软基路堤桩-网复合地基试验研究

桩-网复合地基是近些年发展起来的一种有效的软土地基加固方法,它集复合地基中水平向增强体与竖向增强体两种"单一型"复合地基之长,桩-加筋垫层-桩间土三者协同作用,共同承担上部荷载,其相互作用机理复杂。通过京沪高速铁路试验段中桩-网复合地基处理段进行的路基现场试验,对桩-网复合地基中基底土压力、土工格栅应力应变、桩和土的沉降及地基侧向位移等进行观测测试,分析了桩土应力分担比的变化过程、土工格栅的受力特点、沉降及侧向位移规律,有助于桩-网复合地基各组成部分的承载机理和应力传递机理的深入研究及网垫层对沉降控制的研究,并为提出桩-网复合地基的设计新方法提供一定的依据。

Experimental study on pile-net composite foundation of high-speed railway on soft soils

Pile-net composite foundation has been emerged as an effective alternative successfully adopted worldwide to solve many geotechnical problems.It combines the advantages of the horizontal reinforcement layer and the vertical reinforcement.Related to pile-net-soil cooperative function,pile-net composite foundation is so complicated that designed mainly by experiences,which limits its application.It is very difficult for pile-net composite foundation mechanism to be researched by theoretical analysis.General model test and soil centrifuge modeling test can only solve some problems qualitatively;and some important technical questions need in-situ solution.With in-situ test of a certain high-speed railway trial embankment,pile-net composite foundation has been careful studied in settlement and lateral displacement and contact pressure and the stress and strain of geogrid aspects.The change process in pile-soil stress ratio and the bearing properties of geogrid and settlement have been analyzed.Systematic researches on soft embankment settlement laws,the pile-net composite foundation bearing mechanism and stress transmission mechanism have been performed.How net mat made by geogrid and mat impacts settlement control and how it is designed have been discussed.