考虑岩土参数随机性的三维沉积盆地地震动高效模拟方法  

Evaluation method for stochasticity in seismic response of 3D sedimentary basins based on artificial neural network

作　　者：刘中宪[1] 孟思博 李文轩 赵嘉玮 黄振恩 LIU Zhongxian;MENG Sibo;LI Wenxuan;ZHAO Jiawei;HUANG Zhenen(Tianjin Key Laboratory of Soft Soil Characteristics and Engineering Environment,Tianjin Chengjian University,Tianjin 300384,China;Tianjin Key Laboratory of Structural Protection and Reinforcement,Tianjin Chengjian University,Tianjin 300384,China;School of Civil Engineering,Tianjin Chengjian University,Tianjin 300384,China;School of Architectural Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津城建大学天津市软土特性与工程环境重点实验室,天津300384 [2]天津城建大学天津市土木建筑结构防护与加固重点实验室,天津300384 [3]天津城建大学土木工程学院,天津300384 [4]天津大学建筑工程学院,天津300072

出　　处：《岩土工程学报》2024年第3期529-538,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(U2139208,52208497);天津市科技计划项目(19YFZCSN01180);天津市项目加团队(2020)共同资助项目。

摘　　要：沉积盆地对地震波的散射导致盆地放大效应,增大结构震害。盆地的岩土参数通常具有显著的随机特征,导致盆地响应的可变性。旨在基于快速多极边界元法(FM-IBEM)和人工神经网络(ANN),提出一种考虑岩土参数不确定性的三维沉积盆地地震动有效模拟方法。首先,以岩土参数、入射波频率和地表位置为输入参数,以三维沉积盆地响应为输出参数,建立了人工神经网络模型。其次,利用蒙特卡罗模拟(MCS)来评估沉积盆地地面运动的随机性,并使用ANN模型和数据集中现有的结果来代替数值模拟来求解样本,通过减少计算时间来提高随机问题的计算效率。结果表明,该方法可用于求解和评估考虑岩土参数随机性的三维沉积盆地地震响应,计算效率高。岩土参数的随机性对沉积盆地地震响应的影响不容忽视,沉积盆地地表响应的可变性与地表点的位置、入射频率和分布有关,表现出与均值分布非线性相关的特征。岩土参数的随机性对高频入射波作用下盆地地震动有显著影响,放大效应变异系数可达0.3,是岩土参数变异系数的3倍;与平均值相比,对应于95%置信水平的盆地峰值加速度增加了56%。The scattering of seismic waves by sedimentary basins leads to basin amplification effects and increases earthquake damage of structures.The geotechnical parameters of the basins generally have significantly stochastic characteristics,resulting in the variability of the basin response.This study aims to propose an efficient simulation method for ground motions of 3D sedimentary basins considering geotechnical uncertainty based on the fast multipole boundary element method(FM-IBEM)and artificial neural network(ANN).Firstly,an ANN model is constructed with geotechnical parameters,incident wave frequency and surface location as the input parameters and 3D sedimentary basin response as the output parameter.Secondly,a Monte Carlo simulation is utilized to evaluate the randomness of ground motions in sedimentary basins,and the ANN model and the existing results in the dataset are used instead of numerical simulations for sample solutions,which improves the computational efficiency of stochastic problems by reducing the computational time.The results indicate that the proposed method can be used to solve and evaluate the seismic response of 3D sedimentary basins considering the randomness of geotechnical parameters with high computational efficiency.The influences of randomness of geotechnical parameters on the seismic response of sedimentary basins are not negligible,and the variability of surface response of sedimentary basins is related to the location of surface points,incident frequency and distribution.It shows non-linear correlation characteristics with mean value distribution.The randomness of geotechnical parameters has a significant effect on ground motions of the basin under high-frequency incident waves.The coefficient of variation of the amplification effects can reach 0.3,which is three times the coefficient of variation of geotechnical parameters.The peak acceleration of the basin corresponding to 95%of confidence level increases by 56%compared to the mean value.

关 键 词：盆地效应 人工神经网络 岩土参数随机性 快速多极边界元法 

分 类 号：TU43[建筑科学—岩土工程]