An electromagnetic frequency modulation type hole bottom hammering thin-walled low-resistance soil fetcher

Abstract

The invention discloses an electromagnetic frequency modulation type hole bottom hammering thin-wall low-resistance soil sampler. Related content includes the thin-wall low-resistance soil sampler, an electromagnetic frequency modulation hammering device, a footage and pressure sensor, a wire and a ground surface controller. The thin-wall low-resistance soil sampler comprises resistance-reducing grooves and a threaded connector. The electromagnetic frequency modulation hammering device comprises a superconducting coil, a permanent magnetic hammer, a damping rubber cushion, a rotating lifting ring, a draining hole and a threaded connector. The electromagnetic frequency modulation type hole bottom hammering thin-wall low-resistance soil sampler is lifted to the hole bottom of a drilled hole through a steel wire rope, the ground surface controller is used for starting the electromagnetic frequency modulation hammering device at the bottom, the footage and pressure sensor transmits related data in real time, the ground surface controller automatically controls the hammering force and frequency of the permanent magnetic hammer according to the hardness and the loosening degree of sampled soil, soil sample disturbance caused by mechanical vibration is reduced, and therefore a low-disturbance undisturbed soil sample is obtained. The method is suitable for the technical field of geological engineering and geotechnical engineering and can be widely applied to fast sampling of various undisturbed soil samples.

Description

technical field [0001] The invention belongs to the technical fields of geological engineering and geotechnical engineering, and in particular relates to an electromagnetic frequency modulation hole bottom hammering thin-walled low-resistance soil fetcher. Background technique [0002] The undisturbed soil sample collection is often involved in the engineering drilling process. The original thin-walled soil fetcher hammering device is usually installed above the ground surface, and the soil fetcher is driven into the soil by force transmission to the bottom through the drill pipe. However, the original method will cause the drill pipe to vibrate and twist greatly during the force transmission process, and this process will greatly disturb the obtained undisturbed soil. Based on engineering experience, predecessors have created several mechanical in-hole hammers, which can greatly reduce the disturbance caused by the hammer force transmission to the sample. For example, the ...

AI Technical Summary

Problems solved by technology

However, these existing inventions all adopt the heavy hammer mechanical lifting type excavation method. In this way, an incompletely closed structure is used between the heavy hammer and the collector. When encountering high groundwater pressure, the buoyancy of the water will greatly reduce the effective hammer. At the same time, the traction rope often has a deformation hysteresis effect, so it is difficult to guarantee the hammering frequency

[0003] In addition, due to the long outer wall of the soil extractor, a large friction force will be generated between the outer wall and the surrounding soil during the extraction process, making it difficult to move

The magnitude and frequency of external force are accidental, the disturbance is large, the action of soil extraction is not precise, and the collected soil samples are invalid

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