Application Of Jet Grouting Composite Foundation To The High Building

High pressure sprinkling grouting technology has been introduced into China for more than thirty years since 1970s. At that time, this technology was mainly used in consolidation of soft-soil foundation, it was applied in impermeable dam after 1980s.At present, it has been spreaded over the country, and applied in large-scale conservancy projects such as the Yangtse River three gorges and Dong Feng substation. The technology has remarkable characters of safety, better suitability on soil, lower noises, high pile shaft strength, controllable consolidation figure, aboundant material, lower price and so on., so it is widely applied in consolidation of building foundation, deep foundation pit excavation and retaining, stability of slope, impermeable dam, consolidation around shield tunneling and possible slumping position, etc.High pressure sprinkling grouting technology is one of the methods of soil improvement. Its principle is to chisel pipe with special nozzle in soil lay of appointed depth by drills, then jet slurry or water from the nozzle at the pressure of 20-40Mpa and come into being jet grouting destroying soil layer. Among the destroyed soil granules, the thinner wells up from the ground with slurry or water, and the others mix with slurry under the effect of jet's impact force, centrifugal force, gravity and so on, then are further rearranged according to certain ratio of soil and quality, concreting to form consolidation in the soil layer.Taking the project of high building in Zheng Zhou for an example, this article explains it is successful that high pressure sprinkling grouting composite foundation applies in high building, and bearing capacity of its composite foundation can meet the need of the project. This article also designs and construct High pressure sprinkling grouting composite foundation. In the devise, the article reasonably selects parameters such as diameter of pile, pile length, pile shaft strength, reduced coefficient of pile shaft, and calcutes Eigenvalue of bearing capacity of a pile combining with local facilities of construction, technics of construction and devise experience. In the construction, the article mainly takes charge of selecting construction parameters, and puts up with important questions about engineering. Through the research of the article, the author further understands the keys of calculating high pressure sprinkling grouting composite foundation, advances personal opinions and suggestion on reasonably selecting parameters of devise, which has been proved by engineering data. According to the condition of geological engineering, the author's experience is that the quality of construction can be guaranteed through spot testing pile, confirming construction parameter , adopting information construction and continuously optimizing devise, which has a positive influence on homoplastic engineering.