Optimize the drilling bucket, optimize the drilling bucket as much as possible, make the drilling bucket reduce the drilling resistance, especially the center pilot tip has the positioning function, which can effectively prevent the hole deviation
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When the deviation is not serious and the rock surface hardness is not high, the flat bottom bit is used for leveling and then drilling, or the smaller bit is used for guiding and then reaming
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By lengthening the drill bucket, the hole deviation can be effectively prevented
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Deviation can also be effectively prevented by changing the drilling mode
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Analysis of reasons for hole deviation 1
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At present, many pile machine engineering hole inspection equipment have adopted ultrasonic inspection instrument, which is very accurate for pile length, pile diameter and perpendicularity inspection
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If the geology is loess layer and clay layer, there will be no deviation in the hole
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when the deflection is serious and occurs in a shallow place and the groundwater volume is small, manual hole digging can be used to correct the inclined rock surface..
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With the continuous lowering of the drill pipe, the first section of the drill pipe is always close to the casing in one direction, indicating that the hole is slowly deviated in one direction, and the closer it is, the more the hole deviates
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This kind of deviation is mostly caused by the completely and strongly weathered rock stratum, and the longitudinal deviation is caused by the uneven force on the drill bucket during drilling
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With the extension of the hole depth, the first section of the drill pipe is close to the casing and deviates from the center when the main coil is lowered with slow deviation
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Operation control of floating, pressurization, rotation speed and drilling speed can effectively reduce the deviation
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Drilling mode the current geological condition is judged by vibration and load, and the drilling mode is changed, such as cutting drilling, crushing drilling, toggle drilling and grinding drilling
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B
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Geology is the main reason for hole deviation
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Today, wuchuang equipment will talk about the problem of rotary drilling deviation in detail with colleagues in the industry
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Assuming that the maximum allowable deviation range of 100 m pile length is about 1.7 m, if the pile length is 50 m, it is about 0.85 M
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How to prevent hole deviation 1 understand the geological conditions in detail through geological report, core sampling, geographical environment and so on
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C
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How to remedy the deviated hole? When the bent hole is not serious, the drilling rig can be readjusted to continue drilling
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2
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Analysis of deviated hole phenomenon 1 sharp deviated hole sharp deviated hole is generally caused by geology
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When the deflection is serious and the hardness of rock surface is high, stop drilling and pouring the same grade concrete of pile body immediately; when the concrete strength reaches more than 70%, use a smaller drill to guide the hole and then expand the hole; D
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Through practical verification, spiral drilling bucket can better prevent deviation than double bottom sand bailing bucket, because the drilling resistance of spiral drilling bucket is small, and the pilot drilling method can effectively prevent deviation
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These details can make the force on the left and right sides of the drill bucket uniform and prevent deviation
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Do not use the impact drill to repair the hole directly to avoid sticking
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A 2m long casing can be welded on the top of the auger or double bottom drill bucket, which is consistent with the hole diameter
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5
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6
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At the same time, the pilot tip can change the drilling sequence, whether the number and angle of the drill teeth are consistent, and whether the height of the side cutters or protective strips on both sides of the drill body are consistent
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The main function of drill bucket 2 is cutting and drilling, but it also has the function of guiding and anti deviation
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If it is beyond the specification range, it will affect the hole quality and construction progress
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Due to the degree of rock weathering and uneven rock distribution, when the main roll is lowered to a certain position in the hole, the drill bucket is suddenly stuck, or the drill pipe suddenly deviates to one side, indicating that a certain position in the hole suddenly deviates
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3 operation when there are rocks, boulders, pebbles and weathered rocks in the hole, it is necessary to control the way of floating and pressurization, and rapid drilling will cause sharp hole deviation
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Some industry colleagues asked in wechat how to deal with partial holes
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3 irregular deviation with the drill pipe down, the first section of the drill pipe sways to the left and right, or the irregular spiral deviation in the hole can be seen directly during dry hole drilling
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Most of the deviation is caused by geological changes, uneven distribution of weathered rock and rock, resulting in uneven force on the drilling bucket during drilling
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4
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3
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If it is serious, it should be backfilled with clay and drilled after the deposit is dense
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In the construction specification of rotary drilling rig, the allowable verticality deviation is 1 ﹥ degree
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