A, materials and main machine requirements:
Materials: loose lime, plain soil, main machines and tools: pore-forming equipment: 1.2t diesel pile driver with diameter of 400, tamping machine, tamping machine with eccentric wheel clamping rod, weighing 100-300kg, and the static pressure of its vertical projection area is not less than 20KPa, and the diameter of the largest part of the tamping hammer should be less than the pile hole diameter/kloc. 10 small forklift, 50 forklift, ash sifter; Level, theodolite. Wire rope, electric welding machine, 4 power distribution cabinets, 500m three-phase cable, shovel, lighting lamp, etc.
Second, the operating conditions:
Foundation trench excavation is completed and passed the acceptance of relevant departments of the company, reaching the qualified standard. The foundation trench is flat, and the next working procedure can be carried out, and the lime-soil compaction pile is set out to form a hole. Three. Operation technology and technical parameters 1. Process flow: foundation trench leveling → axis positioning → pile setting-out positioning → hole-forming pile machine positioning → hole-forming → depth measurement → acceptance → ash screening → backfilling and compaction → re-inspection and acceptance.
(1) positioning axis: the positioning axis of the east-west south trough is axis A and axis D (19.2m), the positioning axis of the north trough is axis L and axis N (1 1. 10m), the positioning axis from axis A to axis N is 60m, and the positioning axis from north to south is/kloc. (1) lofting and pile location
1. Technical requirements: First, set out the positioning lines of piles according to the drawings, and form piles at intervals from outside to inside to prevent pile leakage and dislocation.
2, according to the known control points, according to the design requirements of the pile spacing (pile spacing is 900mm, row spacing is 780 mm, according to the equilateral triangle layout) layout out the pile position control points, and drill holes with steel, the hole depth is not less than 30cm, and marked with the method of whitewashing. Due to the complexity of pile spacing and row spacing designed in the drawings, the effective pile length is 10.5m, the virtual pile is 0.50m, the hole-forming * * m is 1 1m, and the compaction * * m is 1 1m, with a total of 7598 piles. The bearing capacity of pile foundation shall not be less than 200KPa, the hole of pile shall be backfilled with 2: 8 lime soil, the compaction coefficient shall not be less than 0.97, and the average compaction coefficient of soil between piles shall not be less than 0.93. Before construction, three piles must be tested, including three groups of piles, one in the north-south east trough and the other in the north-south east trough, with 7 piles in each group. After the pile test, it shall be inspected according to the relevant provisions of Technical Specification for Compacted Pile Foundation Treatment DBJ6 1-2-2006. After the design institute meets the requirements, large-area pile driver construction can be carried out, and pile foundation hole-forming and backfill compaction are carried out in batches at intervals from the inside out, and layered compaction should be carried out immediately after hole-forming
3. Full-time surveyors shall be responsible for the measurement and positioning of pile position, and theodolite orientation and steel ruler shall be adopted for ranging.
4. After pile location measurement and setting out, it must be rechecked by the supervision engineer. 5. Quality standards and inspection methods for pile location measurement and placement. A. pile position deviation: full pile layout ≤0.40D(D is pile diameter), and theodolite and ruler shall check. B. the ground elevation is measured with a level.
(2) Construction technology in hole-forming stage (hammer sinking pipe to form hole)
1 The pile driver should be installed in place accurately, horizontally and stably, and cushion the cushion material between the pile pipe and the pile hammer, and slowly put it down, so that the pile hammer at the end of the pile pipe is located on the same vertical line, and the pile tip is buried by the weight of the hammer and the self-weight of the pile pipe.
2 Before the hole is formed, the quality inspector shall recheck the quality of the pile position and pile point, and the construction unit or supervision unit can only start construction after passing the recheck. During the hole-forming process, there is no movement or inclination, and the shovel head is aligned with the pile position with an alignment deviation of 3. In order to prevent shrinkage, the pore-forming sequence is carried out by skipping, that is, the pore-forming diameter of each row and each hole is not less than 400mm, and the pore-forming diameter error is not less than 20mm； The hole-forming depth is not less than the designed hole depth, and the allowable error is +500mm.
If the hole depth is not enough, it needs to be re-punched. In the process of hole formation, the verticality should be checked frequently, and the deviation should be corrected in time to ensure that the verticality deviation is ≤ 1.5%. If this deviation is exceeded, the pipe should be pulled out to fill the hole and re-punched. Such as high jump of pile hammer, slow pile sinking speed, inclination of pile hole, damage of pile shoe, etc. , should be reflected in time, after each hole is pulled out, the pile tip should be checked in time.
5 After the pile tip is buried deeply, tap it with a hammer first. After sinking to 1-2 meters, check that all aspects are normal, and then sink the pipeline to the design depth at a predetermined speed, drop distance and hammer. When sinking the pipe, measure the permeability. A three-level inspection system of hand self-inspection, quality inspector re-inspection and supervision acceptance shall be implemented after the final hole, and unqualified products are strictly prohibited from entering the next working procedure.
6 Observe the excavation situation at any time after the hole is completed, so as to master possible abnormal phenomena, such as underground obstacles and graves.
7 Check the quality of pile hole in time after hole formation, and take timely measures to deal with out-of-tolerance and shrinkage cavity.
After 8 holes are formed, the pile driver retreats and should be backfilled in time, otherwise it should be compacted immediately. (3) Lime-soil mixing White lime and soil materials are mixed with lime-soil mixer on site, and lime-soil mixing is carried out in strict accordance with the mixture ratio of 2: 8.
1 pure loess excavated in this site shall be used as the earth material, with organic matter content ≤5%, and the earth material shall be sieved, and the mesh hole shall not be greater than 15 mm ... The ash is white ash powder which has just been cured and sieved, and the maximum particle size shall not be greater than 5 mm..
2. Mixing materials: use soil sieve to mix materials on site.
3. The water content of the filler should be controlled within 3% of the optimal water content, so as to achieve the purpose of "holding the ball in hand and blooming everywhere". If the water content of soil is small, the water content of soil must be increased to meet the specification requirements.
Quality control measures of lime-soil mixing: water content of filler w = 18% ~ 20%. If the water content exceeds 3% of its optimum water content, it can be dried and backfilled to meet the requirements; When the water content is less than 3% of the optimum water content, water should be sprayed on the soil appropriately to make the water content meet the requirements. (4) Backfilling and tamping
1 The mixed lime soil shall be transported by small loaders, and the filler shall be controlled at specified intervals, times and quantities. When filling, designate a special person to fill evenly layer by layer according to the specified quantity, and record the compaction quantity. It is not allowed to fill blindly, nor can it be poured directly into the hole with a feeding truck.
2. Packed with rammer, which is a rammer with eccentric wheel clamping rod. The rammer shall be operated by the designated operator, and rammed to the top elevation of the construction pile according to the specified number of strokes during filling. Choose a heavy hammer 100-300kg.
3. The rammer should be positioned stably and centered to ensure smoothness, verticality, stability and solidity, so that the rammer can freely fall into the bottom of the hole.
4 Before filling, the quality inspector and quality engineer of each shift and project department shall report to the site supervisor to check the aperture, hole depth, hole inclination and hole center position, and backfill can be carried out only after passing the inspection. When backfilling, the bottom of the hole should be pre-rammed for 2~3 strokes. If there are sundries at the bottom of the hole, the sundries at the bottom of the hole should be removed first, and then empty tamping should be carried out until the bottom of the hole makes a crisp sound, and then quantitative layered tamping should be carried out under the condition that the water content of the filler is equal to or close to the optimal water content.
5. The filler shall be measured by special machines and tools, and the amount of filler shall be one shovel at a time, and the number of tamping times shall be required: no less than 3 blows below the pile top 2m, and the falling distance shall be no less than 0.8m；; The number of blows over 2m shall not be less than 5 blows, and the falling distance after compaction shall not be less than1.0m. Check and accept the pile length, pile spacing, pore-forming diameter and compaction coefficient after compaction. The allowable error of pile spacing and row spacing is 35mm, and the pile length, pore-forming diameter and pore-forming diameter after compaction can only be larger than the design and disclosure (positive error), but not smaller (negative error). The water content of filler, tamping times and tamping time shall be recorded and managed by special personnel, and the above data shall be spot-checked.
6. Packing and tamping shall be carried out alternately and uniformly compacted to the top elevation of construction pile.
7 In the process of pile hole backfilling, there should be special personnel to monitor the quality of backfilling and compaction, and make construction records. If the foundation soil is found to be inconsistent with the survey data, which will affect the backfilling, the construction shall be stopped immediately. After the situation is found, effective measures should be taken to deal with it before the construction can continue.
8. Check the pile number, arrangement number and pile number of the completed construction one by one according to the construction drawing. If missing construction is found, it should be repaired immediately. The pile foundation engineering data must be submitted to the full-time librarians of the project department for inspection and acceptance before 10: 00 the next morning, and then the librarians of the project department will report the engineering data to the supervisor for signature.
Before the large-scale construction of engineering piles, the pile foundation unit must submit three copies of the pile foundation construction organization design, so that the project department and the supervision company can control the quality and progress. Pile foundation units must declare their qualifications, corresponding management information and professional certificates, and unlicensed operation is strictly prohibited.
1, lime-soil mixture ratio 2: 8 lime-soil, (subject to the experimental report data of construction quality inspection station).
2. The compaction coefficient of pile body is ≥0.97, and the average compaction coefficient of soil between piles should not be less than 0.93. Before pile foundation construction, the lime-soil ratio of 2: 8 lime-soil compaction pile should be released, and the lime-soil ratio should be placed at the lime screening machine, and face-to-face disclosure should be made to the operators of the lime screening machine to ensure the quality of the engineering pile.
4. Before construction, check the quality of soil and lime soil, and release the pile hole. After the hole is formed, the diameter of the pile hole and the length of the pile body should be checked. When tamping, check the tamping times and the water content of the filler. After construction, the quality of finished piles and the compaction coefficient and compaction coefficient of soil between piles should be checked.
5. Management should be strengthened during construction, and careful inspection and technical disclosure should be made. Prevent missing pile holes, check the number of hole-forming and pile-squeezing tables in each shift in time every day, and report them in time. The person in charge of each team and the team leader shall provide technical disclosure and safety education to the pile driver and backfill personnel, and the foundation pit shall not be constructed without educators.
6, strictly control the quality, each working procedure in the construction process should be supervised by designated personnel, and the quality should be compacted and recorded. If abnormal conditions are found, which will affect hole-forming, backfilling or compaction, the construction shall be stopped immediately, and the relevant responsible personnel of Party A's engineering department and supervision unit shall be reported, and the construction shall not continue until the situation is found out or effective measures are taken to deal with it.
7, each working procedure must implement the acceptance system of the next working procedure to the previous working procedure, and the personnel on duty shall conduct acceptance in conjunction with the quality and technology group on the basis of self-inspection.
8, completes the technical data, according to the actual completion of quantities every day, carefully and truthfully fill in the hidden acceptance record of the project and the construction record of lime-soil compaction pile hole filling, and report it to the project department.
9. In the construction process, quality spot checks should be strengthened, and the number of spot checks should not be less than 2% of the number of piles. The compaction coefficient of pile soil and soil between piles should be measured by ring knife sampling, and records should be made. Remedial measures should be taken for unqualified piles. It is forbidden to drive eccentric piles and point piles.
10. The dust screened on the same day is used up on the same day and cannot be reused overnight. Was found to have fined 200 yuan once.
Verb (abbreviation for verb) safety requirements
1, construction personnel enter the construction site for safety education, and make records.
2. On-site construction personnel must strictly abide by relevant laws and regulations, norms and various safety production operation procedures, and correctly use the "three treasures" of safety. The construction personnel must wear safety helmet, and don't wear safety helmet when working, and 20 yuan will be fined every time.
3. When the pile driver is running, it should be balanced to prevent sudden dumping or sudden fall of the sledgehammer when the hole is formed, causing casualties or equipment damage.
4. When the pile driver is drilling, no one is allowed to carry out other operations within 5 meters of the pile driver and pile hammer.
5. When the completed hole is not backfilled, a cover plate should be covered to prevent people or things from falling into the hole.
6, before tamping, should first check whether the power cord insulation of tamping machine is good, such as grounding wire, switch should meet the requirements, the wire should not be used to mop the floor, should be hung empty, when reversing, someone must watch and pull the wire, so as to avoid electric shock accidents caused by pulling the power cord.
7. It is best to fill the hole on the same day. If construction is needed at night, rainproof measures should be taken and the hole should be covered. At the same time, do a good job of drainage in the construction site to ensure safe and civilized construction. If it rains, there will be a fine if the hole of the pile hole is not rainproof.
8, safe use of electricity, one wiring, one guardianship, and by a professional electrician to complete the power operation, non-electrical personnel are not allowed to connect electricity without permission, or a fine of 100 yuan/time. Duration: 30 days. June10,2013-July10,2012. If the construction period is postponed, it will be fined.
Seven, should pay attention to the quality problems
(1) During construction, rainproof work should be done to ensure that lime soil is protected from rain. Those that have become holes should be rammed in time to prevent rain. For site drainage, due to the large area of the site, it is planned to lay simple temporary drainage ditches and collecting wells along the periphery of the construction site, and then discharge them from the construction area with sewage pumps. Or according to the climate change, cover a large area of materials such as striped cloth on the construction site, and cover raw materials in time to ensure the construction quality and construction period.
(2) In the process of hole formation, if the pile hole is slightly reduced in diameter, secondary hole formation or hammer cutting can be used to enlarge the pile diameter to meet the design requirements and ensure that the rammer falls into the bottom of the hole smoothly; If the hole shrinkage of the pile is serious, lime or quicklime can be filled in the hole, and after a short pause, the hole can be re-formed or the pile can be repaired.
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