阅读说明：本技术 沿海吹填地区填海造陆区域沉管灌注桩施工方法 (Construction method of immersed tube cast-in-place pile in sea reclamation area in coastal hydraulic reclamation area ) 是由 陈正益 许春忠 钱程 吴紫峰 于 2021-08-27 设计创作，主要内容包括：本发明公开了一种一种沿海吹填地区填海造陆区域沉管灌注桩施工方法,包括场地平台准备、钢笼的制作和安装、混凝土浇筑、临时套管的提取、施工记录、桩头处理等步骤。本发明施工方便,施工质量好,特别适合中东地区的项目。(The invention discloses a construction method of a immersed tube cast-in-place pile in a land reclamation area filled with sea in a coastal hydraulic reclamation area, which comprises the steps of site platform preparation, steel cage manufacturing and installation, concrete pouring, temporary sleeve extraction, construction recording, pile head treatment and the like. The invention has convenient construction and good construction quality, and is particularly suitable for projects in middle east.)

1. A construction method of a pipe sinking cast-in-place pile in a sea reclamation area in a coastal hydraulic reclamation area is characterized by comprising the following steps: comprises the following steps:

(I) construction step

(1) Site platform preparation

Before piling projects, manual pit/ditch trial work is carried out so as to determine the position of the existing service in a field and take necessary measures according to conditions, and permission must be obtained from related departments; if any other service facilities exist on site, necessary precautions should be taken to protect the service; should transfer/demolish the existing service facility according to the requirement of the contract/relevant authorities, must provide the construction drawing showing the platform elevation/the details such as the existing ground elevation, the cut elevation, the concrete elevation and the steel reinforcement cage elevation, etc., for the consultant to review;

qualified measuring personnel set the center position of the pile from the main datum point according to an approved construction drawing after earth excavation and platform preparation projects are completed;

the center point of the pile needs to be driven out by steel bars, and after the position is checked, the pile is driven to the working platform elevation/at least 25cm below the existing ground of the pile driver; the positioning pin is composed of steel bars and is driven into a position slightly lower than the surface of the platform so as to avoid the interference of piling activities; the pile is marked with colored silk ribbon for easy location/identification; the setting of the borehole position must be confirmed by the engineer before starting the drilling project, two reference points should be added outside the casing to monitor the centre point of the casing during installation; before the sleeve is installed, two datum points are additionally arranged at a certain distance of about 1m from the center point of the pile to the outer surface of the sleeve by taking 90 degrees as datum points; two templates of these two additional reference points should be used during cannulation to avoid deviation from the planned position;

manually excavating the central point of the positioning pile; before the sleeve is installed, two datum points are additionally arranged on the outer side of the sleeve, the distance between the two datum points is 90 degrees, and the distance between the two datum points and the outer surface of the sleeve is equal to 1m, so that the central point of the sleeve can be monitored in the installation process; two templates of these two additional reference points should be used during casing to avoid deviation from the planned position; initially a temporary casing of the required diameter and length should be tunneled and centralised over the centre point of the pile; the tolerance for perpendicularity is 1/100; the deviation of the pile position from the plan view position is not more than 50 mm; the length of the temporary casing should be adjusted to achieve the minimum amount of embedment in the rock/hard formation reported in soil survey reports, i.e. continue to push the temporary casing with the vibratory hammer at least 1 meter below the section of the pile until it is embedded in the rock/hard formation or until rejected to avoid any possibility of collapse of the borehole wall; checking the verticality and elevation according to the regulations in the installation process; if the soil layer below the toe of the casing pipe is found to be collapsed, the casing pipe is continuously pushed until the collapse is stopped; if the sleeve cannot be continuously installed through knocking or vibrating, pre-drilling on the pile position, and then continuously installing the sleeve;

when the casing pipe is drilled, two workers check the offset near a pile point according to a diagram, and one worker regularly checks the verticality of the casing pipe by using a level gauge until the casing pipe is drilled;

after the sleeve is installed at the inspection pile position, a drilling machine is arranged above the pile position, and soil/rock is drilled to a preset/designed height on the premise of the minimum penetration requirement on the hard stratum/rock according to the construction requirement; before starting the drilling operation, the engineer should check the position of the casing;

after drilling is finished, cleaning the bottom of the drilled hole by using a bucket to remove drill cuttings and loose materials at the fundus part of the pile; for this reason, drilling/cleaning bucket boreholes that are easy to "sweep" sand and debris from the pile head should use a temporary casing as a support to maintain stability of the borehole; to obtain stability, the bottom of the casing should be buried 0.5 m into the formation;

the gravel drilled from the pile hole is moved from the position of the pile to an approved position within the site and is placed for one day; after it dries, the crushed stones are transported out of the construction site and disposed according to the requirements of relevant authorities;

the bore of the pile should not be too close to other piles that have been recently cast and contain workable concrete, in order to avoid any pile causing concrete flow or causing any damage;

(2) manufacture and installation of steel cage

In order to hoist and place the reinforcement cage without permanent deformation, the reinforcement in the form of a rigid reinforcement cage and the helical reinforcement are assembled together according to approved pile design drawings; the spiral steel bars are tightly attached to the periphery of the main longitudinal bars, the crossed steel bars are bound together by approved binding wires or bonding welding, and two ends of the crossed steel bars are turned into the piles; a steel bar worker needs to wear safety gloves to operate in the steel bar manufacturing process;

to ensure free flow of concrete in the pile holes and through the reinforcement cage, concrete/PVC shims will be used to ensure coverage of a 75 mm protective layer;

in the manufacturing process, gaskets are fixed at intervals on the length of the reinforcement cage according to the specification, the first group of gaskets are connected at a position one meter away from the bottom of the reinforcement cage, and the last group of gaskets are connected at a position one meter away from the top of the reinforcement cage; 4 support rods in each row are inserted into the reinforcement cage every 3 meters;

before all the reinforcement cages are installed, the reinforcement cages must be inspected and cleaned by a supervision engineer; the length of the reinforcement cage is adjusted according to requirements; the main longitudinal steel bars are continuously used on the specified pile length or the available steel bar length of 12 m;

because the length of the reinforcement cage of the pile exceeds 12m, 2 or more than 2 reinforcement cages with the length of 12m are combined into the reinforcement of the pile by using binding wires;

before or immediately before the concrete delivery mixer arrives at the site, the bottom of the borehole should be cleaned and measures should be taken to ensure that there is no build-up of silt or other loose material at the bottom of the borehole; before installing the steel cage, verifying the bottom of the drilled hole; then, the ready-made reinforcement cage is lifted by a crawler crane with double steel wire ropes, and then the drill hole is put down until the required depth is reached, the method is that before the tripod is placed, a circular gasket is used for keeping the required position, the required circular gasket is covered, the circular gasket is hung down from the top of the casing by three bent hooks, and necessary protrusion is carried out above the cut-off height; the required length of the reinforcement cage is ensured before installation, and the top surface elevation of the reinforcement is checked after the reinforcement cage is installed; the position of the reinforcement cage is checked before and during pouring;

(3) pouring of concrete

The design of the concrete mix should be approved by the consultant before any concrete works are started; the mixed test results should be provided for review by a consultant; the concrete is constructed and tested according to the specification of the project specification;

after the steel reinforcement cage is installed in the piling project, an iron pipe with an elbow at one end and a quick clamping system is placed into the drill hole through the steel reinforcement cage until the iron pipe contacts the bottom of the drill hole; then raising the Teremium tube by 20 cm; the conveying pipe of the concrete pump is brought to the bottom of the Teremid pipe and fixed by a quick clamp, and then the concrete is pumped through the Teremid pipe; the concrete of the pile is poured by using approved premixed concrete and high slump concrete according to the regulation of the specification; the concrete pump and the Teremid pipe form a part of the conveying pipe; allowing withdrawal of the sleeve while setting and ensuring that all cast and surrounding concrete is above critical elevation; after the pile is poured, the sleeve is completely drawn out and put into another pile hole, and the sequence is continued; after concrete is poured, if deviation exists between the concrete and the theoretical concrete amount, recording;

(4) temporary casing extraction

After partial piles are poured but before the concrete setting time, returning to the last poured pile, removing a lifting hook for supporting the reinforcement cage, and under the condition that the internal concrete still has enough working capacity, upwards pulling out the temporary sleeve by using a vibration hammer to ensure that the concrete is not lifted and the driven pile is continuous and has a full section; during the pipe drawing process, enough concrete is added to compensate the slump of the concrete and is kept in the sleeve, so that the bottom of the sleeve is always lower than the surface of the concrete during the pipe drawing process of the sleeve until the sleeve is raised to the required completion degree, the pressure from external underground water or soil is overcome, and the section of the pile is ensured not to be reduced or not to be polluted;

(5) construction record

The final highest water level of the concrete after the casing is extracted is applied to record the detailed conditions of the daily piling activities according to the standard daily report of the pile driver required by the contract specification, and is transmitted to an engineer on the next day; recording the mark of the pile, the pile position, the design load, the pile type, the platform elevation/the existing ground elevation, the pile head height, the sleeve length, the sleeve top height, the pile section elevation, the concrete batch details and the correlation information between the pile number and the concrete test block;

for site control and schedule pile driving rigs, reports should be generated and job inspection requirements should be made daily, wherein all information about the site schedule and all relevant data for each mono pile should be provided; the completed file will be handed over to the advisor for review and recording by the advisor/client representative; carrying out bearing capacity test after the maintenance time meets the requirement so as to meet the design requirement;

pile head treatment

(1) Surface treatment

The surface of the pile head should be free of any cement foam, oil, lipid, curing agent and any other harmful materials, and the glue or the bonded concrete must be repaired by proper repair mortar; nail heads and other bumps that may damage the coating must be removed or ground; repairing irregular places and pores on the surface from the range of POLYCRETE by using repair mortar; cleaning and absorbing dust on the surface to remove dust and debris;

(2) primer coating

Priming before using POLYCOATRBE1000, diluting POLYCOATRBE1000 with 20% clean water, and brushing to 4-6 square/L;

(3) construction treatment

The roller is thoroughly stirred before construction and can be used by a brush, a roller or a scraper; it can be applied to a wet surface, but ensures that no water is deposited; the coating is typically 2 layers, each at 1Lt/m²To provide a wet film thickness of 1000 microns and a dry film thickness of 600 microns; two coats will give a total dry film thickness of 1.2mm, the second coat being applied in a direction at right angles to the first coat direction if a cement plaster or plaster is applied on top of the coat, then to obtain a better adhesive bond, the coat side is brushed with clean dry sand while the coat is still wet, the coat achieving its full cure within 48 hours;

immediately after use, all tools were rinsed with water; after hardening, the coating can only be removed mechanically; and finally, constructing cement mortar with the thickness of 20mm on the full-circle pile head.

Technical Field

The invention relates to a construction method of a pipe sinking cast-in-place pile in a sea reclamation area in a coastal hydraulic reclamation area.

Background

The existing construction of pile foundations in sea reclamation areas in coastal hydraulic reclamation areas has the problems of complex construction, unsatisfactory construction quality and the like, and needs to be further improved.

Disclosure of Invention

The invention aims to provide a method for constructing a sinking pipe cast-in-place pile in a land reclamation area filled with sea in a coastal hydraulic reclamation area, which is convenient to construct and has good construction quality.

The technical solution of the invention is as follows:

a construction method of a pipe sinking cast-in-place pile in a sea reclamation area in a coastal hydraulic reclamation area is characterized by comprising the following steps: comprises the following steps:

(I) construction step

(1) Site platform preparation

Before piling projects, manual pit/ditch trial work is carried out so as to determine the position of the existing service in a field and take necessary measures according to conditions, and permission must be obtained from related departments; if any other service facilities exist on site, necessary precautions should be taken to protect the service; should transfer/demolish the existing service facility according to the requirement of the contract/relevant authorities, must provide the construction drawing showing the platform elevation/the details such as the existing ground elevation, the cut elevation, the concrete elevation and the steel reinforcement cage elevation, etc., for the consultant to review;

qualified measuring personnel set the center position of the pile from the main datum point according to an approved construction drawing after earth excavation and platform preparation projects are completed;

the center point of the pile needs to be driven out by steel bars, and after the position is checked, the pile is driven to the working platform elevation/at least 25cm below the existing ground of the pile driver; the positioning pin is composed of steel bars and is driven into a position slightly lower than the surface of the platform so as to avoid the interference of piling activities; the pile is marked with colored silk ribbon for easy location/identification; the setting of the borehole position must be confirmed by the engineer before starting the drilling project, two reference points should be added outside the casing to monitor the centre point of the casing during installation; before the sleeve is installed, two datum points are additionally arranged at a certain distance of about 1m from the outer surface of the sleeve by taking 90 degrees as datum points from the central point (marked by a steel needle) of the pile; two templates of these two additional reference points should be used during cannulation to avoid deviation from the planned position;

manually excavating the central point of the positioning pile; before the sleeve is installed, two datum points are additionally arranged on the outer side of the sleeve, the distance between the two datum points is 90 degrees, and the distance between the two datum points and the outer surface of the sleeve is equal to 1m, so that the central point of the sleeve can be monitored in the installation process; two templates of these two additional reference points should be used during casing to avoid deviation from the planned position; initially a temporary casing of the required diameter and length should be tunneled and centralised over the centre point of the pile; the tolerance for perpendicularity is 1/100; the deviation of the pile position from the plan view position is not more than 50 mm; the length of the temporary casing should be adjusted to achieve the minimum amount of embedment in the rock/hard formation reported in soil survey reports, i.e. continue to push the temporary casing with the vibratory hammer at least 1 meter below the section of the pile until it is embedded in the rock/hard formation or until rejected to avoid any possibility of collapse of the borehole wall; checking the verticality and elevation according to the regulations in the installation process; if the soil layer below the toe of the casing pipe is found to be collapsed, the casing pipe is continuously pushed until the collapse is stopped; if the sleeve cannot be continuously installed through knocking or vibrating, pre-drilling on the pile position, and then continuously installing the sleeve;

when the casing pipe is drilled, two workers check the offset near a pile point according to a diagram, and one worker regularly checks the verticality of the casing pipe by using a level gauge until the casing pipe is drilled;

after the sleeve is installed at the inspection pile position, a drilling machine is arranged above the pile position, and soil/rock is drilled to a preset/designed height on the premise of the minimum penetration requirement on the hard stratum/rock according to the construction requirement; before starting the drilling operation, the engineer should check the position of the casing;

after drilling is finished, cleaning the bottom of the drilled hole by using a bucket to remove drill cuttings and loose materials at the fundus part of the pile; for this reason, drilling/cleaning bucket boreholes that are easy to "sweep" sand and debris from the pile head should use a temporary casing as a support to maintain stability of the borehole; to obtain stability, the bottom of the casing should be buried 0.5 m into the formation;

the gravel drilled from the pile hole is moved from the position of the pile to an approved position within the site and is placed for one day; after it dries, the crushed stones are transported out of the construction site and disposed according to the requirements of relevant authorities;

the bore of the pile should not be too close to other piles that have been recently cast and contain workable concrete, in order to avoid any pile causing concrete flow or causing any damage;

(2) manufacture and installation of steel cage

In order to hoist and place the reinforcement cage without permanent deformation, the reinforcement in the form of a rigid reinforcement cage and the helical reinforcement are assembled together according to approved pile design drawings; the spiral steel bars are tightly attached to the periphery of the main longitudinal bars, the crossed steel bars are bound together by approved binding wires or bonding welding, and two ends of the crossed steel bars are turned into the piles; a steel bar worker needs to wear safety gloves to operate in the steel bar manufacturing process;

to ensure free flow of concrete in the pile holes and through the reinforcement cage, concrete/PVC shims will be used to ensure coverage of a 75 mm protective layer;

in the manufacturing process, gaskets are fixed at intervals on the length of the reinforcement cage according to the specification, the first group of gaskets are connected at a position one meter away from the bottom of the reinforcement cage, and the last group of gaskets are connected at a position one meter away from the top of the reinforcement cage; 4 support rods in each row are inserted into the reinforcement cage every 3 meters;

before all the reinforcement cages are installed, the reinforcement cages must be inspected and cleaned by a supervision engineer; the length of the reinforcement cage is adjusted according to requirements; the main longitudinal steel bars are continuously used in a specified pile length (including a protruding part above a pile cutting position) or an available steel bar length of 12m (on the basis of less parts);

because the length of the reinforcement cage of the pile exceeds 12m, 2 or more than 2 reinforcement cages with the length of 12m are combined into the reinforcement of the pile by using binding wires;

before or immediately before the concrete delivery mixer arrives at the site, the bottom of the borehole should be cleaned and measures should be taken to ensure that there is no build-up of silt or other loose material at the bottom of the borehole; before installing the steel cage, verifying the bottom of the drilled hole; then, the ready-made reinforcement cage is lifted by a crawler crane with double steel wire ropes, and then the drill hole is put down until the required depth is reached, the method is that before the tripod is placed, a circular gasket is used for keeping the required position, the required circular gasket is covered, the circular gasket is hung down from the top of the casing by three bent hooks, and necessary protrusion is carried out above the cut-off height; required reinforcement cage length is ensured before installation, and the top surface elevation of the steel bar is checked after the reinforcement cage is installed. The position of the reinforcement cage is checked before and during pouring;

(3) pouring of concrete

The design of the concrete mix should be approved by the consultant (proctor) before any concrete works are started; the mixed test results should be provided for review by a consultant; the concrete is constructed and tested according to the specification of the project specification;

after the steel reinforcement cage is installed in the piling project, an iron pipe with an elbow at one end and a quick clamping system is placed into the drill hole through the steel reinforcement cage until the iron pipe contacts the bottom of the drill hole; then raising the Teremium tube by 20 cm; the conveying pipe of the concrete pump is brought to the bottom of the Teremid pipe and fixed by a quick clamp, and then the concrete is pumped through the Teremid pipe; the concrete of the pile is poured by using approved premixed concrete and high slump concrete according to the regulation of the specification; the concrete pump and the Teremid pipe form a part of the conveying pipe; allowing withdrawal of the sleeve while setting and ensuring that all cast and surrounding concrete is above critical elevation; after the pile is poured, the sleeve is completely drawn out and put into another pile hole, and the sequence is continued; after concrete is poured, if deviation exists between the concrete and the theoretical concrete amount, recording;

(4) temporary casing extraction

After partial piles are poured but before the concrete setting time, returning to the last poured pile, removing a lifting hook for supporting the reinforcement cage, and under the condition that the internal concrete still has enough working capacity, upwards pulling out the temporary sleeve by using a vibration hammer to ensure that the concrete is not lifted and the driven pile is continuous and has a full section; during the pipe drawing process, enough concrete is added to compensate the slump of the concrete and is kept in the sleeve, so that the bottom of the sleeve is always lower than the surface of the concrete during the pipe drawing process of the sleeve until the sleeve is raised to the required completion degree, the pressure from external underground water or soil is overcome, and the section of the pile is ensured not to be reduced or not to be polluted;

(5) construction record

The final highest water level of the concrete after the casing is extracted is applied to record the detailed conditions of the daily piling activities according to the standard daily report of the pile driver required by the contract specification, and is transmitted to an engineer on the next day; recording the mark of the pile, the pile position, the design load, the pile type, the platform elevation/the existing ground elevation, the pile head height, the sleeve length, the sleeve top height, the pile section elevation, the concrete batch details and the correlation information between the pile number and the concrete test block;

for site control and schedule pile driving rigs, reports should be generated and job inspection requirements should be made daily, wherein all information about the site schedule and all relevant data for each mono pile should be provided; the completed file will be handed over to the advisor for review and recording by the advisor/client representative; carrying out bearing capacity test after the maintenance time meets the requirement so as to meet the design requirement;

pile head treatment

(1) Surface treatment

The surface of the pile head should be free of any cement foam, oil, lipid, curing agent and any other harmful materials, and the glue or the bonded concrete must be repaired by proper repair mortar; nail heads and other bumps that may damage the coating must be removed or ground; repairing irregular places and pores on the surface from the range of POLYCRETE by using repair mortar; cleaning and absorbing dust on the surface to remove dust and debris;

(2) primer (adhesive layer)

Priming before using POLYCOATRBE1000, diluting POLYCOATRBE1000 with 20% clean water, and brushing to 4-6 square/L;

(3) construction treatment

The roller is thoroughly stirred before construction and can be used by a brush, a roller or a scraper; it can be applied to a wet surface, but ensures that no water is deposited; the coating is typically 2 layers, each at 1Lt/m²To provide a wet film thickness of 1000 microns and a dry film thickness of 600 microns; two coats will give a total dry film thickness of 1.2mm, the second coat being applied in a direction at right angles to the first coat direction if a cement plaster or plaster is applied on top of the coat, then to obtain a better adhesive bond, the coat side is brushed with clean dry sand while the coat is still wet, the coat achieving its full cure within 48 hours;

immediately after use, all tools were rinsed with water; after hardening, the coating can only be removed mechanically; and finally, constructing cement mortar with the thickness of 20mm on the full-circle pile head.

The invention has convenient construction and good construction quality, and is particularly suitable for projects in middle east.

The present invention will be further described with reference to the following examples.

Detailed Description

A construction method of a pipe sinking cast-in-place pile in a sea reclamation area in a coastal hydraulic reclamation area comprises the following steps:

(I) construction step

(1) Site platform preparation

Before piling projects, manual pit/ditch trial work is carried out so as to determine the position of the existing service in a field and take necessary measures according to conditions, and permission must be obtained from related departments; if any other service facilities exist on site, necessary precautions should be taken to protect the service; should transfer/demolish the existing service facility according to the requirement of the contract/relevant authorities, must provide the construction drawing showing the platform elevation/the details such as the existing ground elevation, the cut elevation, the concrete elevation and the steel reinforcement cage elevation, etc., for the consultant to review;

qualified measuring personnel set the center position of the pile from the main datum point according to an approved construction drawing after earth excavation and platform preparation projects are completed;

the center point of the pile needs to be driven out by steel bars, and after the position is checked, the pile is driven to the working platform elevation/at least 25cm below the existing ground of the pile driver; the positioning pin is composed of steel bars and is driven into a position slightly lower than the surface of the platform so as to avoid the interference of piling activities; the pile is marked with colored silk ribbon for easy location/identification; the setting of the borehole position must be confirmed by the engineer before starting the drilling project, two reference points should be added outside the casing to monitor the centre point of the casing during installation; before the sleeve is installed, two datum points are additionally arranged at a certain distance of about 1m from the outer surface of the sleeve by taking 90 degrees as datum points from the central point (marked by a steel needle) of the pile; two templates of these two additional reference points should be used during cannulation to avoid deviation from the planned position;

manually excavating the central point of the positioning pile; before the sleeve is installed, two datum points are additionally arranged on the outer side of the sleeve, the distance between the two datum points is 90 degrees, and the distance between the two datum points and the outer surface of the sleeve is equal to 1m, so that the central point of the sleeve can be monitored in the installation process; two templates of these two additional reference points should be used during casing to avoid deviation from the planned position; initially a temporary casing of the required diameter and length should be tunneled and centralised over the centre point of the pile; the tolerance for perpendicularity is 1/100; the deviation of the pile position from the plan view position is not more than 50 mm; the length of the temporary casing should be adjusted to achieve the minimum amount of embedment in the rock/hard formation reported in soil survey reports, i.e. continue to push the temporary casing with the vibratory hammer at least 1 meter below the section of the pile until it is embedded in the rock/hard formation or until rejected to avoid any possibility of collapse of the borehole wall; checking the verticality and elevation according to the regulations in the installation process; if the soil layer below the toe of the casing pipe is found to be collapsed, the casing pipe is continuously pushed until the collapse is stopped; if the sleeve cannot be continuously installed through knocking or vibrating, pre-drilling on the pile position, and then continuously installing the sleeve;

when the casing pipe is drilled, two workers check the offset near a pile point according to a diagram, and one worker regularly checks the verticality of the casing pipe by using a level gauge until the casing pipe is drilled;

after the sleeve is installed at the inspection pile position, a drilling machine is arranged above the pile position, and soil/rock is drilled to a preset/designed height on the premise of the minimum penetration requirement on the hard stratum/rock according to the construction requirement; before starting the drilling operation, the engineer should check the position of the casing;

after drilling is finished, cleaning the bottom of the drilled hole by using a bucket to remove drill cuttings and loose materials at the fundus part of the pile; for this reason, drilling/cleaning bucket boreholes that are easy to "sweep" sand and debris from the pile head should use a temporary casing as a support to maintain stability of the borehole; to obtain stability, the bottom of the casing should be buried 0.5 m into the formation;

the gravel drilled from the pile hole is moved from the position of the pile to an approved position within the site and is placed for one day; after it dries, the crushed stones are transported out of the construction site and disposed according to the requirements of relevant authorities;

the bore of the pile should not be too close to other piles that have been recently cast and contain workable concrete, in order to avoid any pile causing concrete flow or causing any damage;

(2) manufacture and installation of steel cage

In order to hoist and place the reinforcement cage without permanent deformation, the reinforcement in the form of a rigid reinforcement cage and the helical reinforcement are assembled together according to approved pile design drawings; the spiral steel bars are tightly attached to the periphery of the main longitudinal bars, the crossed steel bars are bound together by approved binding wires or bonding welding, and two ends of the crossed steel bars are turned into the piles; a steel bar worker needs to wear safety gloves to operate in the steel bar manufacturing process;

to ensure free flow of concrete in the pile holes and through the reinforcement cage, concrete/PVC shims will be used to ensure coverage of a 75 mm protective layer;

in the manufacturing process, gaskets are fixed at intervals on the length of the reinforcement cage according to the specification, the first group of gaskets are connected at a position one meter away from the bottom of the reinforcement cage, and the last group of gaskets are connected at a position one meter away from the top of the reinforcement cage; 4 support rods in each row are inserted into the reinforcement cage every 3 meters;

before all the reinforcement cages are installed, the reinforcement cages must be inspected and cleaned by a supervision engineer; the length of the reinforcement cage is adjusted according to requirements; the main longitudinal steel bars are continuously used in a specified pile length (including a protruding part above a pile cutting position) or an available steel bar length of 12m (on the basis of less parts);

because the length of the reinforcement cage of the pile exceeds 12m, 2 or more than 2 reinforcement cages with the length of 12m are combined into the reinforcement of the pile by using binding wires;

before or immediately before the concrete delivery mixer arrives at the site, the bottom of the borehole should be cleaned and measures should be taken to ensure that there is no build-up of silt or other loose material at the bottom of the borehole; before installing the steel cage, verifying the bottom of the drilled hole; then, the ready-made reinforcement cage is lifted by a crawler crane with double steel wire ropes, and then the drill hole is put down until the required depth is reached, the method is that before the tripod is placed, a circular gasket is used for keeping the required position, the required circular gasket is covered, the circular gasket is hung down from the top of the casing by three bent hooks, and necessary protrusion is carried out above the cut-off height; required reinforcement cage length is ensured before installation, and the top surface elevation of the steel bar is checked after the reinforcement cage is installed. The position of the reinforcement cage is checked before and during pouring;

(3) pouring of concrete

The design of the concrete mix should be approved by the consultant (proctor) before any concrete works are started; the mixed test results should be provided for review by a consultant; the concrete is constructed and tested according to the specification of the project specification;

after the steel reinforcement cage is installed in the piling project, an iron pipe with an elbow at one end and a quick clamping system is placed into the drill hole through the steel reinforcement cage until the iron pipe contacts the bottom of the drill hole; then raising the Teremium tube by 20 cm; the conveying pipe of the concrete pump is brought to the bottom of the Teremid pipe and fixed by a quick clamp, and then the concrete is pumped through the Teremid pipe; the concrete of the pile is poured by using approved premixed concrete and high slump concrete according to the regulation of the specification; the concrete pump and the Teremid pipe form a part of the conveying pipe; allowing withdrawal of the sleeve while setting and ensuring that all cast and surrounding concrete is above critical elevation; after the pile is poured, the sleeve is completely drawn out and put into another pile hole, and the sequence is continued; after concrete is poured, if deviation exists between the concrete and the theoretical concrete amount, recording;

(4) temporary casing extraction

After partial piles are poured but before the concrete setting time, returning to the last poured pile, removing a lifting hook for supporting the reinforcement cage, and under the condition that the internal concrete still has enough working capacity, upwards pulling out the temporary sleeve by using a vibration hammer to ensure that the concrete is not lifted and the driven pile is continuous and has a full section; during the pipe drawing process, enough concrete is added to compensate the slump of the concrete and is kept in the sleeve, so that the bottom of the sleeve is always lower than the surface of the concrete during the pipe drawing process of the sleeve until the sleeve is raised to the required completion degree, the pressure from external underground water or soil is overcome, and the section of the pile is ensured not to be reduced or not to be polluted;

(5) construction record

The final highest water level of the concrete after the casing is extracted is applied to record the detailed conditions of the daily piling activities according to the standard daily report of the pile driver required by the contract specification, and is transmitted to an engineer on the next day; recording the mark of the pile, the pile position, the design load, the pile type, the platform elevation/the existing ground elevation, the pile head height, the sleeve length, the sleeve top height, the pile section elevation, the concrete batch details and the correlation information between the pile number and the concrete test block;

for site control and schedule pile driving rigs, reports should be generated and job inspection requirements should be made daily, wherein all information about the site schedule and all relevant data for each mono pile should be provided; the completed file will be handed over to the advisor for review and recording by the advisor/client representative; carrying out bearing capacity test after the maintenance time meets the requirement so as to meet the design requirement;

pile head treatment

(1) Surface treatment

The surface of the pile head should be free of any cement foam, oil, lipid, curing agent and any other harmful materials, and the glue or the bonded concrete must be repaired by proper repair mortar; nail heads and other bumps that may damage the coating must be removed or ground; repairing irregular places and pores on the surface from the range of POLYCRETE by using repair mortar; cleaning and absorbing dust on the surface to remove dust and debris;

(2) primer (adhesive layer)

Priming before using POLYCOATRBE1000, diluting POLYCOATRBE1000 with 20% clean water, and brushing to 4-6 square/L;

(3) construction treatment

The roller is thoroughly stirred before construction and can be used by a brush, a roller or a scraper; it can be applied to a wet surface, but with assuranceNo water accumulation; the coating is typically 2 layers, each at 1Lt/m²To provide a wet film thickness of 1000 microns and a dry film thickness of 600 microns; two coats will give a total dry film thickness of 1.2mm, the second coat being applied in a direction at right angles to the first coat direction if a cement plaster or plaster is applied on top of the coat, then to obtain a better adhesive bond, the coat side is brushed with clean dry sand while the coat is still wet, the coat achieving its full cure within 48 hours;

immediately after use, all tools were rinsed with water; after hardening, the coating can only be removed mechanically; and finally, constructing cement mortar with the thickness of 20mm on the full-circle pile head.