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Determination of ocean tide loading displacements in Hong Kong using GPS technique

Science china Earth Sciences 2010年第7期53卷 993-1007页

作者： YUAN LinGuo1,3, DING XiaoLi1, SUN HePing2, ZHONG Ping1,3 & CHEN Wu1 1 department of Land surveying and Geo-Informatics, The Hong Kong Polytechnic university, Kowloon, Hong Kong, china 2 Key Laboratory of Dynamic Geodesy, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, china 3.department of surveying engineering, school of civil engineering, southwest jiaotong university, chengdu 61003., china department of Land surveying and Geo-Informatics The Hong Kong Polytechnic University Kowloon Hong Kong China department of surveying engineering School of Civil Engineering Southwest Jiaotong University Chengdu China Key Laboratory of Dynamic Geodesy Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan China

Ocean tide loading (OTL) displacements of eight principal constituents at 12 sites in Hong Kong were determined using more than eight years of continuous GPS observations. Parameters of the OTL displacements were estimated using daily GPS solutions obtained with precise point positioning (PPP) technique. The results were compared with predictions from seven latest global ocean tide models. Gravity measurements of OTL in Hong Kong were also used to validate the GPS results. The study shows that the results from both the GPS and gravity measurements agree best with the GOT4.7 and NAO99b models, when the K1 and K2 constituents are excluded. The agreements between the GPS and the model estimates are generally at sub-millimeter level in both the horizontal and vertical directions, except for S2, K2 and K1 constituents that have relatively larger errors. After removing the systematic biases between the GPS and the model estimates, the misfits of M2, S2, N2, O1, P1 and Q1 at all sites are within 0.5 and 1.0 mm in the horizontal and the vertical directions, respectively, whereas K1 and K2 show relatively larger misfits of up to 2.3 mm. Both the GPS and the gravity S2 estimates have large biases with unknown reasons when compared with the modeled values, which needs to be further investigated. The study demonstrates that GPS is capable of estimating the OTL displacements with the same accuracy as the model predictions, especially for coastal areas.

关键词： GPS ocean tide loading ocean tide model site displacement

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Development　of　GPS　Positioning　Software　Package　at　southwest　jiaotong　university（SWJU）　of　china

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Journal of Modern Transportation 1994年第1期11卷 71-75页

作者： Huang Dingfa(department of surveying engineering,southwest jiaotong university,)chengdu 61003., china

This paper provides an overview about GPS positioning software pacforge inSWJU. The mathematical methodology, which the software package bed on, isoutlined for static and kineniatic mode. It is well known that the eyele slip andanibiguity are critical componenta in view of establishins the baseline andreducing observation time. The approaches of dealing with cycle slip andanibiguity utilized in the software, are summarized.

关键词： GPS peitionirig software,double difference cycle slip satellite poitioning

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蒋家沟流域土壤湿度变化模拟

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山地学报 2009年第2期27卷 217-222页

作者：汤家法西南交通大学土木工程学院

土壤水分状况是形成泥石流的关键性水文因素之一,了解土壤水分的变化状况,对于泥石流的形成机理以及预报预测研究都有重要的科学意义。以云南东川蒋家沟为研究对象,基于水分的物理循环过程并与分布式水文分布模型TOPMODEL相结合,建立起... 详细信息

土壤水分状况是形成泥石流的关键性水文因素之一,了解土壤水分的变化状况,对于泥石流的形成机理以及预报预测研究都有重要的科学意义。以云南东川蒋家沟为研究对象,基于水分的物理循环过程并与分布式水文分布模型TOPMODEL相结合,建立起土壤湿度逐日变化模拟模型。从蒋家沟流域2001年的模拟结果来看,基本上能够反映出观测点的表层土壤湿度的取值范围及其基本变化趋势,所构造的模型能够比较好地模拟出流域内土壤湿度逐日变化情况。

关键词：泥石流土壤湿度模拟模型 TOPMODEL

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Seismic response analysis of road vehicle-bridge system for continuous rigid frame bridges with high piers

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Earthquake engineering and engineering Vibration 2012年第4期11卷 593-602页

作者： Li Yongle Chen Ning Zhao Kai Liao Haili department of civil engineering Southwest Jiaotong University CCCC Highway Consultants CO. Ltd.

The objective of this study is to investigate the effects of earthquakes on road vehicle-bridge coupling vibration systems. A two-axle highway freight vehicle is treated as a 13 degree-of-freedom system composed of several rigid bodies, which are connected by a series of springs and dampers. The framework of the earthquake-vehicle-bridge dynamic analysis system is then established using an earthquake as the extemal excitation. The equivalent lateral contact force serves as the judgment criteria for sideslip accidents according to reliability theory. The entire process of the vehicle crossing the bridge is considered for a very high pier continuous rigid frame bridge. The response characteristics of the vehicle and the bridge are discussed in terms of various parameters such as earthquake ground motion, PGA value of the earthquake, incident angle, pier height, vehicle speed and mass. It is found that seismic excitation is the most influential factor in the responses of the vehicle-bridge system and that the safety of vehicles crossing the bridge is seriously impacted by the dual excitations of earthquake and bridge vibration.

关键词： vehicle-bridge system coupling vibration seismic effects safety dynamic response

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Study of Heat Transfer Arising from Running of High Temperature Trains in Tunnel

Study of Heat Transfer Arising from Running of High Temperat...

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2004安全科学与技术国际会议

作者： WANG Ying1 WU Xiyong1 & LIAO Quanyan 2 (1 school of civil engineering southwest jiaotong university chengdu 61003. Sichuan china) (2 civil engineering department university of Arkansas Fayetteville AR USA 72701)

Due to the heat transfer, temperature field of a tunnel will change when high temperature trains pass through. Moving heat transfer resulted from high temperature source is studied in this paper; a th

关键词： moving heat source tunnel temperature heat transfer long-term durability tunnel lining

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Prevention of Seepage of Unsaturated Clay by Chemical Treatment

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Journal of southwest jiaotong university(English Edition) 2003年第1期11卷 58-65页

作者：徐则民杨立中刘丹 department of civil engineering Kunming University of Science and Technology school of civil engineering Southwest Jiaotong University

The aim of the study is to seek a simple and inexpensive method to prevent the permeability rise of unsaturated clay caused by evaporation process and to raise its imperviousness. Taking chengdu clay as an example, four treatment schemes were tried. Na 2CO 3 could reduce conspicuously the permeability of the saturated clay, but could not limit the permeability rise in the alternate wetting and drying process. NaOH had a similar effect to Na 2CO 3. NaCl could not only decrease the saturated hydraulic conductivity, but could also effectively contain the permeability rise caused by evaporation. CH 3COONa had a similar effect to NaCl. The mechanism of Na 2CO 3, NaOH, NaCl and CH 3COONa decreasing the saturated hydraulic conductivity of the clay is that Na + transformed Ca montmorillonites in the original clay into Na montmorillonites and the transformation reduces the sizes of effective pores and the effective porosity of the clay.

关键词： unsaturated clay seepage prevention montmorillonite chengdu clay

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用于大气污染扩散模拟的虚拟地理环境构建研究

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系统仿真学报 2008年第S1期20卷 176-179,186页

作者：朱军林珲林文实徐丙立西南交通大学土木工程学院测量工程系成都610031 香港中文大学太空与地球信息科学研究所中山大学环境科学与工程学院广州510275

重点开展基于虚拟地理环境的空气污染扩散模拟与交互操作研究,为城市空气污染的管理和时空动态模拟提供一个良好的可视化分析环境。以珠江三角洲空气污染为案例,建立虚拟地理环境原型系统,开展空气污染动态扩散模拟,进行实时交互查询与... 详细信息

重点开展基于虚拟地理环境的空气污染扩散模拟与交互操作研究,为城市空气污染的管理和时空动态模拟提供一个良好的可视化分析环境。以珠江三角洲空气污染为案例,建立虚拟地理环境原型系统,开展空气污染动态扩散模拟,进行实时交互查询与分析,实验结果证明,本文的方案能够逼真地模拟大气污染扩散过程,能较好地揭示城市群间空气污染的相互影响规律。

关键词：虚拟地理环境城市群空气污染动态模拟交互查询

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A New GPS System for Continuous Deformation Monitoring

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Journal of Modern Transportation 2000年第2期17卷 169-176页

作者：黄丁发丁晓利阿永奇 school of civil engineering Southwest Jiaotong University Chengdu 610031 China department of Land surveying and Geo-Informatics The HongKong Polytechnic UniversityKowloon HongKong

This paper presents a multi-antenna GPS based system developed for local continuous deformation monitoring. Due to a large number of points that needs to be monitored, the standard approaches of using permanent GPS receiver arrays will cause high cost. It eventually becomes the limiting factor for large-scale use of GPS in these application areas. Multi-antenna GPS system allows a number of GPS antennas to be linked to one GPS receiver by a specially designed electronic component, i. e. the so-called GPS multi-antenna switch (GMS), The receiver takes data sequentially from each of the antennas attached to the receiver. A distinctive advantage of the approach is that one GPS receiver can be used to monitor more than one point. The cost per monitored point (i. e. the expenses of hardware) is therefore significantly reduced.

关键词： multi-antenna GPS system deformation monitoring fast ambiguity resolution multipath

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IONOSPHERIC EFFECTS ON GPS NAVIGATION IN LOW-LATITUDE AREA

IONOSPHERIC EFFECTS ON GPS NAVIGATION IN LOW-LATITUDE AREA

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第一届交通运输工程国际学术会议

作者： GAO Shan1, 2 and CHEN Wu2 1school of civil engineering, southwest jiaotong university, chengdu, Sichuan, china, 61003. 2Dept. of Land surveying and Geo-Informatics, The Hong Kong Polytechnic university, Hong Kong

Ionospheric effects are the major constraints for GPS navigation. Especially, at low latitude, ionospheric delay varies greatly both in space and time. Even for short baselines, ionospheric effects cannot be cancelled out with double difference algorithm. Strong ionospheric disturbances are also observed in the region. In this paper, ionospheric behavior in Hong Kong is investigated by using a dense reference network. The effects of ionospheric disturbances on GPS receiver, such as loss of lock, gross error and measurement noise are studied.

关键词： GPS navigation ionospheric delay loss of lock cycle slip

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无泥型软弱层带饱水前后强度特性现场试验

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山地学报 2011年第2期29卷 210-216页

作者：胡卸文伊小娟胡恒洋曾记全西南交通大学地球科学与环境工程学院西南交通大学土木工程系中国水电顾问集团成都勘测设计研究院科学研究所

针对以粗粒土为代表的软弱层带在水电、铁路等交通领域对边坡及洞室围岩稳定性的控制,结合某水电工程坝区,分别对岩块岩屑型和岩屑夹泥型两种软弱夹层,在考虑一定围压作用下进行了天然含水状态和饱水状态的现场直剪试验。结果显示,剪应... 详细信息

针对以粗粒土为代表的软弱层带在水电、铁路等交通领域对边坡及洞室围岩稳定性的控制,结合某水电工程坝区,分别对岩块岩屑型和岩屑夹泥型两种软弱夹层,在考虑一定围压作用下进行了天然含水状态和饱水状态的现场直剪试验。结果显示,剪应力-剪切位移曲线饱水前、后均呈现出微弱的峰值,整体均表现为塑性破坏特征,饱水前、后发生屈服前的剪切位移分别为5 mm和10 mm以内。在强度参数上,两类夹层饱水前、后峰值强度内摩擦系数降低幅度一般在8%~10%,残余强度一般降低5%以内。表明以粗粒土为代表的软弱层带由于细粒(<0.075 mm)物质少,细粒起不到包裹粗颗粒而作为润滑作用,同时因围压效应,饱水对其强度参数的影响有限,因此不同含水状态对该类软弱层带内摩擦角和内聚力均无显著影响,其强度参数主要还是取决于夹层本身的颗粒成分。

关键词：软弱夹层粗粒土变形强度参数

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