列车荷载作用下活树桩边坡的动力响应规律与稳定性  

Dynamic response law and stability of live tree stump slope under train load

作　　者：江学良 王自豪[2] 杨慧 郭佳慧 王浩冬[2] JIANG Xueliang;WANG Zihao;YANG Hui;GUO Jiahui;WANG Haodong(School of Civil Engineering and Engineering Management,Guangzhou Maritime University,Guangzhou 510725,China;School of Civil Engineering,Central South University of Forestry and Technology,Changsha 410004,China)

机构地区：[1]广州航海学院土木与工程管理学院,广东广州510725 [2]中南林业科技大学土木工程学院,湖南长沙410004

出　　处：《振动工程学报》2025年第4期860-868,共9页Journal of Vibration Engineering

基　　金：广东省普通高校重点领域专项(2023ZDZX4044,2023ZDZX4045);广东省重点建设学科科研能力提升项目(2022ZDJS092);湖南省自然科学基金资助项目(2022JJ31005);国家自然科学基金资助项目(31971727);湖南省科技创新计划项目(2022NK2056);湖南省林业科技创新计划项目(XLK202105-3)。

摘　　要：通过1∶7室内物理活树桩边坡模型试验数据验证的三维有限元边坡动力分析模型,研究了列车移动荷载作用下活树桩边坡附加动应力的衰减特征、活树桩主侧根应力响应特性和活树桩对边坡稳定性的影响规律,探讨了活树桩边坡的动力稳定机理。研究结果表明:基于三维有限元动力分析模型计算的竖向动土压力峰值与室内物理模型实测结果接近,通过Midas GTS NX构建活树桩边坡三维有限元动力分析模型的方法及其计算结果是可靠的。活树桩边坡附加动应力峰值受到列车轴载叠加效应的影响;列车移动速度越大,基床表层土体竖向动应力峰值越大。道砟层附加动应力最大,并呈现半圆弧状向下迅速衰减扩散,仅有较小动应力传递至坡面上部的两排活树桩。不同位置活树桩主根的抗剪能力发挥程度不一,坡脚活树桩主根相较于坡肩活树桩主根受到更大的剪应力作用,活树桩主根类似“抗滑桩”发挥抗剪能力。坡内生长的活树桩侧根类似锚杆,坡外生长的侧根类似支撑,形成“锚⁃撑”效应,协同主根一起发挥抗滑作用。活树桩的存在导致边坡土体应力重新分布,活树桩附近土体的剪应力集中。活树桩阻碍了土体剪应力的传递,抑制了土体塑性区的连通,提升了边坡稳定性。坡面水平动位移受影响程度与其到振动荷载作用位置的距离相关,距离越近,影响越大。活树桩可以减小坡面各处的水平动位移,但坡脚动位移的减小幅度最大。活树桩可以显著提高列车动力作用下边坡的稳定性,其边坡安全系数可提升15%~20%。活树桩边坡的潜在滑动面呈现圆弧状,活树桩使得塑性区向深部土层移动,从而提升了边坡的稳定性。可为活树桩应用于路基边坡提供一定的指导作用。Based on the three-dimensional finite element slope dynamic analysis model which is validated through the test data of 1:7 indoor physical model for live tree stump,the attenuation characteristics of additional dynamic stress on live tree stump slopes,the stress response characteristics of taproot and lateral root of live tree stumps,and the influence of live tree stumps on slope stability are studied.The dynamic stability mechanism of live tree stump slope is explored.The research conclusion is as follows.The peak value of vertical dynamic soil pressure calculated by the three-dimensional finite element dynamic analysis model is close to the measured results of the indoor physical model.The method and calculation results of the three-dimensional finite element dynamic analysis model of the live tree stump slope established through Midas GTS NX are reliable.The peak value of additional dynamic stress on the slope is affected by the superposition effect of train axle load.The higher the train movement speed,the greater the peak value of vertical dynamic stress.The additional dynamic stress in the ballast layer is the largest,it rapidly decays and diffuses downwards showing a semicircular arc shape.Only small dynamic stresses are transmitted to the two rows of live trees on the upper slope.The degree to which the shear resistance of the taproot of live tree stumps varies at different positions,and the taproot at the foot of the slope is subjected to greater shear stress compared to the taproot at the shoulder of the slope.The taproot is similar to the anti-slide pile to exert its shear resistance ability.The side roots of live tree stumps growing inside the slope are similar to anchor rods,while the side roots growing outside the slope are similar to supports,and they form an anchor-support effect that synergizes with the main root to play a sliding resistance role.The existence of live tree stumps leads to a redistribution of stress in soil,and the shear stress concentration near the live tree stumps.The live tree

关 键 词：活树桩支护 动力响应 边坡稳定性 列车荷载 数值模拟 

分 类 号：TU431[建筑科学—岩土工程] U260.171[建筑科学—土工工程]