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Layer-element analysis of multilayered saturated soils subject to axisymmetric vertical time-harmonic excitation

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Applied Mathematics and Mechanics(English Edition) 2017年第9期38卷 1295-1312页

作者： zhiyong ai Lihua WANG Department of Geotechnical Engineering Key Laboratory of Geotechnical and Underground Engineering of Ministry of EducationCollege of Civil EngineeringTongji UniversityShanghai 200092China

The analytical layer-elements for a single poroelastic soil layer and the underlying half-space are established using an algebraic manipulation and Hankel trans- form. According to the boundary conditions and adjacent continuity conditions of general stresses and displacements, a global matrix equation in the transform domain for multi- layered saturated soil media is assembled and solved. Solutions in the frequency domain can be further obtained with an inverse Hankel transform. Numerical examples are used to examine accuracy of the present method and demonstrate effects of soil parameters and load conditions on dynamic responses of the multilayered poroelastic saturated soils.

关键词： multilayered saturated soil axisymmetric vertical excitation steady statedynamic response analytical layer-element method

A new method for solving Biot's consolidation of a finite soil layer in the cylindrical coordinate system

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Acta Mechanica Sinica 2008年第6期24卷 691-697页

作者： zhiyong ai Quansheng Wang Chao Wu Department of Geotechnical Engineering Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji University 200092 Shanghai China

A new method is developed to solve Biot＇s consolidation of a finite soil layer in the cylindrical coordinate system. Based on the governing equations of Biot＇s consolidation and the technique of Laplace transform, Fourier expansions and Hankel transform with respect to time t, coordinate θ and coordinate r, respectively, a relationship of displacements, stresses, excess pore water pressure and flux is established between the ground surface （z = 0） and an arbitrary depth z in the Laplace and Hankel transform domain. By referring to proper boundary conditions of the finite soil layer, the solutions for displacements, stresses, excess pore water pressure and flux of any point in the transform domain can be obtained. The actual solutions in the physical domain can be acquired by inverting the Laplace and the Hankel transforms.

关键词： Biot's consolidation A finite soil layer Laplace transform Fourier expansions Hankel transform

Uncoupled state space solution to layered poroelastic medium with anisotropic permeability and compressible pore fluid

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Frontiers of Structural and Civil Engineering 2011年第2期5卷 171-179页

作者： zhiyong ai Wenze ZENG Yichong CHENG Chao WU Department of Geotechnical Engineering Key Laboratory of Geotechnical and Underground Engineering of Ministry of EducationTongji UniversityShanghai 200092China

This paper presents an uncoupled state space solution to three-dimensional consolidation of layered poroelastic medium with anisotropic permeability and compressible pore *** from the basic equations of poroelastic medium,and introducing intermediate variables,the state space equation usually comprising eight coupled state vectors is uncoupled into two sets of equations of six and two state vectors in the Laplace-Fourier transform *** with the continuity conditions between adjacent layers and boundary conditions,the uncoupled state space solution of a layered poroelastic medium is obtained by using the transfer matrix *** results show that the anisotropy of permeability and the compressibility of pore fluid have remarkable influence on the consolidation behavior of poroelastic medium.

关键词： uncoupled state space solution layered poroelastic medium three-dimensional consolidation anisotropic permeability compressible pore fluid

Effect of Chromium Micro-alloying on the Corrosion Behavior of a Low-carbon Steel Rebar in Simulated Concrete Pore Solutions

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Journal of Wuhan University of Technology(Materials Science) 2017年第6期32卷 1453-1463页

作者：宋丹蒋金洋孙伟 MA Han ZHANG Jianchun CHENG Zhaojun JIANG Jinghua ai zhiyong School of Materials Science and Engineering Southeast University Nantong Ocean and Coastal Engineering Research Institute Hohai University College of Mechanics and Materials Hohai University Suqian Research Institue Hohai University Jiangsu Shagang Group Co. Ltd

A new low-cost corrosion-resistant rebar（HRB400 R） was designed and fabricated by chromium micro-alloying. The effects of Cr on the passivation and corrosion behavior of this rebar in the simulated concrete pore solutions were studied systematically, and its improved corrosion resistance was revealed. In the Cl--free saturated Ca（OH）_2 solution, the HRB400 R rebar presented nearly the same passive film and similar passivation ability compared to the common carbon steel rebar. In the long-term immersion corrosion test in the Cl--contained Ca（OH）_2 solution, the HRB400 R rebar presented improved corrosion resistance and obvious longer passivation-maintaining period. Micro-alloying of Cr element in the rebar matrix enhanced its corrosion resistance against Cl--attack and retarded the corrosion initiation in the matrix. In the alkaline Na Cl salt spraying test, the HRB400 R rebar also presented obviously lower mass-loss rate. The enrichment of Cr element in the rust layer improved its retardant effect to the penetration of aggressive medium, and decreased the corrosion propagation rate of the rebar.

关键词： Cr micro-alloying corrosion-resistant rebar improved corrosion resistance simulatedconcrete pore solutions

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深基坑多层水平支撑温度应力的简化计算方法

同济大学学报（自然科学版） 2011年第2期39卷 199-203页

作者：艾智勇苏辉同济大学地下建筑与工程系上海200092 同济大学岩土及地下工程教育部重点实验室上海200092

假设墙后土体服从Winkler地基模型,地下连续墙变形采用一端固定、多点支承的矩形板模型,同时假定温度变化引起围护体变形较小并在竖向呈线性分布,在考虑支撑—连续墙—土协调变形的基础上,建立了深基坑中多层水平支撑温度应力的一个简... 详细信息

假设墙后土体服从Winkler地基模型,地下连续墙变形采用一端固定、多点支承的矩形板模型,同时假定温度变化引起围护体变形较小并在竖向呈线性分布,在考虑支撑—连续墙—土协调变形的基础上,建立了深基坑中多层水平支撑温度应力的一个简化计算方法.编制了计算程序,探讨了连续墙厚度对支撑温度应力的影响,并将计算结果与实测数据进行了对比,结果表明:墙体厚度越厚,支撑温度应力越大,温度变化对支撑轴力具有较显著的影响.

关键词：深基坑多层水平支撑连续墙 Winkler地基温度应力

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层状地基与弹性薄板相互作用的边界元解

湖南大学学报（自然科学版） 2017年第3期44卷 120-125页

作者：艾智勇蔡建邦同济大学地下建筑与工程系上海200092 同济大学岩土及地下工程教育部重点实验室上海200092

将无限大薄板的基本解作为薄板边界积分方程的核函数,对薄板的内部和边界进行离散,并假定薄板内部和边界上的节点与地基反力的分布情况,得到薄板的边界元方程组;同时基于层状地基的解析层元解,通过Guass-Legendre积分得到地基柔度矩阵;... 详细信息

将无限大薄板的基本解作为薄板边界积分方程的核函数,对薄板的内部和边界进行离散,并假定薄板内部和边界上的节点与地基反力的分布情况,得到薄板的边界元方程组;同时基于层状地基的解析层元解,通过Guass-Legendre积分得到地基柔度矩阵;结合地基与薄板接触面上的位移协调条件,得到层状地基与薄板共同作用问题总的边界元法方程组;求解该方程组,得到层状地基与薄板共同作用问题的解答.基于本文理论,编制了相应的FORTRAN程序,通过与已有文献结果对比验证本文理论及程序的正确性,数值分析结果表明:方形基础薄板情况下,离板中心越近,垂直于坐标轴y(x)方向、距离相等的2条线段的竖向位移差越小,且该位移差随着板-土刚度比减小而减小;随着板长宽比的增大,板中心点与长边中点位移差变化不明显,而短边中心与边界角点的位移差也有相类似的规律.

关键词：边界元层状地基薄板解析层元

层状地基三维Biot固结问题的一个解耦解法

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东南大学学报（自然科学版） 2008年第5期38卷 816-820页

作者：艾智勇成志勇吴超同济大学岩土及地下工程教育部重点实验室上海200092

通过引入位移函数和中间变量,并对时间t进行Laplace变换,对坐标x,y进行双重Fou-rier变换,将直角坐标系下通常包含8个相互耦合状态量的三维Biot固结方程解耦成一组包含6个状态量和一组包含2个状态量的2组方程;进而获得了单层地基三维Bio... 详细信息

通过引入位移函数和中间变量,并对时间t进行Laplace变换,对坐标x,y进行双重Fou-rier变换,将直角坐标系下通常包含8个相互耦合状态量的三维Biot固结方程解耦成一组包含6个状态量和一组包含2个状态量的2组方程;进而获得了单层地基三维Biot固结问题的传递矩阵;结合边界条件和连续条件,应用传递矩阵法得到层状地基三维Biot固结问题在Laplace-Fou-rier变换域内的解,通过进行Laplace-Fourier逆变换得到了该问题物理域的真实解.编制了计算程序,并进行了计算与分析,验证了解的正确性.

关键词： Biot固结位移函数传递矩阵 Laplace—Fourier变换解耦解法

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层状地基上梁的边界元边界元耦合解法

同济大学学报（自然科学版） 2016年第10期44卷 1513-1516页

作者：艾智勇蔡建邦同济大学土木工程学院上海200092 同济大学岩土及地下工程教育部重点实验室上海200092

分别对地基接触面和梁进行离散,假定地基反力的分布情况,并确定梁单元节点和反力未知量;将无限长EulerBernoulli梁的基本解作为梁边界单元法的核函数,然后把Euler-Bernoulli梁边界积分方程应用到各节点,建立起基础梁的边界积分方程组;... 详细信息

分别对地基接触面和梁进行离散,假定地基反力的分布情况,并确定梁单元节点和反力未知量;将无限长EulerBernoulli梁的基本解作为梁边界单元法的核函数,然后把Euler-Bernoulli梁边界积分方程应用到各节点,建立起基础梁的边界积分方程组;将层状地基的基本解作为地基边界积分方程的核函数,通过边界积分方程建立起梁各节点竖向位移与地基反力未知量的沉降-反力柔度矩阵;最后,根据地基与梁接触面的位移协调条件,建立起层状地基与EulerBernoulli梁共同作用问题总的边界元-边界元耦合方程组.根据该理论,编制了相应的程序,通过与现有文献对比验证该理论的正确性,并分析了分层地基特性对基础梁的影响.研究结果表明:相比有限元-边界元耦合法,边界元-边界元耦合法的效率更高.

关键词：层状地基 Euler-Bernoulli梁边界元-边界元耦合法

层状横观各向同性地基性质对刚性条基摇摆振动的影响

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振动与冲击 2017年第8期36卷 55-59页

作者：艾智勇任广鹏同济大学地下建筑与工程系上海200092 同济大学岩土及地下工程教育部重点实验室上海200092

分析了土体的横观各向同性及层状性质对刚性条形基础摇摆振动的影响。首先利用解析层元法得出层状横观各向同性地基的总刚度矩阵。再根据刚性条形基础与地基相互作用的混合边值条件,建立了一组对偶积分方程,并借助Jacobi正交多项式求解... 详细信息

分析了土体的横观各向同性及层状性质对刚性条形基础摇摆振动的影响。首先利用解析层元法得出层状横观各向同性地基的总刚度矩阵。再根据刚性条形基础与地基相互作用的混合边值条件,建立了一组对偶积分方程,并借助Jacobi正交多项式求解了该对偶积分方程,从而得到地基动力柔度系数。计算结果与已有文献的结果吻合较好。同时,算例结果表明:土的水平向与竖向弹性模量比的减小、竖向的剪切模量与弹性模量比的增大,以及水平向泊松比与竖向泊松比比值的增大,都将导致地基动力柔度系数增大;而且,层状地基中上层土的弹性模量的减小使得地基动力柔度系数也增大。

关键词：摇摆振动层状地基横观各向同性对偶积分方程