Construction scheme of manual digging cast-in-place pile

Construction scheme of manual digging cast-in-place pile

2. Project overview

2. 1. Design Overview

Xinyu 3A# Building of emerald city Phase II. * * * The design diameters of 97 manually dug piles are 900, 1000, 1200 and 1300 respectively, and the pile ends are required to be placed on moderately weathered argillaceous sandstone layer, with rock penetration not less than1d. The pile body is made of concrete C30, and the reinforcement is made of HPB235 and HRB335. The longitudinal reinforcement joint of the pile adopts welded joint reinforcement; The protective layer is 50 mm thick. The safety level of pile foundation is Grade II.

2.2. Engineering geological conditions

According to the survey report, the geological conditions of this project are as follows: the terrain of the site is flat, the strength of miscellaneous fill in 1 layer is low, and the water content is high, so this layer is not suitable as the foundation bearing layer; The second layer is silty clay layer, with uniform soil quality, granular structure, large amount of iron and manganese, high dry strength and good toughness, and a small amount of strongly weathered sand and mudstone debris at the bottom; The third layer is sandy mudstone, gray, well-bedded, containing a lot of cuttings, a few cracks, a lot of ferromanganese, and several layers of mudstone, which is soft rock and relatively broken.

3. Construction preparation

1, familiar with construction drawings and underground soil and hydrogeological data.

2. According to the geological data provided and the earthwork excavation of the foundation pit of the water intake pump house, the pile foundation of this project adopts artificial hole-forming pile holes, and the shaft lining support is calculated and designed according to the soil characteristics and groundwater distribution in this area.

3. Before excavation, the site should be leveled, and obstacles such as young crops and trees on the ground should be handled well.

4. Before comprehensive excavation, two test pile holes are dug selectively, and the soil quality, hydrology and other related conditions are analyzed to modify the original construction scheme.

5. In the area with high groundwater level, first reduce the groundwater level to about 0.5m below the pile bottom.

6. The safety of manual excavation is very important. Before excavation, conduct a comprehensive safety technical disclosure to the construction personnel; Check and test the safety and reliability of the spreader before operation to ensure the construction safety.

7, materials and main machines and tools:

7. 1. 1 cement: No.325 ~ No.425 ordinary portland cement or slag portland cement shall be used.

7. 1.2 sand: medium sand or coarse sand, with silt content not more than 5%.

7. 1.3 pebble: pebble or gravel with a particle size of 0.5 ~ 3.2 cm; Small particle size can also be used for pile concrete.

With 5cm stones, and the silt content is not more than 2%.

7. 1.4 water: tap water or clean water without harmful substances should be used.

7. 1.5 plus early strength agent should be selected through experiments, and the content of fly ash should be determined according to the regulations of the laboratory.

7. 1.6 steel bar: the grade and diameter of steel bar must meet the design requirements, with factory certificate and retest report.

7. 1.7 Generally, signs, hoist groups or electric hoists, trolleys or dump trucks, pickaxes, shovels,

Hand shovel, drill pipe, wire pendant, fixed pulley block, guide pulley block, concrete mixer, bucket, chute, conduit, vibrating rod, drill pipe, coarse hemp rope, steel wire rope, safety movable cover plate, waterproof lighting lamp (low voltage 36V, 100W),

Electric welding machine, ventilation and oxygen supply equipment, lifting pump, wooden pulley, movable ladder, safety helmet, safety belt, etc.

7. 1.8 Formwork: Assemble four (or eight) composite steel formworks and arc tool steel formworks. Fixed and suspended

Hooks and spare parts. Wood board, wood square, No.8 or 12 channel steel, etc.

3.2. Construction progress

20 10, 1 1.09, 20 10, 65438+2.08, which have been completed, and the foundation piles are inspected as required.

3.3.ILO

According to the requirements of engineering quantity and overall construction progress, it is planned to arrange 30 people to dig holes manually, in groups of two, foreman 1 person and technician 1 person. Steel processing and binding personnel 5, concrete pouring personnel 3. Technical person in charge of project arrangement 1, quality engineer 1.

4. Main construction methods

Construction flow chart

4. 1. Technical measures for manual digging piles

In the process of manual digging pile, the key points of construction are: the mixture ratio of retaining wall concrete, orifice lofting, the center position of each section and the measurement of hole depth. During construction, the soil quality, water seepage, center deviation and initial depth of each section shall be recorded in time.

1. Before excavation, clean up the sundries at the site, level and compact them, and pay off accurately. Four protection piles are set around the hole center pile 1 m, which are symmetrically arranged in a cross shape. After the completion of the wellhead retaining wall construction, mark the pile center on the wellhead retaining wall.

2. When excavating the same row of pile foundations, it is advisable to dig holes at intervals, and when excavating pile groups, it is advisable to adopt plum blossom excavation to avoid the influence of excavation on the wall protection of adjacent pile foundations. In case of slight sand flow, the length of the retaining wall should be shortened to 0.5m to reduce the exposure time of the excavated hole wall, and the retaining wall concrete should be poured in time.

3. When digging a hole, the concrete retaining wall shall be used once per footage, and the label of the concrete retaining wall shall not be less than C25. Retaining wall formwork shall adopt two semicircular trumpet-shaped steel formwork. Thickness of retaining wall is 12-20cm. Centralized mixing is adopted behind the retaining wall, and steel bars are rammed. Behind the retaining wall, the upper aperture of each section is greater than the designed pile diameter 16cm. When the breast wall concrete is not compacted by vibrating, and there is water seepage in the breast wall, it should be handled in time. When the water seepage is small, it can be blocked directly with waterproof material. Holes with a slightly larger amount of water can be driven into wooden wedges and sealed with waterproof materials around them. For the hole with large water pressure and water seepage, according to the size of the hole, the corresponding plastic pipe can be embedded in the diversion, and the surrounding is sealed with waterproof material. When excavating the pile hole, use the drainage pipe to lead the water out of the hole. Before pouring concrete into the pile, tie the pipe firmly with iron wire and cut it off.

4. Before each section of excavation, after the hole center pile is restored, the center position of the hole in this section shall be released with a hanging hammer to prevent the pile center from deviating. The clay layer is dug with picks and shovels, and the hard soil layer and strongly weathered rock layer are broken with pneumatic picks.

5. When digging a hole below 10m, use a blower for ventilation to keep the air in the hole fresh. Pour in the air and condense.

Soil, usually adopts the method of string tube blanking, layered vibrating or short casing direct feeding. Practice has proved that the combination of the two methods can better ensure the compactness of pile concrete. Because to minimize the influence of groundwater, it is necessary to speed up the pouring as much as possible, and it is required to concentrate enough concrete to complete the pouring in a short time, and use the weight of concrete itself to inhibit the infiltration of groundwater.

6. Groundwater has a great influence on the uniformity and compactness of concrete. The specific construction method should be determined according to the speed of groundwater flow. When the groundwater seeping from the bottom and wall of the hole rises at a high speed (reference value ≧6mm/min), the underwater cast-in-place pile method should be adopted, which has detailed provisions in the construction technical specifications. It should be noted that before pouring concrete, the water level in the hole should be at least as high as or higher than the underground water level outside the hole1~1.5m.

7, vertical lifting equipment to stand firm, should be able to withstand a certain momentum not overturned, vertical lifting equipment must be inspected before it can be put into use. After digging to the designed pile bottom elevation, the verticality and depth of the hole shall be detected by the hole tester. The instruments used in this project mainly include theodolite and automatic level.

8, when the pile hole depth is more than 20m, should be ventilated underground, strengthen air convection. When necessary, deliver oxygen to prevent the harm of toxic gas. During the operation, the upper and lower personnel take turns to work, and the personnel on the pile hole closely observe the situation of the personnel under the pile hole and deal with each other, thus effectively preventing the occurrence of safety accidents. When the underground water volume is not large, the mud water will be transported out with the bucket for excavation. When the local infiltration water is large, the bucket can no longer meet the drainage requirements. First, dig a sump at the bottom of the pile hole, and use the elevation pump to sink into it to pump water, and then drop water while digging. The specifications of the pump are determined according to the pumping capacity. Pumping should be done in three shifts day and night to keep the water level stable.

9. When the underground water level is high, unified precipitation measures should be taken before excavation.

10. Install a movable safety cover plate that moves horizontally at the pile hole. When someone digs in the pile hole, cover the safety cover to prevent debris from falling and hitting people. Irrelevant personnel shall not be near the edge of pile hole. When lifting the soil, open the safety cover again. In the second quarter, earthwork excavation and lifting (trimming) of pile holes, starting from the second quarter, lifting equipment will be used to transport soil, and personnel in pile holes should wear safety helmets, and ground personnel should fasten their safety belts. When the bucket leaves 1.5m above the orifice, push the movable safety cover to cover the orifice to prevent the unloaded clods, stones and other sundries from falling into the orifice and injuring people. After unloading the bucket into the trolley, open the movable cover and lower the bucket to load the soil. After the pile hole is dug to the specified depth, check the diameter of the pile hole and the radian of the hole wall with a strut, make it vertical and smooth, and trim the hole wall.

4.2. Construction survey

Four leveling points are arranged around the proposed building as the basis for building settlement observation. The closing difference of four leveling points should be less than 12 √ h, and the leveling points should be protected during site arrangement and earthwork excavation.

Before excavation, determine the single axis control points according to the secondary control points on site as the basis for axis control and lofting. Measure each control line and axis with theodolite, and measure the center position of each pile with steel tape measure. In order to facilitate the recheck of axis, pile center and verticality, four piles are set around each pile to control the axis position, which is submitted to the supervisor in writing for recheck, and the wall protection is started after signing.

When shuttering for the first time, the concrete retaining wall should be higher than the natural ground150 mm. After the retaining wall in the first section, the axes and control elevation will be measured to the top of the retaining wall, and the standard axis or pile centerline will be nailed with bamboo pieces and marked with red paint to facilitate the control of pile elevation and center.

4.3. Manual hole-digging pile pore-forming construction

4.3. 1. Matters needing attention in pile foundation construction

Before construction every day, well personnel should be arranged to check the wall protection, and the hole can be excavated only if there is no abnormality.

4.3.2. Artificial pore-forming construction of pile foundation

1. Construction process

Earthwork excavation (or pumping) → hole wall cleaning, verticality inspection and pile diameter → concrete wall protection → excavation.

2. Hole-forming construction method

(1). Use short picks, shovels and other simple tools for manual excavation. When encountering hard rock stratum, use pneumatic pick or.

Hand-chiseling construction. Vertical soil transportation, using artificial vertical soil transportation; After the axis is verified, start the first excavation, and make a concrete retaining wall every footage 1 m, that is, take 1 m as a construction section; When the depth of the pile hole exceeds10m, fresh air will be sent into the pile hole through the blower and air duct, and the soil bucket or hanging cage will ensure smooth up and down.

(2) Hole-forming excavation shall be carried out in groups of two persons, and each group shall arrange 2 ~ 3 piles for flow operation every day, so as to ensure that each pile is driven by 1 ~ 2 molds every day. During the construction, * * * set up five teams for cross construction.

(3) When encountering boulders or other obstacles during excavation, manpower, air compressor and pneumatic pick shall be used for construction.

(4) During the hole-forming process, the ground will assign special personnel to repair the drainage ditch, and the water pumped from the pile hole will be discharged in time. Waste soil or ballast excavated from pile holes will be transported out of the site in time by special personnel.

⑤ Inspection of pile position, verticality and diameter: Control points and leveling points of foundation pile axis should be located in places not affected by construction. Before construction, it should be properly protected after review, and it should be repeated frequently during construction. In the first section, after the retaining wall is bored, on-site technicians set the center line of the pile position around the retaining wall with bamboo pieces, control the axis of the pile position with orthogonal crosshairs as the basis for controlling the verticality deviation between the downstream construction template and the pile position, and use a ruler to find the circumference for diameter inspection.

3. Quality inspection

Inspection is divided into earthwork excavation and concrete wall protection, and each section should be inspected. If any deviation is found, it should be corrected at any time to ensure the accurate position.

4.3.3. Construction of retaining wall

Detail drawing of pile top retaining wall

Wall protection detail drawing

Note: C20 fine stone concrete is used as the retaining wall concrete.

1. Construction of retaining wall

After the pile hole is dug to the specified depth, check the diameter of the pile hole and the radian of the hole wall with a strut, make it vertical and smooth, and trim the hole wall. Dismantle the retaining wall formwork in the first section and the second section, and place additional reinforcement. The retaining wall formwork should be used in turn by dismantling the upper section and supporting the lower section. In the second quarter, concrete for retaining wall shall be poured, transported by bucket, manually poured and compacted. Early strength agent can be added to concrete through experiments to accelerate the hardening of concrete. If the aperture decreases downward, it should be equipped with a small template for adjustment. At the top of the formwork, a concrete pouring opening with a height of 100mm should be reserved, and the interface should be compacted. Concrete after formwork removal

Or bricklaying, cement mortar screeding, formwork removal strength reaches 65438±0 MPa. During the construction of concrete retaining wall, the diameter of the upper opening of each pile is the pile diameter, the diameter of the lower opening is the pile diameter plus 500mm, and the height is 1 100mm or 2500mm. The retaining wall in the first section should be 30-50cm higher than the ground, so as to facilitate retaining soil or fixing points.

4.3.4. Final hole inspection

After the hole is drilled to the designed bearing layer, the construction unit shall conduct self-inspection evaluation. The final hole inspection of engineering piles includes the displacement deviation of the center line of the pile hole, the deviation of the pile diameter, the depth of the final hole, the sediment at the bottom of the hole, the bearing layer at the bottom of the pile, etc. All deviations should be within the allowable range of design and specification. Report to the supervision, survey, design institute, owner and other departments for verification, and go through the formalities of concealed acceptance visa.

When the designed bearing layer is verified by the relevant departments, the expansion construction can be carried out. After the expansion construction, the construction unit shall conduct self-inspection and evaluation, and report to the supervision, survey, design institute and owner for review, and go through the formalities of concealed acceptance visa.

4.3.5. Matters needing attention when digging a pit

1. Each section should check the verticality and diameter of the pile hole, correct the deviation in time, and ensure the correct position.

2. The depth of the final hole at the pile end shall be constructed according to the design requirements. After the final hole of each pile, the survey, design, owner and supervisor must be invited for acceptance and concealed inspection one by one.

3. In case of landslide, bricklaying external formwork shall be adopted at the landslide site, the rebar diameter shall be 6mm, the spacing shall be 150mm, and concrete retaining wall shall be poured at the internal formwork.

4. If the local sewage seeps out quickly or the rainwater flows in and the drainage is not timely, there will be water accumulation. During excavation, a sump should be dug at the bottom of the hole, and water should be pumped by a pump in time. If there is a small amount of accumulated water, the initial setting semi-dry concrete can be used when pouring concrete, and when a large amount of accumulated water is temporarily removed, the method of underwater pouring concrete with conduit can be used to ensure the construction quality.

5. There is too much residual virtual soil at the bottom of the hole; There are a lot of empty soil and broken bricks after hole-forming and finishing, which have not been carefully removed. Before and after placing the reinforcing cage, carefully check the bottom of the hole to remove impurities in the virtual soil. When necessary, back cover with cement mortar or concrete.

6. Excessive vertical deviation: the verticality of each section was not verified as required during excavation, resulting in vertical deviation after excavation. After each section is dug, it must be hung straight and trimmed according to the axis of the pile hole to keep the upper and lower arcs of the hole wall straight.

7. The dug pile hole must be covered with wooden boards or scaffolding and steel mesh to prevent clods, sundries and personnel from falling. It is forbidden to cover the door with straw bags and plastic sheets.

Quality standards.

1. Allowable deviation of center line displacement of pile hole position: ≤ 30mm;

2. Allowable deviation of pile diameter: negative deviation is not allowed;

3. Allowable deviation of concrete thickness of retaining wall:15mm; ;

4. Thickness of sediment at the bottom of the hole: not allowed.

4.3. Manufacture and installation of manual digging pile reinforcing cage

It is planned to adopt two construction technologies for reinforcing cage: welding main reinforcement, making and forming on the hole or binding and forming in the hole, which are selected according to the specific situation.

4.3. 1. Fabrication of reinforcing cage

1. Material requirements:

The rebar entering the site must have the factory certificate and quality guarantee. The steel bars entering the site shall be stacked in batches according to specifications, models and requirements, and witness sampling inspection shall be conducted in accordance with regulations. Invite the supervision unit and the construction unit to witness the sampling at the site, and notify the technical director of the inspection results in writing. After the supervision unit approves, the steel bars can be processed and manufactured. Steel yard should be listed for inspection, and marked with the words inspected, qualified and unqualified.

2. Before making the reinforcing cage, dig out the samples one by one according to different piles, first make the stiffening hoop and spiral stirrup according to the samples, and use flash butt welding or arc welding for the main reinforcement. The process is operated on the ground, and can only be used after sampling every 300 joints is sent for inspection. When making, they should be numbered one by one, listed and stacked at the orifice.

4.3.2. Reinforcement cage binding construction method

1. Conditions before construction:

(1), the hole-forming pile has been accepted by the relevant departments, and the final hole acceptance formalities have been handled.

(2), steel raw materials have a certificate of approval and inspection report.

(3) The water in the cave has been drained, and fresh air is sent down with ventilation equipment, and the air in the cave is tested to be qualified.

(4) Safety technical disclosure has been made to the team before underground operation.

2. Process flow:

Loading and unloading of reinforcement shaft → installation of stiffening hoop → welding of main reinforcement and stiffening hoop → binding of spiral reinforcement → hanging reinforcement cage into hole for installation → handling concealment procedures → concrete pouring of pile body.

3. Manufacture of reinforcing cage

According to the design requirements and the actual pile length, the reinforcement is mixed on the hole. When the main reinforcement is laid, the number of laps within 35d or 500m shall not exceed 50% of the main reinforcement. When making stiffening hoop, it should be ensured that the protective layer of the main reinforcement of the pile is not less than 50mm, and the segment length of the spiral disc should meet the required reinforcement length of 3 ~ 5 turns. There shall be no less than 3 horizontal stirrups at the pile end.

4.3.3. Reinforcement cage hoisting construction method

After the reinforcing cage is formed on the hole, in order to ensure the safety of hoisting the reinforcing cage, it is decided to install the reinforcing cage on the pile body by integral hoisting or derrick hoisting.

1. The upper part of the reinforcing cage is provided with a stiffening hoop, which is welded with the main reinforcement as the lifting point of the hanging pile.

2. When the reinforcing cage is made into a section, the reinforcing cage of the pile body is integrally hoisted and installed at one time; After the reinforcing cage is made into segments, hang a reinforcing cage at the orifice, which is about 1.0m higher, then hang a reinforcing cage, and weld after the main reinforcement is aligned. Then, hang the whole reinforcing cage around the spiral stirrups and slowly put it into the hole in place.

3. Hidden inspection of reinforcing cage

After the installation of reinforcing cage, the elevation, diameter of main reinforcement, spacing, stirrup spacing, welding quality, binding quality and protective layer shall be self-inspected. After passing the self-inspection, submit it to the supervision engineer in writing for inspection. After passing the inspection, the concealed works shall be signed in time.

4.3.4. Allowable deviation of reinforcing cage fabrication

1. main reinforcement spacing:10mm;

2. Stirrup spacing or pitch: 20mm；;

3. Reinforcement cage diameter:10mm;

4. Reinforcement cage length: 50 mm ..

4.4. 1. Raw material requirements

1. cement: 425# ordinary silicon or slag cement shall be used, with factory certificate and test report.

2. Sand: medium sand, with silt content not more than 3%.

3. Stones: crushed stones, with a particle size of 10- 15mm and a silt content of no more than 2%.

4.4.2. Concrete supply

Concrete is supplied by centralized mixing station on site, transported by tank car, poured and dumped.

4.4.3. Pile concrete pouring

Because of the different water seepage in the hole of concrete cast-in-place pile, different grouting methods are selected according to the actual situation.

1. When pouring concrete on the pile top, the design elevation of the pile top should be properly exceeded to ensure that the elevation of the pile top meets the design requirements after removing laitance. The reinforcement inserted at the top of the pile must keep the design size, be inserted vertically, and have sufficient protective layer. When there is basically no water in the pile hole, conventional concrete pouring method is adopted, and concrete is pumped by concrete pump if necessary.

2. Simple conduit method is used for pile holes with fast water seepage and fast drainage. On the working platform of pile foundation excavation, build a simple working frame which can support 1-2t and the height is more than 6m; Install the conduit and funnel according to the method of pouring underwater concrete (a small funnel that can hold 0.2m3 concrete without putting balls); Insert the catheter into the bottom of the pile hole as a guide chain and hang it on the simple working frame; Ready for concrete pouring, pump water into the hole with submersible pump; It should be drawn

When the water depth in the hole is only about 10cm, immediately lift the submersible pump and pump the concrete into the funnel and conduit; When the concrete in the conduit is poured to the funnel surface, use the guide chain to raise the outlet of the conduit by 2 cm, so that the concrete in the conduit can fill the bottom of the hole quickly.

And rise around the conduit to continue pouring concrete. When the concrete no longer flows to the bottom of the hole, but rises to the surface of the funnel, the lifting conduit continues to pour concrete. Continue perfusion according to this method. According to this method, when it reaches a certain height (near the top of the guide chain), the upper section of the catheter is cut off; With the rise of concrete surface, the conduits are removed one after another; When the design elevation of the pile top is above 10-20cm, the accumulated water on the surface will be discharged, and the concrete surface will be vibrated with an internal vibrator to remove the surface laitance. The pile head left by this method is short, and the slump in concrete should be controlled at around 16- 18cm.

3. When the water seepage is large (> > 6mm/min) and the pumping construction is difficult, the underwater concrete pouring method of bored piles should be adopted. Pile concrete should be completed at one time from the bottom of the pile to the top elevation of the pile. In case of power failure and other special reasons, when construction joints must be left, appropriate short steel bars can be inserted around the concrete surface. Before pouring new concrete, the joint surface must be cleaned and shaved, and there can be no water and isolation substances.

4. Cast-in-place pile concrete must be separated from the concrete surface by chute and string tube within 2m, and it is not allowed to throw shovels or inclined materials at the wellhead to avoid concrete segregation and affect the overall strength of concrete.

5. In the process of pouring concrete, attention should be paid to prevent groundwater from entering, and there should be no water layer with a thickness of more than 50 mm, otherwise the water layer on the surface of concrete should be drained as much as possible with a conduit before pouring concrete. If the water seepage is too large (> 1M3/H), the construction shall be carried out according to the underwater concrete regulations.

The concrete is vibrated while pouring, and the method of internal vibrator is adopted to ensure the compactness of concrete.

6. When pouring the cast-in-place pile body, stop the excavation operation in the vicinity of 10M, and do not leave people at the bottom of the hole.

7. When pouring the cast-in-place pile body, the test blocks shall be retained, and each pile shall be no less than 1 group (3 pieces), and the test report shall be submitted in time.

According to the design requirements, the pile quality inspection adopts dynamic inspection method, and two piles are tested. The inspection report must be submitted to the design unit for re-inspection.

8. After the concrete pouring of the pile hole is completed, the pile position and pile top elevation shall be rechecked. Support the main reinforcement or iron insert at the pile top.

Yes, surround it with plastic sheets or straw curtains to prevent concrete from shrinking and cracking.

4.4.4. Foundation pile detection

According to the design requirements of drawings, the quality inspection of piles adopts dynamic inspection method, and each pile must be inspected, and the inspection report must be submitted to the design unit for re-inspection.

5. Technical measures to ensure quality

In order to ensure the engineering quality, the following quality assurance measures are formulated:

1, study the drawings carefully, do a good job in the blue prints.the design, and fully understand the intention and process requirements of design changes; Do a good job in technical disclosure at all levels of various construction preparations, and carry out construction in strict accordance with construction procedures.

2, strictly abide by the national construction specifications and technical operation procedures and engineering quality inspection and evaluation standards, in the division, subdivisional work quality evaluation, according to the national engineering quality inspection and evaluation standards for evaluation.

3. Set up an inspection team composed of the project management department and the operation team leader, and conduct regular or irregular inspections.

4. Adhere to the system of self-inspection of operation teams and handover and acceptance between various types of work and working procedures, with full-time quality inspectors following up the inspection. The company conducts quality inspection every month, implements rectification in time, and formulates specific measures to effectively prevent the quality problems found.

5. All raw materials and semi-finished products must have factory certificate or warranty and test report. If there is a copy, it must be stamped by the original unit and indicate where the original is. After the relevant materials enter the site, the material engineer should fill in the Notice of Quality Inspection of Raw Materials in time and send it to the laboratory, and it can only be used after passing the sampling inspection.

6. The project manager is responsible for the unit engineering survey, and do a good job in positioning, measuring, setting-out, axis, elevation, vertical monitoring and settlement. Axis control points and leveling points must be selected in solid and reliable parts and protected. Positioning and setting-out must be checked and accepted by the quality inspector and technical director before entering the next working procedure, and the positioning and setting-out records and the positioning and setting-out review records shall be handled in time.

7, axis, elevation, construction drawing lofting, steel material list and raw materials and processed parts application and other technical review work, must be approved by the engineering technical director and quality inspector, before delivery of construction.

8. Do a good job in the acceptance of concealed works. On the basis of self-evaluation, self-inspection and self-inspection, a "Notice of Acceptance of Concealed Works" will be issued to the site supervision engineer 24 hours in advance, and the construction of the next working procedure can be started only after the acceptance is qualified.

9. Pile core concrete shall be mixed on site, and the required quantity of each batch of concrete shall be distributed to the person in charge of the site. Every time the concrete is cast on site, the feasible concrete casting method must be determined according to the weather forecast, site conditions and structural parts; In strict accordance with the specification requirements for block sampling, the sampled concrete shall be vibrated and compacted, and there shall be no honeycomb pits. There must also be someone who is responsible for the regular maintenance of concrete to ensure the quality of concrete.

10, construction management personnel and special type of work construction personnel must hold relevant certificates, it is forbidden to operate without a license.

1 1, quality problems or hidden dangers raised by superior departments and supervisors.