基于PFEM法的黄土地基振杆密实过程大变形分析  

Large deformation analysis of vibratory probe compaction process of loess foundations based on particle finite element method

作　　者：高常辉 刘松玉[2] 杜广印[2] 郁培阳 吴燕开 Gao Changhui;Liu Songyu;Du Guangyin;Yu Peiyang;Wu Yankai(College of Civil Engineering and Architecture,Shandong University of Science and Technology,Qingdao 266590,China;School of Transportation,Southeast University,Nanjing 211189,China;Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources,Yangtze River Scientific Research Institute,Wuhan 430010,China)

机构地区：[1]山东科技大学土木工程与建筑学院,青岛266590 [2]东南大学交通学院,南京211189 [3]长江水利委员会长江科学院水利部岩土力学与工程重点实验室,武汉430010

出　　处：《东南大学学报（自然科学版）》2024年第1期99-109,共11页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(41977241);山东省自然科学基金资助项目(ZR2022MD061)。

摘　　要：采用粒子有限元方法(PFEM)及结构性土的本构模型,对振杆密实法加固砂质黄土地基的大变形过程进行了数值模拟研究,分析了振杆贯入过程中周围土体的位移场、应力场、速度场以及塑性体应变等分布规律,揭示了砂质黄土地基深层振动密实机理.结果表明:现场实测和数值模拟获得的地面垂直振动速度峰值变化趋势较为一致,验证了粒子有限元方法的可靠性;垂直激振的振杆能够同时引起土体垂直方向和水平方向上位移场、应力场和速度场的变化;在距振源水平距离5R(R为振杆半径)范围内,土颗粒以半梭形向外扩展并趋于密实,同时水平应力大幅增加并产生预压效果;以塑性体应变作为加固范围的评价标准,结果表明土体径向加固范围随振杆贯入深度增加而略有增大,最大径向加固范围约为3.2R,且振杆底端以下1R~2R范围亦有密实效果.A numerical simulation of the large deformation process of sandy loess foundation reinforced by the vibratory probe compaction method was conducted using the particle finite element method(PFEM)combined with the constitutive model of structured soil.The distribution rules of displacement field,stress field,velocity field and plastic body strain of surrounding soil during the process of the probe penetration were analyzed.The mechanism of deep vibratory compaction of sandy loess foundation was revealed.The results show that the trend of the peak value of the ground vertical vibration velocity obtained from the field measurement is consistent with that from numerical simulation,which verifies the reliability of the PFEM.The vertically excited probe can cause the changes of displacement field,stress field and velocity field in the vertical and horizontal directions of soil.The soil in the horizontal direction within 5 R(R represents the radius of the vibratory probe)expands outward in a half shuttle shape and tends to compact,while the horizontal stress increases significantly and produces a preloading effect on the soil.Using the plastic body strain as the evaluation criterion of the reinforcement range,the results show that the radial reinforcement range of the soil increases slightly with the increase of the penetration depth of the probe,and the maximum radial reinforcement range is about 3.2 R,and 1 R-2R below the bottom of the probe also has the compacting effect.

关 键 词：粒子有限元 振杆密实法 大变形 数值模拟 砂质黄土 结构性土 

分 类 号：U472.1[机械工程—车辆工程]