车载测量系统教学试验设计

针对测绘学科从传统测绘到数字化测绘,再到信息化测绘的发展,分析了当前测绘教学模式中存在的一些不足,提出将车载测量系统新技术引入到本科生教学。分析了课堂进行车载测量系统学习的前沿性和可行性,并根据其原理进行课程和试验的模块化设计。结果表明,测绘新产品能够激发学生学习兴趣和创新能力,提高专业技能,符合测绘教育的现代化的要求。     

基于干密度指标的珊瑚砂吹填地基机场跑道沉降计算

珊瑚砂吹填地基中,只有其中细颗粒的珊瑚砂可进行常规室内压缩试验,将细颗粒珊瑚砂压缩试验成果应用到工程实践中不尽合理。通过室内大尺寸样品的压缩试验,获得珊瑚砂、珊瑚枝及珊瑚砂与珊瑚枝混合料的压力-干密度关系曲线和干密度-竖向应变关系曲线。利用关系曲线,结合现场试验得到的干密度,采用分层总和法计算珊瑚砂吹填地基需要虚铺的厚度和机场跑道总沉降量,为珊瑚砂吹填地基的沉降变形提供了一种新的计算方法。     

海洋环境要素的声光集成测量

本文介绍海洋环境要素的声光集成测量原理和测量方法。文中以作者主持的海洋８６３项目“声光悬浮沙粒径谱测量仪”为例,列举了声速、声衰减、悬浮泥沙粒径谱的测量结果。海洋声速、声衰减、温度、盐度、悬浮物等都是海水的重要参数。这些参数的测量,对海洋开发、海洋环保、海洋军事有重要的意义。     

A new project to monitor land subsidence in the northern Venice coastland (Italy)

The paper deals with the implementation of a levelling and Global Positioning System (GPS) network to control land subsidence in the coastal area north of the Venice Lagoon. About 480 km of levelling lines with 527 benchmarks, 45 of which suited for Differential GPS measurements, were established in 2004. A complete survey of the net was carried out in 2004 soon after its establishment. The 2004 records have been compared with previous scattered data obtained by the use of levelling surveys, DGPS and SAR interferometry. The results show a trend in land settlement that increases from the lagoon margin to the north and jeopardize the Venice coastland. Groundwater withdrawals for domestic, agricultural, and health spas uses, peat oxidation of reclaimed marshlands for farming, natural consolidation of the Holocene deposits, and tectonics of the pre-Quaternary basement are the causes of land subsidence in the study area. Since most of the area lies below the mean sea level and on account of the expected sea level rise due to global change, a detailed monitoring of land displacements in the near future will be of paramount importance to plan necessary works for coastland protection.     

洪水灾害风险管理广义熵智能分析的理论框架

基于洪水灾害风险管理的背景分析,提出用广义分布函数及其广义熵理论统一描述、物理解析洪水灾害风险管理系统的各种不确定性信息。基于洪水灾害风险形成机制和风险管理理论与水利科学、信息科学、智能科学综合集成途径,提出由洪水灾害孕灾环境和致灾因子危险性广义熵智能分析、承灾体易损性广义熵智能分析、承灾体灾情广义熵智能分析和风险决策广义熵智能分析组成的洪水灾害风险管理广义熵智能分析的初步理论框架及其主要研究内容,在其它灾害风险管理中具有一定的参考应用价值。     

网格环境的安全需求及解决方案初步分析

网格环境建构在现有的互连网络之上,涉及大量资源的共享与协商使用。而这些资源可能位于多个异构的、地理位置分布的计算机系统上,资源的类别也完全有可能干差万别。虚拟组织涵盖多个分布的个体和组织,允许用户和资源的动态加入和退出。网格环境的这种动态、异构特性引入了具有相当挑战性的网格安全课题。这里分析了网格环境面临的安全挑战以及网格开发工具包Globus Toolkits中GSI的一些关键技术和处理方案。     

地下水水质实时预报系统开发及应用——以下辽河平原为例

地下水数值模拟需要大量的监测数据作为支撑,数据的录入耗时耗力,存在出错的可能,且不能第一时间进行实时快速预报。采用VB语言编程技术,以识别和验证后的下辽河平原地下水流数值模型和地下水溶质运移数值模型为基础,重新编译后的MF2K和MT3DMS为内核计算程序,Microsoft SQL Server 2000为数据库,开发了模型与地下水实时监测系统的接口,集成建立了下辽河平原地下水水质实时预报模型,并开发了操作界面下的操作系统,实现了下辽河平原地下水水质的实时预报功能。该系统将地下水实时监控技术与地下水数值模拟技术结合,操作简便、时效性强、出错概率小,能够实时获取地下水水位、水质监测数据,对地下水流场和地下水溶质浓度场的演化进行快速预报。同时,本系统预留了更新接口,可根据逐步积累的地下水监测数据和系统计算数据进行进一步验证,不断提高系统预报的精度。     

煤、气一体化开采煤层气方法的探讨

我国煤层气资源量为31.46×1012m3,开发煤层气具有重要的意义。本文在系统地分析我国煤层气藏低压、低渗、低饱和及构造煤发育等主要特点的基础上,指出了阻碍我国煤层气开发的主要因素是煤储层的低渗透率,针对我国煤层气藏特点提出了充分利用采动影响区的应力场释放开发煤层气的煤、气一体化开发方案。     

An improved return‐map stress update algorithm for finite deformation analysis of general isotropic elastoplastic geomaterials

This paper develops a novel return mapping algorithm for the numerical integration of general isotropic finite strain elastoplastic constitutive models for geomaterials. The constitutive formulation is founded on multiplicative decomposition of the deformation gradient. The logarithmic strain measure as well as the exponential approximation of the plastic flow rule is utilized to restore the standard infinitesimal format return mapping algorithm. Central to the algorithm is the exploitation of a set of three mutually orthogonal unit base tensors for the representation of constitutive relations and the corresponding integration of the rate form of the constitutive equations. The base tensors constitute a local cylindrical coordinate system in the principal space, which allows to formulate the return mapping algorithm in the three‐dimensional space and reduce the dimension of the problem to be analyzed from six down to three. With the proposed approach, direct determination of the principal axes and the transformation procedure between the general space and the principal space, as required in traditional spectral decomposition, are avoided. Furthermore, the matrices that are involved in the inversion evaluation take simple forms, leading to extremely easy inverse computation. As a result, the consistent tangent operator can be streamlined into a form simpler and more compact than those by conventional integration methods. Following the formulation of the integration procedure, a numerical experiment is performed to assess the accuracy and efficiency of the proposed algorithm. Copyright © 2014 John Wiley & Sons, Ltd.     

利用原始观测数据计算隧道断面面积的方法

本文通过理论变换将断面区域转变为基于测量断面原始观测数据测角的平面直角坐标系中函数曲线在自变量取值范围内与坐标轴所夹的区域的方法,给出数值处理方法的推证及面积计算公式,并对常见的几种形状进行了验算,结果表明该方法可以替代坐标法计算光滑边界的不规则断面的面积,具有较好的实用性。同时,计算公式也比较适合计算机编程实现面积的自动计算。