基于KANQ GIS的城镇地籍管理信息系统的应用

城镇地籍管理信息系统采用先进的图像处理技术、数据库技术、网络技术、GIS技术,建设准确、动态、高效、安全的共享型地籍信息数据库,从而实现空间数据共享.文章就基于KANQ GIS的城镇地籍管理信息系统在城镇地籍调查中的应用作简单介绍.     

MapGIS二次开发解决二调中权属拐点移动的问题

介绍了以MapGIS-SDK6.7为平台,用VB6.0进行二次开发出更适合二调数据库建设的权属拐点移动功能,弥补了二调软件在数据库建设过程中的不足.     

Diffuse and localized failure modes: Two competing mechanisms

The concept of failure is one of the most debated in soil mechanics, for two reasons essentially. First, this is a crucial issue in the engineering of structures and geotechnical project design. Second, this is still a challenging academic issue mobilizing significant scientific interest in the development of a unique framework to describe the different failure modes. In this respect, this paper revisits the localized failure mode, replacing the well‐known Rice criterion within the wider context of bifurcation. Considering a micro‐mechanical model, the main theoretical results are covered. In particular, it is established that localized failure is a particular case of failures observed within the so‐called bifurcation domain: the incremental strain within the localization band is associated with a vanishing value of the second‐order work. Copyright © 2010 John Wiley & Sons, Ltd.     

江西九瑞坳下一丁家山地质特征及找矿前景分析

简要介绍了九瑞成矿带区域地质背景,系统阐述了坳下一丁家山一带地层分布、构造及岩浆岩分带等地质特征,从地层、岩体及其含矿性、断裂系统、蚀变与矿化等方面对该区找矿前景进行了重点分析。发现该带深部产出的奥陶系灰岩及其与志留系砂页岩层间的岩性差异面,与武山、城门山矿区的黄龙组灰岩及其与五通组砂岩岩性差异面极其类似,应是九瑞地区...     

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深埋海底隧洞内水压力下饱和土的动力特性

将衬砌分别视为多孔柔性材料和弹性介质,在频率域内研究内水压力作用下饱和分数导数黏弹性土-深埋圆形隧洞多孔柔性或弹性衬砌系统的耦合简谐振动。土体的宏观力学特性采用多孔介质理论来模拟。通过引入与土体体积分数相关的应力系数,利用衬砌和土体界面处位移连续,分别得到饱和黏弹性土和衬砌的位移、应力和孔隙水压力等的解析表达式。在此基础上,分析了多孔柔性衬砌和弹性衬砌结构的差异,并考察了应力系数、渗透系数、分数阶导数本构参数等对系统动力响应的影响,结果表明:多孔柔性衬砌材料条件下系统的动力响应明显大于弹性衬砌材料条件下系统的动力响应;随着分数导数阶数和材料参数比的增加,系统共振效应明显减弱;衬砌边界透水和不透水只是反映边界渗透性的两种极限状态。     

Sensitivity of the Parameterizations of Vertical Mixing and Radiative Heat Fluxes on the Seasonal Evolution of the Thermal Structure of Lake Erie

A sensitivity analysis of the parameterizations of vertical mixing and radiative fluxes on the seasonal evolution of Lake Erie's thermal structure is performed using the Massachusetts Institute of Technology general circulation model (MITgcm) and the General Estuarine Transport Model (GETM). The models have the same horizontal resolution and are forced with observed meteorological data from April to October of 2002 and 2008. For turbid waters like Lake Erie, the three-band model for the parameterization of downward shortwave radiation produces more accurate temperatures in the thermocline and less error in simulating the mixed-layer depths than the widely used two-band model. Although the two models differ in vertical and horizontal mixing, numerical methods, and vertical discretization, they produced qualitatively comparable results. Comparison with observations shows that the models can reproduce the time evolution of the lake temperature reasonably well. The MITgcm and the GETM with the Mellor-Yamada level 2.5 (MY2.5) closure produce a deeper mixed layer than observed at a station located in the eastern basin, causing large errors in simulating the temperature in the thermocline while the GETM, using a turbulence scheme called “gen,” reproduces a mixed layer in better agreement with observations. The mixed-layer obtained with the k-ε closure is between those obtained with gen and MY2.5. The error in simulating the mixed-layer depths and the thermocline temperature at a station located in the central basin using the gen closure and the GETM was about 2°C lower than that obtained by the K-Profile Parameterization mixing scheme of the MITgcm. The models simulated a lake-wide anticyclonic circulation occupying the southwest part of the central basin but showed distinct differences in simulating gyres in the northwestern part of the central basin and in the eastern basin of the lake. The signature of a basin-scale Poincaré wave observed in the current data is also well represented by the two models.     

精密三角高程测量技术在高海拔山区的应用

介绍了精密三角高程测量技术的原理和方法,分析了高海拔山区大气折光对三角高程测量的影响,并结合高海拔山区实际情况提出了相应的解决方案。根据在高海拔山区的作业经验制定了最佳作业时段,结合测量仪器参数和相关数学模型,从定量角度分析和阐述了温度气压对精密三角高程测量的影响,并提出了具体的解决方法,通过实践工程数据分析,验证了精密三角高程测量代替二等水准测量在高海拔山区应用的可行性。     

土地变更调查现状及其问题与对策

为准确掌握土地利用变化情况,保持第二次全国土地调查成果的现势性,每年底需进行年度土地变更调查工作,更新土地调查数据库。近年来,各类标准的更新,3S技术的广泛应用,使土地变更调查的操作更趋数字化、成果更趋多元化,迅速变革的同时也暴露出问题的存在。本文结合宁夏2011年土地变更调查工作,介绍了土地变更调查的工作流程及其关键环节,阐述了土地变更调查的发展历程和“二调”后土地变更调查的新变化,在分析土地变更调查存在问题的基础上提出相应对策建议,为今后土地变更调查工作的开展提供借鉴。     

Analytical approach for circular-jointed shield tunnel lining based on the state space method

This paper presents a new analytical solution to the circular segmental tunnel lining subjected to overburden and surrounding earth pressures. The governing equations are derived by adopting the curved Euler beam theory and the principle of minimum potential energy. Based on the state space method, the displacements and the relevant energy-conjugated internal forces are treated as the fundamental unknown state vector and can be obtained by solving the state function. The inter-segment joints on the lining are modeled by a set of linear springs, including shear, compression, and rotation. The presented method allows for the arbitrary distribution of the segmented joints and loads along the circumferential direction. The most striking advantages of the proposed method include the rigid body displacement treatment, lining-displacement-dependent soil reaction, and internal force direction dependency of the joint stiffness. Using this method, the displacements and internal forces of the entire lining can be obtained conveniently and simultaneously under the arbitrary loading and joint distribution conditions. The verification of the analytical solutions is provided by several examples.