高速铁路软土路基沉降试验研究

高速铁路无砟轨道的高平顺性对路基的工后沉降提出严格要求,在软土地基上修筑无砟轨道路基需要对地基进行有效加固。对原京沪高铁昆山路基试验段进行重新堆载预压,通过路基顶面及路基底面沉降观测,对浆喷桩、粉喷桩、塑料排水板真空预压及砂桩四种软基加固效果进行分析及工后沉降预测。得出路基本体的竖向变形较小,工后沉降主要有地基沉降引起;复合地基的加固效果要好于排水固结法;复合地基中加固效果优劣排序为砂桩、浆喷桩、粉喷桩;四种加固方法的工后沉降均满足铺设无砟轨道的要求等结论。为高速铁路路基设计及施工提供一定的借鉴作用。

Experimental Study on Settlement of Soft Soil Ground of High-speed Railway

The unballasted track of high-speed railway in ride comfort needs small settlement of subgrade after construction.The effective reinforcement is necessary for constructing the unballasted track on soft soil ground.Here,the former Kunshan testing embankment of Jing-Hu high-speed railway is re-preloaded.The reinforcement effects are analysed for mortar jetting pile, powder jetting pile,vacuum precompression of plastic drainage board,and sand pile in improving of foundation by observing the settlement of embankment.At the same time,the post-construction settlement is forecasted.The underside conclusions are testified: The vertical deformation in the basic body of embankment is small,the post-construction settlement is mainly caused by foundation settlement;the reinforcing effect of composite foundation is better than the drainage consolidation method;the orders of the pros and cons of composite foundation reinforcement are sand pile,mortar jetting pile,powder jetting pile,vacuum precompression of plastic drainage board;but any of the foundation reinforcement methods could meet the requirements for constructing the unballasted track.These conditions could provide references for the design and constrution of high-speed railway.