Method and apparatus for triple pipe rotary spray of reinforced concrete pile foundation

Abstract

A technology for constructing the reinforced concrete pile foundation by three-pipe rotary spray includes drilling, cutting earth body, discharging earth, grouting and additional steps including opening surface earth, setting-up reinforcing bar cage, pouring broken stone as aggregate ,vibrating and curing. Its apparatus features that three pipes are collectively sealed, the inner cavity of water nozzle is composed of conic body and cylindrical body, and the inner cavity of air nozzle consists of conic barrel and cylindrical ring barrel. The grouting nozzle is under the water and air nozzle by a distance of 800-1200mm.

Description

Technical field: [0001] The invention relates to a triple pipe rotary spraying reinforced concrete pile foundation method, which belongs to the technical field of construction engineering foundation treatment and foundation engineering. It is applicable to the construction technology of underground building structures in industrial and civil buildings, public works, bridges and culverts, subways, civil air defense, port engineering, hydraulic engineering and mining engineering. Background technique: [0002] High-pressure rotary jet grouting technology was developed in my country in the early 1970s. Its technical performance has been gradually improved from single pipe, double pipe and triple pipe to meet the increasing needs of foundation treatment in construction projects. However, it is difficult to surpass the scope of foundation treatment on the road of development. It can complete the cutting of the soil, stirring the slurry and obtaining a consolidated body of a sing...

AI Technical Summary

Problems solved by technology

This is because when the rotary spraying reaches 400-500mm from the ground surface, the soil layer will break into pieces and fall into the pile core to affect the quality of the pile.

Therefore, it is difficult to meet the higher needs of construction projects without improving the jet spraying pile forming process.

In addition, the existing high-pressure rotary spray equipment is difficult to meet the requirements of new economic and technical indicators, and there are the following problems: (1) The seal of the triple tube deflector is only suitable for water pressure below 40Mpa, and cannot meet the high-pressure requirements above 50MPa

(3) The distance between the slurry nozzle and the water-air nozzle is too close (140-150mm), causing the slurry jet to be in the stirring area of ​​the water-air jet, which causes the slurry to be mixed and discharged from the surface by water, air, mud and sand on the one hand. On the one hand, the slurry is diluted by water-air sand (β=0.3-0.6), the strength of the consolidated body formed by low slurry concentration is poor, and the defects of low engineering quality and high cost