Magnetic card type fishing method for drill dropping during rotary drilling of large-diameter cast-in-place pile

Abstract

The invention relates to the technical field of rotary drilling machine drill rod salvage, and discloses a magnetic card type fishing method for drill dropping during rotary drilling of a large-diameter cast-in-place pile. The magnetic card type fishing method comprises the steps that S1, preparation work before salvage is conducted, specifically, the detailed situation of drill falling in a hole is known, and salvage materials are prepared; S2, sediments around a drill rod in the hole are removed through reverse circulation till a drill bit of a falling drilling tool is completely exposed, and the sediments in the hole are removed downwards as far as possible; S3, a fisher is manufactured according to the diameter of the pile hole and the diameter of the drill rod, and a steel wire rope and the fisher are fixed through a shackle; S4, the fisher is placed, the fisher is provided with a clamping area and comprises a magnet block used for adsorbing the drill rod, and the fisher is lowered to the magnet block to effectively adsorb a protruding part of the drill rod connector on the surface of the drill rod, S5, the fisher enters the hole and is attracted to the outer surface of the drill rod in the hole through a movable magnet block; S6, the steel wire rope is lifted, so that the protruding part of the drill rod connector is clamped into the clamping area; and S7, the steel wire rope is lifted to fish the drill rod out of the hole.

Description

technical field [0001] The invention relates to the technical field of drilling rod fishing with a rotary drilling rig, in particular to a rotary drilling method for large-diameter cast-in-situ piles with a magnetic card type. Background technique [0002] When the diameter of the cast-in-situ pile is greater than 2000mm and the hole depth exceeds 80m, the reverse circulation rotary drilling process is often used. The rotary drilling rig is controlled by the power device to rotate the rotary table of the drilling rig, driving the drill bit to cut the formation. Drilling pressure and torque are completed through the drill bit; when drilling, the drill pipe is lengthened joint by joint at the hole. When the drilling depth is high and the depth of penetration is large, the force on the drill pipe will gradually increase with the increase of drilling time. In addition, the screw connection is affected by the sand in the mud, and the screw thread of the drill pipe is easy to wear...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a large-diameter cast-in-place pile rotary drilling into the magnetic clip type fishing method, aiming to solve the problem in the prior art that the drill pipe and the drill bit of the ultra-deep hole fall off together, and the existing fishing method for the drill pipe cannot Quickly salvage the drill pipe

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