基于激光扫描和形貌等效的行道树风荷载模拟  

Simulation of wind load on street trees based on laser scanning and crown morphological equivalence

作　　者：孙梦思 周晓青[1] 黄希桂 蔡鸣 崔冬瑾 李伟文[1] 李利孝 SUN Mengsi;ZHOU Xiaoqing;HUANG Xigui;CAI Ming;CUI Dongjin;LI Weiwen;LI Lixiao(College of Civil and Transportation Engineering,Shenzhen University,Shenzhen 518060,Guangdong Province,P.R.China;School of Civil and Environmental Engineering,Harbin Institute of Technology Shenzhen,Shenzhen 518055,Guangdong Province,P.R.China;School of Architecture and Urban Planning,Shenzhen University,Shenzhen 518060,Guangdong Province,P.R.China;Shenzhen Key Laboratory of Structure Safety and Health Monitoring of Marine Infrastructures,Shenzhen 518060,Guangdong Province,P.R.China)

机构地区：[1]深圳大学土木与交通工程学院,广东深圳518060 [2]哈尔滨工业大学(深圳)土木与环境工程学院,广东深圳518055 [3]深圳大学建筑与城市规划学院,广东深圳508060 [4]深圳市海上基础设施安全与监测重点实验室,广东深圳518060

出　　处：《深圳大学学报（理工版）》2024年第2期127-135,共9页Journal of Shenzhen University(Science and Engineering)

基　　金：国家自然科学基金资助项目(52178491);广东省自然科学基金资助项目(2021A1515011769,2022A1515011499);深圳市自然科学基金资助项目(JCYJ20210324093809023)。

摘　　要：行道树风荷载的准确模拟是对其开展风致失效模式分析以及加固处置的先决条件.为精确模拟行道树的风荷载,提出一种基于三维(three dimensional,3D)激光扫描与树冠形貌等效融合的典型行道树风荷载数值模拟方法,对典型行道树的风致失效模式进行了探讨.首先通过移动式3D激光扫描建立山茶树和南洋楹两种行道树的点云模型,并采用树冠形貌等效方法构建了两种行道树数值分析模型;然后探讨等效建模方法中模型尺寸随风速变化的折减规律;最后分析行道树模型在不同等级风速作用下的风振响应特性和失效模式.研究表明,基于3D激光扫描和树冠形貌等效的行道树风荷载模拟方法可准确模拟行道树风荷载特性,行道树顺风向阻力模拟值与试验值的误差在5%以内;树木破坏形态以弯曲破坏为主,且树木各级枝干初始破坏呈现出3级枝条、2级枝条、1级枝条和主干的顺序特征,但在风速较大时则出现主干或重要枝干破坏先于次要枝干的现象.本研究提出的树冠形貌等效的行道树风荷载模拟方法精确性良好,对城市行道树风致易损性分析以及城市绿化系统的防灾减灾规划具有重要指导意义.Accurate simulation of wind loads on street trees is a prerequisite for analyzing wind-induced failure modes and implementing reinforcement treatments.In order to precisely simulate the wind loads on street trees,we propose a numerical simulation method for wind loads on typical street trees based on the equivalent fusion of 3D laser scanning and tree crown morphology,and discuss the wind-induced failure modes of typical street trees.Firstly,the point cloud models of the Camellia and Jacaranda street trees are established through mobile 3D laser scanning,and the numerical analysis model of the street trees is constructed by applying the morphological equivalence principle for the crown part.Next,the reduction pattern of model size with different wind speeds in equivalent modeling method is explored.Finally,the wind vibration response characteristics and failure modes of the street tree model under different wind speeds are discussed.The results indicate that the wind load simulation method of street trees based on the 3D laser scanning and crown morphology equivalence can accurately simulate the wind load characteristics of street trees,with an error between the simulated and experimental values of downwind resistance of street trees less than 5%.The predominant damage pattern of trees is mainly bending deformation,and the initial damage of branches at all levels of trees presents the sequence characteristics of tertiary branch,secondary branch,primary branch and trunk.However,when the wind speed is high,the damage of trunk or important branches precedes that of secondary branches.The proposed method for simulating wind loads on street trees with equivalent crown morphology is accurate and has important guiding significance for analysis of wind-induced vulnerability of urban street trees and disaster prevention and mitigation planning of urban greenery systems.

关 键 词：结构工程 风荷载 行道树 形貌等效 有限元模拟 失效模式 风振响应 

分 类 号：TU312[建筑科学—结构工程]