盾构隧道环向开挖面破坏机制及剪胀效应研究

采用刚性滑块构建两种圆形隧道失稳环向开挖面破坏模式,利用编制的非线性规划程序求解隧道失稳环向开挖面支护力系数σ_T /c（σ_T为均布支护荷载,c为有效黏聚力）最优上限解及地层破坏模式,揭示地层参数对隧道稳定性的影响,提出简单实用的极限支护力简化公式。研究结果表明：不排水条件下,当隧道埋深比H/D（H为埋深,D为隧道直径）和重度系数γD/c（γ 为重度）较小时,破坏区域主要集中在隧道中上部,随着H/D和γD/c增大,滑移线起始位置沿着隧道轮廓逐渐向隧道底部扩展,破坏区域向水平方向扩展。排水条件下,地层破坏模式主要有3种。当内摩擦角ϕ 和γD/c较大时,随着剪胀系数的减小,极限支护力和地层破坏范围变化较大,甚至可能引起破坏模式的改变。针对不同深度提出的极限支护力简化公式可快速获得隧道环向开挖面极限支护力。     

深部大采高沿空留巷围岩结构沉降破坏与控制

为了解决深部沿空留巷围岩控制难题,选取邢东矿(埋深850 m)1126大采高工作面沿空留巷为研究对象。采用UDEC模拟分析关键块B不同下沉量围岩的响应特征。结果表明:1实体煤帮偏应力峰值和位置与关键块B下沉量呈线性关系增大且向深部转移;2实体煤帮深部变形对关键块B下沉量的响应较弱,愈靠近煤帮表面其敏感性越强,深浅部围岩位移有明显拐点;3顶板下沉量、帮变形量与关键块B下沉量呈正指数关系;4随关键块B下沉,实体煤帮的破坏形式经历了从不稳定三角块滑落→X共轭破坏→双X共轭破坏过程。认为:1巷旁采空区充填可有效限制关键块C下沉对块体B的带动作用;2钢管混凝土支架可适应关键块B的下沉特征,具有较强的抗压缩和弯曲特性;3高性能、高预紧力锚杆可更好地提高锚固体承载和抵御变形能力;4顶桁架锚索可以锚固在关键块B上,锚固基础稳固可靠;帮锚索可以穿越帮潜在滑移面,锚固在位移拐点内的锚固区内,限制帮结构性滑移。基于此提出了巷旁采空区充填+钢管混凝土支架+顶桁架、帮锚索+高强高预紧力锚杆联合控制方案;沿空留巷完成30 d后围岩趋于稳定,顶底板和两帮最大相对移近量分别为613 mm和374 mm,实现了深部大采高沿空留巷围岩的有效控制。     

智慧城市视角下城市洪涝模拟研究综述

智慧城市是城市发展的新兴模式。然而,近年来频发的城市洪涝给智慧城市的管理和发展带来了严峻的挑战。暴雨洪涝模拟是城市防洪减灾的关键技术之一,也是智慧城市风险应急管理中重要的决策支持依据。本文首先分析了智慧城市以及智慧水务的内涵,探讨了智慧城市发展和管理对于城市洪涝模拟新的需求;在此基础上梳理了智慧城市发展给城市洪涝模型带来的新的数据支撑;面向智慧城市应急管理决策,对比分析了3种现有的水文模型方法,认为在智慧城市大数据和技术的支持下,基于物理基础的分布式模型是未来城市洪涝模拟的主流发展方向。最后,探讨了建立城市洪涝模型的建模机制、尺度、基础数据库的建立、更新和管理、地表与地下管网模拟并重等关键问题,分析认为精细化、与RS和GIS技术融合、注重时空过程和智慧服务是智慧城市背景下城市洪涝模拟发展的必然趋势。     

地震应急辅助决策支持系统的设计与实现

地震发生之后需要立即对地震灾情做出初步评估,评估结果将为政府快速部署救灾资源和救援力量提供辅助决策支撑。由于我国国土面积广阔、地形地貌复杂多样,不同省份不同地区的经济状况和人口分布差异较大,因此目前的地震应急辅助决策支撑系统具有一定的地域局限性,可扩充性和针对性差。针对这一状况,该文采用成熟的三层式C/S架构,通过ArcSDE管理空间数据库,实现地震灾害评估模型库和微软Office接口与GIS无缝集成。通过在2013年4月宁洱的两次地震中的应用,证明系统能够仅仅通过输入地震三要素即可快速响应、将评估结果直接以word报告形式产出、准确判定应急响应等级,为政府提供有效的辅助决策支撑。     

基于支持向量机的作物叶绿素含量反演模型

针对现有研究在准确估算叶绿素含量方面的不足,该文运用粒子群优化算法和支持向量机构建叶片尺度作物叶绿素含量高光谱反演模型:利用PROSPECT模型模拟作物光谱,并运用所对应的叶绿素含量建立训练数据集,然后采用粒子群优化算法支持向量机学习训练数据集,最后建立实测叶片叶绿素含量估测模型。研究结果表明,粒子群优化算法和支持向量机构建的反演模型能准确预测作物的叶绿素含量,能够解决小样本作物采样点情况下叶绿素含量反演问题,可以作为作物叶绿素含量估测的参考方法。     

An experimental approach for selection/elimination in stream network generalization using support vector machines

Multi-representation databases (MRDB) are used in several Geographical Information System applications for different purposes. MRDB are mainly obtained through model and cartographic generalizations. The model generalization is essentially achieved with the selection/elimination process in which a decision must be made to include or exclude the object at the target level. In this study, support vector machines (SVM) was, for the first time, used for the selection/elimination process in stream network generalization. Within this context, the attributes to be used as input data in the SVM method were determined and weighted according to the associations determined in a chi-squared independence test. 1:100,000-scale (medium resolution) stream networks were derived from two 1:24,000-scale (high resolution) stream networks with different patterns in the United States Geological Survey National Hydrography Data-sets. The derived stream networks were quite similar to the 1:100,000-scale original stream networks in both qualitative and visual aspects.     

智慧城市空间信息基础设施支撑力评价体系研究

针对当前智慧城市规划、建设中对空间信息基础设施作用普遍认识不足的问题,深入分析了空间信息基础设施对于智慧城市建设、运营的重要支撑作用。通过空间信息服务体系分析并根据研究者近年来从事智慧城市规划建设的实践经验,提出从空间信息基础设施的服务能力、融合能力和协同能力等3个方面综合评价其支撑能力。在此基础上,建立综合评价指标体系,以便提升城市空间信息基础设施建设力度,完善智慧城市建设的评价指标体系。也为下一步开展定量分析和综合评价打下坚实基础。     

Application of a spatially explicit backcasting model: A case study of sustainable development in Salzburg,Austria

The high cost of land for housing within urban centres and the common desire to live within extensive residential areas in the green countryside have, in some cases, led to increasing residential development in the urban hinterland, often resulting in dispersed and sprawling development. In order to counteract such development this article seeks to provide a methodology for implementing strategies which aim is to achieve sustainable development in spatial planning. The proposed methodology, which is known as “backcasting”, aims to improve our ability to avoid undesirable future developments and to encourage those developments that are desirable. Backcasting has previously mostly been used within theoretical processes or frameworks. The backcasting exercise presented in this paper used a Python-based model to create often visionary future scenarios based on interviews with relevant experts, and then used these scenarios as input for a backwards running model. This model simulates a development that runs backwards in time, converging towards the present situation. The backcasting model presented herein has been applied to a case study in Salzburg, Austria.     

Coastal livelihood vulnerability to marine resource degradation: A review of the Indonesian national coastal and marine policy framework

In rapidly developing countries, where large sections of the population are highly dependent on marine resources, coastal livelihoods are vulnerable to sudden shocks and long-term change. National policy can attempt to mitigate this vulnerability within a multi-level framework by addressing the three aspects of vulnerability (exposure, sensitivity, adaptive capacity) through well-documented interventions. This article reviews the Indonesian policy framework for coastal and marine policy interventions that either directly or indirectly address different dimensions of coastal livelihood vulnerability. The findings show that the policy environment for addressing coastal livelihood vulnerability is heavily based on developing adaptive capacity and to a certain extent sensitivity without adequately addressing exposure, the initial cause of vulnerability. In addition, the complexities and inconsistencies within the Indonesian governmental structures, as well as more general issues of funding gaps and poor coordination, mean that policies created at national level rarely filter down to provide the intended benefits to coastal communities. It is recommended that practitioners and policymakers engage in a more cohesive and balanced approach to addressing livelihood vulnerability in coastal management by focusing more on the causes of the disease, exposure, rather than healing just the symptoms.     

From unjust uneconomic growth to sustainable fisheries in Newfoundland: The true costs of closing the inshore fishery for groundfish

Neoliberal economic and social policies during the last 65 years have placed a premium on continuous economic growth. Concern among ecological economists and other critics that economic growth results in loss of natural capital and ecosystem services led to introduction of the concept of “uneconomic growth,” defined as “growth of the macro economy that costs us more than it is worth” (Daly and Farley, Ecological economics principles and applications. Washington: Island Press; 2004). This paper proposes the concept of “unjust uneconomic growth” to pinpoint the additional costs of policies that promote uneconomic growth to the neglect of other considerations and uses the case of Newfoundland and Labrador fisheries policies since 1992 to document it. Newfoundland and Labrador fisheries experienced uneconomic growth in the 1980s leading to the collapse of ground fish stocks. The policies enacted since 1993 based on economic growth goals have failed to solve the ecological-social crisis and entailed additional costs to small-scale fisheries.