混凝土芯水泥土搅拌桩群桩复合地基的承载特性  

Bearing Characteristics for Composite Pile Foundation with Concrete-cored Deep Chemical Mixing Pile

作　　者：李丹[1] 王吉霖 谭玄 汪洪平 LI Dan;WANG Ji-lin;TAN Xuan;WANG Hong-ping(School of Urban Construction,Wuhan University of Science and Technology,Wuhan 430065,China)

机构地区：[1]武汉科技大学城市建设学院,武汉430065

出　　处：《科学技术与工程》2018年第9期118-123,共6页Science Technology and Engineering

基　　金：国家自然科学基金(51208395;41372299)资助

摘　　要：为了探讨混凝土芯水泥土搅拌桩群桩基础在软土地基中的受力特征,以及褥垫层的移动趋势,进行混凝土芯水泥土搅拌桩群桩复合地基加固软土地基的室内模型试验。通过监测分级荷载作用下复合地基的沉降和桩顶、桩底以及桩间土不同位置的应力分布的变化来探讨复合地基承载特性。对桩顶平面处A桩周围土层表面埋设标志物,分析了褥垫层材料的移动态势和桩间土体的沉降量的规律。试验结果表明:复合地基在上部荷载作用下,加载初期是由桩来承担大部分上部荷载;由于褥垫层的调节作用,桩顶面处的桩土应力比逐渐增大,达到峰值后比值有所减小直到趋于稳定。混凝土芯水泥土搅拌桩群桩复合地基在上部荷载作用下的沉降曲线(P-S曲线)为缓变型;褥垫层向群桩所围成几何图形的中心移动,桩周土的水平位移和竖向沉降都以桩为中心呈现由近及远不断减少的趋势。研究结果为工程实践提供了有益的参考。In order to discuss stress characteristics and moving tendency of cushion of the concrete-cored DCM pile foundation in soft soil foundation,the concrete-cored DCM pile reinforcing soft soil foundation pile group composite foundation of indoor model test was carried on.By monitoring the settlement of composite foundation under rating load,the pile top,the bottom of the pile and soil between piles at different positions of the change of the stress distribution to load-bearing characteristics of composite foundation is discussed,and the surface of the soil around the A pile top is embedded with markers,analyzed the cushion material moving trend and settlement law of soil between piles.The experimental results show that the initial loading of the load is carried by the pile while the composite foundation under upper load.Due to the adjustment of the cushion,the stress ratio of pile soil in the top of the pile is increasing gradually,after peaking the ratio decreases until stabilized.The settlement curve(P-S curve)of the composite foundation under the upper load is a slow variation;The cushion is moved to the center of the piles,the horizontal displacement and vertical subsidence of the soil are the trend of the near and far decreasing.The research results provide useful reference for engineering practice.

关 键 词：混凝土芯水泥土搅拌桩 复合地基 桩土应力比 P-S曲线 褥垫层 

分 类 号：TU470.3[建筑科学—结构工程]