Construction technology of manual holing pouring pile

1 scope

This technology is applicable to industrial and civil construction in the clay, and silty clays containing small amounts of sand, stone and clay layers, and underground water level low manual holing pouring piles.

2 construction preparation

2.1 materials and equipment:

2.1.1 cement: No. 325, ~425 should be used, ordinary Portland cement and slag Portland cement.

2.1.2 sand: sand or coarse sand, clay is less than 5%.

2.1.3 stones: diameter of 0.5~3.2cm of pebbles or gravel; the pile the stones in the concrete can also be used particle size is not greater than 5cm, and clay content of not more than 2%.

2.1.4 water: tap water or clean water that contains no harmful substances.

2.1.5 external accelerator experiments use fly ash admixture shall be determined according to the laboratory.

2.1.6 steel: steel grade, diameter must conform to the design requirements, certificate and retest report of the factory.

2.1.7 General should has three wood take, and hoist group or electric gourd, and trolleys or dump truck, and picks, and spade, and hand shovel, and soldering, and line pendant, and set pulley group, and oriented pulley group, and concrete mixer, and bucket, and chute, and catheter, and vibration pound rod, and plug soldering, and rough rope, and wire rope, and security activities cover Board, and waterproof lighting lamp (low voltage 36V, and 100W), welding machine, and ventilation and the for oxygen equipment, and head pump, and wood windlass, and activities ladder, and helmet, and belt,.

2.1.8 template: combined steel formwork, Arc tool steel mold four (or eight) assembled. Clamps, hooks and spare parts. Wood, wood, 8th or 12th channel steel and so on.

2.2 operating conditions:

2.2.1 Manual excavating pile hole wall support should be based on the characteristics of soil and groundwater in the area of distribution of the preparation of the practical construction programme, supporting calculation and design of shaft lining.

2.2.2 three connections and one leveling the excavation site before. Aboveground and underground cables, pipelines, old buildings, equipment and other obstacles have been excluded have been disposed. The temporary facilities such as lighting, power, ventilation and safety facilities in place.

2.2.3 familiar with construction drawings and the site of the underground soil and hydrogeological data, be aware.

2.2.4 on the basic floor plan, set axis and anchor pile; pile around the gray lines. Determination of elevation bench marks. Line after the operation is finished, go through the preflight procedures.

2.2.5 good design fabricated steel cage.

2.2.6 prior to full excavation and selective test pile to dig two holes, analyzing soil, hydrologic and other relevant circumstances, to modify the original knitted construction program.

2.2.7 in the area of the underground water level is relatively high, lowering the underground water level below low 0.5M.

2.2.8 artificial digging hole is critical to the security of the operation, excavation prior to construction personnel conduct comprehensive safety technology gives the low-down; operation to secure the spreader inspection and testing to ensure safety.

3 operational processes

3.1 process:

Line position and elevation → excavation pile Earth → the first section against templates for additional steel →

Casting section retaining concrete → check position (Center) → set up the axis vertical transport →

Installation of electric hoist (hoist or wooden winches) → install bucket, lighting, event cover, water pump, fan →

Lifting section excavation pile of Earth (trimming) → split the first savings section Dado template (attached steel) →

Section II of the water retaining concrete → check position (Center) axis → cycle down layer by layer →

Excavation expanding bottom part hanging → check → on reinforcing cage → concrete slip tube (catheter) →

Pouring concrete pile (with the cast with vibration) → Insert pile head reinforcing bar →

3.2 line position and elevation: in sites based on the three connections and one leveling according to building surveying control network information and basic floor plans, determination of pile axial and Gao Chengji permitted point of square control network. Decide on a Center, the midpoint circle, with the radius of the pile and wall thickness as the RADIUS to draw the upper (the first step) circumference. Lime Wire as excavation of pile holes size line. Hole after the line set, must be reviewed by the relevant departments, run the pre-screening procedures of excavation.

Section 3.3 excavation pile earth moving: excavation pile layers from top to bottom, dig the middle part of the Earth, and then spread in and around, effectively control the excavation hole size. The height of each section should be based on soil quality is good or bad, depending on the operating conditions, generally to 0.9~1.2m is appropriate.

3.4 Dado template bar: to prevent the pile hole collapse to ensure safe construction, a hole should be well set, the two kinds of plain concrete and reinforced concrete. With in-situ reinforced concrete ring as well, and soil-wall seamless integration, stability and overall performance are good, and even stress can be preferred. When the hole diameter is small, relatively shallow soil and groundwater under low conditions or Jet concrete wall. Wall thickness according to material, performance, rigidity and stability, convenient operation, simple construction requirements, and force, inherit the Earth section in the bottom of the side pressure and lateral pressure of groundwater, determined by calculation.

Dado template removal section, under the support section on turnover for the same purpose. Fixed template using clamps, fasteners or at each node template to set the upper and lower ends of the arc, made of steel or steel internal rims as a medial support, prevent tension and deformation of memes. No level of support to facilitate the operation.

Higher wall to floor 150~200mm the first section is appropriate, for retaining, watertight. Axis and elevation shall be calibrated in the first quarter caused by the catchy, wall thickness and generally the 100~150mm.

3.5 section retaining concrete pouring: pile wall excavation of concrete each completed section immediately after pouring the concrete. Artificial casting artificial tamp, concrete strength is typically C20, slump-control in 100mm, ensure the stability of hole wall.

3.6 check the position (Center) and elevation axes: pile wall after making each section, you must cross the axis and elevation surveying in retaining the catchy, and then use the crosshairs, wait for fall to bottom cast is set, with vertical RADIUS gauge Rod hole wall smoothness. Followed by trimming depth must be according to the datum point, measured one by one. Ensure pile hole axis position, elevation, section meets the design requirements.

3.7 build vertical transportation: section after Kong Chengkong, which began at pile head erect vertical transportation support. Brackets: wooden, pipe hangers, wooden hangers, or I-beam rail bracket forms called building stable, solid.

3.8 installation of electric hoist or hoist: install in vertical transportation pulley and electric or worn hoist wire rope, choose the appropriate location for installing the hoist. If piles and small pile, you can also use wooden hangers, wooden wheel or human use thick hemp rope as a promotion tool. Ground earth-moving trolleys or dump truck.

3.9 installing buckets, lighting, event cover, water pump and fan.

3.9.1 pulley and bucket when it is installed, take care that the bucket coincides with the hole Center location, intuitive control as a digging pile and the centerline of the wall formwork.

3.9.2 bottom lighting must use low voltage power supply (36V, 100W), waterproof cover safety lamps. Arranged on the surrounding fence.

3.9.3 when the depth is greater than 20m, to the underground ventilation, air convection. Oxygen, if necessary, to prevent harm of poisonous gases. When rotation operations, personnel closely observe the pile on pile under the situation, respond to each other and prevent the occurrence of safety accidents.

3.9.4 underground water when digging mud with buckets out. Underground water is larger, bucket which could not meet the drainage, dig in pile bottom sump, sink with elevation pump into the pump, while precipitation excavation, determined according to the pumping of water pump specifications. Class three day and night pumping water level remains stable. Underground water level is high, should adopt measures to consolidate the precipitation, further excavation.

3.9.5 pile installation horizontal activities over safety cover, when the hole was dug, cover the safety cover plate to prevent debris dropped one. Staff shall not be closer to the hole. When lifting the soil, then open the safety cover.

Lifting section 3.10 excavation pile of Earth (trimming), from the beginning of the second section, lifting equipment, personnel should wear a helmet in the pile, ground crews tie belt. Bucket above the left hole 1.5M, promoting event safety cover, mask hole to prevent unloading of clods of soil, stones and other debris falling hole internal damage people. Bucket in a small cart after removing the soil, and then open the cover plate, lower buckets with soil.

After excavation of pile holes to the required depth, using poles to check the diameter of the hole and shaft arc, vertical up and down smoothly, finishing hole.

3.11 dismantled the first savings caused by the template in section II, additional reinforcement, retaining savings in turn used in the following section on the template removed. Aperture narrowed down, should be equipped with a small block template to adjust. Template is 100mm room at the upper concrete pouring and tamping compaction at the interface. After stripping with concrete or masonry block, cement mortar trowel, stripping strength 1MPa.

Section 3.12 pouring retaining concrete: concrete barrels come pouring of artificial, artificial plug pound density. Experimental determination by adding early-strength admixture for concrete, to speed up the hardening of the concrete.

3.13 check the central axis and elevation: to pile hole of the anchor line on the basis of the calibration section by section.

3.14 down layer by layer cyclic operation would pile hole dug to design depth, clear tilled soil, check the soil, pile bottom force-bearing the design requirements for the bearing layer.

3.15 excavation expanding bottom: end of piles can be divided into bottom-enlarged and does not spread at the end of both. Dig pile expanding bottom pile in first cylinders dug, spread bottom of sizes and shapes cut from top to bottom soil expansion into design drawings requirements; no clear requirements such as design, bottom-enlarged diameter for 1.5~3.0d. Spread bottom diameter is 1:4.

3.16 inspection and acceptance: the hole must pile diameter, head size, expansion of hole-bottom elevation, pile the Middle, perpendicular to the wall, Virtual Earth determine the full thickness. Well construction record, for the covert acceptance procedures.

3.17 hanging steel cage: steel cage should tie before in mortar for blocks, according to the design requirements for the 70mm (steel cage around every 3~4m or so in the main bar of a φ 20 earrings, as the positioning pad); dipping steel cage, must aim at the hole, hanging straight steady, slow down, avoid collision wall. Steel cage to design position, should be fixed immediately. In case of two-stage connection of steel cage should be used in welding (lap-welded or welded), both sides, joint by 50% staggered to ensure that the bar is correctly positioned, the thickness meets the requirements.

3.18 pouring concrete pile: pile the stones in the concrete using particle size is not greater than 50mm, 80~100mm slump, mechanical mixing. Chute plus barrel of pouring concrete into the pile. Concrete difference is greater than 2m, pile hole depth exceeds 12m, the pouring of concrete ducts should be used. Concrete should be continuous, layered vibration compacting. Generally the first step should be poured to the top of pedestal parts and upper concrete pouring. Lamination height to tamping tool, but should not be larger than 1.5M.

3.19 when pouring concrete pile, due over the pile design elevation, after the removal of laitance by guarantee, top level meets the design requirements. On top of the pile of steel and iron must be inserted to keep the design sizes, vertical insert, and there is sufficient cover.

3.20 in winter and rain during construction:

3.20.1 in winter when the temperature is lower than 0 ℃ when pouring concrete, heating and insulation measures should be taken. Pour into mould temperature should be determined by the winter programme. Top of the pile is not to design strength 50% must not be frozen. When summer temperatures above 30 degrees centigrade, retarding measures should be taken according to the specific circumstances of concrete.

3.20.2 cannot do the work of manual hole digging pile in the rain. Site must have drainage measures, to prevent ground water into the pile, pile hole collapse.

4 quality criteria

4.1 project:

4.1.1 piles of raw material and concrete provisions must comply with the design requirements and specifications.

4.1.2 the actual pouring of concrete, no less than the calculated size.

4.1.3 top elevation of pouring concrete pile and treatment of laitance must meet the requirements of specification for design and construction.

4.2 Basic project:

4.2.1 the pile diameter should be strictly controlled. Generally should not exceed a length of 3, and a maximum of 50mm.

4.2.2 virtual depth should not exceed the end of hole. Belled shape and size to fit the design requirements, should be vested in the bearing at pile bottom soil layer, bearing stratum of soil should not be destroyed.

4.3 allowable deviation, as shown in table 2-9.

Poured pile by artificial hole tolerance table 2-9

Project tolerance (mm) test method

1 steel cage reinforcement spacing ± 10 ' check

2 Stirrup spacing of reinforcement cage ± 20 foot check

3 steel cage diameter ± 10 ' check

4 length of steel cage ± 50 foot check

5 position the central axis ± 10 cable and check

6 3 ‰ l vertical pile, and no more than 50 hanging and foot check

7 pile diameter ± 10 ' check

8 bottom elevation ± 10 ' check

9 wall thickness ± 20 feet of concrete check

Note: • for length.

5 finished product protection

5.1 has been digging pile holes must be boarded or scaffold, steel mesh cover to prevent the clods of soil, debris, people fall. No grass bag, plastic sheeting behind.

5.2 has dug pile in time to put the steel cage, pouring concrete in a timely manner, time interval shall not exceed 4H in case of collapse. Groundwater pile hole should be dug, with check, with the reinforcement cage, to keep the concrete-filled well, avoid water immersion.

5.3 pile outside the circle should be retaining, prevention of water and soil.

5.4 protecting steel cage, not twisted, loose shape. Into the hole, do not hit the hole wall. Barrel should be vertically positioned to prevent the concrete wall thickness of oblique shock, damage caused by the soil, resulting in clips.

5.5 reinforcing cage not contaminated by slurry; when pouring concrete, at the top of the steel cage fixation and limited reinforcement cage floating.

5.6 finished pouring concrete pile should review pile and the pile height. Pile reinforcement or to insert iron fuzheng, enclosed with plastic sheeting or straw, and prevention of concrete shrinkage and cracking.

5.7 the axes properly protect the site construction process, standard point. Not compacted head, bending steel bars.

6 quality problems to be noticed

6.1 vertical deviation is too large: as the excavation procedure does not check the verticality of each section as required, after finishing digging vertical overload and unbalanced. Each dug up a section had to be lifted according to axis of the hole on the straight, edge trimming, keeping the hole arc straight up and down.

6.2 hole wall collapse: poor quality of the soil or groundwater seepage and the hole wall collapse. Field soil should be mastered before excavation, stagger excavation of pile, shortened each section height, observe the loosening of soil conditions at any time and, if necessary, can collapse with bricks, steel sheet pile, wood pile plugging operation process to compact, not space gaps and avoid collapse.

6.3-well tilled soil residues at the end of too many after drilling, trimming more Virtual Earth, brick, is not hard to clear. Steel cage should be carefully checked before and after the hole bottom, clear tilled soil debris. When necessary, with cement mortar or concrete.

6.4-well water at the end of: when fast seeping groundwater or rainwater, drainage, and water will appear. During excavation of holes dug at the end of sump, pump pumping water in a timely manner. If you have a small amount of water, pouring concrete in the first set and a half dry and hard, a lot of water sometimes exclude difficult circumstances, using catheter method of placing concrete under water to ensure construction quality.

6.5 bad quality of pile concrete: neck, empty, folder and so on. In front of the concrete must be ready to operate technology gives the low-down, insisted on stratified pouring and vibrating, continuous operation. Necessary auxiliary plug for iron pipes, bamboo poles, steel drill pound, to supplement the lack of mechanical vibration.

6.6 distortion of steel cage: steel cage processing spot when not in prison, is not supported for reinforcing, transport, dipping time distortion, distortion. Machined steel cage should be on a dedicated platform, main bars and hoops spot-strong reinforcement measures to support reliable, lifted vertically so that it smoothly into a pile, keep the skeleton intact.

7 quality records

This standard shall meet the following quality records

7.1 cement factory certification and proof of reinspection.

Factory certificate or certificate of 7.2 bars and rebar test single copies.

7.3 test pressure test records.

7.4 pile construction records.

7.5 test of concrete application form and mix orders issued by the laboratory.

7.6 28D compressive strength of standard curing concrete block test report.

7.7 floor map.

7.8 reinforced and pile covert acceptance form.