GBInSAR在大坝变形监测中的应用     

郭乐萍  岳建平  岳顺  邱志伟  汪学琴 《测绘工程》2017,26(2)

评判水工建筑物的工作性态,需高精度的变形、应力等信息。根据大坝安全监测特点和要求,介绍GBSAR监测系统构成和测量基本原理,分析该系统测量误差来源及特征,探讨该技术在大坝变形监测中的可行性。以隔河岩大坝3d的实测数据为例,分析该技术实际测量精度,研究显示成果达亚毫米级,能够满足大坝变形监测的精度要求。  相似文献   

一种高精度的基坑水平位移监测方法探讨     

吕文军 《测绘与空间地理信息》2016,(4):201-203,206

将CPⅢ(高速铁路轨道控制网)平面控制测量的自由测站施测方法应用到基坑水平位移变形监测中,其特点是根据施工现场情况选择任意合适的地点架设测站,避免了施工环境对测量工作的影响和仪器的对中误差。介绍了Helmert方差分量估计定权原理和置平平差原理,通过自编程序完成了基坑变形监测的仿真计算。计算结果证明:利用自由测站采集观测数据,Helmert方差分量估计定权约束平差和置平平差均能够高精度地得到毫米级的基坑变形量,可以应用到基坑水平位移变形监测中。  相似文献   

Wavimeter     

Andrew B. Martinez  Brian S. Bourgeois 《Marine Geodesy》2005,28(1):1-17

A method of extracting wave parameters from surface displacement measured from a moving platform is presented. The article first presents a method for accurately measuring surface displacement using a single beam altimeter and heave sensor. A least squares approach is presented to estimate wave parameters using vessel velocity and perceived wave frequency that eliminates Doppler due to vessel motion. Two techniques for estimating wave frequency are presented: a block data method using MUSIC and a real-time method using demodulation. Sea trial results demonstrate that this method is as effective as a WaveRider buoy for estimating wave parameters.  相似文献   

Juvenile-adult Colour Patterns and Coexistence in the Territorial Coral Reef Fish Pomacanthus imperator     

Hans W.  Fricke 《Marine Ecology》1980,1(2):133-141

Abstract. The coexistence of juvenile and adult territorial Pomacanthus imperator was studied in the Red Sea. The role played by their divergent colouration in the settlement of juveniles among adults on the reef is interpreted as the intraspecific equivalent of character displacement.  相似文献   

基于GPS监测的芦山地震周围地区同震位移与运动速度          下载免费PDF全文

唐文清  张清志  潘忠习  刘宇平  杨成 《沉积与特提斯地质》2016,36(2):105-112

通过对2013年"4.20"四川芦山地震前后GPS观测数据的处理,得到地震周围地区GPS测站同震位移及速度矢量场。GPS测站同震位移大小为5.09~51.05mm,平均为14.18mm;GPS测站运动速度为2.64~52.37mm/a,平均为18.89mm/a。利用断裂两侧GPS测站速度矢量差得到了龙门山断裂带南段次级断裂的运动速度,龙门山断裂带南段的后山断裂、中央断裂、前山断裂运动速度大小分别为49.66±3.90mm/a、79.58±3.33mm/a、50.94±3.91/a;中央断裂以右旋挤压为主,而后山断裂、前山断裂表现为左旋拉张的特性。综合分析表明,芦山地震是发生在龙门山断裂带南段东南侧的逆冲型地震,发震构造为前山断裂与新津断裂之间的小断层。芦山地震对周围地区的影响不大,主要集中在龙门山断裂带南段及震中附近区域。  相似文献   

PPP网解UPD模糊度固定技术监测尼泊尔Ms8.1级地震对中国珠峰地区及周边地震同震位移     

王虎  李建成  党亚民  成英燕  王解先  杨强  许长辉  张守建 《测绘学报》2016,45(Z2):147-155

利用UPD模糊度固定技术无需顾及基线解算基站地震所带来的影响,可以进行高精度非差PPP解算,"真实"获取地震周边地区GNSS站点高精度同震位移变化。为此,本文利用"国家基准一期工程""中国大陆构造环境监测网络"以及国家测绘地理信息局在珠峰周边所观测的GNSS观测资料,基于UPD模糊度固定技术高精度非差解算2015年4月25日尼泊尔Ms8.1级地震对我国珠峰地区及周边地震同震位移影响。首先,本文选取全国及周边IGS均匀分布、站点稳定、远离震区的GNSS连续观测网络数据计算卫星端的宽、窄巷UPD,采用PPP网解UPD模糊度固定技术,对解算地震区域内的GNSS测站的载波相位模糊度进行固定,得到无模糊度的精确相位观测值,进行高精度非差PPP解算;通过对平静日IGS测站数据处理与ITRF2008历元坐标对比分析,验证了该方法的精确性;最后,对2015年4月25日、5月12日地震以及地震前后数据,进行了UPD模糊度固定技术的非差PPP解算,分析了中国珠峰地区及周边GNSS站的同震位移;同时也分析了中国珠峰地区在2005—2015年10年的位移变化情况。UPD模糊度固定技术整网解算的方法也证实了能够为GNSS用于监测地震同震位移等,提供了一种精确、可靠的技术手段。  相似文献   

加劲桩配合工法桩在软土基坑中的支护效果评价     

李焕焕 《地质与勘探》2016,52(4):725-733

以嘉兴晶辉广场深基坑工程为背景,研究了旋喷加劲桩在软土深基坑中的支护效果。结合监测数据,利用FLAC 3D有限差分软件,对旋喷加劲桩配合SMW工法桩(劲性水泥土搅拌桩)这种组合结构在基坑各个开挖工况下的受力情况以及深层土体水平位移变化情况进行模拟计算。结果表明:深层土体水平位移曲线呈"鼓肚状",最大水平位移安全合理,位于基坑开挖底面以上1m~2m处;SMW工法桩所受剪力随开挖深度的加深而增大;三排加劲桩所受拉力呈现为越接近基坑开挖底面越大的规律。模拟结果与实际监测结果基本一致,且均在安全范围内。说明旋喷加劲桩在软土基坑中的支护效果较好,此次模型的建立较合理,为今后类似基坑工程的设计计算提供了参考。  相似文献   

高速公路类土质路堑边坡施工期变形监测预警探讨          下载免费PDF全文

李勇  庄生明  黄文洁 《探矿工程》2016,43(10):36-39

高速公路类土质路堑边坡是边坡领域的一种重要类型,在工程特性方面与土质边坡或岩质边坡具有明显差异。深入认识该类边坡的工程特性和失稳机理,对该类边坡施工期间的安全建设以及正常运营期间安全评估具有重要意义。基于高速公路类土质路堑边坡工程地质特点、边坡变形影响因素,结合盘兴高速公路K5滑坡变形监测预警实例,提出了采用位移速度比率作为预警参考值的滑坡预警方法,并在松铜一标ZK5 410～485段左侧边坡成功预警,避免了人员伤亡,减轻了经济损失。为类土质路堑边坡工程设计、工后防治、安全运营提供指导。  相似文献   

More than gentrification: geographies of capitalist displacement in Los Angeles 1994–1999     

J. Revel Sims 《Urban geography》2016,37(1):26-56

Little is understood about displacement in urban contexts. While some of the difficulties are methodological, the more serious problem is conceptual. Outside of the rent gap hypothesis or the philosophy of property rights, there has been little theoretical inquiry into the causal dynamics of displacement. In this article, I present a study of evictions in Los Angeles that addresses these conceptual and empirical shortcomings. A spatial analysis of more than 70,000 georeferenced evictions between 1994 and 1999 documents the existence of four distinct geographies of displacement, each produced by separate types of causal circumstances. Gentrification explains only one of the four displacement geographies, while the other three are nongentrifying or pre-gentrifying contexts and more appropriately described through growth machine models, global city theory, and financial restructuring. The extent of displacement in pre- and nongentrifying areas reinforces Mark Davidson’s emphasis on Lefebvre’s production of space as a crucial framework for understanding displacement processes.  相似文献   

A graph deep learning method for landslide displacement prediction based on global navigation satellite system positioning     

《地学前缘(英文版)》2024,15(1):101690

The accurate prediction of displacement is crucial for landslide deformation monitoring and early warning. This study focuses on a landslide in Wenzhou Belt Highway and proposes a novel multivariate landslide displacement prediction method that relies on graph deep learning and Global Navigation Satellite System (GNSS) positioning. First model the graph structure of the monitoring system based on the engineering positions of the GNSS monitoring points and build the adjacent matrix of graph nodes. Then construct the historical and predicted time series feature matrixes using the processed temporal data including GNSS displacement, rainfall, groundwater table and soil moisture content and the graph structure. Last introduce the state-of-the-art graph deep learning GTS (Graph for Time Series) model to improve the accuracy and reliability of landslide displacement prediction which utilizes the temporal-spatial dependency of the monitoring system. This approach outperforms previous studies that only learned temporal features from a single monitoring point and maximally weighs the prediction performance and the priori graph of the monitoring system. The proposed method performs better than SVM, XGBoost, LSTM and DCRNN models in terms of RMSE (1.35 mm), MAE (1.14 mm) and MAPE (0.25) evaluation metrics, which is provided to be effective in future landslide failure early warning.  相似文献