Application of micropolar plasticity to post failure analysis in geomechanics

A micropolar elastoplastic model for soils is formulated and a series of finite element analyses are employed to demonstrate the use of a micropolar continuum in overcoming the numerical difficulties encountered in application of finite element method in standard Cauchy–Boltzmann continuum. Three examples of failure analysis involving a deep excavation, shallow foundation, and a retaining wall are presented. In all these cases, it is observed that the length scale introduced in the polar continuum regularizes the incremental boundary value problem and allows the numerical simulation to be continued until a clear collapse mechanism is achieved. The issue of grain size effect is also discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

An explicit representation of steady state response of a beam on an elastic foundation to moving harmonic line loads

A closed‐form deflection response of a beam rest is presented in this paper using the integral transform method. The theory of linear partial differential equations is used to represent the deflection of beam subjected to a moving harmonic line load in integration form. The solution is finally carried out using the inverse Fourier transform. To evaluate the integration analytically, poles of the integrand are identified with the help of algebraic equation theory. Residue theorem is then utilized to represent the integration as a contour integral in the complex plane. Closed‐form deflections and numerical results are provided for different combinations of load frequency and velocity. Copyright © 2002 John Wiley & Sons, Ltd.     

Influence of large-diameter pipe pile driving on surrounding marine soils and adjacent submarine pipelines

Abstract

With the large-scale development and utilization of ocean resources and space, it is inevitable to encounter existing submarine facilities in pile driving areas, which necessitates a safety assessment. In this article, by referring to a wharf renovation project as a reference, the surrounding soil response and buried pipe deformation during pile driving in a near-shore submarine environment are investigated by three-dimensional (3D) numerical models that consider the pore water effect. Numerical studies are carried out in two different series: one is a case of a single pile focusing on the effect of the minimum plane distance of the pile–pipe, and the other is a case of double piles focusing on the effect of the pile spacing.     

Treatment of Hydrodynamic Loading for Random Sea State

- In order to employ cost effective frequency domain analysis for off-shore structures treatment of hydrodynamic loading is essential. Drag and inertia dominated, resonating and antiresonating cases under random sea states are analyzed to highlight the implications and relative merits of four salient linearization techniques.     

基于GIS地层剖面数据库和岩性柱状图符号库的创建

本文基于ArcGIS Deskto P9.2,建立了塔城盆地地层剖面的空间数据库,并利用ArcGIS系统本身的图形编辑功能,制作一套岩性符号库,用于实现岩性柱状图的填充,并将符号库中的每个岩性符号进行编码,通过岩性符号柱状图属性码与相应的岩性符号编码的匹配自动实现所有岩性柱状图的符号化表达。     

基于有限差分法的抗滑桩计算机辅助设计

基于地基系数“m-m”法、“m-k”法、“k-k”法的原理,考虑桩顶和桩底边界条件以及桩在滑动面处位移、转角、弯矩和剪力的连续条件,可解得桩身各节点的位移和内力,提出了进行抗滑桩全桩内力计算的有限差分法。根据差分方程并用VB6.0编制了实用的计算程序,既可避免繁琐的查表计算,提高计算速度,又可提高计算精度,直观生动,真正实现了人机交互,在界面的引导下,设计人员可完成全部计算,并绘出内力图形和抗滑桩截面配筋图,使设计更方便快捷,该软件可以极大地提高生产效率,降低工程造价,从而实现抗滑桩的优化设计。最后采用上述方法对某滑坡的悬臂抗滑桩进行了设计与计算。     

土屋铜矿上方覆盖层元素分布规律研究

通过对土屋铜矿上方覆盖层不同层位样品进行分析发现，成矿元素Cu在覆盖层底部靠近基岩的原地风化残积层和地表弱胶结层中富集，而在地衰弱胶结层中又倾向于向两“极”富集，即在最粗粒级和最细粒级含量较高．考虑到采样效率和成本等综合因素，在区域调查中，以采集弱胶结层（5～40cm）、细粒级样品（-160目）为最佳采样介质．     

胶莱盆地含金建造地球化学特征

胶莱盆地蓬家夼金矿床及宋家沟金矿床均赋存于下白垩统莱阳群一段含金建造中,该含金建造由砾岩、含砾砂岩、碳质泥岩及碳酸盐岩等组成,Au100.2～241.0ng/g,Ag1.50～3.73μg/g,Zn560～1021μg/g,Pb356～364μg/g,Cu60～394μg/g,As11.0～25.4μg/g,同时富硫及有机碳。含金建造K-Rb、K-Ba呈正相关,K-Sr、K-Ca不相关,Sr/Ba<1,B、V关系均显示了陆相淡水沉积特征。La/Y-REE组成显示了沉积特征。围岩、矿石及矿石中黄铁矿及磁铁矿的稀土元素分布模式相似,该含金建造是矿源层也是容矿层,是区内重要的成矿地质条件及找矿标志。     

资源环境与社会经济协调发展探析

文章首先回顾了资源环境与社会经济发展的理论，提出资源环境与社会经济协调发展内涵：一方面，要在资源环境承载力范围内发展社会经济，追求社会经济发展的最大化，另一方面，环境承载力是动态的，要依靠社会经济发展不断提高，这两个方面是相互作用、相互制约的。在此基础上，详细论述了资源环境与社会经济协调发展的内容,并从社会经济发展、资源环境管理等角度探讨了资源环境与社会经济协调发展的政策调控，通过建立节约型国民经济体系、深化资源环境管理，实现区域一体化，以保证资源环境与社会经济协调发展的实现。     

甘肃北山公婆泉盆地中生代地层特征与砂岩型铀成矿条件分析

根据野外实地考察，综合前人的工作资料，从地层结构、层位、沉积体系、岩性及形成砂岩型铀矿的条件出发，概括了公婆泉盆地中生代地层的主要特征；确定了目的层并浅要分析了砂岩型铀成矿条件，对下一步铀矿找矿工作具有一定的现实意义。