气泡轻质土高铁拓宽路基性能离心模型试验研究  

Centrifugal model test research on the performance of high-speed rail widening subgrade with bubble light soil

作　　者：张振[1] 刘洪伟 叶观宝[1] 饶烽瑞 戚得健 ZHANG Zhen;LIU Hong-wei;YE Guan-bao;RAO Feng-rui;QI De-qian(Department of Geotechnical Engineering,College of Civil Engineering,Tongji University/Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院地下建筑与工程系/同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《地基处理》2022年第3期220-225,共6页Journal of Ground Improvement

基　　金：上海市科技计划项目(22ZR1466600);国家自然科学基金项目资助(41772281,41972272)。

摘　　要：路堤拓宽工程中新旧路基结合部差异沉降控制一直是人们关注的核心问题。路基拓宽工程可采用换填、轻质材料回填、桩承路堤、土工合成材料、排水固结等技术控制新旧路基的差异沉降。但轻质材料应用于高铁拓宽路堤的研究尚处于起步阶段。本文开展了50 g加速度下的离心模型试验,模拟原路堤阶段、拓宽路堤阶段(包括运营阶段),研究了常规填料和气泡轻质土用于高铁拓宽路堤的变形特性与应力分布。测得并分析了试验过程中新老路堤沉降、地基土中孔隙水压力和土压力的发展规律。结果表明,路基拓宽引起的附加应力主要集中在新老路基交界处靠近拓宽路堤一侧,同时,仍会引起原路堤下土中附加应力的增加,但对原路堤地基土的附加应力影响较小。相较于常规填料,采用气泡轻质土进行路堤拓宽可以有效减小地基土中最大超孔隙水压力增量和附加应力,同时还可以减小拓宽路基与原路基之间的差异沉降。In the embankment widening project,the control of differential settlement at the junction of new and old embankment has always been the core issue.Various techniques have been used to mitigate the uneven settlement between existing and widened embankments in embankment widening,e.g.,over-excavation and replacement,lightweight backfill,piled embankment,geosynthetic reinforcement and preloading etc.However,research on the lightweight material in the widening of high-speed railway embankment is still at the initial stage.This study conducted a centrifugal test at 50 g acceleration field,modeling the existing embankment stage and widening of embankment,investigating the deformation and stress of widened embankment constructed by conventional backfill and the foamed light soil.During the test,the settlement between existing embankment and widened portion,pore water pressure and earth pressure in soil were monitored and analyzed.The settlement of new and old embankments,pore water pressure and earth pressure in foundation soil after widening with conventional filler and foamed light soil filler were compared.The results show that the additional stress caused by embankment widening is mainly concentrated on the side near the junction of new and old embankment.At the same time,the additional stress in the soil under the original embankment will still increase,but the effect on the additional stress of the original embankment base is small.Compared with the conventional filler,the use of foamed light soil for embankment widening can effectively reduce the maximum excess pore water pressure increment and additional stress in the foundation soil,and reduce the differential settlement between the widened embankment and the original embankment.

关 键 词：路堤拓宽 气泡轻质土 孔隙水压力 差异变形 离心模型试验 高速铁路 

分 类 号：TU41[建筑科学—岩土工程]