ã€China Deep Hole Rig Trading Network】
During the drilling process of long spiral drilling rig, attention should be paid to the verticality of drilling, and the main technical measures for controlling the verticality of drilling are:
(1) Compact and level the construction site.
(2) When installing the drilling rig, the flatness of the drilling and the verticality of the active drill pipe should be strictly checked. The verticality of the active drill pipe should be regularly checked during the drilling process, and the deviation should be immediately adjusted.
(3) Regularly check the drill, drill pipe, drill pipe joints, find problems and repair or replace them in time.
(4) Drilling at the interface of soft and hard soil or at the inclined rock face should be done at low speed and low pressure. Found that drilling deviation, should be timely backfill clay, and then low-level drilling and low pressure drilling.
(5) Drilling in complex formations, if necessary, add a grooving machine on the drill pipe.
Underwater perfusion process should pay attention to:
1 When using high-grade cement for preparation, attention should be paid to the relationship between the initial setting and final setting time of the concrete and the perfusion time of the single pile. If necessary, add the antimony retarder. The construction site should strictly control the mix ratio (especially water-cement ratio) and mixing time. To master the workability and slump of slugs, prevent the segregation and plugging of the sputum during the infusion process.
2 Depth of buried pipe at the time of initial irrigation
China's JGJ94-94 specification stipulates that the distance from the bottom of the perfusion catheter to the bottom of the hole should be 300-500mm, and the initial depth of the catheter should be ≥800mm. When calculating the initial volume of concrete, individual construction units only calculated the amount of plutonium needed for a 1.3m pile length, and calculated the amount of plutonium accumulated in the pipe. The lack of initial filling caused the depth of the buried pipe to fall below the specified value. On the other hand, the length of the pipe length prepared by the construction unit is too small, the pipe is difficult to install when installing the pipe, and sometimes the distance between the pipe and the bottom of the hole is too large, and the pipe installer does not inform the piling class of the actual distance in time, resulting in insufficient initial filling capacity. The depth of the buried pipe did not reach the specified value. The amount of initial irrigation volume V should be calculated according to the design of pile diameter, diameter of the conduit, installation length of the conduit, and mud density in the hole, and V≥V0+V1. V0 is the length of the pile of 1.3m long, V0=1.2×1.3Ï€D2/4 (unit: m3); 1.2—the theoretical filling factor of the pile; D—the designed pile diameter (m). V1 is the amount of helium accumulated in the catheter at the time of initial irrigation, V1=(hÏ€d2/4)(Ï+0.55Ï€d)/2.4 (unit: m3); h—the length of the catheter installation (m); d—the diameter of the catheter (m) ; Ï - mud density in the hole (t/m3); 0.55 - coefficient of friction of the inner wall of the conduit; 2.4 - density of helium (t/m3).
3 blocked tube during infusion
Intubation occurs when the blockage occurs mainly due to leakage of the perfusion catheter, the depth of the perforation of the catheter at the bottom of the hole is too small, the preparation time for infusing the fistula after completing the secondary clearance is too long, the septum is not standardized, the quality of the osmium preparation is poor, and the perfusion process Infusing catheter is too deep and other reasons.
The perfusion catheter should be inspected by the person in charge prior to installation. The inspection can be performed by a combination of naked eye observation and tapping. The inspection items are mainly whether the perfusion catheter has small holes and cracks, whether the joint of the perfusion catheter is sealed, and the thickness of the perfusion catheter. Eligibility. If necessary, use the test assembly pressure water method to check whether the catheter is leaking. The distance from the bottom of the infusion tube to the bottom of the hole should be 300-500mm. If the initial filling volume of the grouting equipment is sufficient, it should be as large as possible. The sluice should be carefully and carefully manufactured, its diameter and garden should meet the requirements of use, and its length should be ≤ 200mm.
After the completion of the second clearing, the infusion should be started immediately. If the infusion is delayed for some reason, the clearing should be performed again. Otherwise, sand particles suspended in the pores may sink and the bottom sediment may be too thick, which may lead to the occurrence of plugging accidents due to the fact that the hydrants cannot escape the conduit.
4 Rebar cage floats during filling process
There are three main reasons for the rise of reinforcement cage during the infusion process:
(1) The initial setting time and the final setting time of the concrete are too short, so that the inside of the hole will be agglomeration prematurely. When the surface of the concrete rises to the bottom of the reinforcement cage, the concrete will hold up the reinforcement cage.
(2) There are too many sand particles suspended in pores during cleaning, and the sand particles sink back to the surface during the perfusion process to form a denser sand layer and gradually increase with the internal porosity. When the sand layer rises to the reinforcement cage Hold the reinforcement cage at the bottom.
(3) When the concrete is poured into the bottom of the reinforcement cage, the perfusion rate is too fast, causing the reinforcement cage to float.
In the event of a reinforcement cage floating up, the cause should be immediately identified and appropriate measures taken to prevent recurrence.
5 Low strength or enthalpy of piles
It was found that the main reasons for the low strength of concrete piles or the segregation of concrete piles in Henan Sanli Machinery were the poor control of concrete mix ratio at the construction site, insufficient mixing time, and poor cement quality. Strictly controlling the quality of the incoming cement, controlling the mixing ratio at the construction site, and mastering the mixing time and workability of the concrete, is an effective measure to prevent pile separation and low strength.
6 Pile slag or broken pile
There are four main reasons for causing piles, mud, or broken piles:
(1) The amount of irrigation at the beginning is not enough, resulting in the depth of the buried tube after the initial irrigation is too small or the catheter is not inserted into the fistula at all.
(2) The length of the extubation was not controlled during the perfusion, and the catheter was pulled out.
(3) The initial coagulation time and final coagulation time are too short, or the filling time is too long, causing the upper part of the bowl to agglomerate, causing slag inclusion in the pile body.
(4) There are too many sand particles suspended in the hole during cleaning, and the sand sinks back to the surface during the perfusion process, forming a sedimentary sand layer and impeding the normal rise of the earthworm. When the earthworm breaks through the sedimentary sand layer, part of the sand and floats The slag is packed into the pot. In severe cases, it may cause a pipe plugging accident, resulting in disrupted perfusion.
The depth of the buried pipe of the pipe should be controlled between 2 and 6 meters. If the pouring is successful and the mud returns from the hole, the depth of the pipe can be appropriately increased to increase the filling speed and shorten the time of pouring the single pile.拔 Infuse the extubation process should be specially responsible for directing, and use the theoretical amount of filling into the hole to calculate the hole surface and the weight of the hole inside the measured surface, take the low value of the two to control the extubation length, to ensure the depth of the buried pipe ≥ 2 meters. Single piles should be controlled at 1.5 times the initial setting time.
7 The top of the pile is not dense or the strength cannot meet the design requirements. The main reason is that the height of the overfilling is not enough.
For piles with a pile diameter ≤ 1000 mm, the height of the overburden is not less than 4% of the pile length. For piles with a pile diameter of >1000mm, the overfilling height is not less than 5% of the pile length. For large piles of concrete piles, the mix within 10 meters of the top of the pile should be properly adjusted to increase the content of gravel and reduce the top of the pile. In the final stage of perfusion, the determination of the surface in the hole shall be determined by a hard-barrel sampling method.
For more information, please pay attention to the China Deep Hole Rig Trading Network ()
PET/PP Packing Strap Production Line
PET Packing Strap Production Line,PP Packing Strap Production Line,Packing Strap Production Line
zhangjiagang sevenstars machinery co.,ltd , https://www.sevenstarmachienry.com