摘要
为确定降雨入渗过程影响均质地基基质吸力演化的主导因素,首先基于BP神经网络建立饱和渗透系数、去饱和系数、储水能力、降雨强度和降雨历时5个影响因素与基质吸力分布改变量之间的非线性映射关系模型,并采用Levenberg-Marquardt算法进行神经网络训练,得到隐含层与输入层、输出层之间的连接权值。然后利用Olden方法处理神经网络的连接权值,获得各因素对基质吸力分布改变影响显著性的量化值表达式,建立了降雨入渗作用下地基基质吸力影响因素显著性分析的BP-Olden方法。最后以概化均质地基模型为研究对象进行算例分析,结果表明,地基基质吸力分布改变主要受土体去饱和系数和土体储水能力影响,降雨强度和降雨历时的影响显著性次之,土体饱和渗透系数的影响最小。研究成果为采用针对性地基土体性能改良措施来降低雨水入渗引起的不良影响提供了技术支持。
The paper aims to determine the dominant factors influencing matric suction of homogeneous foundation during rainfall infiltration.Based on BP neural network,we first established a nonlinear mapping relationship model between the five main factors(saturated permeability coefficient,desaturation coefficient,water storage capacity,rainfall intensity,rainfall duration)and the amount of change in matric suction distribution.Then we used the Levenberg-Marquardt algorithm to train the BP neural network to achieve the connection weights between the hidden layer and the input layer,and the connection weights between the hidden layer and the output layer.Next,we obtained the quantitative value expressions of the influence of various factors on the change of matrix suction distribution by processing the connection weights with the Olden method and established the BP-Olden method for analyzing the significance of the factors affecting matric suction of the foundation during rainfall infiltration.Finally,we took the generalized analysis model of homogeneous foundation as an example and designed 25 experimental schemes by combining the five main factors with the orthogonal experiment.The sensitivity of the influencing factors on the change of matric suction distribution of homogeneous foundation is investigated using the established BP-Olden method in this paper.The quantitative significant values of saturated permeability coefficient,desaturation coefficient,water storage capacity,rainfall intensity,and rainfall duration on matrix suction distribution were 4.24,46.83,24.27,12.39,and 12.27,respectively.The results show that the change of foundation matrix suction distribution mainly depends on the soil desaturation coefficient and soil water storage capacity,followed by the impact of rainfall intensity and rainfall duration.The soil saturation permeability coefficient has a minimal impact.The results of this work can provide technical support for the research of soil performance improvement to reduce the adverse effects of rainfall infiltration.
作者
秦卫星
胡惠仁
廖紫欣
李蕾
吴卫东
QIN Wei-xing;HU Hui-ren;LIAO Zi-xin;LI Lei;WU Wei-dong(School of Hydraulic Engineering,Changsha University of Science and Technology,Changsha 410114,China;Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province,Changsha 410114,China;Hunan Hydro&Power Design Institute,Changsha 410021,China;Department of Civil,Chemical&General Engineering,The University of Tennessee at Chattanooga,Chattanooga TN37403,USA)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2022年第1期103-108,共6页
Journal of Safety and Environment
基金
国家自然科学基金项目(51208062,51508039)
湖南省交通科技计划项目(201140)
2019年湖南省研究生科研创新项目(CX20190680)。
