Drill bit for constructing bored pile and hole forming method using the drill bit

Abstract

The invention discloses a drill bit for constructing a cast-in-situ bored pile and a hole forming method. The drill bit is provided with a detachable mud scrapping assembly, the mud scrapping assembly comprises mud scrapping plates (8) and installing plates (9), the installing plates (9) are welded to the inner circumferential face of a check ring (3), a steel brush (14) is arranged at the outer side of each mud scrapping part (8.2), the mud scrapping plates (8) are hooked and hung on the check ring (3) through clamping grooves (10), and an installing part (8.1) of each mud scrapping plate (8) is located between two corresponding installing plates (9) in the same set and fixed to the corresponding installing plates (9) at the two sides through threaded connection. The hole forming method is characterized in that in the drilling process, the mud scrapping plates (8) are installed on the check ring (3) to drill a big hole matched with a pile casing in size, and then the mud scrapping plates (8) are dismantled to drill a small hole, wherein the size of the small hole is matched with the design size of the cast-in-situ bored pile. By means of the drill bit and the hole forming method, sandy soil between the pile casing and the pile hole can be effectively drilled away without substantially increasing time and economic cost.

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 hole-forming method using the drill bit. Background technique [0002] Concrete bored piles have become a popular choice for domestic and foreign buildings (structures), especially large buildings (structures) such as bridges, The preferred foundation form for oil tanks, liquefied natural gas tanks, and nuclear power plants. The main construction process of concrete bored piles includes: forming holes, lowering steel cages, and pouring concrete. In the above-mentioned main construction process, hole forming is the key link. During the hole forming process, a three-wing scraper drill bit is usually used to drill into the formation. [0003] Such as figure 1 As shown, the three-wing scraper drill bit of the prior art includes a hollow base rod 101, a drill tip 102, a retaining ring 103, three connecting plates 104 and th...

AI Technical Summary

Problems solved by technology

[0005] However, although sinking into the casing is beneficial to 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 A series of problems such as lowering the reinforcement cage smoothly and affecting the quality of the pile body, etc., in order to completely eradicate the above-mentioned disadvantages, someone proposed 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 at the height of the casing and the diameter of the casing. Use a small drill bit to drill a small hole with the same diameter as the bored pile design

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 will be heavier after being stuck with mud, which makes the replacement process bothersome and laborious, very inconvenient, and further delays the work process, so no matter from the perspective of time cost and economic cost The loss outweighs the gain

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