基于FLAC3D和BP神经网络的边坡抗剪强度参数反演分析  

Back-analysis of Slope Shear Strength Parameters Based on FLAC3D and BP Neural Network

作　　者：周鑫磊 张卫兵[1,2] 顾小军 ZHOU Xin-lei;ZHANG Wei-bing;GU Xiao-jun(College of Civil and Hydraulic Engineering,Ningxia University,Yinchuan 750021,China;Engineering Research Center for Efficient Utilization of Water Resources in Modern Agriculture in Arid Regions,Yinchuan 750021,China;Ningxia Highway Survey and Design Institute Co.Ltd.,Yinchuan 750004,China)

机构地区：[1]宁夏大学土木与水利工程学院,银川市750021 [2]旱区现代农业水资源高效利用教育部工程研究中心,银川市750021 [3]宁夏公路勘察设计院有限责任公司,银川市750004

出　　处：《公路》2023年第9期26-34,共9页Highway

基　　金：宁夏回族自治区自然科学基金项目,项目编号2021AAC03067。

摘　　要：针对静态强度参数无法反映不同位移下动态衰减过程的问题,提出利用位移直接判断安全系数大小的方法。通过定期监测实际边坡位移,建立FLAC3D三维边坡模型计算获得样本数据,同时建立BP神经网络反分析模型,经样本数据训练后反演得到变化位移下抗剪强度参数,然后基于反演的参数计算了边坡安全系数,同时拟合得到了安全系数与位移间的定量函数关系,从而实现了边坡动态稳定性分析。结果表明:(1)位移与抗剪强度参数之间具有较高的关联性,尤其是内摩擦角对位移变化的敏感性较高;(2)通过FLAC3D模拟了滑坡形成过程中滑面不同位置位移变化,依此确定边坡破坏模式为滑移-拉裂型;(3)通过反演直观呈现了抗剪强度的衰减和安全系数的降低过程,基于动态安全系数与监测位移拟合所得的理论公式可较为准确反映不同位移下边坡安全系数的大小,具有一定的工程适用性。Since the static strength parameters cannot reflect the dynamic attenuation process under different displacements,displacement is directly used to judge the range of safety factor.Through regular monitoring of the actual slope displacement,FLAC3D slope model is established to calculate the sample data,and BP neural network is established to reverse the shear strength parameters under the variable displacement after sample data training.Then the slope safety factor is calculated based on the inversion parameters,and the quantitative functional relationship between the safety factor and displacement is obtained by fitting so as to realize the dynamic stability analysis of the slope.The results show that(1)there is a high correlation between displacement and shear strength parameters,especially the sensitivity of internal friction angle to displacement is high;(2)The displacement changes of the sliding surface at different positions during the formation of landslide are simulated by FLAC3D,according to which the slope failure mode is determined to be slip-tension crack type.(3)The attenuation of shear strength and the reduction of safety factor are intuitively presented through inversion.The theoretical formula based on the fitting of dynamic safety factor and monitored displacement in this paper can accurately reflect the size of slope safety factor under different displacement and has certain engineering application.

关 键 词：公路边坡 位移反分析 动态抗剪强度参数 安全系数 FLAC3D BP神经网络 

分 类 号：U416.14[交通运输工程—道路与铁道工程] TU432[建筑科学—岩土工程]