美、英国家研究计划揭示国际地球科学研究新动向     

张树良 《国际地震动态》2012,(5):1-5

近日,在美国最新国家研究计划“大数据计划”框架下,包括美国国家科学基金会、美国地质调查局和美国国家航空航天局在内的美国政府主要机构同时推出新的研究项目,并对现有研究部署做出相应调整,此举将带动包括地球科学在内的各领域研究的新发展;与此同时,英国地质调查局也公布了其地球科学新领域的最新研究进展.通过解读这些最新的研究计划,可以揭示出国际地球科学研究的新动向.  相似文献   

Newmark sliding block model for pile-reinforced slopes under earthquake loading     

《Soil Dynamics and Earthquake Engineering》2015

Recent studies have demonstrated that the use of a discretely-spaced row of piles can be effective in reducing the deformations of slopes in earthquakes. In this paper, an approximate strain-dependant Newmark sliding-block procedure for pile-reinforced slopes has been developed, for use in analysis and design of the piling scheme, and the model is validated against centrifuge test data. The interaction of the pile within the slipping soil was idealised using a non-linear elasto-plastic (P–y) model, while the interaction within the underlying stable soil was modelled using an elastic response model in which (degraded) soil stiffness is selected for an appropriate amount of shear strain. This combined soil–pile interaction model was incorporated into the improved Newmark methodology for unreinforced slopes presented by Al-defae et al. [1], so that the final method additionally incorporates strain-dependent geometric hardening (slope re-grading). When combined with the strain-dependent pile resistance, the method is therefore applicable to analysis of both the mainshock and subsequent aftershocks acting on the deformed slope. It was observed that the single pile resistance is mobilised rapidly at the start of a strong earthquake and that this and the permanent slope deformation are therefore strongly influenced by pile stiffness properties, pile spacing and the depth of the slip surface. The model shows good agreement with the centrifuge test data in terms of the prediction of permanent deformation at the crest of the slope (important in design for selecting an appropriate pile layout/spacing i.e. S/B) and in terms of the maximum permanent bending moments induced in the piles (important for appropriate structural detailing of the piles), so long as the slip surface depth can be accurately predicted. A method for doing this, based on limit analysis, is also presented and validated.  相似文献   

利用低空无人机摄影测量快速构建矿区线状地物信息   总被引：4，自引：2，他引：2  

张建勇  赵艳玲  肖武  陈永春  李文顺  田帅帅  王鑫 《测绘通报》2017,(10):106-110

矿区线状地物是矿山生产建设的重要部分,狭长的形态特征和有限的测量人力限制了监测工作。低空无人机摄影测量具有响应快、周期短、精度高、易操作、成本低的特点,而且获取数据内容丰富、可视性强,为矿区线状地物的快速监测提供了可能。本文选取典型高潜水位井工矿区的线状地物——以矿区专用铁路和防洪堤坝为例,设计3个相对航高（50、75、100 m）作业方案,快速构建矿区线状地物信息,评价模型结果的平面和高程精度,并检验了其可靠性,讨论了无人机摄影测量的时间与效率的权衡问题。研究表明,低空无人机摄影测量可快速获取矿区线状地物的厘米级地形信息,具有较高的平面与高程精度,平面精度可达1∶500比例尺地形图的要求,高程基本能满足1∶1000比例尺制图规范。植被覆盖对模型高程值的精度影响显著,模型内部的空间关系相对稳定可靠,经成本与效率的权衡后优选相对航高100 m为最优作业方案。矿区测绘可尝试低空无人机与传统测绘方法相结合的作业新模式,快速高效地获取监测结果。  相似文献   

On behavior of load transfer for drilled shafts embedded in weak rocks     

《Computers and Geotechnics》2017

This study deals with the formulation of an analytical solution for load transfer in drilled shaft and its application. The emphasis is on quantifying the mobilization of side resistances, which are closely related to shear behaviors of the concrete-rock interface. In this modelling, the side resistance is idealized by using elasticity-brittleness-plasticity, and a simple slip-line field is built to identify the critical shear displacement. The closed-form solution of load transfer is obtained by using the proposed shear model. Comparison between predictions and field observations is also made to validate performance of the proposed method.  相似文献   

Cone penetration test in sand: A numerical-analytical approach     

《Computers and Geotechnics》2017

Separation of the effects of initial horizontal stress and relative density on cone tip resistance in sandy soils has been a complicated issue for many years. In order to overcome this problem, a numerical modeling of CPT which has been verified by calibration chamber tests, has been used in this paper to achieve a reliable analytical solution. The analytical solution has resulted in two relationships for sleeve friction and cone tip resistance in terms of the initial conditions of sandy soil. Based on the presented solution, the initial horizontal stress and relative density can be determined according to CPT measurements.  相似文献   

沙漠地区页岩气地质调查井施工技术          下载免费PDF全文

尹亮先  李得新  田小林  谢治国 《探矿工程》2017,44(3):17-20

武威盆地儿马湖凹陷地质调查井武地1井钻井工程位于内蒙古自治区腾格里沙漠腹地,施工条件恶劣。上部第四系覆盖层主要岩性为黄色砂土和红色细砂,厚度大,松散易垮塌。针对武地1井钻井难点,从井场建设、钻井设备的选择、井身结构、钻井液优化等方面采取措施,为沙漠地区钻井施工积累了经验。  相似文献   

圆弧状多层沉积谷地在Rayleigh波入射下动力响应的解析解   总被引：1，自引：0，他引：1       下载免费PDF全文

张郁山 《地球物理学报》2010,53(9):2129-2143

利用波函数的Fourier-Bessel级数展开法,推导出了含任意多个圆弧状沉积层的谷地在Rayleigh波入射下二维稳态动力响应的解析解,分析了该级数形式解析解随截断项数的收敛问题,讨论了在获取该解析解的过程中,用于计算Rayleigh波自由场的有限Fourier级数的项数和用于模拟水平地表的大圆弧的半径对解的影响.研究结果表明,该解析解能够在一个非常宽的频带内收敛.最后,利用该解析解,在一个较宽的频带范围内,讨论了谷地中沉积介质的成层性,包括沉积层的层数、软弱夹层的存在及其厚度等因素对地面运动的影响.  相似文献   

ITRF��ܵ��໥ת��     

刘立  成英燕 《大地测量与地球动力学》2010,30(2):141-143

??IERS??????14??ITRF???????(7???????????7???????????????)??????ITRF??IGS????????????????IGS??????????????????????ж??????????????????????  相似文献   

地下工程施工监控地质地理信息系统研究   总被引：1，自引：0，他引：1  

曾立斌  黄牧  戎晓力 《岩土力学》2010,31(Z1):342-348

主要设计与实现了地下工程施工监控地质地理信息系统（MGGIS）。首先分析了系统特点、结构、具有的功能以及采用的平台和相关技术,定义了数据的获取和存储格式。然后在此基础上进行了3个功能独立的子系统的详细设计与实现,分别为工程计划显示子系统、平面时空效应子系统和断面图显示子系统。首次提出在RIA技术支持下,实现B/S架构下的工程地质地理信息系统;提出了反映随施工进度变化地下工程及环境空间信息的显示平台技术方案,充分反应了地下工程施工中空间信息具有时空效应的特点,适合地下工程安全风险管理的需要。该系统与同类型地理信息系统平台相比具有使用简单、交互性强、速度快等优点,研究成果已经在北京轨道交通工程安全风险监控系统和南京地铁工程安全风险监控系统等相关项目中得以应用。  相似文献   

Back to the Future? Planning for environmental outcomes and the new Caring for our Country program     

T.H. Morrison  C. McAlpine  J.R. Rhodes  A. Peterson  P. Schmidt 《The Australian geographer》2010,41(4):521-538

The Australian government Caring for our Country (CfoC) program, first announced in 2008, has sought to build on and enhance previous experience with Australian natural resource management policy. This paper critically examines the initial design, planned delivery, and first round of competitive funding outcomes of the new program. This analysis shows that the initial design and delivery of the CfoC model was ad hoc, politicised, and lacking in transparency. The paper concludes that a more systematic and transparent approach for achieving sustainable environmental outcomes is required in order for this new program to achieve its intended objectives. These implications are of interest to Australian and international geographers, natural resource planners, scientists and policy makers concerned with the design, delivery and outcomes of large natural resource and environmental management programs.  相似文献