Drill bit for construction of bored pile and construction method using the same

Abstract

The invention discloses a drill bit for constructing bored piles and a construction method using the drill bit. The drill bit is provided with a mud scraping assembly and a detachable rib protecting block. The mud scraping assembly comprises a mud scraping plate (8) and installing plates (9), and the installing plates (9) are welded to the circumferential face of the inner circle of a block ring (3). A steel brush (17) is arranged on the outer side of the mud scraping plate (8). The mud scraping plate (8) is hung on the block ring (3) through a first clamping groove (10). An installing part (8.1) of the mud scraping plate (8) is located between the two installing plates (9) of the same set, and the installing part (8.1) of the mud scraping plate (8) and the installing plates (9) on the two sides are fixed in a threaded connection mode. The method is characterized in that in the drilling process, the mud scraping plate (8) is firstly installed on the block ring (3) so that a large hole with the size matched with that of a pile casing can be drilled, then the mud scraping plate (8) is taken down, and the rib protective block is installed so that a small hole with the size matched with the designed size of the bored piles can be drilled. By means of the drill bit and the construction method, sand soil between the pile casing and the pile holes can be effectively removed in a drilling mode.

Description

Technical field [0001] The invention relates to the field of pile foundation construction, in particular to a drill bit for constructing bored piles and a construction method using the drill bit. Background technique [0002] Because of the advantages of high bearing capacity, strong adaptability, pile length up to 100 meters, which reduces the number of piles, concrete bored piles have become domestic and foreign constructions (structures), especially large-scale constructions (structures) such as bridges, The preferred basic form of oil tanks, LNG tanks, and nuclear power plants. The main construction process of concrete bored piles are: forming holes, lowering the steel cage, and pouring concrete. In the above-mentioned main construction process, hole formation is the key link. In the process of hole formation, a three-wing scraper bit is usually used to drill into the formation. [0003] Such as figure 1 As shown, the prior art three-wing scraper drill bit includes a hollow ...

AI Technical Summary

Problems solved by technology

[0005] However, although sinking into the casing is beneficial for drilling, within the height range of the casing, this part of the sandy soil body between the casing and the pile hole may still collapse, and there is still sediment, which buries the drill bit and drill pipe, and cannot be drilled smoothly. A series of problems such as lowering the reinforcement cage and affecting the quality of the pile body, etc., in order to completely eradicate the above-mentioned disadvantages, someone put forward the technical idea of ​​using drill bits of two sizes, one large and one small, that is, first use the large drill bit to drill the diameter of the casing at the height of the casing. Use a small drill bit to drill a large hole with the same inner diameter as the designed diameter of the bored pile

Yet the actual operability of above-mentioned assumption is not strong, and this is because two kinds of drill bits need to be prepared for each construction, which increases the construction cost, and the drill bit needs to be mentioned outside the hole every time, and then the whole drill bit is removed from the drilling rig. After unscrewing and replacing a new drill bit, the overall weight of the drill bit itself is not light, and it is even heavier after being stuck with mud, which makes the replacement process troublesome and laborious, which is very inconvenient and further delays the work process. Therefore, no matter from the perspective of time cost and economic cost, All gains outweigh the losses

Moreover, there is also a defect in this technical solution. Although the protection of the reinforcement block has avoided the wear of the retaining ring, the constant friction between the reinforcement block and the hole wall soil will also be worn. Once the reinforcement block is worn and scrapped, it can only be Cutting it off and then welding a new reinforcement block is a troublesome and laborious process, and repeated welding will cause great damage to the retaining ring

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