precise butt joint and locking between the female joint of a drill rod fixedly arranged at the lower end of the second group of power head assemblies and the male joint exposed out of the ground on the drill rod which is fixedly arranged at the lower end of the first group of power head assemblies and drilled into the ground, realizes that the construction requirement of the drilling depth can be met only by additionally connecting the drill rod once in the drilling process, and avoids the frequent butt joint between the drill rods, the drill rod and the drilling tool, and when all drill rods and drilling tools are lifted to the ground after drilling and digging operations are finished, only the female and male connectors of the drill rods are needed to be disassembled in sequence, so that the operation intensity of operators is reduced, and the operation efficiency of drilling and pile planting is effectively improved. In addition, the inclination sensors respectively arranged on the side surfaces of the frames of the first group of power head assembly and the second group of power head assembly transmit the perpendicularity deviation value of the drilling and digging hole body monitored at any time to a control panel of the control system, so that the deviation correction is facilitated for operators, and the perpendicularity of the drilling and digging hole body is ensured to meet the design requirement. And in the pile planting process, on the one hand through changing the bearing frame on the bush internal diameter size, the direction is good when guaranteeing that the precast pile implants the pore-forming, on the other hand passes through the frame side surface mounting's of second group unit head assembly slope sensor, guarantees that the straightness that hangs down that the precast pile of implanting gets into in the pre-drilled hole reaches the designing requirement, and carry out accurate pile planting location in order to reach the design elevation requirement to the degree of depth size of implanting the pile in the pre-drilled hole, thereby further guarantee the construction quality that the stake was planted in the drilling, reduce construction unit's equipment purchasing cost.

Claims

1. A grouped drilling pile planting construction method comprises the following steps:

1) preparation before construction

b) the theodolite is used for adjusting and determining the longitudinal direction and the transverse direction to be used as the reference of the walking displacement of the pile frame chassis (51) of the walking pile frame (5);

c) assembling a walking-pedrail pile frame (5), hoisting two transverse pedrails (551,551 ') and two longitudinal pedrails (552,552') of a walking mechanism (55) by utilizing hoisting equipment along the transverse direction and the longitudinal direction determined by a theodolite respectively and arranging in front of a pile planting station, arranging a jacking mechanism (56) below a pile frame chassis (51), wherein the upper ends of a front jacking oil cylinder (561,561 ') and a rear jacking oil cylinder (562,562') are fixedly arranged below the front part, the rear part and the left part of the pile frame chassis (51) respectively, and the lower ends of the front jacking oil cylinder (561,561 ') and the left jacking oil cylinder (562,562') are fixedly arranged on two transverse pedrails (551,551 ') and two longitudinal pedrails (552,552') of the walking mechanism (55) respectively, so as to finish the installation of the pile frame chassis (51); a vertical column (52) formed by butting a plurality of sections of vertical column cylinders (521) with two pairs of guide rails (522, 522 '), a top pulley frame (53) and two inclined support rods (54, 54') are arranged at the front part of the pile frame chassis (51); the upright post (52) of the walking pile frame (5) is positioned right in front of the pile frame chassis (51); two inclined supporting rods (54, 54') are symmetrically arranged at the left side and the right side of the upright post (52), one end of each inclined supporting rod is hinged to a support on the back of a section of upright post cylinder (521) close to the upper end in the upright post (52), and the other end of each inclined supporting rod is hinged to supports on the left rear side and the right rear side of the pile frame chassis (51); two pairs of guide rails (522, 522') of the upright post cylinder (521) are arranged on the left side and the right side of the upright post cylinder in a V-shaped symmetrical mode along the vertical direction of the upright post cylinder, and after being connected with each other, a pair of left long guide rails and a pair of right long guide rails are respectively formed on the left side and the right side of the upright post (52); the top pulley yoke (53) is fixedly arranged at the upper end part of a section of upright post cylinder (521) at the top end of the upright post (52), and the front end of the top pulley yoke is provided with two pulley blocks (531,531') which are symmetrically arranged in a V shape;

2) two power head assembly (1, 1')

a) Respectively enabling steel wire ropes led out from two groups of hoisting mechanisms on a pile frame chassis (51) of the walking pile frame (5) to pass through two pulley blocks (531,531 ') of a pulley yoke (53) at the top of the walking pile frame (5), then bypassing a lifting pulley (11) of each group of power head assemblies (1, 1 '), and connecting the two groups of power head assemblies (1, 1 ');

b) two groups of power head assemblies (1, 1 ') are respectively arranged on two pairs of long guide rails of an upright post (52) of a walking pile frame (5) through back guide blocks (121) on a rack (12), two groups of hoisting mechanisms on a pile frame chassis (51) of the walking pile frame (5) are operated to respectively hoist the two groups of power head assemblies (1, 1') to different heights along the two pairs of long guide rails of the upright post (52), wherein, after the lower end of a hollow output shaft (224) of a first group of power head assembly (1) is provided with a connecting disc, a plurality of sections of drill rods (3) with stirring blades (31) and cambered surface protection blocks (32), a spiral drill rod (7) with spiral blades (71) and a drilling tool (4) are fixedly arranged, and after the lower end of the hollow output shaft (224) of a second group of power head assembly (1') is provided with a connecting disc, a plurality of sections of drill rods (3) with stirring blades (31) and cambered surface protection blocks (32) are fixedly arranged;

c) supporting frames are respectively installed below the two pairs of long guide rails of the upright post (52), and each supporting frame (6) is respectively and fixedly installed on the two pairs of long guide rails through a pair of guide plates (64) at the rear end of the supporting frame;

d) the travelling mechanism of the stand column (52) is controlled to move along the transverse direction of the pile planting station for fine adjustment, so that the rotating centers of a first group of power head assemblies (1) and drill rods (3) thereof, a spiral drill rod (7) and a drilling tool (4) which are arranged on a pair of left long guide rails of the stand column are aligned to the center of the pile planting station;

e) cables and grouting pipelines of the two power head assemblies (1, 1') are respectively connected with a control system and a back-stage grouting supply system, wherein a grouting pipe is communicated with the grouting pipeline of an inner cavity of the grouting pipe through a rotary joint at the upper end of a hollow output shaft (124) to carry out no-load operation test, so that the construction requirements are met;

3) the first group of power head assembly (1) and the drill rod (3), the spiral drill rod (7) and the drilling tool (4) thereof are drilled and cut

The control system is operated, the vertical motor of the first group of power head assembly (1) is started to rotate in the forward direction, the hoisting mechanism of the walking pile frame (5) is operated to enable the power head assembly to move downwards along the pair of left long guide rails of the upright post (52), so that a plurality of sections of drill rods (3) with stirring blades (31) and arc surface protection blocks (32), spiral drill rods (7) with spiral blades (71) and drilling tools (4) are driven to rotate in the forward direction and drill into a cutting soil layer downwards, and the drilling depth L1 is completed;

the cutting wings of the drilling tool (4) at the lowest end are used for drilling, the helical blades (71) of the helical drill rod (7) are convenient for soil dumping and stirring, the stirring blades (31) arranged on the outer wall of the drill rod (3) are convenient for fully stirring soil, and the cambered surface protection blocks (32) arranged on the outer wall of the drill rod (3) are extruded to protect the formed holes, so that smooth and compact hole walls can be formed; the drilling tool (4), the spiral drill rod (7) and the drill rod (3) are guided and supported by the support frame (6) fixedly arranged on a pair of left long guide rails at the lower end of the upright post (52), so that the drilling precision and the hole forming quality are effectively guaranteed;

after drilling and digging operations are completed when a plurality of sections of drill rods (3), spiral drill rods (7) and drilling tools (4) all enter the stratum, the vertical motor is turned off, the power head assembly stops running, an operator enters a pile planting station to detach a locking pin shaft at the joint of a male joint of the section of drill rod (3) with the uppermost end exposed out of the ground and a female joint of the section of drill rod (3) connected with an output end connecting disc of a hollow output shaft (124), a first group of power head assembly (1) is lifted along a pair of left long guide rails of an upright column (52) to be completely separated from the section of drill rod (3), and a traveling mechanism of a walking pile frame (5) is operated to travel leftwards for a distance of H along the transverse direction of the pile planting station;

4) the second group of power head assembly (1') and the drill rod (3), the spiral drill rod (7) and the drilling tool (4) thereof are drilled and cut

When a second group of power head assemblies (1 ') and a plurality of sections of drill rods (3) fixedly arranged on the second group of power head assemblies reach a pile planting station, the second group of power head assemblies (1') are put down along a pair of right long guide rails of an upright post (52), so that female joints of the lowermost drill rod (3) in the plurality of sections of drill rods fixedly arranged at the lower ends of the second group of power head assemblies are aligned to male joints of the drill rod (3) exposed out of the stratum, and the second group of power head assemblies are locked by a pin shaft after being;

the control system is operated, the vertical motor of the second group of power head assembly (1') is started to rotate in the forward direction, the hoisting mechanism of the walking pile frame (5) is operated to release a steel wire rope to enable the second group of power head assembly to continuously move downwards along a pair of right long guide rails of the upright post (52), so that a plurality of sections of drill rods (3) with stirring blades (31) and arc surface protection blocks (32), spiral drill rods (7) with spiral blades (71) and drilling tools (4) with expansion wings (41) are driven to rotate in the forward direction and continuously drill downwards into a cut soil layer, and the drilling depth L2 is finished, so that the total drilling depth reaches L1+ L2;

the cutting wings of the drilling tool (4) at the lowest end are used for drilling, the helical blades (71) of the helical drill rod (7) are convenient for soil dumping and stirring, the stirring blades (31) arranged on the outer wall of the drill rod (3) are convenient for fully stirring soil, and the cambered surface protection blocks (32) arranged on the outer wall of the drill rod (3) are extruded to protect the formed holes, so that smooth and compact hole walls can be formed;

the drilling tool (4), the spiral drill rod (7) and the drill rod (3) are guided and supported by the support frame (6) fixedly arranged on a pair of right long guide rails at the lower end of the upright post (52), so that the drilling precision and the hole forming quality are effectively guaranteed;

operating a second group of power head assemblies (1') and drill rods (3), spiral drill rods (7) and drilling tools (4) fixedly arranged on the second group of power head assemblies to continuously drill and cut along a pair of long guide rails on the right side of the upright post (52) until the depth of a soil bearing stratum required by the design is reached;

5) the second group of power head assembly (1') and a plurality of sections of drill rods (3), spiral drill rods (7) and drilling tools (4) thereof carry out guniting and stirring operations

A hoisting mechanism of the walking pile frame (5) is operated to release a steel wire rope, a second group of power head assemblies (1') and a plurality of sections of drill rods (3), a spiral drill rod (7) and a drilling tool (4) of the second group are lifted along a pair of right long guide rails of an upright post (52), a slurry preparation and supply system equipped in a background is operated at the same time, solidified cement slurry is injected into inner cavities of a hollow output shaft (124), the plurality of sections of drill rods (3), the spiral drill rod (7) and the drilling tool (4) through a slurry injection pipeline, finally, slurry injection is carried out on formed holes through a slurry injection hole arranged at the lower end part of the drilling tool (4) in a rotating and grouting mode, so that the solidified cement slurry is injected into the formed holes to be fully stirred with original soil in the process of lifting the plurality of sections of drill rods (3), the spiral drill rod (7) and the drilling tool;

6) lifting and dismounting of multi-section drill pipe (3), spiral drill pipe (7) and drilling tool

a) Operating a second group of power head assemblies (1 ') to ascend along a pair of right long guide rails of an upright post (52), when the second group of power head assemblies (1') ascend to the limited position of the guide rails, detaching a locking pin shaft at the joint of a female joint of one section of drill rod (3) connected with the lower end of the second group of power head assemblies (1 ') and a male joint of the uppermost section of drill rod (3) in a plurality of sections of drill rods (3) connected with the second group of power head assemblies (1'), hoisting all the extracted sections of drill rods (3) by using a crane, detaching the female joint of the endmost section of drill rod (3) in the extracted sections of drill rods (3) and the locking pin shaft at the joint of the male joint of one section of drill rod (3) exposed out of the ground, and hoisting the sections of drill rods (3) to a stacking object;

b) operating a second group of power head assemblies (1') to descend along a pair of right long guide rails of the upright post (52), aligning a female joint of a section of drill rod (3) connected with the lower end of the second group of power head assemblies with a male joint of a section of drill rod (3) exposed out of the ground, and locking the second group of power head assemblies by using a pin shaft; operating the hoisting mechanism to release the steel wire rope to lift the second group of power head assembly (1 '), lifting the rest of the multiple sections of drill rods (3), the spiral drill rods (7) and the drilling tools (4) left in the stratum to the ground, dismounting all the drill rods (3), the spiral drill rods (7) and the drilling tools (4), dismounting a locking pin shaft at the joint of a male joint of the connecting disc at the lower end of the second group of power head assembly (1 ') and the topmost drill rod (3) in the multiple sections of drill rods (3) connected below the connecting disc, separating the multiple sections of drill rods (3) from the second group of power head assembly (1 '), and then using a crane to hoist the multiple sections of drill rods (3), the spiral drill rods (7) and the drilling tools (4) to a stacking;

7) precast pile implantation

a) A pile feeding cap is arranged at a connecting disc of a second group of power head assembly (1'), a precast pile to be implanted is hoisted into a pile planting hole by a crane, and the precast pile is sunk into the pile planting hole by self weight;

b) a hoisting mechanism of the walking pile frame (5) is operated to release a steel wire rope, so that a second group of power head assemblies (1 ') descend along a pair of right long guide rails of an upright post (52) of the walking pile frame (5), and a pile conveying cap is sleeved on a precast pile head along with the descending of the second group of power head assemblies (1');

c) and continuously winding the steel wire rope by the winding mechanism to enable the second group of power head assemblies (1 ') and the pile feeding caps connected with the second group of power head assemblies to descend, pressing the precast pile into the drilled hole by virtue of the self weight of the precast pile and the weight of the second group of power head assemblies (1') to finally reach the designed elevation, and forming an integrated pile planting body foundation by the precast pile, the pile end and the soil body around the pile after the pile end and the solidified cement paste around the pile are hardened.

2. The construction method according to claim 1, wherein in step 3), the vertical motors in the two power head assemblies (1, 1') both adopt a starting control mode of an 8-pole variable frequency motor and an external frequency converter, and stepless regulation and control of the rotating speed and the torque of the hollow output shaft (124), the multi-section drill rod (3), the spiral drill rod (7) and the drilling tool (4) can be realized.

3. The construction method according to claim 1, wherein in the step 5), the rotation speed of the second group of power head assemblies (1') and the plurality of sections of drill rods (3), the spiral drill rod (7) and the drilling tool (4) which are fixedly arranged on the second group of power head assemblies is adjusted and controlled by an external frequency converter while the drilling and stirring are carried out, so that the technical requirements of the injection and stirring speed of the solidified cement paste in unit time are met.

4. The construction method according to claim 1, wherein in step 7), the bush (63) is arranged in the guide through hole (621) of the support frame (6), and the gap between the inner diameter of the bush and the outer diameter of the precast pile is 4.00-6.00 mm, so that good guide is ensured when the precast pile is implanted into the hole.