Pile foundation construction method for pre-drilling guide hole in inclined rock stratum

Abstract

The invention discloses a pile foundation construction method for pre-drilling a guide hole in an inclined rock stratum. The method comprises the following steps of setting a first hole site on a cross section, and performing drilling by a drill rod from the first hole site to form a first guide hole; setting a second hole site group on the cross section, wherein the second hole site group comprises two second hole sites, and performing drilling by the drill rod from the second hole sites to form a second guide hole; drilling a pile site by a drill bit, transferring a reinforcement cage into the pile hole; and pouring concrete grout. The defects of a traditional inclined rock construction mode can be overcome; a good pile forming effect is achieved; a small-aperture drill rod is used for pre-drilling the guide hole; the possibility of drilling hole deflection is reduced; and the drilling speed is high. Due to the advanced drilling of the first guide hole and the second guide hole, when a pile machine drills or impacts the holes, the drill bit cannot deflect under the limiting effect of the guide holes, so that the inclination degree of pile bodies of pipe piles and cast-in-place piles is controlled within the allowable error range; the whole cross section can be enabled to be embedded into an inclined rock stratum; the error of the perpendicularity of pile holes is reduced; the pile forming quality and the pile bearing capacity are improved; and the construction cost is reduced.

Description

technical field [0001] The invention relates to a pile foundation construction method for pre-drilling guide holes in inclined rock formations in the technical field of pile foundation construction. Background technique [0002] Pile foundation is the most widely used foundation type in deep foundation. When the pile foundation uses the rock formation as the bearing layer, the pile tip often needs to be embedded in the rock formation to a certain depth in its entire section. Sedimentary rocks form horizontal rock formations in a still water environment, but after undergoing tectonic movements and volcanic eruptions, igneous rocks or metamorphic rocks are formed, and the rock formations change from horizontal occurrences to rock formations with different orientations and different dip angles; there are also limestones, etc. Due to the development of karst, the rock surface is completely uneven, even steep; due to weathering and denudation of granite, the rock surface fluctua...

AI Technical Summary

Problems solved by technology

Generally, the pile ends of prestressed pipe piles and drilled (punched) piles need to be embedded in the rock formation or sit on a flat rock formation so that "hanging piles", "semi-hanging piles" and "sliding piles" will not cause pile foundations The problem of insufficient carrying capacity

In the project construction site, the rock surface of moderately weathered and slightly weathered rock formations often fluctuates greatly, has no stable direction and inclination, and the inclination angle changes greatly. The foundation construction is difficult, the drill bit follows the rock face, the drill pipe tilts and the drill hole tilts, and the pile end does not fall into the complete rock layer, and even most of the section falls into the soil layer, resulting in "hanging piles" and "semi-hanging piles" , "broken pile" and other phenomena; if the perforated pile is constructed, the inclined rock will easily lead to the deviation of the punching hammer to form an inclined pile, and even the reinforcement cage cannot be lowered to the bottom of the pile

The traditional construction method usually needs to backfill the rock and cohesive soil to the inclined rock face in advance, and then punch and break the rock after leveling the rock face, and repeat the cycle operation. The pile diameter at this position may be enlarged, and the rock and soil near the inclined rock face need to be removed. Slag cleaning is time-consuming and laborious, and the construction efficiency is low, which may lead to waste piles and affect the vertical bearing capacity of pile foundations

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