从刚性桩复合地基发展历程看短螺旋挤土工艺刚性桩复合地基综合技术优势

Technical Advantages of Rigid Pile Composite Foundation with Short Spiral Soil Squeezing Technology from the Development History of Rigid Pile Composite Foundation

刚性桩复合地基因加固效果显著而备受工程界青睐,目前已在高层建筑、市政、高铁等土木工程领域地基处理中得到广泛应用。通过对刚性桩复合地基形成机理和成桩工艺沿革的简述和梳理,着重阐述钻头改进后的短螺旋挤土工艺(简称SDS工艺)及其综合技术优势。具有挤密和置换双重作用的SDS工艺所形成的刚性桩复合地基,可使处理后桩间土承载力特征值达到天然地基承载力特征值的1.1~1.5倍,且当地基土层构成和刚性桩复合地基设计参数相同时,刚性桩单桩竖向极限承载力比传统长螺旋非挤土工艺提高30%~50%。与此同时,SDS工艺与振动沉管工艺和传统长螺旋非挤土工艺相比,适应地层范围广,无噪声和振动影响,无泥土污染、渣土运输及弃土场地等不良环保和资源浪费问题。

Rigid pile composite foundation,due to its remarkable reinforcement effect,is favored by the engineering community and has been widely used in foundation treatment in civil engineering fields such as high⁃rise buildings,municipalities,and high⁃speed railways,etc.This paper briefly describes and summarizes the formation mechanism of rigid pile composite foundation and the evolution of the pile forming technology,and focuses on short soil displacement screw technology(SDS technology)and its comprehensive technological advantages after the improvement of drilling bit.The rigid pile composite foundation,formed by the SDS technology with the dual functions of compaction and replacement,can make the characteristic value of the bearing capacity of the soil between the piles after treatment reach 1.1 to 1.5 times that of the natural foundation.Furthermore,when design parameters of the foundation soil composition and the pile composite foundation are the same,the vertical ultimate bearing capacity of a rigid pile is 30%to 50%higher than that of the traditional long spiral non⁃squeezing soil technology.Meanwhile,compared with the vibratory immersed pipe technology and the traditional long spiral non⁃squeezing technology,SDS technology has a wider range of stratums,yet resulting in no environmental problems and such as noise,vibration,soil pollution,muck transportation,disposal site,and resource waste,etc.