新型预应力路基水平向附加应力扩散规律研究  

Diffusion laws of horizontal additional stress in a new prestressed subgrade

作　　者：冷伍明[1,2] 艾希 徐方[1,2] 张期树[1] 杨奇 聂如松[1,2] 刘晓豪[1] LENG Wu-ming;AI Xi;XU Fang;ZHANG Qi-shu;YANG Qi;NIE Ru-song;LIU Xiao-hao(School of Civil Engineering,Central South University,Changsha 410075,China;National Engineering Laboratory for High Speed Railway Construction,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学高速铁路建造技术国家工程实验室,湖南长沙410075

出　　处：《岩土工程学报》2019年第8期1445-1454,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目（51678572,51878666）

摘　　要：基于弹性理论,推导了新型预应力路基内水平向附加应力计算公式,并获得了预应力自坡面向路堤内的扩散规律;同时运用ABAQUS有限元软件建立三维预应力路基模型,分析了不同侧压板布设位置下路堤内的水平向附加应力分布情况。研究表明:①理论公式的适用条件为侧压板上边界距路肩距离不小于2.0 m;②板覆盖区(除板左下角点外)路基内水平向附加应力系数及其衰减速率随距路堤坡面水平距离的增加逐渐减小,且水平向附加应力逐步由"腹鼓形"差异分布过渡呈"腹平状"较均匀分布;③距侧压板距离大于0.1 m时,附加应力系数随水平距离增加先增大后减小,且扩散峰值点距坡面水平距离随外延距离的增加而增大;④通过合理布置板间距,可在路堤受荷核心区外部形成一道连续、稳定、有效的受压加固区,进而改善路堤土体受力状态,提高路堤整体服役性能。研究成果可为预应力路基的设计计算和推广应用提供理论基础和参考。Based on the theory of elasticity, the theoretical formulas are derived to calculate the horizontal additional stress(σ_H)in a new type prestressed embankment, and the diffusion laws of the additional stress from the slope surface to the inside of the embankment are revealed. Meanwhile, a 3 D finite element model for a prestressed embankment is established to analyze the distribution of the horizontal additional stress in the prestressed embankment with different placement positions of the lateral pressure plate. The results show that:(1) The application condition of the theoretical formulas requires that the net spacing between the lateral pressure plate and the embankment shoulder should be more than 2.0 m.(2) In the region covered by the lateral pressure plate, the horizontal additional stress coefficient as well as its attenuation rate gradually decreases with the increase of the horizontal distance from the slope surface, and the distribution of σH gradually transits from a "raised abdomen"pattern to a relatively uniform "flat abdomen" one.(3) When the distance away from the lateral pressure plate is greater than 0.1 m, the additional stress coefficient of σH increases first and then decreases with the increasing horizontal distance, and the horizontal distance between the peak point and the slope surface increases as the epitaxial distance increases;(4) A continuous,stable and effective pressure-reinforced zone is likely to be formed when the spacing of the lateral pressure plate is properly designed, therefore, the stress state of the embankment soil and the overall service performance of the embankment can be improved. The research findings can provide theoretical bases and references for the design and promotion application of the prestressed embankments.

关 键 词：预应力 路基 侧压力板 水平向附加应力 扩散规律 板间距 

分 类 号：TU43[建筑科学—岩土工程]