Erect column pile construction method under geologic condition of pebble bed sandstone

Abstract

The invention relates to an erect column pile pore-forming construction method under the geologic condition of sandstone pebble bed. The mud weight is controlled in a range from 1.15 g / cm<3> to 1.25 g / cm<3>, the viscosity is controlled in a range from 20 s to 30 s, and the sand ratio is not more than 2.5%; clockwise rotary trepanning on site is performed during drilling, and drilling bucket weight, drilling rod weight and hydraulic pressure are taken as drilling pressure; an excavating drill bit is firstly utilized for drilling, a double-baseboard bailing bit is adopted to drill in a silty-fine sand layer, when the double-baseboard bailing bit drills into the pebble bed, a spiral bit is utilized to stir the pebble bed to be loosened, then a rotary excavating barrel is utilized to collect slag, a rock-socketed short spiral bit is utilized for drilling when the sandstone is drilled, and is matched with the double-baseboard bailing bit for cleaning slag, and a large boulder grabbing bit is utilized for treating boulders when larger boulders are encountered during drilling; and a bottom-clearing bit is utilized for cleaning sediments at the pile tip when the bit drills to designed elevation. With the adoption of the erect column pile pore-forming construction method, the problem of pore-forming difficulty under the geologic the condition of sandstone pebble bed can be solved, the soil stability during a drilling process is guaranteed, good pore-forming quality is ensured, and influence on the environment is small.

Description

technical field [0001] The invention relates to a construction technique for forming a hole with a column pile, in particular to a construction method for forming a hole with a column pile under the geological condition of a sandstone pebble layer. Background technique [0002] A certain project in Lanzhou is a landmark building in Lanzhou and even the entire northwest region. The main building is 250m high, making it the tallest building in the northwest region. The project is located in the bustling area of ​​the city center, adjacent to the city's main road and many residential buildings, and there are many municipal pipelines under the road, so the surrounding environmental protection requirements are relatively high. The area of ​​the foundation pit in the first phase of the project is about 20,100m2, the extension of the surrounding area of ​​the foundation pit is 558m, there are four underground floors, and the deepest excavation depth is 23.6m, which is the deepest f...

AI Technical Summary

Problems solved by technology

The stratum of this project is significantly different from that of the eastern coastal area, mainly consisting of pebbles and sandstone. At present, there is almost no practice of column pile construction in pebbles and sandstone strata in the northwest region.