共查询到20条相似文献，搜索用时 99 毫秒
1.
《测绘与空间地理信息》2020,(7)
大跨径悬索桥和斜拉桥的索塔都非常高,施工过程复杂,这对索塔线形测控的方法和精度提出了更高的要求。本文首先考虑地球曲率影响,提出一种改化索塔设计坐标的方法;然后讨论了一种测定索塔区域大气竖直折光系数的方法,并通过实验验证了此方法用于改正索塔高程测控时单向三角高差的可行性;最后提出采用自由设站测量新技术来测控索塔平面线形。经过分析和计算,上述方法能够提高索塔线形测控的精度和效率,使索塔线形测控结果满足设计要求。本文对指导悬索桥和斜拉桥高大索塔施工测量具有借鉴意义。 相似文献
2.
3.
江阴长江大桥索塔施工测量控制方法与精度分析 总被引：2，自引：0，他引：2
本文介绍了江阴长江大桥悬索桥南塔施工控制测量三维坐标法的主要实施过程与精度分析。通过实施表明该方法能完全满足施工所提出的精度要求。该方法具有一定的合理性、先进性和实用住,对大型悬索桥和斜拉桥索塔施工测量控制是一种比较好的方法。 相似文献
4.
南京五桥索塔测量是整个索塔工程施工质量控制的关键。区别于钢塔与常规混凝土塔施工测量,钢混结合塔施工测量需要解决的重难点是新工艺、新施工方法对索塔线形控制测量带来的难题。为了提高南京五桥索塔施工测量控制精度,重点对索塔测点的布置、索塔专用控制网的建立、索塔施工测量方法、索塔隐蔽点测量以及索塔"摆动临界点"等一系列施工难题进行了研究,并提出了解决办法。索塔施工完成后,通过对南京五桥索塔测量控制的实施与验证,各项指标均优于评定标准及规范要求。该研究的内容和方法,对今后类似工程有一定指导作用。 相似文献
5.
通过斜拉桥的塔梁同步施工状态下的索塔定位测量的研究分析,根据测量索塔已浇节段的变形值,模拟索塔的变形曲线,计算出索塔待浇节段的理论变形值,对模板和索导管的定位数据进行修正,使索塔线型和定位精度符合设计要求. 相似文献
6.
斜拉桥索塔三维相对基准定位方法研究 总被引：1，自引：0，他引：1
结合斜拉桥索塔基准放样及斜拉索预埋钢管的精密定位的需要，提出了一种新的基于测量机器人的三维相对基准放样方法，并成功用于灌河特大桥斜拉桥主桥的施工放样。实践证明，与传统的方法相比，该方法具有方便、高效、精度高等特点。 相似文献
7.
关于斜拉桥塔梁同步施工测量技术的研究 总被引：1，自引：0，他引：1
针对斜拉桥塔梁同步施工时主塔的线形控制和索道管测量定位等测景技术进行研究与分析,精确测量并计算出塔梁同步施工产生的不均匀水平力使主塔位置产生的偏移量。然后在主塔测量控制和索道管商精度定位测量中进行修正处理,通过测量误差分析和精度计算的方法,保证斜拉桥塔梁同步施工时塔柱的线形和索道管测量定位的精度。 相似文献
8.
9.
本文以大型铁路桥梁建设线形监控项目为研究对象,探讨线形控制监测的目标意义和技术方法,建立仿真模型进行计算分析,利用测量监测技术对影响线形和受力的参数进行现场采集,并对具体的监控方法和过程进行了详细介绍。经现场监测数据与理论计算值进行比较分析,各施工阶段高程控制准确,高程误差在控制范围内,主梁控制截面应力变化规律与理论计算一致,符合线形控制的预期目标。 相似文献
10.
11.
采用Landsat TM数据分析了阿克苏河—塔里木河断面水质污染状况,通过波段的DN值和常规监测数据建立能反映水质状况的
污染物监测模型。结果发现,将2000年常规监测数据代入模型后,与遥感数据的结果基本吻合| 重建阿克苏河—塔里木河的连续水体
污染变化曲线,得出污染物浓度随着远离上游而增加。 相似文献
12.
13.
Monitoring drought dynamics in the Aravalli region (India) using different indices based on ground and remote sensing data 总被引：5，自引：0，他引：5
C. Bhuiyan R.P. Singh F.N. Kogan 《International Journal of Applied Earth Observation and Geoinformation》2006,8(4):289-302
The hard-rock hilly Aravalli terrain of Rajasthan province of India suffers with frequent drought due to poor and delayed monsoon, abnormally high summer-temperature and insufficient water resources. In the present study, detailed analysis of meteorological and hydrological data of the Aravalli region has been carried out for the years 1984–2003. Standardised Precipitation Index (SPI) has been used to quantify the precipitation deficit. Standardised Water-Level Index (SWI) has been developed to assess ground-water recharge-deficit. Vegetative drought indices like Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) and Vegetation Health Index (VHI) have been computed using NDVI values obtained from Global Vegetation Index (GVI) and thermal channel data of NOAA AVHRR satellite. Detailed analyses of spatial and temporal drought dynamics during monsoon and non-monsoon seasons have been carried out through drought index maps generated in Geographic Information Systems (GIS) environment. Analysis and interpretation of these maps reveal that negative SPI anomalies not always correspond to drought. In the Aravalli region, aquifer-stress shifts its position time to time, and in certain pockets it is more frequent. In comparison to hydrological stress, vegetative stress in the Aravalli region is found to be slower to begin but quicker to withdraw. 相似文献
14.
15.
Piyoosh Rautela Ramesh Chandra Lakhera 《International Journal of Applied Earth Observation and Geoinformation》2000,2(3-4)
The area around Sataun in the Sirmur district of Himachal Pradesh, India (falling between the rivers Giri and Tons; both tributaries of the Yamuna River) was studied for landslide vulnerability on behalf of the inhabitants. The study was made using extensive remote sensing data (satellite and airborne). It is well supported by field evidence, demographic and infrastructural details and aided by Geographic Information System (GIS) based techniques. Field observations testify that slope, aspect, geology, tectonic planes, drainage, and land use all influence landslides in the region. These parameters were taken into consideration using the statistical approach of landslide hazard zonation. Using the census data of 1991, vulnerability of the populace to the landslide hazard was accessed. As most of the infrastructure in the region is concentrated around population centres, population data alone was used for vulnerability studies. 相似文献
16.
ZHAN F. Benjamin 《地球空间信息科学学报》2011,(1)
Although it is well known that coseismic gravity changes take place during an earthquake, previous research has not yielded convincing evidence demonstrating that significant gravity changes occur before large earthquakes. Furthermore, even if we suspect that gravity changes occur before large earthquakes, we have yet to demonstrate how to consistently observe these changes for useful earthquake forecast that would bring benefits to society. We analyzed ground gravity survey data obtained in 1998, 2000, 200... 相似文献
17.
GNSS系统及其技术的发展研究 总被引：3，自引：1，他引：2
阐述了国际上卫星导航系统的总体发展,对美、俄、欧、中的四大全球系统,以及相关的区域系统和增强系统进行了简单的介绍,研究分析了GNSS系统及其技术的发展趋势,同时分析了我国Compass全球系统面临的机遇和挑战,并提出了我国未来工作的建议. 相似文献
18.
“4D”技术及其应用 总被引：13，自引：0，他引：13
介绍“４Ｄ”（即数字地面模型、数字正射影像、数字栅格地图和数字线划地图）系列产品的生产流程、关键技术、及其在耕地保护、防灾减灾救灾和城市规划等方面的应用方法。 相似文献
19.
《International Journal of Digital Earth》2013,6(1):66-87
Abstract Virtual Australia is not a well-defined or agreed concept. This discussion paper conceptualises Virtual Australia as a ‘virtual [digital] model containing and representing all non-trivial objects and their contextual environment – from blue sky to bedrock – in real world Australia’. It describes a scenario for Virtual Australia, one or two decades from now, in which the locations and conditions of non-trivial objects and their environment are updated automatically through a combination of remote sensing and wireless communication technologies in support of a ‘Supranet’. It then examines the concept of the ‘Supranet’ – a pervasive information network based largely on wireless technology linking the physical world to a virtual model in real time – and develops and discusses three principal characteristics of the Supranet: the ability to have or collect specific information (know); the ability to process information (think); and the ability to communicate that information. If, in the near future, any or all non-trivial devices are to some extent able to know, think and communicate, the potential for object autonomy will be realised. 相似文献
20.
自动车辆定位导航系统中传感器的误差分析 总被引：1，自引：0，他引：1
对国界定位导航系统中几种常见的辅助传感器所产生的误差进行了分析，导出了不同传感器的误差模型。这些误差模型是估计车辆位置的扩展卡尔曼滤波器的基础，同时也为选择适当的传感器提供了理论根据。 相似文献