路堤荷载下浅层就地固化联合管桩复合地基桩-土应力比及沉降计算  

Pile-soil stress ratio and settlement of in-situ shallow solidification-combined pipe-pile composite foundation under embankment load

作　　者：周杨[1] 陈永辉[1] 孔纲强[1] 陈龙[1] 陈庚[1] ZHOU Yang;CHEN Yong-hui;KONG Gang-qiang;CHEN Long;CHEN Geng(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing,Jiangsu 210098,China)

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098

出　　处：《岩土力学》2022年第3期688-696,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51778212)。

摘　　要：浅层就地固化联合管桩复合地基是超软土地基加固的有效方法之一。基于复合地基荷载传递法理论,将路堤填料、固化层、基桩、桩间土和下卧层作为一个系统,建立考虑应力、沉降变形连续性的浅层就地固化联合管桩复合地基的理论计算方法,探讨浅层固化层对管桩复合地基桩-土应力比及地基沉降的影响规律。通过与浅层就地固化联合管桩复合地基现场试验结果的比较分析,并与传统管桩复合地基现场试验结果对比,验证了所建立的理论计算方法的准确性和可靠性。研究结果表明,浅层固化层的设置能够充分发挥管桩复合地基中基桩的承载性能,桩-土应力比随着浅层固化层模量的增大而呈线性增加(斜率约为1.6MPa^(-1));现场工况下,桩体中性点位置随浅层固化层模量的增大而上移(介于0.12~0.45之间);考虑到发挥固化剂材料性能及加固效果,选取水泥掺量不超过11%的固化剂较为合适。Ground improvement using a joint technology of combined in-situ shadow solidification and pipe-pile-reinforced foundation is one of effective methods used for deep soft clay treatment under infrastructure embankments. Based on the load transfer theory of the composite foundation, this paper analyzes the embankment filling, solidified layer, pile, soil between piles and underlying layer as a whole, and establishes the calculation method of stress and settlement of composite foundation considering the continuity of stress and settlement deformation. The deformations of pipe piles, the surrounding soil, and the overlying solidified layer are compatible by applying the stress continuity and volume deformation continuity at the bottom of the solidified layer. This paper discusses the influence of the in-situ shadow solidification on the pile-soil stress ratio and settlement of the composite foundation. The established method has been verified via comparisons with field tests data about the joint technology and traditional pipe pile-reinforced foundation. It shows that the pile-soil stress ratio in composite foundation increases linearly with the modulus of the solidified layer(with 1.6 MPa^(-1)). The position of the neutral point of pile moves up with the increase of the solidified layer modulus(between 0.12 and 0.45). Considering the performance and reinforcement effect of curing agents, it is more appropriate to select the curing agent with cement content no more than 11%.

关 键 词：浅层就地固化 管桩复合地基 荷载传递 桩-土应力比 

分 类 号：TU431[建筑科学—岩土工程]