堆载预压下塑料排水板地基的侧向变形预测方法  

Prediction method for lateral deformation of prefabricated vertical drains improved ground under surcharge preloading

作　　者：徐方[1,2] 吴其长[1,2] 门小雄 杨俊芳 彭扬发 解裕荣 杨奇 XU Fang;WU Qichang;MENG Xiaoxiong;YANG Junfang;PENG Yangfa;XIE Yurong;YANG Qi(School of Civil Engineering,Central South University,Changsha 410075,China;Mechanics Teaching Experiment Center,Central South University,Changsha 410083,China;Zhuhai Rail Transit Co.,Ltd.,Zhuhai 519060,China;School of Advanced Manufacturing,Nanchang University,Nanchang 330031,China;China Railway Guangzhou Engineering Group Co.,Ltd.,Guangzhou 511458,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学力学教学实验中心,湖南长沙410083 [3]珠海市轨道交通有限公司,广东珠海519060 [4]南昌大学先进制造学院,江西南昌330031 [5]中铁广州工程局集团有限公司,广东广州511458

出　　处：《铁道科学与工程学报》2025年第1期416-428,共13页Journal of Railway Science and Engineering

基　　金：湖南省自然科学基金资助项目(2021JJ40766);珠海隧道工程科技研发项目;中铁广州工程局集团有限公司施工关键技术研究项目(城建青岛地铁09-01字(2023)工程-技术-06)。

摘　　要：为深入研究堆载预压下塑料排水板地基的侧向变形特性,并建立相应的侧向变形预测方法,利用自研的改进三轴试验装置,开展堆载预压下径向排水的三轴压缩试验及多工况仿真分析,系统研究竖向应力、水平应力、加载速率及初始有效应力对土体侧向变形及应力比的影响。研究结果表明:土体侧向变形随竖向应力的增加、水平应力的减小、加载速率的增大及初始有效应力的减小而非线性增长;土体代表性应力比K_(e)^(*)则随加载速率的增大及初始有效应力的减小而非线性减小,随水平应力的增加近似线性增长,随竖向应力的增加先线性减小再非线性减小;堆载预压下地基浅层存在较大的水平向附加应力,其对地基侧向变形的影响不可忽视;水平向附加应力及竖向附加应力的综合作用,促使堆载预压下的排水板地基侧向变形随深度呈现先增大后减小的“弓”形分布规律。基于分析结果,建立土体应力比K_(e)^(*)与最终水平应变εh之间的归一化关系;并提出可考虑堆载预压加载因素及土体固结特性的综合影响因子β,由β与K_(e)^(*)之间的线性拟合关系可对不同工况下的K_(e)^(*)进行估算;综合ε_(h)-Ke及K_(e)^(*)-β关系,提出了堆载预压下排水板地基侧向变形轮廓的预测方法,并将该方法运用于分析2个实际工程案例,取得了良好的预测效果。研究结果可为堆载预压下塑料排水板地基的分析与设计提供参考。To investigate the lateral deformation characteristics of prefabricated vertical drains improved ground under surcharge preloading and establish corresponding prediction method for lateral deformation,a radial drained triaxial test and numerical simulations under multiple conditions were conducted based on a self-developed improved triaxial test device.The influence of vertical stress,horizontal stress,loading rate,and initial effective stress on the soil lateral deformation and stress ratio was systematically studied.The results indicate that the lateral deformation of soil increases nonlinearly with the increase of vertical stress,the decrease of horizontal stress,the increase of loading rate,and the decrease of initial effective stress.The representative stress ratio of soil(K_(e)^(*))nonlinearly decreases with the increase of loading rate and the decrease of initial effective stress,approximately linearly increases with the increase of horizontal stress,and first decreases linearly and then nonlinearly with the increase of vertical stress.There is a significant horizontal additional stress in the shallow layer of the ground under surcharge preloading,and its impact on the ground lateral deformation cannot be ignored.The combined effect of horizontal and vertical additional stresses promotes the lateral deformation of vertical drains improved ground under preloading first increases and then decreases with depth,presenting an arched distribution shape.Based on the results,a normalized relationship between the stress ratio K_(e)^(*) and the final horizontal strainεh of the soil is established.Additionally,a comprehensive influence factorβis proposed,which considers the surcharge preloading parameters and the radial consolidation properties of the soil.The K_(e)^(*) under different conditions can be estimated through the linear fitting relationship betweenβand K_(e)^(*).Combining theε_(h)-K_(e)^(*) and K_(e)^(*)-βrelationships,a prediction method for the lateral deformation profile of the vertical drains imp

关 键 词：堆载预压 塑料排水板 改进三轴试验 侧向变形 预测方法 

分 类 号：TU433[建筑科学—岩土工程]