利用DInSAR和GPS综合方法估计地表3维形变速率   总被引：2，自引：0，他引：2  

罗海滨  何秀凤  刘焱雄 《测绘学报》2008,37(2):0-249

在分析基于贝叶斯统计和马尔科夫随机场理论的解析优化法的基础上,提出以GPS提供的高精度的水平形变速率作为约束,利用直接分解法,将DInSAR的斜距向形变速率分解成垂直形变速率。试验结果表明,直接分解法有效地综合了GPS的高水平精度与DInSAR的高垂直精度优点,且计算简单,克服了解析优化法可能出现的数值不稳定问题。  相似文献   

分布式光纤传感技术在滑坡监测中的应用   总被引：5，自引：1，他引：4  

史彦新  张青  孟宪玮 《吉林大学学报(地球科学版)》2008,38(5)

将分布式光纤传感技术引入滑坡监测,既可得到整个滑坡体的概要特征,又能提高监测效率。FBG与BOTDR是两种最具代表性的分布式光纤传感技术,FBG通过测量其反射光波长的变化获得应变或温度值。BOTDR通过测定后向布里渊散射光的频移实现分布式温度、应变测量。FBG传感器灵敏度高,但只能实现离散点的准分布式测量,BOTDR可实现分布式、长距离、不间断测量,但其空间分辨率不高。笔者提出FBG与BOTDR联合监测滑坡的方案。在巫山残联滑坡,在整个滑坡体上铺设监测光纤,利用BOTDR获得整个滑坡体的概要信息;在滑坡体变形的关键部位———变形缝安装FBG传感器,获得某些关键部位的应变信息,从而实现由点到线再到面的监测,获得滑坡体较完整的应变信息。  相似文献   

遥感技术在煤炭资源开发状况监督管理中的应用研究   总被引：1，自引：0，他引：1  

康高峰  卢中正李社 金谋顺 《中国煤炭地质》2008,20(1):13-16

利用高分辨率遥感图象可以快速查明煤炭资源开发状况以及煤炭资源开发的合法性（界内开采、界外开采、越界开采）等,对煤矿安全生产及维护矿业秩序具有重要意义。以我国中部某煤炭开采密集区为试验区,选择不同分辨率的遥感数据,从矿山铺助设施、道路、矿堆、矸石的特征出发,进行矿山开采状况遥感解译;以地理信息系统技术（GIS）为支撑实现采矿权数据、规划数据图层与遥感专题数据的叠加分析和相关分析,判断非法与越界矿山,评价矿产资源开发与保护规划执行情况。  相似文献   

煤炭采空区处理的新方法与实例分析     

彭树宏张晓帆  王金山 《中国煤炭地质》2008,20(1):47-49

位于乌鲁木齐市南湖路以西的煤炭采空区面积达67 100.5m^2,区内构造从南到北主要由八道湾向斜和七道湾背斜组成,地层产状变化不大。该矿区开采较深,且采空区塌陷区有明显的地下水活动迹象。在对深孔大体积采空区注浆时,比较各种常见注浆治理方法,均存在不同的制约因素,故决定采用灌浆爆破压密法对采空区进行压实加固。经现场爆破试验,该区重复爆破次数在3～5次左右。灌浆爆破压密处理后,对不同土层进行取样对比分析,得到其相应密度（增加）及空隙比（减少）的变化分别为：杂填土14.1%,-7.9%;素填土5.9%,-3.3%;塌落煤层7.8%,-7.7%。根据压缩数据及现场测量,处理后的土体沉降2～4m,部分空体地段的沉降量达10～20m,治理效果明显。  相似文献   

基于GPS技术监测高层建筑物变形的研究     

肖炜枝  王天应  施闯  陶本藻  李敏 《地理空间信息》2008,6(1):15-17

以武汉大学信息学部教学实验大楼为实验对象,分析了大楼在N、E、U方向上的每h变化、d变化及变形规律,阐明GPS技术在高层建筑变形监测中的应用。  相似文献   

自动化监测技术在我国首条大型电力隧道中的应用   总被引：1，自引：0，他引：1  

宋蓓  沈刚  朱伟林 《上海国土资源》2008,(2):51-53

通过自动化监测在超大工程项目中的应用,利用现有技术手段,对工程进行有效管理,逐渐将对工程的安全、预判起到越来越重要的作用,它可以在为工程节约大量资金情况下,提高预判安全施工的能力,是提高工程管理的重要手段。  相似文献   

基于改进PSO-SVM的噪声稳健建筑物变形监测方法     

张建奇 《北京测绘》2021,35(2):166-171

对高层、超高层建筑物进行实时,高精度的变形监测对提前预防安全隐患,保证人民生命财产安全具有重要意义。建筑物变形作为一种典型的随机性和微弱性过程,噪声等误差的存在会影响从中提取有用的变形信息。针对该问题,提出一种改进粒子群(Particle Swarm Optimization,PSO)算法优化支持向量机(Support Vector Machine,SVM)的噪声稳健建筑物变形监测方法,利用改进PSO算法的全局搜索能力对SVM的核参数进行优化,提升预测精度的同时增强算法的噪声稳健性。基于实测数据的试验结果表明,相对于传统交叉验证SVM和小波方法,所提方法可以获得更高的变形预测精度,并且在低信噪比条件下优势更加明显。  相似文献   

The role of bathymetry and directional wave conditions on observed crescentic bar dynamics     

Rinse L. de Swart  Francesca Ribas  Gonzalo Simarro  Jorge Guillén  Daniel Calvete 《地球表面变化过程与地形》2021,46(15):3252-3270

Nearshore sandbars are important features in the surf zone of many beaches because they strongly influence the mean circulation and evolving morphology. Due to variations in wave conditions, sandbars can experience cross-shore migration and vary in shape from alongshore uniform (shore-parallel) to alongshore rhythmic (crescentic). Sandbar dynamics have been studied extensively, but existing observational studies usually do not quantify the processes leading to crescentic bar formation and straightening. This study analyses the dynamics of crescentic bar events at the fetch-limited beach of Castelldefels (northwestern Mediterranean Sea, Spain) using 7.5 years of hourly time-exposure video images and detailed wave conditions. The results show that, despite the generally calm wave conditions, the sandbars were very dynamic in the cross-shore and longshore directions. They often migrated rapidly offshore during storms (up to 70 m in one day) and more slowly onshore during post-storm conditions. Crescentic bars were often present at the study site (48% of the time), but only when the sandbar was at least 10 m from the shoreline. They displayed a large variability in wavelengths (100–700 m), alongshore migration speeds (0–50 m/day) and cross-shore amplitudes (5–20 m). Wavelengths increased for larger bar–shoreline distances and the alongshore migration speeds were strongly correlated with the alongshore component of the radiation stresses. Crescentic patterns typically developed during low–medium energetic waves with limited obliquity ( $\theta \lesssim 20$° at 10 m depth), while bar straightening occurred during medium–high energetic waves with strong oblique angles of incidence ( $\theta \gtrsim 15$°). Overall, this study provides further proof for the important role of wave direction in crescentic bar dynamics and highlights the strong dependence of crescentic bar development on the initial bathymetric configuration.  相似文献   

A laboratory experiment to monitor the contact state of a fault by transmission waves   总被引：1，自引：0，他引：1  

Naoto Yoshioka  Koji Iwasa 《Tectonophysics》2006,413(3-4):221-238

We performed a series of laboratory experiments in which elastic waves were transmitted across a simulated fault. Two types of experiments were carried out: (1) Normal Stress Holding Test (NSHT): normal stress was kept constant for about 3 h without shear stress and transmission waves were observed. (2) Shear Stress Increasing Test (SSIT): shear stress was gradually increased until a stick-slip event occurred. Transmission waves were continuously observed throughout the process of stress accumulation. We focused on the change in transmission waves during the application of shear stress and especially during precursory slips.It was found in NSHT that the amplitude of transmission waves linearly increased with the logarithm of stationary contact time. The increase amounted to a few percent after about 3 h. Creep at asperity contacts is responsible for this phenomenon. From a theoretical consideration, it was concluded that the real contact area increased with the logarithm of stationary contact time.We observed in SSIT a significant increase in wave amplitude with shear stress application. This phenomenon cannot be attributed to the time effect observed in NSHT. Instead, it can be explained by the mechanism of “junction growth” proposed by Tabor. Junction growth yields an increase in real contact area. It is required for junction growth to occur that the material in contact is already plastic under a purely normal loading condition. A computer simulation confirmed that this requirement was satisfied in our experiments. We also found that the rate at which the amplitude increased was slightly reduced prior to a stick-slip event. The onset time of the reduction well coincides with the onset of precursory slip. The cause of the reduction is attributed to the reset of stationary contact time due to displacement. This interpretation is supported by the result of NSHT. Taking the time of stationary contact in SSIT into account, we may expect the change in wave amplitude to be, at most, only a few percent. The observed slight reduction in increasing rate is, in this sense, reasonable. The static stiffness of the fault also decreases with precursory slip. It was also found that low frequency waves are a better indicator of precursory slip than high frequency waves. This might suggest that low frequency waves with longer wavelength are a better indicator of average behavior of faults. The problem, however, merits a further investigation. The shifts in phase were also found to be a good indicator of the change in contact state of the fault. The changes in both amplitude and phase of transmission waves are unifyingly understood through the theory of transmission coefficient presented by Pyrak-Nolte et al. Rough surfaces have a tendency to give larger stick-slips than smooth surfaces. The amount of precursory slip is larger for rough surfaces than for smooth surfaces. Although it was confirmed by a computer simulation that rough surfaces have larger contact diameters than smooth surfaces, the rigorous relationship between the surface roughness (contact diameter) and the amount of precursory slips was not established.  相似文献   

Slope instability of San Miniato hill (Florence, Italy): possible deformation patterns   总被引：1，自引：1，他引：1  

Riccardo Fanti 《Landslides》2006,3(4):323-330

The hill of San Miniato (Florence, Italy) has been repeatedly identified in the past as the site of a slow moving, intermittent landslide. Possible hypotheses regarding the mechanisms responsible for past movements and for cracks and fissures present today are formulated based on the comparison of historical information and processed monitoring data. Although it is not possible to completely exclude a large inactive landslide that involves the entire northern slope, it seems more probable that the slide, if it does exist, is no longer active and that present-day damage is due to separate shallow movements concentrated in man-made deposits. This hypothesis can only be verified with a temporal extension of the monitoring activities, necessary in any case for planning possible safeguarding measures for the cultural heritage in the area.  相似文献