高速铁路软土地基的差异沉降试验研究

Experimental Research on the Differential Settlement of Soft Soil Ground in High-speed Railway

研究目的:在软土地基上修建高速铁路时,由于其差异沉降要求非常严格,目前常用的软土地基处理方法能否满足要求是高速铁路建设必须面临的重大课题。本文通过采用粉喷桩、浆喷桩、真空联合堆载预压、塑料排水板超载预压、砂桩超载预压等方法处理高速铁路软土地基及桥梁、涵洞地基的现场试验,对不同方法处理软土地基之间及不同结构物之间的差异沉降进行研究。研究结论:(1)地基处理方法及结构物类型是影响软土地基剩余纵向差异沉降的主要因素,而荷载对剩余纵向差异沉降的影响较小;(2)在填筑完成后的3个月内,横向差异沉降变化较大,对于需要有较长时间预压期(或放置期)的软土地基,横向差异沉降不会对列车运营造成不良影响;(3)建议在设计时同一工点应尽量避免采用不同地基处理方法,若无法避免时应考虑在不同处理方法和不同结构物之间设置过渡段;(4)本研究结果可为高速铁路设计、施工等提供指导。

Research purposes： It is a problem to choose economic and reasonable method of soft soil ground treatment to meet the strict standard of differential settlement of high - speed railway engineering. The differential settlement of soft soil ground treated with dry jet mixing pile, deep cement mixing pile, vacuum preloading combined with heaped preloading, plastic drain belt combined with surcharge preloading, sand pile combined with surcharge preloading, among soft soil ground, bridges, and culverts, were studied through the field test in high -speed railway. Research conclusions： （ 1 ） The methods of soft soil ground treatment and type of structures have great influence on residual longitudinal differential settlement. （2）The transverse differential settlement changes greatly during 3 months after embankment being filled. The transverse differential settlement will not do harm to train with a longer period of preloading. The load is not a main factor to residual longitudinal differential settlement. （3）It should be avoided to changing method of soft soil ground treatment in same site. The transition area should be adopted among embankment, bridges, culverts, and soft soil ground treated with different methods. （4）The research results can be used in the design and the construction of high - speed railway.