A Feasibility Study on the Application of Fiber-Optic Distributed Sensors for Strain Measurement in the Taiwan Strait Tunnel Project

Taiwan Strait Tunnel (TST) will be an extra-long tunnel or tunnel-bridge complex, running over 150 km of seafloor geologic body with complicated topographic and geologic units. It is therefore necessary to measure and monitor the strain distribution along the TST. In this article, the Brillouin optical time-domain reflectometer (BOTDR), a newly developed strain measurement and monitoring technology, is introduced, and the feasibility of its application in the strain monitoring for TST is analyzed through the monitoring achievement with BOTDR of a tunnel located in Nanjing City, China. The results indicate that the BOTDR has many unique merits such as distributed measurement, long-distance, real-time, and resistibility for strain monitoring application in a tunnel such as TST. Finally, apreliminary scheme for BOTDR application in TST monitoring is proposed.     

Major Features of Topography, Geology, and Crustal Stability in the Taiwan Strait: A Scientific Approach to the Problem of the Taiwan Strait Tunnel Project

This article discusses briefly the major features of topography, geology, and crustal stability of the possible Taiwan Strait Tunnel Project (TST Project) area. Any one route of the conceived TST Project is larger than either of the English Channel Tunnel or the Seikan submarine Tunnel (Japan) by at least three times in length, and the topographic and geologic conditions are rather more complex and complicated than those of the former two projects. Moreover, the Taiwan Strait is a seismic risk area. Hence, the selection of the route of the submarine tunnel should take advantage of the favorable conditions in the topographic, geologic, seismologic, and other fields to avoid the unfavorable circumstances. At the end of the article, two supposed by comparable routes, especially the south one of TST Project are discussed.     

Major Features of Topography,Geology, and Crustal Stability in the Taiwan Strait: A Scientific Approach to the Problem of the Taiwan Strait Tunnel Project

This article discusses briefly the major features of topography, geology, and crustal stability of the possible Taiwan Strait Tunnel Project (TST Project) area. Any one route of the conceived TST Project is larger than either of the English Channel Tunnel or the Seikan submarine Tunnel (Japan) by at least three times in length, and the topographic and geologic conditions are rather more complex and complicated than those of the former two projects. Moreover, the Taiwan Strait is a seismic risk area. Hence, the selection of the route of the submarine tunnel should take advantage of the favorable conditions in the topographic, geologic, seismologic, and other fields to avoid the unfavorable circumstances. At the end of the article, two supposed by comparable routes, especially the south one of TST Project are discussed.     

Early Stage Characteristics of Macro Engineering and Suggestions for the Taiwan Strait Tunnel Project

Taiwan Strait Tunnel (TST) is a Macro Engineering Project (MEP). Countries all over the world have accumulated much experience on MEPs. To study the early stage characteristics of MEPs would be significant for advancing the progress of TST project. This article summarizes some common characteristics in early stage of MEPs, such as Three Gorges, South-to-North Water Diversion, The Channel Tunnel, Confederation Bridge projects, and so on. Some suggestions on early stage development are given to TST project for reference.     

Early Stage Characteristics of Macro Engineering and Suggestions for the Taiwan Strait Tunnel Project

Taiwan Strait Tunnel (TST) is a Macro Engineering Project (MEP). Countries all over the world have accumulated much experience on MEPs. To study the early stage characteristics of MEPs would be significant for advancing the progress of TST project. This article summarizes some common characteristics in early stage of MEPs, such as Three Gorges, South-to-North Water Diversion, The Channel Tunnel, Confederation Bridge projects, and so on. Some suggestions on early stage development are given to TST project for reference.     

Back analysis of an operating subsea tunnel considering the degradation of ground and concrete lining

ABSTRACT

An evaluation of the stability of subsea tunnels during operation is very important considering the risks involved with subsea tunnels. Although a large volume of monitoring information can be obtained, back analysis has been performed based on the internal displacement. In this study, the efficiency of an estimation of the safety of an operating subsea tunnel has been improved by implementing the back analysis algorithm based on various monitoring information. The differential evolution algorithm was adopted for back analysis of an operating subsea tunnel. The differential evolution algorithm was improved to accommodate the multiple target variables for back analysis, such as the elastic modulus, cohesion, friction angle of the ground, and the time-dependent elastic modulus of concrete lining. In addition, the elastic modulus of the concrete lining and the properties of reinforced ground can be evaluated with the proposed algorithm using a range of monitoring data, such as the internal displacement and stress acting on the lining. In summary, back analysis with a differential evolution algorithm can be used to evaluate the stability of an operating subsea tunnel.     

WebGIS技术在海洋地质领域中的应用

WebGIS是指利用World Wide Web向各种类型的用户提供地理空间信息服务的地理信息系统,是Internet与GIS结合的产物,通过向用户提供多样化的、直观易懂的图形用户界面,来动态地客户化地表现数据。在海洋地质领域中WebGIS主要应用于海洋地质图件的管理、发布以及海洋地质调查船的实时动态监控。随着全国海洋地质资源信息化的发展,WebGIS在海洋地质领域将拥有良好的应用前景。     

Examining fault architecture and strain distribution using geospatial and geomechanical modelling: An example from the Qaidam basin,NE Tibet

The investigation of complex geological setting is still dominated by traditional geo-data collection and analytical techniques, e.g., stratigraphic logging, dip data measurements, structural ground mapping, seismic interpretation, balance section restoration, forward modelling, etc. Despite the advantages of improving our understanding in structural geometry and fault architecture, the geospatial modelling, applying computer-aided three-dimensional geometric design, visualization and interpretation, has rarely been applied to such complex geological setting. This study used the Lenghu fold-and-thrust belt (in Qaidam basin, NE Tibetan Plateau) to demonstrate that the application of geospatial and geomechanical modelling could improve our understanding and provide an effective technique for investigating the fault architecture and strain distribution. The three-dimensional configuration of the Lenghu fold-and-thrust belt was initially derived from traditional analysis techniques, such as regional stratigraphic logging, cross section construction, meso-scale ground mapping and landsat image interpretation. The high-resolution field data and landsat image were integrated to construct the geospatial model, which was subsequently used to quantitatively investigate the fault throw changes along the Lenghu thrust fault zone and to understand its control on the lateral structural variation. The geospatial model was then restored in three dimensions to reveal the kinematic evolution of the Lenghu fold-and-thrust belt. Geomechanical modelling, using a Mass-Spring algorithm, provided an effective three-dimensional tool for structural strain analysis, which was used to predict the strain distribution throughout the overall structure, e.g., normal faults with throws ranging from meters to tens of meters in the hanging-wall. The strain distribution predicted by geomechanical modelling was then validated by the natural normal faults in the hanging-wall. The high accordance between the strain prediction and statistics of natural normal faults demonstrates good applicability of geospatial and geomechanical modelling in the complex geological setting of the Lenghu fold-and-thrust belt. The geospatial models and geomechanical models, therefore, can provide a robust technique for analyzing and interpreting multi-source data within a three-dimensional environment. We anticipate that the application of three-dimensional geospatial modelling and geomechanical modelling, integrating both multi-source geologic data and three-dimensional analytical techniques, can provide an effective workflow for investigating the fault architecture and strain distribution at different scales (e.g., ranging from regional-to meso-scale).     

无人机及三维激光扫描仪技术在沙滩剖面动态监测中的应用及测量精度分析

沙滩剖面动态监测是沙滩整治修复工程效果评价的基础性工作,同时也是工程实践中及时发现问题并提出解决方案的关键步骤。由于常规测量手段存在工作效率低、周期长、难以全面覆盖测区等局限性,新型技术在沙滩剖面动态监测中的应用研究显得尤为重要。本研究以厦门天泉湾沙滩养护工程为案例,通过无人机航拍技术和三维激光扫描仪获取沙滩数字正射影像和高程数据,与人工测量结果进行比对和统计分析,研究两种技术的应用价值。研究结果表明,无人机平面坐标精度较高,但高程精度有所偏离;三维激光扫描仪测量数据满足沙滩剖面地形测量精度要求,但易受视场角限制,结果存在扫描噪点和盲区。因此,采用无人机及三维激光扫描仪技术,结合传统测量手段进行沙滩剖面动态监测,在我国广泛分布的沙滩养护工程实践中,具有良好的应用价值。     

Erratum

Abstract

Several physical aspects of continuous subbottom profiling are presented, and their relationship to operating characteristics of profiling instruments is discussed. Interpretation of data produced by shallow‐penetration continuous profilers, such as the SONIA system, is a process of transformation of the continuous measurement of the travel times of reflected sound pulses into geologic phenomena. Essentially, the continuous profiler is a geologic tool; interpretation of the data is based on geologic observation and reasoning, irrespective of the further use of the information obtained in applied science. However, interpreters must have sufficient knowledge of the geophysical system and of the equipment design to be in a position to evaluate the significance of their interpretation.     

无人船监测与测量技术进展

为了促进无人船技术得到快速发展,较系统地综述了无人船监测与测量的基本原理、主要性能和典型应用,同时对无人船的船身结构、动力系统、测量载荷等硬件设备以及数据处理、岸基控制等软件系统做了较为详细的阐述。最后对当前无人船测量技术发展中存在的难题进行了深入分析与探讨,以期我国的无人船监测与测量技术能够得到较为迅速的发展并得到广泛的应用,满足社会发展的需要。     

海底底质声学原位测量电路控制系统研究

介绍了一种液压驱动贯入式海底沉积声学原位测量系统的电路控制单元的研究实现过程,以及该控制单元在南海北部海底沉积声学调查中的应用。该电路控制单元以Cortex-A8处理器为核心,集成大容量FLASH存储器,与单片机接口控制板进行串口通讯,实现对声学发射采集单元和机械液压贯入单元的可视化控制和监测。基于该电路控制单元,海底底质声学原位测量系统兼具自容式和在线式两种工作模式,可自容记录或实时采集声学原位测量单元在海底的工作状态数据、海底沉积物声速和声衰减系数等声学特性数据。该声学原位测量系统的实验室联调及南海海试结果表明,使用该电路控制单元对海底底质声学测量过程的监测与控制是有效的,对精确获取海底底质的原位声学特性有重要作用,可以促进海底底质声学原位测量系统的产品化。     

渤海中部馆陶组层序地层特征及底部界限研究

通过以岩电性、古生物、地震层序为基础的层序地层学研究,结合区域研究资料,在馆陶组识别出低位、水进和高位三种体系域;利用基准面旋回技术识别出短期基准面旋回（SSC）、中期基准面旋回（MSC）和长期基准面旋回（LSC）;馆陶组划分为2个长期基准面旋回,4个中期基准面旋回MSC1～MSC4,建立了渤海中部馆陶组及东上段高分辨率等时地层对比格架。D5-1井2 782～2 917 m井段确定为东一段地层,其顶界即为馆陶组的底界。通过对馆陶组底部界限的确定和区域馆陶组及东上段高分辨率层序地层等时对比格架的建立,对该区馆陶组底部界限进行了重新厘定,以解决油气勘探中遇到的问题。     

Precise positioning for near-bottom equipment using a relay transponder

The Marine Physical Laboratory of the Scripps Institution of Oceanography has developed an acoustic relay transponder for precise relative positioning of near-bottom instruments and geologic sampling devices. Although specifically designed to position equipment lowered on standard wire ropes without a need to maintain direct electrical contact with the surface ship, the relay transponder may be used to track free vehicles, such as deep submersibles, from the surface. The relay transponder is positioned relative to an array of bottom-anchored acoustic transponders. It is interrogated acoustically from the surface ship; it then sequentially interrogates the bottom transponders which, in turn, reply to the ship. From the measurement of the total travel time (ship to relay transponder to bottom transponder to ship) and assuming, or knowing, the sound velocity of the water, we obtain a relayed range measurement. These relayed ranges, used in conjunction with ship to bottom-transponder ranges, allow us to calculate the position of the relay transponder. A recent application of this technique is described in which several gravity core samples from the crest of the Horizon Guyot were positioned with respect to the detailed bathymetry and the geology within the area. The estimated error in positioning the samples is less than 20 m inside a navigational net extending over 100 km².Contribution of the Scripps Institution of Oceanography, new series.     

The Ocean Community

Development of ocean community systems relating to the Taiwan Strait Tunnel (TST) project, with regionalization and multistage approach is proposed. The purposes of these systems are to assist the development of coastal marine lands and harbor facilities and to develop connecting isolated islands into an organized community by means of embankment roadways, tunnels, bridges, ferryboats, and so on. The major aim of such an approach is to develop the isolated abandoned islands into useful land improvement, expand the forest, agriculture, and fishing industries and other resources to generate additional revenue to subsidize some of the cost for building the TST. This article points out the systems' importance, outlines the general procedures, and discusses a possible transportation network connecting islands with land; and the outlines development of the knowledge-based expert system computer program to be applied to the ocean community systems relating to the TST project.     

The Ocean Community

Development of ocean community systems relating to the Taiwan Strait Tunnel (TST) project, with regionalization and multistage approach is proposed. The purposes of these systems are to assist the development of coastal marine lands and harbor facilities and to develop connecting isolated islands into an organized community by means of embankment roadways, tunnels, bridges, ferryboats, and so on. The major aim of such an approach is to develop the isolated abandoned islands into useful land improvement, expand the forest, agriculture, and fishing industries and other resources to generate additional revenue to subsidize some of the cost for building the TST. This article points out the systems' importance, outlines the general procedures, and discusses a possible transportation network connecting islands with land; and the outlines development of the knowledge-based expert system computer program to be applied to the ocean community systems relating to the TST project.     

Study on the Long-term Settlement of Subway Tunnel in Soft Soil Area

The long-term settlement of a subway tunnel, especially the differential settlement affects the safe operation of the subway. In this article, the settlement of a subway tunnel was studied from the theoretical and numerical analyses based on the monitoring data. According to the monitoring data, the deformation of segments at different locations is different, and the deformation around a channel is larger than other places. The settlements of tunnel calculated by two theoretical methods are consistent with that obtained in the centrifuge model test. The numerical simulation indicates that the vertical displacement is much bigger than the horizontal displacement.     

动力定位系统与单波束测深仪在科考船定点作业中的应用

科考船定点作业时会受到海洋风、涌、浪、流等外界环境因素影响，导致工作效率降低，原位测量精度下降，甚至影响作业安全。动力定位系统 （DP） 具有自动定位功能，能够抵抗外界环境因素的影响，可实现科考船高精度定点控位。 单波束测深仪不仅可以测量水深，也可反映水下设备深度信息，可以起到辅助监控水下设备功能。本文在介绍定点作业施工现状与局限性的基础上，分析 DP 系统与单波束测深仪工作原理，以“向阳红 01”船为载体，在定点作业时开启 DP 系统与单波束测深仪，发现该方法可以提高科考船定点作业工作效率、原位测量精度并保障作业安全，可为其他科考船定点作业提供参考。     

基于监测数据的深水水下井口循环弯矩计算方法

水下井口的疲劳完整性是海洋油气田长期安全开采的前提。工业界往往采用贴应变片直接测量水下井口应变来计算弯矩和疲劳损伤,但水下井口应变片粘贴困难且不能长时间连续工作。采用对水下井口监测方法,基于隔水管—防喷器组—水下井口的运动和力学特性,考虑防喷器组惯性力矩建立系统耦合动力学方程,最终形成基于监测数据的水下井口循环弯矩计算方法。以南海某深水水下井口为例,建立隔水管—防喷器组—水下井口系统有限元模型并进行动态分析,提取隔水管底部张力、转角、防喷器组加速度及转角等参数,代入所建立的系统耦合动力学模型,得到水下井口弯矩与有限元计算结果吻合良好。研究表明只需通过在线监测获得所需的输入数据,无需监测水下井口应变即可获取水下井口循环弯矩。建立的系统耦合动力学模型可为水下井口疲劳完整性评估提供理论依据。     

精细磁法在胶州湾口海底隧道工程地质勘察中的应用

结合胶州湾湾口海底隧道工程的地质物探勘察工程,介绍了精细海洋磁法勘测的海上调查方法,阐述了利用GEOCAP软件的磁力实测数据资料的高精度数据处理技术,说明了利用GRAPHER软件、SURFER软件和MAGPICK软件绘制磁力异常ΔT剖面图、平面等值线图和平面剖面图的方法,最后讨论了应用磁测资料进行地质解释的方法。