基于随机有限元法的溶蚀坝基系统建坝适应性评价     

张社荣  严磊  王超  孙博  撒文奇 《岩土力学》2012,33(2):597-603

依托溶蚀地基上建坝的典型工程问题,在研究坝基溶蚀空间展布特征的基础上,建立溶蚀带力学参数随机场模型,采用随机有限元方法研究坝体工作性态的统计特性,评价了溶蚀坝基建坝适应性。采用溶蚀带力学参数随机场模型,等效模拟了空间内溶蚀体的无序分布系统,排除地质统计中线溶蚀率的人为假定,避免了以往确定性分析模型中溶蚀体缺失现象。研究方法和成果亦可以为其他相似复杂地基工程的数值分析提供新的思路和参考。  相似文献   

一种基于最短优先的最短路径算法的实现     

萨贤春  辛赟  陈宪东  杨超 《测绘通报》2015,(5):117-119

最短路径问题作为GIS分析中的一个主要内容而被广泛深入地进行研究。本文在设计一种网络数据结构的基础上, 通过一种基于节点与弧段标号的最短优先路径搜索策略, 设计并实现了一种结构简单、便于理解并且高效的最短路径求解算法。  相似文献   

钻孔应变水位辅助观测标定的探讨     

李峰  卢双苓  吴海宾  邢强  王强  洒荣利  崔居全 《华北地震科学》2010,28(3):58-60

分析了采用"延时法"标定水位带来的不便和产生的误差,总结了新的标定方法—"探头升降法"标定仪器的原理和操作方法,经过几个台站的反复实验,效果很好,精度达99%,有推广价值。  相似文献   

不同热岛类型的划分方法适用性研究     

冯晓刚  杨鑫  撒利伟 《测绘与空间地理信息》2012,(12):41-43

不同的热岛类型划分方法会得出不同的热环境信息,主流的热岛划分方法主要包括等距法和中误差法两种。本文以咸阳市和兴平市热红外数据为数据源,在采用单窗算法获取研究区热环境信息的基础上,分别采用两种热岛类型划分方法获得了研究区域的热环境信息。研究结果表明:①两种不同划分方法均能有效反映研究样区存在较为明显的城市热岛效应;②等距方法获取的热空间格局中的强热岛区呈点状和小斑块状分布于城镇内部,而中误差方法获取的热空间格局中的强热岛区呈片状分布于城镇内部;③基于等距的划分体系适合于大中城镇构建热环境指标与评价体系;而基于中误差的划分体系更适合于市、县、镇、乡四级热环境指标及其评价体系的构建。  相似文献   

南海湖沉积物中Hg的形态分布特征   总被引：2，自引：0，他引：2  

萨茹莉  何江  吕昌伟  樊庆云  宝金花 《沉积学报》2009,27(6):1178-1183

以包头市南海湖为研究对象,采用连续化学提取法,系统开展了沉积物中Hg的形态分布研究。结果表明,表层沉积物中Hg含量的水平分布总体呈现湖心区低,西南和东北部湖区高的趋势。腐殖酸结合态为表层沉积物中Hg的主导形态,次为交换态和水溶态。表层沉积物中生物有效态Hg的含量甚高,占总汞的76%~94%,对整个生态系统具有潜在危害性。沉积柱芯中总Hg表现为表层富集并随深度增加而降低的变化趋势。B、F站位柱状沉积物中腐殖酸结合态Hg随深度有规律的递减,H站位20 cm以上Hg的主导形态为腐殖酸结合态,残渣态次之;20～30 cm的主导形态则为残渣态及可交换态。  相似文献   

Chemical reaction rates and entrainment within the Endeavour Ridge hydrothermal plume   总被引：1，自引：0，他引：1  

D.C. Kadko  N.D. Rosenberg  J.E. Lupton  R.W. Collier  M.D. Lilley 《Earth and Planetary Science Letters》1990,99(4)

The aging of the hydrothermal plume over the Endeavour segment of the Juan de Fuca Ridge was estimated by measuring the²²²Rn³He ratio in the plume as it dispersed. Despite uncertainties in the source function of hydrothermal input, it wa determined that the relative sequence of removal from the plume isH₂ > Δc >²²²Rn>CH₄ Mn, whereΔc is a measure of particle concentration and the mean life of²²²Rn is 5.5 days. H₂ is removed from the plume within hours of input while Mn is not removed within the two-week timescale of the radon-helium clock.Entrainment of bottom water within the buoyant plume may introduce additional chemical signatures into the spreading effluent layer over that which would be introduced by hydrothermal discharge alone. This is particularly significant for those chemical species which are not greatly enriched in the vent fluids relative to bottom water concentration and which display a nutrient-like profile in the deep ocean. Thus we found that significant fractions of the Si and²²⁶Ra anomalies in the plume were not of hydrothermal origin but were derived from entrained bottom water which has a higher concentration of these elements than ambient water at plume height.  相似文献   

琼北火山岩激光⁴⁰Ar/³⁹Ar定年研究   总被引：1，自引：1，他引：0  

洒骁  季建清  周晶 《岩石学报》2013,29(8):2789-2795

新生代以来,雷琼地区多次、大量地喷发了一系列火山岩。前人主要基于K-Ar法对此划分了期次。本文采用激光40Ar/39Ar年代学方法,对琼北火山岩区进行了精细定年研究。低本底激光40Ar/39Ar法能够对低钾含量,极少量样品(毫克级)进行精细测定,非常适合极年轻火山岩的定年工作。结果显示的火山岩激光40Ar/39Ar法高质量数据表明琼北火山喷发活动时限跨越1.3～0.052Ma。在比较了表观年龄与等时线年龄差异之后,本文给出了年龄推荐值。正如测试数据所显示,本地区新生代火山岩普遍存在40Ar和36Ar过剩的问题,此时只有等时线年龄才代表喷发的真实年龄。  相似文献   

A compilation of Australian heat‐flow measurements     

F. E. M. Lilley  Merren N. Sloane  J. H. Sass 《Australian Journal of Earth Sciences》2013,60(7-8):439-445

A map is presented based on all known Australian heat‐flow estimates, including five new ones. A second map, based on the first, also is presented, but excludes any determinations judged for any reason to be unreliable. The data show that heat flow over large areas of the continent is effectively uniform to within 0.5 heat flow units (i.e. to within 20 mW m^‐2), with perhaps three major regional heat‐flow provinces being defined in western, central, and eastern Australia.  相似文献   

煤岩变形破坏电磁辐射记忆效应的力电耦合规律   总被引：1，自引：0，他引：1       下载免费PDF全文

撒占友  何学秋  王恩元 《地球物理学报》2006,49(5):1517-1522

理论分析了煤岩变形破坏过程中电磁辐射脉冲数与损伤之间的关系,探讨了煤岩变形破坏电磁辐射产生机制及电磁辐射记忆效应的力电耦合规律,建立了等围压三轴应力状态下含瓦斯煤岩变形破坏电磁辐射记忆效应的力电耦合模型,实验测定并分析了单轴压缩状况下含瓦斯煤岩变形破坏电磁辐射记忆效应的力电耦合规律.结果表明,含瓦斯煤岩变形破坏电磁辐射记忆效应力电耦合模型很好地反映了煤岩变形破坏电磁辐射记忆效应特征规律和微观损伤机理.  相似文献   

Magnetometer array studies in India and the lithosphere     

B.J. Srivastava  B.P. Singh  F.E.M. Lilley 《Tectonophysics》1984,105(1-4)

Two magnetometer array experiments were conducted in India during 1978–1980, under an Indo-Australian collaboration project, using 21 Australian three-component magnetometers of the Gough-Reitzel type. The first array study was made in the northwestern region covering the Aravallis, the Punjab, and the lesser Himalaya, while the second experiment was carried out in the southern peninsular shield area. Both these sets of geomagnetic deep sounding (GDS) observations yielded valuable results on the crustal and upper mantle structure in the two geologically and geophysically important regions of India.Geomagnetic induction patterns observed in northwest India have revealed a variety of electrical conductivity structures. The primary conductivity structure providing paths for induced currents is found to be striking at right-angles to the Himalayan Mountains. The conductivity structure is indicated to be a northward continuation of the Aravalli belt and, thus, suggesting the continuation of the Indian shield at depth into the base of the Himalayan foothills under the Ganga basin.The induction effects observed in the southern tip of peninsular India are by far the most complex geophysical phenomenon due to the simultaneous occurrence of the sea coast, the crustal and upper mantle conductivity anomalies between India and Sri Lanka under the sea, and the day-time equatorial electrojet as part of the external heterogeneous inducing field. It is further complicated by the existence of a conductive step, structure along the coastline at the Moho boundary and a “graben” structure in the Palk Strait, as revealed by the array observations.  相似文献