Method for increasing rock core recovery rate of pile foundation construction investigation in limestone areas

Abstract

The invention relates to a method for increasing the rock core recovery rate of pile foundation construction investigation in limestone areas. The method comprises the following steps of S1, cleaning a site, enabling equipment to enter the site, assembling, welding a drill bit body on a drill pipe, and mounting the drill pipe on a drilling machine; S2, ensuring that a water outlet of a water feeding pump is communicated with a water distribution disc at the top of the drilling pipe through a pipeline, and the pipeline is rotatably and hermetically connected with a water inlet of the water distribution disc; S3, drilling, and ensuring that specifically, when a rock core is taken through drilling, a return drilling footage is controlled to be not larger than 1 m, and when a broken rock stratum or a karst cave occurs, drilling is conducted at the low speed of 160-200 r / min, the drilling speed of 10-12 cm / min and the small pumping capacity of 20-30 L / min; S4, sealing, conducting drill lifting, and ensuring that specifically, the bottom of the drill bit body is blocked, then drill lifting is conducted, and then core retreating is conducted. The method has the advantage that the rock core recovery rate can be greatly improved.

Description

technical field [0001] The present application relates to the technical field of geological prospecting, in particular to a method for improving the recovery rate of rock cores for pile foundation construction surveys in limestone areas. Background technique [0002] Before the piles are poured, it is necessary to conduct geological surveys in the construction area in advance, especially in limestone areas. The judgment of the integrity of the limestone at the pile tip plays a decisive role in the quality of the construction survey. [0003] In related technologies, the number of cutters used by surveyors in geological surveys is small, the nozzle width is large, and the height is small, which is not conducive to the cutting and grinding of rocks by the cutters and the circulation of mud. The most important thing is that the drill bit is basically a The empty pipe structure is only provided with cutting teeth at the lower end of the empty pipe structure. [0004] However, t...

AI Technical Summary

Problems solved by technology

[0004] However, the inventors found that the above-mentioned related technologies have the following defects: the collection rate of construction survey cores is not high, so that the division of broken limestone thickness layers is inaccurate, resulting in problems such as inaccurate stratum divisions recorded on site, resulting in problems such as construction survey results and later pile foundations. The formation conditions reflected in the hole-forming construction do not match, so that the rework is re-surveyed, which greatly consumes the construction period, wastes manpower and material resources, and increases the cost unnecessarily. The sub-footage is relatively large, and high-speed gear and large pump volume are used for drilling, which may also easily cause the problem of low core sampling rate

Images