Drill bit device for variable diameter drilling and construction method

Abstract

The invention belongs to drilling tools for pile foundation engineering, and relates to a drill bit for variable diameter drilling. The device is modified and optimized on the basis of a traditional drill bit. The device comprises a drill pipe, a movable knife row mounting base, a movable knife row, an oil cylinder, an oil cylinder mounting base, a pin, a spiral drill bit, the movable knife row isinstalled on the movable knife row base and tightened by the oil cylinder, and the size of opening of movable knife row blades can be controlled by controlling telescoping of the oil cylinder so as to achieve the variable diameter effect. Compared with the prior art, the drill bit has the advantages that drilling and hole expanding are conducted simultaneously, the hole collapse probability is effectively lowered, drilling resistance can be reduced, the drilling efficiency is high, the drilling sticking risk is reduced, and the drilling safety is guaranteed.

Description

technical field [0001] The invention relates to a drill bit device and a construction method for variable-diameter drilling, which are mainly used in the fields of foundation reinforcement, improvement, earth displacement prevention and the like in municipal foundation, industrial and civil engineering construction. Background technique [0002] The bored pile is a pile made by forming a pile hole in the foundation soil by means of mechanical drilling, steel pipe extrusion or manual excavation, and placing a steel cage in it and pouring concrete. [0003] At present, bored piles are generally used in coastal and soft soil areas to increase the bearing capacity of the foundation, resist the lateral pressure of the earth and prevent the displacement of the earth. At present, the bored pile machine uses a fixed drill bit for drilling operations. When it is necessary to ream the hole, the method of replacing the drill bit can only be adopted, which is not only complicated to ope...

AI Technical Summary

Problems solved by technology

At present, the bored pile machine uses a fixed drill bit for drilling operations. When it is necessary to ream the hole, the method of replacing the drill bit can only be adopted, which is not only complicated to operate, but also time-consuming, labor-intensive and low in drilling efficiency; Otherwise, the drilling resistance is large when the fixed bit is drilled down, and it is easy to cause hole collapse and drill sticking failure

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