真空-填土自载联合预压软基加固技术及其应用研究

STUDY ON COMBINED METHOD OF VACUUM-SURCHARGE PRELOADING AND ITS APPLICATION IN TREATING DEEP AND SOFT FOUNDATION OF HIGH-SPEED RAILWAY

对于深厚软基而言,特别是含有硬夹层和透水性较好的砂土夹层的复杂软基,工程施工中最关心的是真空预压加固效果、工后沉降及其对周围环境影响控制技术问题。本文结合上海某高速铁路软土地基处理的实际情况,通过综合分析与现场测试试验,就真空-填土自载联合预压法加固深厚软基的设计方法、施工工艺和对周围环境影响控制措施等,进行了试验研究。工后沉降的预测分析表明,真空卸载后1个月和11个月可分别满足工后沉降10 cm和5 cm的要求。该法是高效低价的软基处理方法,具有填土速度快、工期及预压时间短、处理深度较大、固结速度快等优点,能有效地减少工后沉降,达到预压和超载的目的。

Through theoretical analyses and site model testing and experiencing, this paper puts forth the design of combined method of vacuum-surcharge preloading in treating deep and soft foundation of high-speed railway, its construction techniques and effects to surround environment.Some key techniques, such as effective consolidation depth, settlement control after projection and measures to control affecting on surrounding environment,etc.,are solved to some extent.The results obtained are important to develop and perfect the mechanism of vacuum preloading in consolidating soft foundation,The forecast of post-construction settlement indicated： it can satisfy the request of settlement l0 cm and settlement 5 cm after vacuum unloading the latter 1 month and ll months. This method is the highly effective low price soft ground processing method and can effectively reduce the post-construction settlement to achieve the preloading and overload, and the advantages as followings： fill earth quickly; short construction time and preloading, processing depth bigger, and so on.