CN112281897A

CN112281897A - Construction method of bridge pile foundation

Info

Publication number: CN112281897A
Application number: CN202011115875.8A
Authority: CN
Inventors: 何瑞华; 张安俊; 吴凯朋; 任康; 郑凯; 吴雪雷
Original assignee: China Railway Sixth Group Co Ltd; Guangzhou Engineering Co Ltd of China Railway Sixth Group Co Ltd
Current assignee: China Railway Sixth Group Co Ltd; Guangzhou Engineering Co Ltd of China Railway Sixth Group Co Ltd
Priority date: 2020-10-19
Filing date: 2020-10-19
Publication date: 2021-01-29

Abstract

The invention relates to the technical field of bridge pile foundations, and discloses a construction method of a bridge pile foundation. Through set up the construction place of fore shaft reinforcing pile hole on the pithead position in pile hole, reduce the probability that inclined hole easily appears in drilling, improved the pile foundation bearing capacity of building out to and reduce dropping of construction residue, still select the excavation mode that corresponds according to different terranes when tunnelling according to the pile hole simultaneously, solved when bridge pile foundation construction meet the great problem of the construction degree of difficulty when the complicated geological conditions such as the stratum is more, the construction quality in the pile hole of assurance.

Description

Construction method of bridge pile foundation

Technical Field

The invention relates to the technical field of bridge pile foundations, in particular to a construction method of a bridge pile foundation.

Background

With the continuous development of economy in China, the demand of infrastructure in the aspect of traffic is also gradually accelerated. In order to cross rivers, lakes, straits, valleys or other obstacles, the bridges are required to have large acceptable loads, large bearing impact force and high standard of resisting natural disasters, and particularly the structures are required to have certain vertical and transverse rigidity and dynamic performance.

This requires that the foundation of the bridge must be very stable. Nowadays, the pile foundation is internationally used as the foundation of the bridge, and compared with the foundation of a common building, the pile foundation is deeply embedded so as to achieve the purpose of using the rock stratum at the deeper part of the ground bottom as the support.

However, because different pile foundation construction sites have large geographical conditions, when the stratum change of the construction sites is complicated, if a machine is adopted for drilling, the situation that the construction is difficult or even cannot be continued occurs when a more complicated and variable stratum is encountered; even if the construction can be carried out, the problems that inclined holes appear in pile holes and the bearing capacity of the built pile foundation single pile cannot meet the design requirements easily occur.

Disclosure of Invention

The invention aims to solve the problems that in the prior art, when a bridge pile foundation is constructed, the construction difficulty is higher when complex geological conditions such as more rock stratums are met, inclined holes are easy to appear when a machine is used for drilling under the complex geological conditions, or the bearing capacity of the constructed pile foundation is insufficient.

The invention provides a construction method of a bridge pile foundation, which comprises the following steps:

(1) construction preparation before pile foundation construction: detecting a construction site by using a detection tool, determining a geological condition, trimming and tamping the construction site, and measuring and positioning the trimmed and tamped construction site by using a measuring instrument to obtain a pile foundation position;

(2) and (3) locking construction: primarily excavating the pile foundation to obtain a pithead of a pile hole, arranging an annular baffle plate and a locking die plate at the periphery of the pithead, arranging reinforcing steel bars and injecting concrete between the annular baffle plate and the locking die plate to form a concrete locking port, wherein the central line of the annular baffle plate is superposed with the axis of the pithead, and the locking die plate is arranged around the outer side of the annular baffle plate;

(3) pile hole construction: selecting a corresponding excavation mode according to the geological condition, taking the pile foundation position as the center of a pile hole, performing excavation operation on the position of the pile hole on the basis of the excavation mode, and stopping excavation until the excavation depth meets a preset condition to obtain the pile hole, wherein the excavation operation comprises land excavation treatment and retaining wall pouring treatment of the pile hole;

(4) pile hole inspection: carrying out size inspection on the pile hole by using a measuring instrument, and cleaning residual sediments in the pile hole after determining that an inspection result is within an allowable deviation range; after the residual sediment is cleaned, flattening the hole bottom of the pile hole; the pile hole size inspection comprises the inspection of the displacement deviation of the central line of the pile hole, the size deviation of the pile diameter and the depth of the pile hole;

(5) installing a reinforcement cage: vertically lowering the processed reinforcement cage into the pile hole, and enabling the reinforcement cage to coincide with the center of the pile hole;

(6) pouring pile body concrete: and placing a guide pipe into the reinforcement cage, injecting concrete into the pile hole along the guide pipe, gradually and slowly pulling up the guide pipe at a constant speed to finish concrete pouring of the pile hole, and thus obtaining the bridge pile foundation.

Preferably, in the first implementation manner of the present invention, after the detecting the construction site with the detecting tool, determining a geological condition, trimming and tamping the construction site, and measuring and positioning the trimmed and tamped construction site with the measuring instrument to obtain a pile foundation position, the method further includes:

pouring a concrete layer with the thickness of 10cm in the ground range with the width of 1m around the pile foundation, wherein the concrete layer is used for reinforcing the ground around the pithead; and arranging a pile protection pile at the position of the pile foundation, wherein the pile protection pile is used for checking the perpendicularity of the pile hole and the deviation of the center of the pile hole.

Preferably, in the second implementation manner of the present invention, when the geological condition is loose soil, the selecting a corresponding excavation method according to the geological condition, taking the pile foundation position as the center of the pile hole, performing excavation operation on the pile hole position based on the excavation method, and stopping excavation until the excavation depth meets a preset condition, to obtain the pile hole includes:

selecting a manual excavation mode, wherein the manual excavation mode is an excavation mode by using a shovel or an air pick;

excavating a loose soil layer at the position of the pile hole through the spade or the air pick;

measuring whether the depth of excavation is equal to 1 m;

if yes, installing a retaining wall template in the pile hole, and pouring concrete after the retaining wall template is installed to obtain a retaining wall;

and removing the retaining wall template, and continuously excavating the lower pile hole by using the spade or the pneumatic pick until the excavating depth is equal to the depth required by the design of the pile hole, and stopping excavating to obtain the pile hole.

Preferably, in a third implementation manner of the present invention, when the geological condition is a hard rock stratum, the selecting a corresponding excavation method according to the geological condition, taking the pile foundation position as a center of a pile hole, performing excavation operation of the ground at the pile hole position based on the excavation method, and stopping excavation until an excavation depth satisfies a preset condition, to obtain the pile hole includes:

selecting a micro-blasting excavation mode, wherein the micro-blasting excavation mode is an excavation mode of separating a hard rock stratum by using gunpowder blasting;

blasting, separating and excavating the hard rock stratum at the position of the pile hole through the gunpowder;

measuring whether the depth of excavation is equal to 1 m;

and removing the retaining wall template, continuously utilizing gunpowder to blast and separate the hard rock stratum to excavate the lower pile hole, and stopping excavating until the excavated depth is equal to the depth required by the design of the pile hole to obtain the pile hole.

Preferably, in a fourth implementation manner of the present invention, the blasting, separating and excavating the hard rock stratum at the pile hole position by the gunpowder includes:

calculating the number of blastholes, the size of the blastholes and the positions of the blastholes for placing gunpowder according to the hardness degree of the rock stratum and the type of the gunpowder used;

arranging blastholes in rock stratums in the pile holes by utilizing a handheld pneumatic rock drill according to the number of the blastholes, the size of the blastholes and the positions of the blastholes;

filling explosives into the blastholes, blocking the blastholes by using a filling material, and connecting the explosives in the blastholes by using a blasting control circuit to obtain a blasting network;

and sequentially detonating the explosives in the blasting holes through the blasting network by adopting an electric initiator to blast and separate the rock stratum.

Preferably, in a fifth implementation manner of the present invention, the selecting a corresponding excavation manner according to the geological condition, taking the pile foundation position as a center of a pile hole, performing excavation operation of the ground at the pile hole position based on the excavation manner, and stopping excavation until an excavation depth satisfies a preset condition to obtain the pile hole further includes:

loading earth and stones excavated from the pile hole into a slag discharging barrel, hanging a hook on the slag discharging barrel, installing a hook anti-falling safety device, lifting the slag discharging barrel out of the pile hole by utilizing lifting equipment, and continuing excavation operation by personnel in the hole after the slag discharging barrel is lifted out of the pile hole;

and arranging a protection plate at a position which is 0.3m higher than the constructors in the hole, wherein the protection plate is used as a shelter for the constructors in the hole when the slag outlet barrel is lifted out of the pile hole by hoisting equipment.

Preferably, in a sixth implementation manner of the present invention, the installing a retaining wall formwork in the pile hole, and after the installing of the retaining wall formwork, pouring with concrete to obtain the retaining wall includes:

using a cross line to check the excavation aperture, and installing a retaining wall template into the pile hole after the checking result is not smaller than the designed aperture, wherein the retaining wall template is formed by assembling two 4mm steel dies;

putting the retaining wall reinforcing steel bars into the retaining wall template, and pouring concrete;

and vibrating the poured concrete by adopting a reinforcing steel bar or an attached vibrator to obtain the retaining wall.

Preferably, in a seventh implementation manner of the present invention, the vertically placing the finished reinforcement cage into the pile hole, and making centers of the reinforcement cage and the pile hole coincide includes:

pre-processing a reinforcement cage meeting the size requirement of the pile hole;

welding a hoisting ring on the processed reinforcement cage, hoisting the reinforcement cage by adopting a two-point hoisting method, vertically lowering the reinforcement cage into the excavated pile hole, and checking the position of the reinforcement cage by using a measuring instrument to enable the centers of the reinforcement cage and the pile hole to be coincided;

when the reinforcement cage is hoisted, the first hoisting point is arranged at the lower part of the reinforcement cage, and the second hoisting point is arranged between the middle point and the upper third of the length of the reinforcement cage.

Preferably, in an eighth implementation manner of the present invention, the placing a guide pipe into the steel reinforcement cage, injecting concrete into the pile hole along the guide pipe, and slowly pulling up the guide pipe at a constant speed to complete concrete casting of the pile hole includes:

hoisting a guide pipe into the pile hole, and placing an inflatable hollow rubber ball in the guide pipe before pouring;

pouring concrete into the pile hole through the guide pipe, lifting the guide pipe by using a crane to move up and down after the concrete is poured, so that the guide pipe generates a vibrating effect and is slowly pulled out;

the guide pipe is a steel pipe with the diameter of 300mm, the length of each section is 3m, 1-2 m short sections are arranged, the length of each bottom section is 4m, and the guide pipe joint is connected through threads of a rubber sealing ring.

Preferably, in a ninth implementation manner of the present invention, after placing a guide pipe into the reinforcement cage, pouring concrete into the pile hole along the guide pipe, gradually pulling up the guide pipe at a constant speed, and completing concrete pouring of the pile hole to obtain the bridge pile foundation, the method further includes:

clearing up the deficient soil and the laitance around the pile body concrete of the bridge pile foundation;

and horizontally cutting the designed position of the pile head by using a cutting ring, and breaking the pile head at the upper part of the designed position by using an air pick after cutting.

According to the technical scheme provided by the invention, the construction site for reinforcing the pile hole through the locking notch is arranged at the position of the pithead of the pile hole, so that the probability of inclined holes easily occurring in drilling is reduced, the bearing capacity of the built pile foundation is improved, the falling of construction residues is reduced, meanwhile, a corresponding excavation mode is selected according to different rock stratums when the pile hole is excavated, the problem of higher construction difficulty when complex geological conditions such as more rock stratums are met during the construction of the bridge pile foundation is solved, and the construction quality of the pile hole is ensured.

Drawings

FIG. 1 is a schematic cross-sectional view of pile hole excavation according to an embodiment of the present invention;

fig. 2 is a schematic flow chart of a construction method of a bridge pile foundation according to a first embodiment of the present invention;

fig. 3 is a schematic flow chart illustrating a construction method of a bridge pile foundation according to a second embodiment of the present invention;

fig. 4 is a schematic flow chart illustrating a construction method of a bridge pile foundation according to a third embodiment of the present invention;

fig. 5 is a schematic diagram of the position of the blasthole of the blasting in the embodiment of the invention.

Detailed Description

The construction method of the bridge pile foundation provided by the invention is further explained by the specific embodiment.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Furthermore, the terms "comprises," "comprising," or "having," and any variations thereof, are intended to cover non-exclusive inclusions, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The first embodiment:

for convenience of understanding, a specific flow of the first embodiment of the present invention is described below, and referring to fig. 1 and fig. 2, a construction method of a bridge pile foundation in the embodiment specifically includes the following steps:

201. construction preparation before pile foundation construction;

and checking geological data and performing geological test before starting construction, and knowing the geological condition of the construction area. In this example, the geological conditions were measured as clay with a small amount of crushed stone on the surface and granite from full weathering to weak weathering on the lower layer of the construction area.

The method comprises the steps of measuring and positioning a site by using a total station to obtain an approximate construction area of a pile foundation, then manually finishing and tamping the site of the construction area, and after finishing and tamping, accurately measuring and positioning the pile foundation position again. And then performing ground hardening treatment around the pile foundation position. The accuracy of the construction position of the pile foundation is ensured, and the error is small; after the ground hardening treatment, the phenomenon that the pressure on the ground of the pile hole opening is too large to cause the opening collapse or influence the size of the opening when constructors use the machine in the construction process can be avoided.

In addition, this embodiment still sets up fender pile and cushion cap in pile foundation construction area, and the fender pile is the basis of checking the straightness that hangs down in the stake hole and whether the stake center is off normal when being under construction. And building an orifice canopy at the position of the pile foundation, digging a water intercepting ditch around the pile foundation, arranging a drainage system, and digging a drainage ditch around the bearing platform. Through this kind of mode will follow downthehole exhaust water and properly lead away from the pile foundation through the escape canal and flow into current irrigation canals and ditches, prevent that construction site ponding from too much leading to the construction difficulty. Then, necessary equipment for excavation construction such as the lifting equipment 101, the drainage equipment 108, the ventilation equipment 109, etc. are installed, and the surrounding roads are arranged as preparation work before construction.

202. Constructing a locking notch;

after preparation before construction is completed, the reinforced concrete locking notch 102 is manufactured to protect the excavated pile hole and constructors in the pile hole in an all-around manner.

In this embodiment, a preliminary excavation is performed at the determined position of the pile foundation, a pit opening of the pile hole is excavated, and an annular baffle is provided inside the obtained pit opening. The position of the annular baffle is adjusted to ensure that the central line of the annular baffle is superposed with the axis of the pithead.

Meanwhile, a locking port template is arranged around the pithead, and the position of the locking port template is adjusted to ensure that the central line of the locking port template is also superposed with the axis of the pithead. Subsequently, reinforcing steel bars are arranged between the annular baffle and the locking notch plate according to the strength requirement of the concrete locking notch 102. And then pouring concrete, pouring concrete between the arranged annular baffle and the locking port template, and removing the annular baffle and the locking port template after the concrete is solidified to obtain a poured concrete locking port 102.

In this embodiment, the width of the manufactured concrete locking notch 102 is 30cm, and the height thereof is 30cm higher than the ground, and the pouring concrete locking notch 102 can effectively fix the initially excavated pit, prevent the pit from collapsing and prevent sundries from rolling into the hole to hurt people.

After the concrete locking hole 102 is poured, the total station is used again to carry out recheck on the position and the size of the pile foundation, a cross line is placed on the concrete locking hole 102 to determine the accurate excavation position of the pile foundation, and the pile hole is prepared to be excavated formally.

203. Pile hole construction;

in this step, it specifically includes the following two construction steps, i.e., excavation and casting of the retaining wall 106.

In this embodiment, the step of pile hole construction specifically adopts segmental construction, that is, excavation and wall pouring 106 are alternately used, for example, excavation of a first segment of a soil layer is performed based on a selected excavation mode, wherein the depth of the first segment of the soil layer is 1m, after excavation is performed for 1m, a wall protection template is installed, then concrete pouring is performed, after the concrete is solidified, the wall protection template is removed, excavation of a second segment of the pile hole is continued, after the excavation depth reaches 1m, pouring of the wall protection 106 is performed, and in turn, the excavation is stopped until the overall depth of the pile hole reaches a preset depth.

In practical application, in the excavation process, the geological condition needs to be detected, different excavation modes are selected according to the detected geological condition, that is, the soil layer excavated by the pile hole is gradually excavated, the texture of the soil layer is changed, and in order to improve the excavation speed, the excavation mode is adjusted by detecting the texture of the soil layer in real time.

Firstly, a shovel or a pneumatic pick is used for loosening 0.1-0.2 m in the whole operation surface range, then the shovel is used for loading loosened soil and stones into a slag discharging barrel 107 for discharging slag, and then the soil and stones are conveyed out of pile holes.

The slag discharging barrel 107 is hung with a hook, and the hook anti-falling safety device is arranged, wherein the contained slag soil is not more than 80% of the volume of the slag discharging barrel 107.

More than 0.3m of constructor in being higher than the hole sets up protection plate 105, when needs transport out the stake hole with the soil stone through going out slag barrel 107, downthehole personnel hide in protection plate 105 below, inform drill way lifting personnel to lift by crane, utilize hoisting equipment 101 to promote out the stake hole with going out slag barrel 107, wait to slag tap bucket 107 and promote out the stake hole after, downthehole personnel continue to excavate the operation. Prevent the falling of the earth and the stone from hurting people in the process of transporting the earth and the stone out.

The size of the dug pile hole and the axial position of the center of the pile hole need to be frequently checked in the hole digging process, and the dug pile hole is prevented from generating large size deviation. If water seeps into the pile hole in the excavation process, the water seepage is pumped away and drained by using the drainage equipment 108, and the collapse hole caused by water seepage at the hole wall is prevented.

Checking whether the excavation depth reaches 1m or not, if so, checking the excavation aperture by using a cross line, clearing loose earth and stones on the hole wall after the checking result is not less than the designed aperture to finish the excavation of the pile hole, and then pouring a retaining wall 106 for the newly excavated pile hole.

In this embodiment, for the step of pouring the retaining wall 106, the specific implementation may be:

firstly, the retaining wall 106 is constructed in sections, and after each section of pile hole is excavated, a retaining wall template is installed in the pile hole to ensure that the concrete thickness and strength of the retaining wall 106 can meet the requirements. The retaining wall 106 is in the shape of an inverted trapezoid, and has a large aperture, a large upper opening and a small lower opening. The platform staggering is carried out for 5cm at the joint of the pipe joint, and in order to consider construction errors, the pile foundation clearance is increased by 5cm, so that the thickness of the retaining wall 106 meets the requirement, and the phenomenon that the collapse hole is caused due to the fact that the strength of the retaining wall 106 is insufficient is avoided.

In this embodiment, before each retaining wall 106 is cast, the position of the retaining wall template is detected by using a cross line when the retaining wall template is installed, so as to ensure the accuracy of the position and the size of the pile hole.

Pouring prepared concrete into the installed retaining wall formwork, and adding reinforcing steel bars into the retaining wall formwork when the soil layer of the section changes or has a sliding surface. And (3) inserting and tamping the concrete poured into the dado template by adopting a reinforcing steel bar or an attached vibrator to solidify the concrete.

And (4) removing the retaining wall template after the concrete is solidified to obtain the retaining wall 106 of the pile hole of the section just excavated. And after obtaining the retaining wall 106 of the section, checking whether the excavation depth of the pile hole meets the design depth, if the excavation depth of the pile hole does not meet the design depth, continuing to alternately excavate the pile hole and pour the retaining wall 106, and stopping excavation until the excavation depth meets the design depth of a preset condition to obtain the pile hole.

204. Pile hole inspection;

and (3) using a measuring instrument to inspect the displacement deviation of the center line of the pile hole, the size deviation of the diameter of the pile and the depth size of the pile hole, and cleaning residual sediments in the pile hole after the inspection result is determined to be within the allowable deviation range.

And after the residual sediment is cleaned, finishing the hole bottom of the pile hole to ensure flatness without soft layers such as loose soil layers, sludge, sediment and the like. In this embodiment, the pile foundation is to be built continuously after the inspection of the pile hole meets the requirement, and the strength of the built pile foundation can be improved by inspecting the pile hole to meet the requirement.

205. Installing a reinforcement cage;

after the pile hole is checked to be correct, welding a hoisting ring on a pre-processed reinforcement cage which meets the size of the pile hole, and hoisting the reinforcement cage by a crane by adopting a two-point hoisting method; the two-point hoisting mode can keep the verticality of the reinforcement cage and prevent the reinforcement cage from deforming. And slowly and vertically lowering the reinforcement cage into the excavated pile hole, and checking the position of the reinforcement cage at any time by using a measuring instrument to ensure that the center of the reinforcement cage is finally coincided with the center of the pile hole.

206. Pouring pile body concrete;

and after the reinforcement cage is installed, constructing by using an anhydrous concrete pouring method. Specifically, a conduit required for pouring concrete is hung into a reinforcement cage of an excavated pile hole. And (3) pouring concrete into the pile hole along the guide pipe, lifting the guide pipe by using a crane to move up and down after the concrete pouring is finished, generating a vibrating action by using the up-and-down movement of the guide pipe, and slowly pulling out the guide pipe to finish the pouring of the concrete of the pile body.

In this embodiment, after the pile foundation is formed, the method further includes cleaning and detecting the pile foundation; firstly, cleaning up the deficient soil and the laitance around the pile body concrete of the bridge pile foundation; after the pile head is cleaned, the ring cutter is used for horizontally cutting the designed position of the pile head, and after the cutting is finished, the redundant pile head on the upper part of the designed position is broken by an air pick, so that the built pile foundation meets the design size, and the follow-up next test and construction of the pile foundation are facilitated.

This embodiment is through setting up the construction place of fore shaft reinforcing pile hole on the pithead position in pile hole, reduce the probability that inclined hole easily appears in drilling, improved the pile foundation bearing capacity of building out to and reduce dropping of construction residue, still select the excavation mode that corresponds according to different terranes when tunnelling according to the pile hole simultaneously, solved when bridge pile foundation construction meet if the more complicated geological conditions such as rock stratum the great problem of the degree of difficulty of constructing, the construction quality in the pile hole of assurance.

Second embodiment:

for convenience of understanding, a specific process of the first embodiment of the present invention is described below, and referring to fig. 1 and fig. 3, the method for constructing a bridge pile foundation in the present embodiment specifically includes the following steps:

301. construction preparation before pile foundation construction;

before the construction is started, the geological data is checked and geological test is carried out, so that the geological condition of the construction area is known. In this example, the geological conditions were measured as clay with a small amount of crushed stone on the surface and granite from full weathering to weak weathering on the lower layer of the construction area.

The method comprises the steps of measuring and positioning a site by using a total station to obtain an approximate construction area of a pile foundation, then manually finishing and tamping the site of the construction area, and after finishing and tamping, accurately measuring and positioning the pile foundation position again. And then, carrying out ground hardening treatment on the periphery of the pile foundation position, wherein the ground hardening method adopted in the embodiment is to pour a concrete layer 103 with the thickness of 10cm in a ground range with the width of 1m around the pile foundation position. After the obtained concrete layer 103 is poured, the problem that the pressure on the ground of the pile hole opening is too large to cause the opening collapse or influence the size of the opening when constructors use machines in the construction process can be avoided.

In addition, in this embodiment, a fender pile and a bearing platform are further arranged in the pile foundation construction area, and the fender pile is used as a basis for checking the perpendicularity of a pile hole and whether the center of the pile deviates or not during construction, so that the fender pile cannot move randomly during construction. And building an orifice canopy at the position of the pile foundation, digging a water intercepting ditch around the pile foundation, arranging a drainage system, and digging a drainage ditch around the bearing platform. Through this kind of mode will follow downthehole exhaust water and properly lead away from the stake base through the escape canal and flow into current irrigation canals and ditches, prevent that construction site ponding from too much leading to the construction difficulty. Subsequently, necessary equipment for excavation construction, such as the lifting equipment 101, the drainage equipment 108, and the ventilation equipment 109, is installed, and the surrounding road is arranged as preparation before construction.

302. Constructing a locking notch;

Meanwhile, a locking port template is arranged around the pithead, and the position of the locking port template is adjusted to ensure that the central line of the locking port template is also superposed with the axis of the pithead. Then, reinforcing steel bars are arranged between the annular baffle and the locking port template, and axial, radial and annular reinforcing steel bars meeting the requirements are added according to the strength requirement of the concrete locking port 102. And then pouring concrete, namely pouring concrete between the arranged annular baffle and the locking notch template, vibrating the poured concrete by using a tool, and removing the annular baffle and the locking notch template after the concrete is solidified to obtain the poured concrete locking notch 102.

In this embodiment, the width of the concrete locking notch 102 is 30cm, and the height thereof is 30cm above the ground. Can effectively fix the initially dug pithead and prevent sundries from rolling into the hole to hurt people.

After the concrete locking hole 102 is poured, the total station is used again to carry out recheck on the position and the size of the pile foundation, and a cross line is placed on the concrete locking hole 102 to determine the accurate position of the pile foundation. After the position is determined, the pile core is used as the center, the size of the pile hole is designed, the range of the diameter of the pile which is enlarged by 5cm and then added by 30cm is taken as the radius is taken as the pile hole excavation line, and then the formal excavation of the pile hole is prepared.

303. Manually digging a pile hole and pouring a protective wall;

in this embodiment, the two construction steps of excavating and pouring the retaining wall 106 need to be used alternately, for example, excavating the first section of the soil layer based on a selected excavating mode, wherein the depth of the first section of the soil layer is 1m, installing a retaining wall template after excavating for 1m, then pouring concrete, removing the retaining wall template after the concrete is solidified, continuing excavating the second section of the pile hole, pouring the retaining wall 106 after the excavating depth reaches 1m, and sequentially and alternately circulating until the overall depth of the pile hole reaches a preset depth, and stopping excavating.

In this embodiment, when the geological conditions are relatively loose soil layers such as soil layers, accumulations, strongly weathered rock layers, etc., the holes are manually drilled along the ladder 104, and shovels or pneumatic picks are used for excavation.

More than 0.3m of constructor in being higher than the hole sets up protection plate 105, when needs transport out the stake hole with the soil stone through going out slag barrel 107, downthehole personnel hide in protection plate 105 below, inform drill way lifting personnel to lift by crane, utilize hoisting equipment 101 to promote out the stake hole with going out slag barrel 107, wait to slag tap bucket 107 and promote out the stake hole after, downthehole personnel continue to excavate the operation. The lower part of the protection plate 105 is made of a round wood material with the diameter of 10cm, and the upper part is paved with a layer of bamboo springboard to reduce the impact force and prevent soil and stones from falling off to hurt people in the process of transporting the soil and stones out.

Checking whether the excavation depth reaches 1m or not, if the excavation depth reaches 1m, checking the excavation aperture by using a cross line, clearing loose earth and stones on the hole wall after the checking result is not less than the designed aperture, finishing excavation of the pile hole, and then pouring a retaining wall 106 for the pile hole obtained by just excavation.

Specifically, in this embodiment, the retaining wall 106 is constructed in sections, and after each pile hole is excavated, a retaining wall formwork is installed in the pile hole to ensure that the concrete thickness and strength of the retaining wall 106 can meet the requirements. The wall protection 106 is in the shape of an inverted trapezoid, and has a large aperture, a large upper opening and a small lower opening. The platform staggering is 5cm at the joint of the pipe joint, and in order to consider construction errors, the pile foundation clearance is increased by 5cm, so that the thickness of the retaining wall 106 meets the requirement, and the phenomenon that the collapse hole is caused by insufficient strength of the retaining wall 106 is avoided.

In this embodiment, the retaining wall template is formed by assembling two 4mm steel molds, the hole position is corrected by using a cross line and a hanging ball before the retaining wall template is installed, the size of the pile hole is checked by using a steel ruler, and the position of the retaining wall template is determined after the excavation hole diameter is checked to be not smaller than the design size, so that the accuracy of the position and the size of the pile hole is ensured, and meanwhile, the concrete thickness of the retaining wall 106 is not smaller than the design size.

Pouring the prepared concrete with the strength grade of C25 into the installed retaining wall template, and adding reinforcing steel bars into the retaining wall template when the soil layer of the section changes or has a sliding surface, wherein the reinforcing steel bars adopt phi 10 steel bars and are connected in a binding connection mode at the interval of 25cm multiplied by 25 cm. In addition, if the hole depth exceeds 2 meters, the concrete is conveyed to the pouring platform by using the string barrel, and the concrete is conveyed into the wall protection template by a spade manually. And (3) inserting and tamping the concrete poured into the dado template by adopting a reinforcing steel bar or an attached vibrator to solidify the concrete. The concrete with the strength grade of C25 poured into the retaining wall 106 can ensure that the concrete has good workability, and is convenient for feeding, pouring and vibrating to be compact.

304. Pile hole inspection;

305. Manufacturing and installing a reinforcement cage;

a steel reinforcement cage which accords with the size of a pile hole is manufactured in advance, the raw material of the steel reinforcement cage adopts steel reinforcement with the advantages of clean surface, no oil stain, paint skin, scale rust and the like, smooth and straight main body and no local bending. When the cold-drawing straightening reinforcing steel bar is adopted, the cold-drawing rate of the I-grade reinforcing steel bar is not more than 2%. When carrying out the welding preparation of steel reinforcement cage in this embodiment, the main muscle adopts the overlap joint welding, and the welding requirement satisfies design and standard requirement, and same cross-section soldered connection is no more than 50%, and two interplanar joint intervals are not less than 35d (wherein d is the great diameter of vertical atress reinforcing bar), and are not less than 50cm to guarantee that the intensity of steel reinforcement cage accords with the design requirement, guarantee then that the pile foundation of building out can accord with the design requirement.

And then, after the pile hole is checked to be correct, welding a hoisting ring on the pre-processed reinforcement cage which meets the size of the pile hole, wherein a first hoisting point is arranged at the lower part of the reinforcement cage, a second hoisting point is arranged between the middle point and the upper third of the length of the reinforcement cage, and the reinforcement cage is hoisted by a crane by adopting a two-point hoisting method. And keeping the verticality of the reinforcement cage, slowly and vertically lowering the reinforcement cage into the excavated pile hole, and checking the position of the reinforcement cage by using a measuring instrument to ensure that the centers of the reinforcement cage and the pile hole coincide.

306. Pouring pile body concrete;

after the reinforcement cage is installed, a guide pipe required by pouring concrete is hung in the excavated pile hole. The pipe in this embodiment is the diameter 300mm steel pipe, and the subsection length is 3m, disposes 1 ~ 2m nipple joint, and bottom section length 4m, pipe joint are rubber seal screw thread and connect, and the pipe inner wall circle is in the same direction as, and according to different hole depth serial numbers and mark the yardstick from bottom to top, and when the pipe was hung downtheholely, use the pipe anchor clamps to fix its position at the hole center, prevent that the pipe card from hanging on the steel reinforcement cage skeleton.

Before pouring, a hollow rubber ball with the diameter of 250mm is placed in the guide pipe, and then concrete is poured into the pile hole by using a waterless concrete pouring method. Aerify in the hollow rubber ball of laying in this embodiment for play the cushioning effect when making the concrete whereabouts, reduce the speed that the concrete whereabouts, prevent because the fall too big can produce powerful impulsive force to the pile foundation bottom and vibrate, lure the local sand bed in stake hole, gravel layer to drop, lead to the hole collapse phenomenon to appear.

After the concrete is poured, the guide pipe is lifted by a crane to move up and down, the guide pipe moves up and down to generate a vibrating effect, and the guide pipe is slowly pulled out. Meanwhile, the phi 50 inserted vibrating rod begins to vibrate within the range of 4m of the pile top. When the concrete is tamped, the periphery of the concrete is high, the middle of the concrete is low, the tamping bar is 5-10 cm away from the hole wall when the concrete is tamped, and the concrete is tamped from the periphery to the middle until the concrete does not continuously bubble. This is done to enhance the compactness of the concrete of the pile top. And maintaining the concrete at the top of the pile after pouring.

307. Cleaning and detecting the pile foundation;

specifically, the method comprises the steps of cleaning up the soil and laitance around the pile body concrete, measuring the size of a pile foundation by using a measuring instrument again, horizontally cutting the design position of the pile head by using a cutting ring, breaking the redundant pile head on the upper portion of the design position by using an air pick after the cutting is finished, reserving 10cm for each pile body pile top for manual breaking and finishing to enable the pile body pile top to reach the design position (namely a cutting surface), performing plane wire lofting on the pile body after the pile head is finished, and determining whether the axis deviation of the pile body meets the design requirement. And after the deviation of the axis is qualified, straightening the pile body reinforcing steel bars, and determining the size and height of the bell mouth according to the difference of the diameters of the reinforcing steel bars. The pile head treatment should meet the following regulatory requirements:

(1) the upper-layer laitance at the top end of the pile head needs to be chiseled off, the top surface is smooth after chiseled off, the coarse aggregate is uniform, the pile foundation steel bar cannot be damaged, and the elevation deviation of the pile top after chiseled off is controlled to be 0-3 cm;

(2) the pile head chiseling adopts the air operated machine construction, and the concrete strength is not less than 10 Mpa;

(3) the length of the pile head chiseling or the pile body extending into the bearing platform and the length of the pile top main reinforcement anchoring into the bearing platform meet the design requirements.

And repairing or cutting the pile body sounding pipe to expose the pile top by 10cm, performing trial connection by using a reinforcing steel bar head, and filling water into the sounding pipe after the trial connection is completed so as to test the pile body of the pile foundation in the follow-up process.

According to design requirements, the bored pile in the embodiment is subjected to low-strain detection on pile body quality and integrity by a third-party detection unit with relevant qualification. And (2) finishing concrete pouring to reach 70% of the design strength (at least 7 days, generally 14 days), after pile head chiseling is finished, carrying out pile foundation integrity detection according to design and technical rules for foundation pile detection in railway engineering (TB10218-2008), detecting by adopting low strain, and detecting the concrete strength by adopting a compression test after the concrete strength is in the age of 56 days, so as to ensure that the strength of the pile foundation meets the design requirements.

This embodiment is through setting up the construction site of fore shaft reinforcing pile hole on the pithead position in the pile hole, reduce the probability that inclined hole easily appears in the drilling, the pile foundation bearing capacity of having built has been improved, and reduce dropping of construction residue, still select the excavation mode that corresponds according to different terranes when tunnelling according to the pile hole simultaneously, the excavation mode of manual utilization spade or pneumatic pick when the geology situation is comparatively loose soil layers such as soil layer, accumulation body and strong weathering rock stratum, excavation mode in this embodiment can guarantee to dig the hole size accuracy, difficult inclined hole, the construction quality of the pile hole of guaranteeing simultaneously in the speed of having accelerated excavation construction, in addition still reduced the requirement to the wide width of construction site to a certain extent, the cost of construction has also been reduced simultaneously.

The third embodiment:

for convenience of understanding, a specific process of the second embodiment of the present invention is described below, and referring to fig. 1, fig. 3 and fig. 4, the method for constructing a bridge pile foundation in the present embodiment specifically includes the following steps:

401. construction preparation before pile foundation construction;

The method comprises the steps of measuring and positioning a site by using a total station to obtain an approximate construction area of a pile foundation, then manually finishing and tamping the site of the construction area, and after finishing and tamping, accurately measuring and positioning the pile foundation position again. And then, carrying out ground hardening treatment on the periphery of the pile foundation position, wherein the ground hardening method adopted in the embodiment is to pour a concrete layer 103 with the thickness of 10cm in a ground range with the width of 1m around the pile foundation position.

In addition, in this embodiment, a fender pile and a bearing platform are further arranged in the pile foundation construction area, and the fender pile is used as a basis for checking the perpendicularity of a pile hole and whether the center of the pile deviates or not during construction, so that the fender pile cannot move randomly during construction.

And building an orifice canopy at the position of the pile foundation, digging a water intercepting ditch around the pile foundation, arranging a drainage system, and digging a drainage ditch around the bearing platform. Through this kind of mode will follow downthehole exhaust water and properly lead away from the pile foundation through the escape canal and flow into current irrigation canals and ditches, prevent that construction site ponding from too much leading to the construction difficulty. Then, necessary equipment for excavation construction such as the lifting equipment 101, the drainage equipment 108, the ventilation equipment 109, etc. are installed and the surrounding roads are arranged.

402. Constructing a locking notch;

403. Calculating blasting parameters;

and (3) detecting the geological condition while excavating, and selecting different excavating modes according to the detected geological condition.

In this embodiment, when the geological conditions are relatively hard rock formations such as medium and weak weathering, blasting tests are performed for corresponding lithology and structure, and a micro-blasting excavation mode is selected on the basis according to the actual conditions of the field surrounding environment and protection and the hardness degree of the rock.

Wherein, the micro blasting excavation mode is an excavation mode of separating a hard rock stratum by utilizing gunpowder blasting. The excavation mode of micro blasting is that when the blasting construction is carried out in the rock, the free surface is narrow, the working surface is deep, the clamping force of the rock is large, when the holes are formed in the sections above the weathered layer, the holes are easily influenced by mud, and the shock resistance of some sections is small, so that the blasting construction in the embodiment adopts small-diameter shallow hole differential blasting.

In the present embodiment, the unit dose coefficient q obtained by calculating, correcting and calculating according to the hardness of the rock formation, the type of gunpowder used, and the parameter analogy of the conventional construction blasting in consideration of the diameter of the excavated pile hole is as shown in the following table 3-1:

TABLE 3-1 statistical table of unit dose coefficient q

In this embodiment, a hand-held pneumatic rock drill is used to drill a borehole, and the diameter d of the borehole is 42 mm.

The depth of the peripheral holes 503 is 1.1m, and the depth of the slotted holes 502 and the central holes 501 is 1.3 m.

In this embodiment, the number of blastholes for placing gunpowder is 1 central hole 501, 3 slotted holes 502, and 7 peripheral holes 503 of 1m pile foundation during each blasting. In the embodiment, the slotted holes 502 are arranged in a conical shape, and the inclination angle is 10-15 degrees; the peripheral holes 503 are uniformly arranged by vertical holes, and the distance between the pile foundation of 1m and the hole wall is 12.5 cm.

The charge of the blasthole was calculated as follows:

(1) q, required for each cycle of the ruler is 0.33 × Q × 3.14 × r2 × h (because the calculation amount is more general than the actual calculation amountThe dosage is slightly larger, so that the dosage is reduced by 0.05-0.1 kg on the basis of calculation, and actual construction is carried out). Wherein q is the explosive quantity (kg/m) required by blasting rock soil with unit volume³) Selecting a unit dosage coefficient according to table 3-1; r is the pile hole radius (m); h is the shot hole depth (m); q is the total loading (kg) of each pile hole;

(2) theoretical single-well charge Q, Q ═ Q/N, where: q-single-hole theoretical charge (g); q-the amount of footage per cycle (g); n-number of working face blastholes;

(3) the distribution of the medicine loading is generally that the medicine quantity Qt of the cutting hole 502 is 20-25% more than the medicine quantity qb of the peripheral hole, and Qt is (1.2-1.25) q; qb is (0.85-0.95) q, wherein: qt-the amount of slotted eye charge (g); qb-peripheral eye charge (g);

(4) the charge length in the blast hole is 1/2-1/3 of the hole depth generally, and the maximum charge length does not exceed 2/3 of the hole depth. Specific blasting parameters are shown in the following table 3-2:

TABLE 3-21.0 m pile foundation blasting parameter table

404. Blasting construction and wall protection pouring;

in this step, it specifically includes the following two construction steps, i.e., blasting construction and wall-protecting 106 pouring.

In this embodiment, when the geological condition is a hard rock formation such as medium or weak weathering, a micro-blasting excavation method is selected, wherein the micro-blasting excavation method is an excavation method of separating the hard rock formation by using powder blasting construction. Specifically, the blasting construction also adopts subsection construction, and the construction depth of each subsection is 1 m. And drilling a blast hole on the rock to be blasted by using an electric rock drill according to the position and the size of the blast hole calculated in the step, and filling the explosive according to the calculated loading amount of the blast hole. In this embodiment, both the undercut hole 502 and the peripheral hole 503 adopt a continuous reverse charge structure. The blast hole filling is an important process, and the filling can ensure that the explosive is completely exploded and improve the blasting effect.

The blast hole needs to be plugged while the explosive is being loaded. Use sand, clay or the mixture of sand and clay as the stemming in this embodiment, the stemming ratio is sand: clay: water-4: 5: 1. The blast hole is filled, so that the explosive can be completely exploded, and the explosion effect is improved. And detonating by adopting different-section electric millisecond detonators in each hole, plugging the blast holes by using a filling material mixed in advance, and connecting the electric millisecond detonators in the blast holes by using a blasting control circuit to obtain a blasting network.

After the personnel in the hole withdraw out of the hole along the ladder 104, cover the steel plate on the top of the hole, pile the sand bag on it, adopt the electric initiating explosive device, detonate the explosive in the big gun hole in proper order through the blasting network, carry on the blasting construction operation to the rock stratum.

And (4) finishing blasting construction operation, ventilating and detecting gas in the hole, and continuing construction after confirming no error. The loosened earth and stone can be loaded into the slag discharging barrel 107 for slag discharging by using a shovel, and then the earth and stone can be transported out of the pile hole.

The slag discharging barrel 107 is hung with a hook, and the hook anti-falling safety device is arranged, wherein the contained slag soil is not more than 80% of the volume of the slag discharging barrel 107, so as to prevent the slag soil from falling from the barrel in the conveying process. More than 0.3m department sets up protection plate 105 at being higher than downthehole constructor, when needs transported out the stake hole with earth and stone through going out slag bucket 107, downthehole personnel hide in protection plate 105 below, inform the drill way lifting personnel to lift by crane, utilize hoisting equipment 101 to promote out the stake hole with going out slag bucket 107, wait to slag tap bucket 107 and promote out the stake hole after, downthehole personnel continue the operation. The lower part of the protection plate 105 is made of a round wood material with the diameter of 10cm, and the upper part is paved with a layer of bamboo springboard to reduce the impact force and prevent soil and stones from falling off to hurt people in the process of transporting the soil and stones out.

Checking whether the excavation depth reaches 1m or not, if so, checking the excavation aperture by using a cross line, clearing loose earth and stones on the hole wall after the checking result is not less than the designed aperture to finish the excavation of the pile hole of the section, and then pouring a retaining wall 106 for the pile hole obtained by the excavation of the blasting construction.

Specifically, in this embodiment, the retaining wall 106 is constructed in sections, and after each pile hole is excavated, a retaining wall formwork is installed in the pile hole to ensure that the concrete thickness and strength of the retaining wall 106 can meet the requirements. The wall protection 106 is in the shape of an inverted trapezoid, and has a large aperture, a large upper opening and a small lower opening. The platform is staggered by 5cm at the joint of the pipe joint, and the pile foundation clearance is increased by 5cm in order to consider construction errors.

And removing the retaining wall template after the concrete is solidified to obtain the retaining wall 106.

And after obtaining a section of retaining wall 106, checking whether the excavation depth of the pile hole meets the design depth, if not, continuing excavating the pile hole and pouring the retaining wall 106 until the excavation depth meets the preset condition, and stopping excavating to obtain the pile hole.

405. Pile hole inspection;

after the pile hole is dug to the designed depth, the pile hole is firstly inspected. In this embodiment, the measurement instrument is used to inspect the pile hole, including displacement deviation of the center line of the pile hole, deviation of the diameter of the pile hole and depth and size of the pile hole, after the inspection result is determined within the allowable deviation range, the residual sediment in the pile hole is cleaned, and in practical application, the allowable deviation of the pile foundation pile hole is set as shown in the following table 3-3:

TABLE 3-3 pile hole tolerance

Serial number	Item	Tolerance deviation
			1	Center position	±50mm
2	Size of cross section	Not less than design size
			3	Depth of hole	Not less than the design requirement
4	Perpendicularity of pile hole	0.5％

And after the residual sediment is cleaned, finishing the hole bottom of the pile hole to ensure flatness without soft layers such as loose soil layers, sludge, sediment and the like.

406. Manufacturing and installing a reinforcement cage;

after the pile hole is checked to be correct, the measuring instrument is used again to measure the elevation of the locking opening, a prefabricated reinforcement cage which accords with the size of the pile hole is welded with a hanging ring, a first hanging point is arranged at the lower part of the reinforcement cage, a second hanging point is arranged between the middle point and the upper third of the length of the reinforcement cage, a crane is used for hoisting the reinforcement cage by adopting a two-point hoisting method, the verticality of the reinforcement cage is kept, the reinforcement cage is slowly and vertically placed into the excavated pile hole, and meanwhile, the measuring instrument is used for checking the position of the reinforcement cage, so that the centers of the reinforcement cage and the pile hole are coincided.

When the reinforcement cage is processed in advance, the raw materials are the reinforcement with the surfaces cleaned, no oil stain, paint skin, scale rust and the like, and the main body is straightened and has no local bending. When the cold-drawing straightening reinforcing steel bar is adopted, the cold-drawing rate of the I-grade reinforcing steel bar is not more than 2%. When the steel reinforcement cage is welded and manufactured in the embodiment, the main reinforcements are welded in an overlapping mode, the welding requirements meet the design and specification requirements, the welding joint of the same section is not more than 50%, the distance between joints between two planes is not less than 35d (d is the larger diameter of the longitudinal stress steel reinforcement), and is not less than 50 cm.

407. Pouring pile body concrete;

408. Cleaning and detecting the pile foundation;

This embodiment is through setting up the construction site of fore shaft reinforcing pile hole on the pithead position in the pile hole, reduce the probability that inclined hole easily appears in the drilling, the pile foundation bearing capacity of having built out has been improved, and reduce dropping of construction residue, still select the excavation mode that corresponds according to different terranes when tunnelling according to the pile hole simultaneously, be well in geology situation, use the excavation mode of micro-blasting when comparatively hard stratum such as weak morals and manners, excavation mode in this embodiment can make deep at the narrow and small operation face of construction face, under the big circumstances of stratum clamp power, can accomplish the excavation to hard stratum fast. And the hole deviation is not easy to occur during excavation, the excavation construction speed is accelerated, the construction quality of the pile hole is ensured, the requirement on the width of a construction site is reduced to a certain extent, and the construction cost is also reduced.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A construction method of a bridge pile foundation is characterized by comprising the following steps:

(2) and (3) locking construction: primarily excavating the pile foundation to obtain a pithead of a pile hole, arranging an annular baffle plate and a locking die plate at the periphery of the pithead, arranging reinforcing steel bars and injecting concrete between the annular baffle plate and the locking die plate to form a concrete locking hole, wherein the central line of the annular baffle plate is superposed with the axis of the pithead, and the locking die plate is arranged around the outer side of the annular baffle plate;

(3) pile hole construction: selecting a corresponding excavation mode according to the geological condition, taking the pile foundation position as the center of a pile hole, performing excavation operation on the pile hole position based on the excavation mode, and stopping excavation until the excavation depth meets a preset condition to obtain the pile hole, wherein the excavation operation comprises land excavation treatment and retaining wall pouring treatment of the pile hole;

(4) pile hole inspection: carrying out size inspection on the pile hole by using a measuring instrument, and cleaning residual sediments in the pile hole after determining that an inspection result is within an allowable deviation range; after the residual sediment is cleaned, flattening the hole bottom of the pile hole; the pile hole size inspection comprises the inspection of the center line displacement deviation, the pile diameter size deviation and the pile hole depth of the pile hole;

2. The method for constructing a bridge pile foundation according to claim 1, wherein after the detecting a construction site with a detecting tool, determining a geological condition, trimming and tamping the construction site, measuring and positioning the trimmed and tamped construction site with a measuring instrument, and obtaining a pile foundation position, the method further comprises:

3. The construction method of the bridge pile foundation according to claim 2, wherein when the geological condition is loose soil, the selecting a corresponding excavation mode according to the geological condition, taking the pile foundation position as the center of the pile hole, performing excavation operation on the pile hole position based on the excavation mode, and stopping excavation until the excavation depth meets a preset condition to obtain the pile hole comprises:

measuring whether the depth of excavation is equal to 1 m;

4. The construction method of the bridge pile foundation according to claim 2, wherein when the geological condition is a hard rock stratum, the corresponding excavation mode is selected according to the geological condition, the pile foundation position is taken as the center of the pile hole, excavation operation of the ground is performed on the pile hole position based on the excavation mode, and excavation is stopped until the excavation depth meets a preset condition, and obtaining the pile hole comprises:

measuring whether the depth of excavation is equal to 1 m;

5. The method for constructing a bridge pile foundation according to claim 4, wherein the blasting, separating and excavating the hard rock layer at the pile hole position by the gunpowder comprises:

6. The method according to claim 3 or 4, wherein the selecting a corresponding excavation method according to the geological condition, taking the pile foundation position as the center of the pile hole, performing excavation operation of the land on the pile hole position based on the excavation method, and stopping excavation until the excavation depth satisfies a preset condition to obtain the pile hole, further comprises:

7. The construction method of the bridge pile foundation according to claim 3 or 4, wherein the step of installing the retaining wall formwork in the pile hole, and after the retaining wall formwork is installed, pouring by using concrete to obtain the retaining wall comprises the following steps:

8. The method of constructing a bridge pile foundation of claim 1, wherein vertically lowering the finished reinforcement cage into the pile hole and aligning the reinforcement cage with the center of the pile hole comprises:

9. The construction method of the bridge pile foundation according to claim 1, wherein the placing of the guide pipe into the reinforcement cage, the pouring of the concrete into the pile hole along the guide pipe, the slow uniform pulling of the guide pipe, and the completion of the concrete pouring of the pile hole comprises:

the guide pipe is a steel pipe with the diameter of 300mm, the section length is 3m, 1-2 m short sections are arranged, the bottom section length is 4m, and the guide pipe joint is connected through threads of a rubber sealing ring.

10. The method for constructing a bridge pile foundation according to claim 1, wherein after the step of placing a guide pipe into the reinforcement cage, pouring concrete into the pile hole along the guide pipe, gradually and slowly pulling up the guide pipe at a uniform speed to complete concrete casting of the pile hole and obtain the bridge pile foundation, the method further comprises: