The following is what Zhongda Consulting brings to you about the construction organization design of powder spray pile treatment of soft soil foundation engineering for your reference.
1. Project Overview
The powder-jet pile treatment soft soil foundation project in this section is located in the Yangtze River Valley Plain Engineering Geology Area. The main unfavorable geological conditions are soft soil and sand liquefaction. In order to reduce post-construction settlement, ensure the stability of the roadbed, and solve problems such as vehicle jumping at structures, powder spray piles are designed to treat soft soil foundations. The treatment sections are K73 643-K76 815, with a total of 14,498 powder spray piles and a total length of 93,512 meters.
II. Construction Organization
According to the conditions of the construction site, we have dispatched experienced construction personnel and sophisticated construction equipment to construct 490,000 linear meters of powder spray piles for the A2 standard of the northern connection of Runyang Bridge. In preparation for entering the site, a powder spray pile working group was formed at the same time, with the road engineer as the team leader and the quality inspection engineer, test engineer, material supervisor, and safety supervisor as team members. All-weather quality management was implemented for the project, and the project manager was fully responsible for the operation. Management, unified management, command and deployment of personnel, machinery, equipment, etc.
It is planned that all management personnel and construction personnel will be in place before January 15th. The specific personnel entering the site are as follows:
1. Personnel organization
(1), project department organizational structure management network diagram
(2), labor arrangement
p>The construction organization arranges one pile driver with 3 captains and about 4 general workers. During construction, a number of auxiliary workers may be considered based on the actual progress of the project.
2. Organization of construction instruments and mechanical equipment
(1) Instruments and equipment
Instrument name, model, quantity, status, date of entry, level DS33, good quality 2003-1- 1 Aluminum alloy tower ruler 5 meters, 3 pieces good 2003-1-1 Steel ruler 50 meters, 3 pieces good 2003-1-1
(2) Construction machinery and equipment
Used in construction The machinery and equipment are transported to the site by truck, and based on the progress of on-site access roads and meter clearing construction, they are gradually brought into the site. The specific machinery and quantities are as follows:
Equipment name, equipment model, quantity, status, entry date, where to use Pile driver GPP-7PH-710 sets good 2003-1-15 soft foundation treatment air compressor 3W1.6/1010 sets good 2003-1-15 soft foundation treatment diesel generator set 75KW120KW10 sets good 2003-1-15 soft foundation treatment electric welding Machine BX1-3008 sets are good for soft base treatment on 2003-1-15 Electronic weighing device PJ4-1FZ-110 sets are good for soft base treatment on 2003-1-15
3. Material organization
Cement 8776T under construction will use Po32.5 bagged ordinary Portland cement produced by Jiangsu Leda Cement Co., Ltd. in five source cement plants according to Tonggao Zicai 2002 No. 4 document. The mode of transportation is by land with dump trucks.
3. Construction methods and process flow
1. Preparation work at the construction site
(1) The construction site should be equipped with various measuring instruments and equipment to prepare Calibration of measuring devices.
(2) Conduct experiments on on-site cement and other raw materials, and then carry out indoor trial design of cement dosage for powder-blasted piles, and determine the cement dosage per linear meter of pile body.
(3) Draw the pile layout plan according to the construction drawings and submit it to the surveying engineer for approval.
(4) According to the pile layout plan, use a steel ruler to determine the pile position of each powder-coated pile at the construction site, and insert a bamboo stick into the soil to mark the pile position of each pile. The position error shall not be greater than 5cm. At the same time, do a good job in retesting. In future construction, you should frequently check whether the pile position marks have been moved to ensure the accuracy of the powder spray pile position.
(5) Set up a cement shed at the construction site. Fill the bottom of the cement shed with soil to make it 30cm to 50cm higher than the surrounding ground, lay a layer of wooden boards, and then lay a layer of colored striped cloth. , and finally lay a layer of plastic film to ensure that the cement does not harden due to moisture.
The cement storage capacity in the cement shed should be no less than 60 tons.
(6) Assemble and debug the machinery and equipment entering the site to ensure the integrity of the machinery and ensure that it meets the construction requirements.
(7) After all preparations are completed, submit a written application to start construction, and ask supervisors to come to the site to test the piles to determine the technical parameters of the completed piles. Generally, test piles should meet the following requirements:
a. Determine technical parameters such as drilling speed, lifting speed, pipe pressure during lifting and pipe pressure during ash spraying
b. Cement The degree of uniformity of mixing, the difficulty of drilling and lifting, and the determination of appropriate technical treatment measures. The number of piles in the pile test shall not be less than 5. When encountering new construction sections, the test pile work should be carried out again.
(8). After the pile test is completed, various technical parameters should be sorted out in a timely manner and a formal pile test report should be submitted to the supervision team for approval. Construction can begin after receiving the start notice from the supervision team.
2. Construction method
(1) Positioning: According to the design drawing (pile position plan), use a steel ruler to determine the powder spray pile position on site, and insert it with a bamboo stick Mark the soil layer with an error of no more than 5cm. Move the machine tool to the pile position and make the drill bit face the bamboo stick to check the verticality of the frame.
(2) Start the air compressor to supply air, the drilling rig rotates forward and drills vertically. When the double-spiral mixing head is controlled to reach the designed pile bottom elevation, the drilling rig rotates in the opposite direction, starts the ash feeder to deliver ash, and then lifts the drill bit after the cement is delivered to the ash spray port (usually about one minute). According to the electronic weighing device display The amount of ash sprayed is adjusted by the speed-adjustable motor, so that the powder is sprayed, stirred, lifted and compacted at the same time.
(3) When the drill bit is raised to 0.25 meters below the ground, stop feeding ash and close the ash feeding machine. At this time, the drilling rig changes gears quickly and stirs repeatedly until the current meter reaches above 100A and stops stirring again.
(4) After the re-stirring is completed, turn off the air compressor, dissipate all pipeline pressure, and stop the main motor of the drilling rig.
(5) Start the hydraulic action and shift the drilling rig.
3. Piling process
IV. Measures to ensure project quality and construction period
1. Quality assurance measures
To ensure The quality of the project shall comply with the design requirements and relevant specifications. Process control shall be the main method and post-construction inspection shall be supplemented. The project quality shall be pre-controlled from the aspects of personnel, equipment, materials, pre-construction preparation, project construction process, etc.
(1) Personnel
a. Implement a job responsibility system to ensure that machines, people, positions and responsibilities are determined. A captain is determined for each construction site, and a detailed job responsibility system for operators, captains, and self-inspection personnel is formulated. Provide training to on-site construction and quality inspection personnel, and strengthen quality awareness from cadres to employees. Before taking up the job, all personnel involved in powder spray pile construction must first understand, master, and review relevant construction technical specifications, clarify job responsibilities, and ensure that they have not been Training is not allowed on the job.
b. Give full play to the role of quality inspection personnel in controlling project quality, and conduct full-process self-inspection by the construction team and project department on each pile after it is formed. Only when all piles are qualified can they be submitted to the supervision team for random inspection. The quality inspection personnel and supervisory personnel of the project department have veto power over quality.
(2) Equipment
Equipment is the prerequisite for ensuring construction quality. The powder spray pile driver entering the site must meet the following requirements: a. Good performance; b. Frame stability Good; c. Equipped with advanced weighing tools and capable of automatically printing the amount of powder sprayed.
According to the progress of the overall design plan, mechanical equipment that meets the requirements will be equipped and numbered. Before construction, the measurement department should be entrusted to calibrate each powder spray pile machine entering the site. Only those who pass the test can be used.
(3) Materials
Only qualified materials can ensure qualified projects. A sound material management ledger should be established during construction. The cement used in construction should undergo self-inspection before proceeding. After entering the site, the cement should be inspected in batches, and can be put into use only after it passes the sampling inspection by the supervision engineer.
a Total cement quantity control: Provide the supervision team with the feed contract signed with the cement manufacturer in a timely manner, and use the triple cement feed acceptance form.
b Establish a cement ledger review and approval system for powder-jet pile machines. The ledger should indicate the date and quantity of cement picked up, as well as the construction pile point number, etc. The cement for the powder-blasted pile machine must be collected by the captain, and must be verified and signed by the on-site personnel. The construction personnel should indicate the construction pile number of each powder-blasted pile on the original record.
(4) Preparation before construction
a. Indoor proportioning test: Carry out indoor proportioning test according to the actual conditions of each section to determine the amount of powder spraying per linear meter . For road sections with natural moisture content of 50 < W soil ≤ 70, an additional set of 53kg/m proportions will be added, and five additional test piles with a cement content of 53kg/m will be installed.
b. Process test pile: Before the construction of each powder spray pile machine, a process test pile should be carried out according to regulations to determine the various technical parameters (drilling speed, powder spraying lifting speed, re-stirring sinking speed etc.) and submit the test pile report to the supervision team.
c. Tag: Make a nameplate with the technical parameters determined by the test pile and hang it next to the machine.
(5). Project construction process
a. The construction site should be flat and there should be no accumulation of water. There should be drainage facilities on both sides of the construction section. The position of the piles on the plane must be clearly identifiable and the pile positions must be accurate. The cement should be stacked at a high place, and the bottom should be about 15cm from the ground to ensure good ventilation below. The area where the cement is stacked should have smooth drainage around it to ensure that there is no accumulation of water in rainy weather. Cement must be neatly stacked by type. It is strictly forbidden to mix cement from different manufacturers and types. Waste cement bags must be recycled and cleaned in time to ensure a clean and tidy construction site. The rainproof covering facilities for the cement should be improved to ensure that the cement does not get wet or deteriorate.
b. There must be obvious reflective marks on the powder spray pile driver, and the scale of the marks must be approved by the on-site supervision. Lighting facilities must be provided during night construction to make the markings on the drill frame clear and eye-catching.
c. The mechanical operation must be skillful, the powder spraying must be uniform, and the cement dosage and remixing depth must meet the requirements. When spraying powder, it is best to spray enough powder at one time. For piles with longer pile lengths, measures should be taken to ensure that the cement dose per meter at the lower end of the pile body reaches the standard.
d. Develop construction points based on various technical parameters determined by process test piles for on-site operators to comply with. Strictly control the drilling depth, powder spraying elevation and dust stop surface to ensure that the powder spraying pile depth and powder spraying amount meet the design requirements. The depth error should not be greater than 5cm, and the error of cement injection amount should be less than 1.
e. Each time the mixer sinks or lifts, the time must be recorded by a dedicated person. The time error should not be greater than 5s. There must be a wait before lifting. The time it takes for the powder to reach the bottom of the pile is to prevent the situation from being lifted but not sprayed. The specific time can be determined by the process test pile.
f. The pipeline pressure during drilling and lifting should not be too high to prevent drilling mud from squeezing around the hole wall to form cavities. In order to ensure the construction quality of powder spray piles, when the drill bit is raised to 25cm below the ground elevation, dust spraying should be stopped and only stirring should be carried out, and re-stirring measures should be taken at the same time. No powder is sprayed during the second stirring, and the depth of re-stirring shall be subject to the current meter reaching 100A. The drilling and lifting speed of the drill bit during re-stirring is the same as the first time. The time of drilling and lifting of the powder spray pile each time is recorded by a dedicated person, and any unexpected situations should be noted in the remarks column.
g. Strictly control the lifting speed of the drill pipe during powder spraying to ensure the uniformity of powder spraying for each pile. If an accident occurs that affects the quality of the pile body, re-spraying measures should be taken within 12 hours. The overlap length of the re-spraying should not be less than 1 meter. In particularly difficult cases, the ammeter reading will be subject to significant changes. Otherwise, they should be re-drilled. The distance between the new piles and the scrapped piles should not be greater than 15% of the pile spacing, and should be filled in the construction records for reference.
h. The ash conveying pipes must be inspected frequently to prevent leakage or blockage. The length of the ash conveying pipes should be about 60 meters and should not exceed 70 meters. The drill bit used should be checked regularly to ensure that the diameter wear is no more than 1cm, but it is not advisable to use a drill bit with an excessive diameter (less than 53cm is appropriate).
i. A comprehensive inspection of the pile driver should be carried out before construction. Use a level ruler and a vertical ball to correct the front, rear, left and right levelness of the frame. Control the inclination of the drill pipe of the frame not to be greater than 1. After forming The verticality error of each pile is less than 1.5.
j. During construction, original records must be filled in promptly and carefully, and subsequent writing is not allowed.
The data should be signed and summarized every day, and problems should be corrected in a timely manner.
k. Carefully check the pile driver's picking quantity and construction pile positions every day, check whether the pile driver's picking quantity of each batch is consistent with the number of meters of powder-coated piles completed by the machine, and review the printout Accuracy of information. Strengthen data management, and fill in relevant technical data carefully during construction. Each pile must fill in the data carefully and responsibly based on the actual data generated. All data must be true and reliable and signed and approved by the supervising engineer. All data during construction must be Complete and archived.
l. For the formed powder mixing piles, the supervision department should randomly check the pile forming conditions, mixing uniformity and pile strength 7 and 28 days after the piles are formed. The number of random inspections shall be 2‰ of the number of piles and shall not be less than 2. The 28-day compressive strength of powder-coated piles shall not be less than 0.8Mpa, and the 90-day compressive strength shall not be less than 1.2Mpa.
2. Construction period guarantee measures
a. The project department will set up a powerful powder spray pile working group and select outstanding backbones to organize and coordinate the entire project construction.
b. Develop a scientific organizational management system, strive to improve the management level, and arrange monthly and ten-day operation plans and sub-project construction plans based on the total construction period. Strictly arrange the on-site construction of materials, personnel and mechanical equipment in accordance with the requirements of the overall plan progress, while further optimizing and improving the "project progress plan" to make full use of effective resources.
c. Strive to improve the integrity rate of mechanical equipment, and strengthen the repair, overhaul and maintenance of mechanical equipment to ensure the integrity rate of mechanical equipment and ensure that 300 meters of pile foundations are completed every day.
d. Summarize the project quantities every day and compare them with the overall plan progress. If problems are found, take timely measures to ensure that the construction period is completed ahead of schedule.
5. Construction measures in winter and rainy season
1. Winter construction measures
(1) Preparation work
Construction during freezing period For projects, all preparations should be made in advance, snow and frost protection and other measures should be taken in advance for various facilities and materials, and special safety measures should be formulated. During construction during the freezing period, in order to prevent a sudden drop in temperature and avoid freezing damage to the project, it is necessary to pay attention to weather changes before and after construction during the freezing period and take anti-freezing measures in a timely manner.
(2) Safety protection
Strengthen safety protection measures such as fire, anti-freeze, anti-electricity and dust pollution, and assign dedicated personnel to be responsible for regular inspections and timely processing and improvement. Arrange production to avoid high cold and freezing weather as much as possible to avoid personal injury accidents.
2. Construction measures during the rainy season
(1) Do a good job of drainage at the project site, including the living area and construction area (especially the cement warehouse), set up drainage ditches and water collection wells, and equip A water pump with appropriate flow rate is used to remove accumulated water on the surface and prevent the cement from getting damp.
(2) Strengthen contact with the local meteorological department, and on the premise of ensuring quality and safety, make arrangements for construction and production on rainy days to minimize the impact of the rainy season on the construction schedule.
(3) Construction materials must be prepared for rain protection, and necessary rain protection measures must be taken for electrical appliances, switch boxes and communication lines at the work site to avoid safety accidents such as electric shock and leakage.
In short, taking into account the characteristics of the rainy season and winter, the project projects should be reasonably arranged to ensure the overall progress of the project flow operations and minimize the impact on the project progress.
6. Quality, safety assurance system and quality inspection
1. Quality assurance system
In addition to personnel, equipment, materials, pre-construction preparation, and project construction In addition to pre-control of processes and other aspects, we also need to establish corresponding rules and regulations and establish a complete quality management network to ensure the quality of the project.
(1) Organizational guarantee and ideological guarantee measures
a Frequently publicize the slogan "A century-old plan, quality first" and implement it in the work.
b Form a strong powder spray pile working group and select outstanding construction backbones to organize and coordinate the entire project construction.
c Develop a scientific organizational management system, strive to improve management levels, implement the captain responsibility system, and implement a one-vote veto system for quality.
The d quality control team conducts regular and irregular inspections on project quality to ensure project quality.
e Conduct technical briefings for all personnel before the start of construction, be responsible for studying design documents, understand design intentions, and ensure implementation during construction.
f Regularly carry out quality evaluation work, reward crews with excellent quality, and impose punishment measures such as criticism, warnings, fines, and clearance for crews with poor quality. Crews who are incompetent will be removed from the field and removed from the field. Summarize the quality accidents that occurred and implement "three let-offs" to prevent similar accidents from happening again.
(2), Quality management network
2. Safety assurance system
(1), Safety production management
a. Establishment And improve the production safety leading group headed by the project manager (see safety management network diagram) to carry out safety production management activities.
b. Establish a safety production responsibility system for personnel at all levels, clarify their respective personnel safety responsibilities, implement safety responsibilities, implement responsibility and target management, and conduct regular inspections on the implementation of safety production responsibilities.
c. Establish a safety ledger and record the safety ledger during construction.
(2) Safety technical measures
a Safety helmets and safety belts must be worn when assembling and dismantling machinery and climbing operations, and there is unified command. It is strictly prohibited to wear safety equipment when entering the construction site. slippers.
bThe construction site should be equipped with a complete range of electrical protection devices that can effectively prevent rain and waterproofing. All motors should be grounded, and the grounding resistance should not be greater than 4Ω. Strengthen electrical safety inspections in rainy and snowy days to ensure that electrical appliances are waterproof.
c During construction operations, pay strict attention to voltage, current and other instruments. The current is controlled within 100A, and overload operation is not allowed for a long time.
d. There must be a dedicated person to direct the movement and steering of machinery and equipment, and a dedicated person is responsible for the safety of moving cables and pipelines to prevent collisions, extrusion and abrasion of electrical appliances.
e On-site operators should wear dust-proof protection to prevent dust from adhering to the skin or being inhaled into the lungs. All operating actions must have unified signals and unified command, and operations must be coordinated with each other.
(3), Safety management network diagram
3. Quality inspection Quality inspection
The construction process is strictly in accordance with the design drawings and specifications. In order to ensure that deep powder The quality of spray-mixing piles should be strictly implemented according to the following requirements.
(1). Cement shall be inspected regularly according to the incoming batch.
(2), pile spacing, pile length, ash spray volume, pile strength, and drill pipe inclination meet the following requirements:
Specified values ??of item inspection items and allowable deviation inspection Method (each lane) 1 Pile spacing (mm) ±100 Spot check 22 Pile diameter (cm) is not less than the design Spot check 23 Pile length (m) is not less than the design Check construction records 4 Verticality () 1 Check construction records 5 Single pile The amount of ash sprayed () is in line with the design. Check the construction record 6. The intensity is not less than the design spot check 2‰
7. Civilized construction
Install all kinds of machinery and equipment required during the construction of powder spray piles. Materials are rationally arranged in space to achieve the best combination of people and things, people and places, things and places, and things and things, so that the construction site is orderly and standardized, and reflects the level of civilized construction.
1. Establish complete rules and regulations, establish the idea of ??"safe production, civilized construction", and always pay attention to your own image during the production process.
2. Pay attention to environmental sanitation. The cement ash (gas) discharged from the ash tank should be treated to prevent contamination of nearby crops and the environment.
3. Maintain the integrity of the machinery and prevent oil leakage and pollution.
4. Cement bags must be recycled and cleaned in time to ensure the cleanliness of the construction site. At the same time, the erection of cement sheds should be planned neatly and random installation is strictly prohibited.
5. Closely cooperate with the tendering party in public security and publicity work, and at the same time strengthen coordination with local relations to ensure a good cooperative relationship with towns, villages, and groups.
6. Pay attention to your own image during construction and avoid drinking, gambling and committing illegal crimes.
8. Construction Plan
This section is planned to conduct test piles on January 5th. The test piles will be successfully submitted to the powder spray pile start report and will be approved on January 15th. The project has started in full swing and strives to complete the powder spray pile construction task within two months.
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