金地国际城钻孔扩底灌注桩设计与施工     

武长民  梁敏莲 《安徽地质》2006,16(4):301-304

介绍钻头设计思路,计算依据和制作技术要点。采用我公司自制的机械式扩底钻头进行扩底施工,可代替人工挖孔桩扩大头,收到了满意效果。  相似文献   

无人机低空飞行障碍物环境风险评估方法研究——以京津新城为例     

贺洪波  徐晨晨  叶虎平 《地理科学进展》2021,40(9):1503-1515

无人机应用日益广泛,但随着城市环境建设的不断推进,无人机在城市中安全运行的问题也日益突出,因此无人机低空障碍物环境风险评估成为无人机领域研究的关键问题之一。论文按照不同类型无人机及运行高度将低空空域划分为微型、轻型和小型无人机风险评估区域,在充分考虑无人机自身形状大小、运动约束以及障碍物约束等条件的基础上,提出一种近似点扩张算法,基于障碍物原始边界生成扩张边界,并将其作为低空飞行环境中高风险与低风险之间的风险过渡区。以京津新城为例,分别提取不同风险评估区内的障碍物要素,并基于风险评估技术生成面向微型、轻型和小型无人机多高度层的低空飞行障碍物环境风险地图,按其对无人机威胁程度分为高风险区、高风险过渡区、中风险区和低风险区。实验结果表明:研究区内微型、轻型、小型无人机风险评估区内的风险过渡区分别占10.9%、7.3%、9.0%,该方法可以在考虑无人机与障碍物相互影响的基础上,计算飞行区域内无人机潜在碰撞风险区域,实现对低空障碍物环境风险的科学有效评估,为不同机型的无人机在飞行区域内的可航行性提供科学参考。  相似文献   

水稻土中微量营养元素全量与有效态含量评价     

许伟  彭培好  刘应平  陈文德  管磊 《四川地质学报》2011,31(2):251-254

以简阳三岔镇土地整理区水稻土中B、Mn、Zn、Cu、Fe元素全量与有效态含量,有机质含量,pH值为数据源,对土壤微量营养元素有效态进行了分级评价,并结合有效态与全量、pH值、有机质含量的相关性进行分析,对研究区提出了养分管理建议。  相似文献   

论云南古镇美学价值在旅游开发中的运用   总被引：1，自引：0，他引：1  

杨丽君 《云南地理环境研究》2014,(2):48-51

通过回顾文献资料、实地走访调研等方法,对云南古镇的自然景观美和人文景观美进行分析研究.并以云南腾冲和顺古镇为代表,从水文地貌、生物气候、历史文化、民居建筑、民俗风情等方面对和顺古镇的自然景观和人文景观美进行深入剖析.在此基础上阐述云南古镇自然景观和人文景观的美学价值与旅游的关系,及其在旅游开发中的运用.  相似文献   

京郊农村社区宜居性评价研究——以延庆县大榆树镇为例     

郑圆圆  郭洁  黄大全 《福建地理》2014,(1):75-83

随着新农村建设的推进,农村社区宜居性研究越发重要。本研究基于马斯洛需求层次理论,构建农村社区主客观宜居性评价指标体系,通过对延庆县大榆树镇进行问卷调查,采用层次分析、多元回归等统计方法进行主客观宜居性及二者差异评价。研究结果表明:1)大榆树镇社区宜居性主客观总体评价一般且较一致,社区建设水平层次仍较低,主观满意度各村差异较大;2)自来水稳定性、污水排放处理等生理层面需求,以及治安状况所体现的安全层面需求与主观满意度关联性最强;3)年龄差异与宜居性满意度评价显著相关,老年人较关注生态环境、道路交通等生理层面需求,年轻人则更关注社交、尊重和自我实现层面需求。  相似文献   

Relationship between the Landslides Triggered by the Tongwei M7 1/2 Earthquake in 1718 AD and the Disappearance of Yongning Ancient Town     

XU Yueren  DU Peng  LI Wenqiao  TIAN Qinjian  CHEN Lize 《中国地震研究》2020,34(4):546-559

Although China''s historical earthquake documentation is relatively rich, it is not all based on scientific records. Therefore, the verification of the seismic information in historical records can effectively avoid exaggerating or underestimating the damage they produced. In this paper, we analyze the detailed information of the 1718 AD Tongwei M7 1/2 earthquake through field surveys, document sorting, and manual visual interpretation of UAV images. Major conclusions are listed as follows:①The low-level terraces of Weihe River between Gangu and Wushan are fully developed with flatted surface, and the residents here are mostly killed by house collapses. In addition, the disappearance of Yongning Ancient Town is not directly related to the earthquake-induced landslides; ② In fact, "Yongning Town is entirely buried by the earthquake" in the historical records describes the phenomenon that loess dust has pervaded the entire Weihe Valley. These dust grains are produced by the sliding of earthquake-induced landslides. Thus, there is no possibility that large-scale landslides have slipped over Weihe bedrock and buried Yongning Town; ③After the earthquake, survivors abandoned the ruins and selected a new site to live. They built a new town named "Pan''an (means always peaceful in the future)". earthquake-induced landslides may be the reason of burying the residential areas on valley-side slopes, while those locations inside the valley are associated with the amplification effect of ground vibration. On the basis of compiling historical seismic data, scientific methods are used to explore the real meaning of these documents, for the purpose of providing basic data for the risk evaluation of strong historical earthquakes.  相似文献   

乡镇中小学校舍抗震抗倒安居安学设防目标——汶川地震北川擂鼓镇中小学校舍震害原因探究   总被引：1，自引：1，他引：0  

孙柏涛  周强  杨玉成 《地震工程与工程振动》2011,31(2):1-10

汶川地震中,在10度区擂鼓镇调查到7幢校舍,6幢有不同程度的破坏,均裂而不倒,1幢局部倒塌,探究原因主要是抗震构造措施和抗震能力不同.实例表明,乡镇中小学教学楼采用构造柱圈梁抗震体系,单边外走廊的3层砖砌体房屋,平面布置合理的,可达到大震不倒的安居安学设防目标.本文将楼层综合抗震能力指数发展为抗倒能力指数,用以判别多层...  相似文献   

土地整理可持续发展评价研究   总被引：1，自引：0，他引：1  

郑志林 《现代测绘》2011,34(4):40-42

现阶段我国多数地区土地整理的目标主要是扩大耕地数量、补偿建设占用的耕地,并未进入以提高土地生产能力、改善生态环境为目标的可持续发展阶段。因此,在土地整理活动中融入"可持续发展"的理念是非常重要。本文以外屯土地整理项目为例,以期推动土地整理可持续发展评价的理论研究和实践工作。  相似文献   

Using neural networks and cellular automata for modelling intra‐urban land‐use dynamics     

C. M. Almeida  J. M. Gleriani  E. F. Castejon  B. S. Soares‐Filho 《International journal of geographical information science》2013,27(9):943-963

Empirical models designed to simulate and predict urban land‐use change in real situations are generally based on the utilization of statistical techniques to compute the land‐use change probabilities. In contrast to these methods, artificial neural networks arise as an alternative to assess such probabilities by means of non‐parametric approaches. This work introduces a simulation experiment on intra‐urban land‐use change in which a supervised back‐propagation neural network has been employed in the parameterization of several biophysical and infrastructure variables considered in the simulation model. The spatial land‐use transition probabilities estimated thereof feed a cellular automaton (CA) simulation model, based on stochastic transition rules. The model has been tested in a medium‐sized town in the Midwest of São Paulo State, Piracicaba. A series of simulation outputs for the case study town in the period 1985–1999 were generated, and statistical validation tests were then conducted for the best results, based on fuzzy similarity measures.  相似文献   

Spatial multi-objective land use optimization: extensions to the non-dominated sorting genetic algorithm-II     

Kai Cao  Michael Batty  Bo Huang  Yan Liu  Le Yu  Jiongfeng Chen 《International journal of geographical information science》2013,27(12):1949-1969

A spatial multi-objective land use optimization model defined by the acronym ‘NSGA-II-MOLU’ or the ‘non-dominated sorting genetic algorithm-II for multi-objective optimization of land use’ is proposed for searching for optimal land use scenarios which embrace multiple objectives and constraints extracted from the requirements of users, as well as providing support to the land use planning process. In this application, we took the MOLU model which was initially developed to integrate multiple objectives and coupled this with a revised version of the genetic algorithm NSGA-II which is based on specific crossover and mutation operators. The resulting NSGA-II-MOLU model is able to offer the possibility of efficiently searching over tens of thousands of solutions for trade-off sets which define non-dominated plans on the classical Pareto frontier. In this application, we chose the example of Tongzhou New Town, China, to demonstrate how the model could be employed to meet three conflicting objectives based on minimizing conversion costs, maximizing accessibility, and maximizing compatibilities between land uses. Our case study clearly shows the ability of the model to generate diversified land use planning scenarios which form the core of a land use planning support system. It also demonstrates the potential of the model to consider more complicated spatial objectives and variables with open-ended characteristics. The breakthroughs in spatial optimization that this model provides lead directly to other properties of the process in which further efficiencies in the process of optimization, more vivid visualizations, and more interactive planning support are possible. These form directions for future research.  相似文献