强震短期前兆异常特征物理分析和解释的研究进展

总结了“十五” 国家科技攻关项目强震短期前兆异常特征的物理分析和解释方面的研究成果, 并将主要进展归纳为4个方面, 即: 通过大量台网数据的扫描处理和震例研究, 分析了地电、 地形变、 地下流体强震短期前兆的典型特征; 提出了典型短期前兆特征依托的实验基础和理论依据, 进行了数值模拟和理论解释; 通过数值模拟方法, 探讨了短期地震活动性图像特征和强余震触发机理; 总结了大陆强地震的卫星热红外异常演化过程, 提出了活动断裂带内、 外温度和地表温度场提取的技术方法。     

水泥土搅拌桩的施工质量问题和解决方法

介绍了水泥土搅拌桩在我国的应用情况和可行性、危机性,指出了当前搅拌桩施工质量上存在的搅拌不均和桩身不连续问题,分析了出现质量问题的3方面原因：规范检测方法严重滞后;成桩工艺不合理;施工管理混乱,并针对性的提出了3大对策和9项工艺改进措施。     

数字制图中地图符号的标准化研究

随着地理信息技术和数字技术的发展,电子地图的制作日益简便,应用日益普及,数字化网络化传播日益广泛,故此,电子地图符号的规范化、标准化势在必行,以保证地理信息感知和认知的一致性和准确性。在传统纸张地图图式规范的基础上,本项研究参照国际类似的标准文本,电子地图符号体系和符号实体应当适应数字技术和视觉环境的变化,进行合理的改进,原则上继承纸张地图符号的内容分类体系和形状分类体系,延续长期以来形成的纸张地图阅读的地理信息传输与读者认同的惯性。在深入审视符号视觉变量及符号视屏显示的复杂特征之后,提出对基本符号实体内容适当简化、对符号色彩、图元组合关系适当调整的实验方案,在通用地理信息系统软件平台上制作了基本地理底图的符号库标准草案,通过相关地图项目进行了大量的效果对比试验,并多次征求同行意见进行了补充、修改和完善,并在“中国空间信息网”网站上发布。     

一种半无限土体中圆孔扩张的分析方法

在静压桩贯入问题的研究中,常用无限土体中圆孔扩张法来模拟桩端对土体的扩张。实际上,压桩问题属于半无限问题,必须考虑从无限问题转化到半无限问题后地面边界处应力的差异。针对半无限问题中地表应力的修正,在现有研究的基础上引入了应力函数解答来求解弹性条件下半无限问题,很好地修正了地表应力,得到了相应的解答。与原有的解答相比,提出的解答能够更好地反映半无限的特性,为进一步分析压桩问题奠定了基础。     

Data assimilation using the particle filter for identifying the elasto‐plastic material properties of geomaterials

A computational method, incorporating the finite element model (FEM) into data assimilation using the particle filter, is presented for identifying elasto‐plastic material properties based on sequential measurements under the known changing traction boundary conditions to overcome some difficulties in identifying the parameters for elasto‐plastic problems from which the existing inverse analysis strategies have suffered. A soil–water coupled problem, which uses the elasto‐plastic constitutive model, is dealt with as the geotechnical application. Measured data on the settlement and the pore pressure are obtained from a synthetic FEM computation as the forward problem under the known parameters to be identified for both the element tests and the ground behavior during the embankment construction sequence. Parameter identification for elasto‐plastic problems, such as soil behavior, should be made by considering the measurements of deformation and/or pore pressure step by step from the initial stage of construction and throughout the deformation history under the changing traction boundary conditions because of the embankment or the excavation because the ground behavior is highly dependent on the loading history. Thus, it appears that sequential data assimilation techniques, such as the particle filter, are the preferable tools that can provide estimates of the state variables, that is, deformation, pore pressure, and unknown parameters, for the constitutive model in geotechnical practice. The present paper discusses the priority of the particle filter in its application to initial/boundary value problems for elasto‐plastic materials and demonstrates a couple of numerical examples. Copyright © 2012 John Wiley & Sons, Ltd.     

Sinusoidal oscillations radiating from a cylindrical source in thermal conduction or groundwater flow: Closed‐form solutions

The diffusion equation governs thermal conduction and groundwater flow phenomena. In this paper, we study the two‐dimensional radial propagation of a sinusoidal perturbation radiating from a cylindrical source within an infinite slab of homogeneous material. The solution of this problem has several applications. For instance, it can be used to determine the hydraulic diffusivity of the subsurface based on measurements of the hydraulic head around a vertical well during its development. For thermal problems, it can be used to determine the thermal diffusivity based on measurements of the temperature distribution around a cylindrical heat source generating a sinusoidal power per unit length. In this paper, we present a comprehensive analytical solution of this problem and we compare these solutions with numerical solutions. Two approximate analytical solutions, which can be relevant in practice, are also presented. Finally, we give an upper bound for the survival time of the transient part of the solution and we provide an estimate of the radius of influence of the sinusoidal solicitation. Copyright © 2010 John Wiley & Sons, Ltd.     

Numerical analysis of a one‐dimensional infiltration problem in unsaturated soil by a seepage–deformation coupled method

A multiphase coupled elasto‐viscoplastic finite element analysis formulation, based on the theory of porous media, is used to describe the rainfall infiltration process into a one‐dimensional soil column. Using this framework, we have numerically analyzed the generation of pore water pressure and deformations when rainfall is applied to the soil. A parametric study, including rainfall intensity, soil–water characteristic curves, and permeability, is carried out to observe their influence on the changes in pore water pressure and volumetric strain. From the numerical results, it is shown that the generation of pore water pressure and volumetric strain is mainly controlled by material parameters α and n′ that describe the soil–water characteristic curve. A comparison with the laboratory results shows that the proposed method can describe very well the characteristics observed during the experiments of one‐dimensional water infiltration into a layered unsaturated soil column. Copyright © 2010 John Wiley & Sons, Ltd.     

青岛市崂山区宅基地用地现状与对策

以青岛市崂山区3个街道的农村宅基地用地调研为基础,介绍崂山区农村宅基地用地现状,指出当前存在的问题,提出先行解决一部分住房困难村民的宅基地问题、加快编制报批村庄系列规划、强化执法监察、加大土地法律法规的宣传教育力度、积极推进农村建设用地整理等对策和建议。     

基于Web Service的地图符号库的设计与实现

研究了C/S结构和B/S结构的特点,根据不同平台的客户端对地图操作的要求,提出了一种基于WebService的分布式框架结构,实现了不同客户端的跨平台互操作。根据面向对象的要求对符号库进行了图素和结构设计,建立了一种基于WebService的面向对象的读取符号库的框架结构。指出WebService是地图符号在多客户端可视化的最佳解决方案。