As we all know, pile driver is a kind of equipment used in construction machinery. Appropriate operation technology will play a certain role in the operation of the pile driver. This article will tell you about some specific operating processes of the pile driver.
1. Hole making process flow:
(1) Drilling machine in place → drilling → checking quality → hole bottom cleaning → orifice cover → moving drilling machine
(2) Pouring concrete process flow:
Move the cover plate to measure the depth and verticality of the hole → place the reinforcement cage → place the concrete slip hole → pour the concrete (follow the pouring and vibrate) → insert the top reinforcement
2. The drilling machine is in place: when the drilling machine is in place, it must be stable without tilting or displacement. In order to accurately control the drilling depth, a control ruler should be made on the rack or the machine pipe to facilitate the construction. Observe and record.
3. Drilling: Straighten the frame tappet, align the pile position (using the registration ring), start the machine to drill and unearth, and stop drilling and lifting after reaching the control depth.
4. Check the quality of the hole:
(1) Determination of drilling depth. Use a sounding rope (hammer) or a hand lamp to measure the hole depth and the thickness of the virtual soil. The thickness of the virtual soil is equal to the difference of the drilling depth. The thickness of the virtual soil should not exceed 10cm.
(2) Aperture control. When drilling into a soil layer with a lot of stones or a soft plastic clay layer with a large water content, it is necessary to prevent the drill stem from sloshing and cause the hole diameter to expand, causing the hole wall to adhere to the disturbed soil and the hole bottom to increase back fall.
5. Hole bottom soil cleaning. After drilling to a predetermined depth, it is necessary to perform idling to clear the soil at the bottom of the hole and then stop rotating; lifting the drill rod is not allowed to bend the drill rod. When the thickness of the virtual soil at the bottom of the hole exceeds the quality standard, it is necessary to analyze the cause and take measures to deal with it. The soil scattered on the ground during drilling must be removed at any time.
6. Move the rig to the next pile. After the hole-forming inspection, the pile hole construction record should be filled. Then cover the orifice cover and prevent driving or walking on the cover. Finally, remove the drilling rig to the next pile.
7. Pouring concrete:
(1) Remove the drilling cover plate and recheck the hole depth, aperture, hole wall, verticality and the thickness of the virtual soil at the bottom of the hole. If there is any non-compliance with the requirements of the quality standard, it should be dealt with before passing the next procedure.
(2) Lifting the steel cage: before putting the steel cage, tie the mortar pad (or plastic card); when lifting the steel cage, aim at the hole position, hang it upright, slowly sink, and avoid colliding with the hole wall . When the reinforcement cage is placed in the design position, it should be fixed immediately. When two sections of steel cages are connected, welding shall be adopted to ensure the correct position of the steel bars and ensure that the layer thickness meets the requirements.
(3) Put concrete in the slide tube. Before placing the slide tube, the thickness of the virtual soil in the borehole should be checked and measured again. When pouring concrete, it should be carried out continuously, the layering is vibrated and compacted, and the layering height depends on the tamping tool. Generally not larger than 1.5m.
(4) When pouring concrete to the top of the pile, the design elevation of the pile top should be properly exceeded to ensure that the height of the pile top meets the design requirements after the floating slurry is chiseled.
(5) Withdraw the slide tube and insert steel bars at the top of the pile. When the concrete is poured to 1.5m from the top of the pile, the slide tube can be pulled out and the concrete can be directly poured. The steel bar inserted on the top of the pile must be inserted vertically, with sufficient protective layer and anchor length to prevent insertion deviation and insertion skew.
(6) The slump of concrete should generally be 8 ~ 10cm; in order to ensure its workability and slump, attention should be paid to adjusting the sand rate and adding water reducing agent, fly ash, etc.
(7) There should be no less than one group of test blocks of the same mix ratio.
8. Construction during winter and rain:
(1) When pouring concrete in winter when the temperature is below 0℃, heating and heat preservation measures should be taken. When pouring, the temperature of concrete shall be implemented according to the winter application plan. The top of the pile shall not be frozen until it reaches 50% of the design strength. When the temperature is higher than 30 ℃, concrete should take retarding measures according to the specific situation.
(2) Strictly adhere to the regulations of drilling while pouring concrete during the rainy period to prevent the collapse of the hole caused by irrigation after the hole is formed in the rain. Drilling is not allowed on rainy days. There must be various measures for drainage on the site to prevent ground water from flowing into the trough, so as not to cause slope collapse or foundation soil subsidence, and drilling machine tilting.
