Application Of As-unyielding Large-diameter Cement Soil Mixing Pile In Deep Excavation Engineering

Southeast coastal cities of our country were mainly sludge and mucky soil,which was soft and with high underground water level,saturated water content,deep osmotic coefficient,small internal friction angle and cohesive force,and had creep property.In big cities,they have had vertical and horizontal transportation networks,intensive buildings,numerous underground utilities,and high demands of environment protection,which takes many challenges to the design and construction of excavation.Hence,we should consider the reality of projects,act according to circumstances when we take part in excavation design and construction.We cannot apply mechanically which may lead to terrible consequences.Currently our deep excavation supports' cost and duration has been obviously cut down,with sharp decrease of engineering accidents,which can't do without nowadays scientific and targeted design and construction.Our overall level in deep excavation has been much improved and it almost reached the advanced international level.This issue simply introduced the technologies of deep excavation project protects and some of their main characters,technical principles,background,relevant construction technologies and technical standards.Based on the background,range of application,development of the new technologies of cement soil mixing piles,a new kind of support form,which contained the characteristics of high strength,strong cutting,large diameter,called as-unyielding large-diameter cement soil mixing piles,was emphatically introduced and analyzed in the issue with its definition,development,and theoretical knowledge etc.Meanwhile in the issue,an actual excavation project in Foshan City was as an example introduced.It contained the kind of support form called as-unyieldinglarge-diameter cement soil rotary jet(mixing)piles & plain concrete stiffening piles,which had a maximum pile diameter reached ? 1500 mm.During the implementation process,exact geological exploration,right selection in engineering design,mature construction technology and detailed foundation monitoring,which was fused,referenced and take examples from each other,made the theory and reality combined,and made the situation of the whole excavation fed back and the potential safety hazard controlled.All of these bring up the whole excavation become successful,and give references to similar projects in the future.