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1 – 10 of 507Jiang Chen, Junli Zheng and Feng Xiong
The spatial resolution of seepage monitoring methods based on fiber Bragg grating (FBG) temperature sensing technology is limited by the distance between measurement points…
Abstract
Purpose
The spatial resolution of seepage monitoring methods based on fiber Bragg grating (FBG) temperature sensing technology is limited by the distance between measurement points. Improving the spatial resolution for a given number of measurement points is a prerequisite for popularizing this technology in the seepage monitoring of rockfill dams. The purpose of this paper is to address this problem.
Design/methodology/approach
This paper proposes a mobile-distributed seepage monitoring method based on the FBG-hydrothermal cycling seepage monitoring system. In this method, the positions of the measurement points are changed by freely dragging the FBG sensing cluster within the inner tube of a dual-tube structure, consisting of an inner polytetrafluoroethylene tube and outer polyethylene of raised temperature resistance heating tube.
Findings
A seepage velocity calibration test was carried out using the improved monitoring system. The results showed that under a constant seepage velocity, the use of the dual-tube structure enables faster cooling, and the cooling rate accelerates with an increase in the diameter of the inner tube. The use of the dual-tube structure can improve the sensitivity of the seepage evaluation index ζv to the seepage velocity. When the inner diameter increases, ζv becomes more sensitive to the seepage velocity.
Originality/value
A mobile-distributed seepage monitoring method based on FBG sensing technology is proposed in which the FBG sensors are not fixed. Instead, the positions of the measurement points are changed to improve the spatial resolution. Meanwhile, the use of the dual-tube structure in the presented monitoring system can improve its sensitivity.
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Technical means now exist to monitor, predict a danger and issue early warnings when something devastating is estimated to happen in the human environment. In order to adapt such…
Abstract
Technical means now exist to monitor, predict a danger and issue early warnings when something devastating is estimated to happen in the human environment. In order to adapt such means for the benefit of humanity, existing monitoring methods, basic system design principles and natural short and long environmental transformations were investigated. Finally an integrated automatic system for deformation monitoring and surveying of the Chernobyl disaster area, was proposed. The conclusion was that airborne remote sensing including GPS and photogrammetry can be considered the optimum solution.
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Yongxing Guo, Jianjun Fu, Longqi Li and Li Xiong
Centrifugal model tests can accelerate the characterization of landslides and demonstrate the form of slope failure, which is an important measure to research its instability…
Abstract
Purpose
Centrifugal model tests can accelerate the characterization of landslides and demonstrate the form of slope failure, which is an important measure to research its instability mechanisms. Simply observing the slope landslide before and after a centrifugal model test cannot reveal the processes involved in real-time deformation. Electromagnetic sensors have severed as an existing method for real-time measurement, however, this approach has significant challenges, including poor signal quality, interference, and complex implementation and wiring schemes. This paper aims to overcome the shortcomings of the existing measurement methods.
Design/methodology/approach
This work uses the advantages of fiber Bragg grating (FBG) sensors with their small form-factor and potential for series multiplexing in a single fiber to demonstrate a monitoring strategy for model centrifugal tests. A slope surface deformation displacement sensor, FBG anchor sensor and FBG anti-slide piling sensor have been designed. These sensors are installed in the slope models, while centrifugal acceleration tests under 100 g are carried out.
Findings
FBG sensors obtain three types of deformation information, demonstrating the feasibility and validity of this measurement strategy.
Originality/value
The experimental results provide important details about instability mechanisms of a slope, which has great significance in research on slope model monitoring techniques and slope stability.
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Xiao Fang, Yajie Zeng, Feng Xiong, Jiang Chen and Fei Cheng
Seepage of the dam is an important safety problem, which may cause internal erosion of the structure. In the field of seepage monitoring in civil engineering, the distributed…
Abstract
Purpose
Seepage of the dam is an important safety problem, which may cause internal erosion of the structure. In the field of seepage monitoring in civil engineering, the distributed optical fiber sensing technology based on the temperature tracing method has been paid more attention due to its unique advantages of high sensitivity, good stability and high resolution. The purpose of this paper is to make a review of the existing related research, so as to facilitate the later scholars to understand and further study more systematically.
Design/methodology/approach
In this paper, three kinds of commonly used distributed fiber temperature measurement technologies are introduced. Based on the working principle, monitoring system, theoretical analysis, experimental research and engineering application of the fiber seepage monitoring technology, the present situation of dam seepage monitoring based on distributed fiber is reviewed in detail and their advantages and disadvantages are compared.
Findings
The thermal monitoring technology of seepage measurement depends on the accuracy of optical fiber temperature measurement (including the accuracy of the system and the rationality of the discrimination method), the correct installation of optical fiber and the quantitative analysis of temperature data. The accuracy of the current monitoring system can basically meet the existing measurement requirements, but the correct installation of optical fiber and the calibration of temperature data need to be further studied for different discrimination methods, and this field has great research value.
Originality/value
At present, there are many applications and research studies of optical fiber sensing in the field of structural health monitoring, and there are also reviews of related aspects. However, there is little or no review only in the field of seepage monitoring. This paper summarizes the research and application of optical fiber sensing in the field of seepage monitoring. The possibility of the gradient method to find its new prospect with the development of monitoring systems and the improvement of temperature resolution is discussed. The idea of extending the seepage monitoring method based on distributed optical fiber thermal monitoring technology to other monitoring fields is also given in the paper.
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Gao Zhan‐feng, Du Yan‐liang, Sun Bao‐chen and Jin Xiu‐mei
The purpose of this article is to suggest that Fraby‐Perot optic sensor is a practical measurement gage to monitor the strain of great structures such as railway bridges.
Abstract
Purpose
The purpose of this article is to suggest that Fraby‐Perot optic sensor is a practical measurement gage to monitor the strain of great structures such as railway bridges.
Design/methodology/approach
A remote strain monitoring system based on F‐P optic fiber and virtual instrument is designed to monitor the strains of a railway bridge.
Findings
The application results show that the Fraby‐Perot optical fiber sensors can accurately measure strain and they are suitable for the long‐term and automatic monitoring. In addition, the system has several advantages over conventional structural instruments including fast response, ability of both static and dynamic monitoring, absolute measurement, immunity to interferences such as lightning strikes, electromagnetic noise and radio frequency, low attenuation of light signals in long fiber optic cables.
Practical implications
Health monitoring of structures is getting more and more recognition all over the world because it can minimize the cost of reparation and maintenance and ensure the safety of structures. A strain monitoring system based on F‐P optic fiber sensor was developed according to the health monitoring requirements of Wuhu Yangtze River Railway Bridge, which is the first cable‐stayed bridge with a maximum span of 312 m carrying both railway and highway traffic in China. It has run stably in the monitoring field more than two years and fulfilled the monitoring requirement very well. Now the system has been transplanted successfully to the Zhengzhou Yellow Railway Bridge for strain monitoring. So the work can be referenced by other similar health monitoring projects.
Originality/value
Long‐term, real‐time monitoring of strain using FP fiber optic sensors in railway bridge is an innovation. A remote strain data acquisition and real‐time processing are another character of the system. The work studied can be referenced by other structures monitoring, such as tunnel, concrete bridges, concrete and earth dams.
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Cristian Fosalau, Cristian Zet and Daniel Petrisor
The paper aims to present a device devoted to detect and measure earth displacements produced by landslides. This device is an inclinometer type geotechnical instrument. It is…
Abstract
Purpose
The paper aims to present a device devoted to detect and measure earth displacements produced by landslides. This device is an inclinometer type geotechnical instrument. It is widely known that landslides are categorized among the most destructive disasters that yearly produce huge damages and even human lives losses.
Design/methodology/approach
The principle of operation is based on measuring the deformation produced during soil layers sliding to a rod vertically mounted into the ground. The rod deformation is detected by highly sensitive strain gauges developed by authors using the stress impedance effect occurring in non-magnetostrictive magnetic amorphous microwires. The gauges are mounted in bridge configurations along the rod, beside the corresponding analogue and digital signal processing circuitry.
Findings
The landslide transducer is able to calculate the displacement of the soil layers at different levels of depth and the direction of the landslide. It has been tested in laboratory in terms of sensitivity and accuracy. A resolution of less than 1 mm has been achieved for displacement detection, whereas orientation may be calculated with about a maximum accuracy of less than 20 degrees.
Research limitations/implications
Problems occurred in the manufacturing process of the gauges because of the quite large dispersion of the microwire parameters, as well as with gluing the gauges on the rod, that is compulsory to be well done, otherwise the gauges relaxation occurs with consequence in time stability decay.
Originality/value
With respect to other commercial devices, our inclinometer is characterized by high sensitivity and also by possibility of 3D measuring, it being able to gauge in depth the amplitude and orientation of the landslide.
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Faris Elghaish, Sandra Matarneh, Saeed Talebi, Michail Kagioglou, M. Reza Hosseini and Sepehr Abrishami
In this study, a critical literature review was utilized in order to provide a clear review of the relevant existing studies. The literature was analyzed using the meta-synthesis…
Abstract
Purpose
In this study, a critical literature review was utilized in order to provide a clear review of the relevant existing studies. The literature was analyzed using the meta-synthesis technique to evaluate and integrate the findings in a single context.
Design/methodology/approach
Digital transformation in construction requires employing a wide range of various technologies. There is significant progress of research in adopting technologies such as unmanned aerial vehicles (UAVs), also known as drones, and immersive technologies in the construction industry over the last two decades. The purpose of this research is to assess the current status of employing UAVs and immersive technologies toward digitalizing the construction industry and highlighting the potential applications of these technologies, either individually or in combination and integration with each other.
Findings
The key findings are: (1) UAVs in conjunction with 4D building information modeling (BIM) can be used to assess the project progress and compliance checking of geometric design models, (2) immersive technologies can be used to enable controlling construction projects remotely, applying/checking end users’ requirements, construction education and team collaboration.
Practical implications
A detailed discussion around the application of UAVs and immersive technologies is provided. This is expected to support gaining an in-depth understanding of the practical applications of these technologies in the industry.
Originality/value
The review contributes a needed common basis for capturing progress made in UAVs and immersive technologies to date and assessing their impact on construction projects. Moreover, this paper opens a new horizon for novice researchers who will conduct research toward digitalized construction.
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Patrick T.I. Lam, Francis K.W. Wong and Franky W.H. Wong
Buildability is concerned with enhancing building designs to achieve ease of construction. Adapting from the Buildable Design Appraisal System in Singapore, a tailored‐made…
Abstract
Purpose
Buildability is concerned with enhancing building designs to achieve ease of construction. Adapting from the Buildable Design Appraisal System in Singapore, a tailored‐made Buildability Assessment Model (BAM), which scores buildability of building designs, has been devised for use in Hong Kong. In developing the BAM, local factors and terrain characteristics, e.g. highly constrained and sloping site conditions, which are common features besetting the industry, are particularly considered. The purpose of this paper, therefore, is to report on the effects of building sites on buildability.
Design/methodology/approach
A questionnaire survey with 39 valid responses was administered on construction practitioners, aimed at understanding the relative buildability importance of a number of building features and site‐specific factors in Hong Kong. Analysis was carried out using the relative importance index method.
Findings
It is found that the most important buildability considerations for building features and site‐specific factors are “simplicity” and “allowing working space for safe construction and minimising water ingress and geotechnical difficulties”, respectively.
Research limitations/implications
The small sample size, though statistically significant, can be increased in further studies of similar type, to enhance the representativeness of the rankings.
Originality/value
The survey findings are valuable in that they offer a practical reference for design professionals, by scoring their designs, to comprehend the degree to which various building features and site‐specific factors impact on the ease of constructing their designs.
Sifeng Liu, Yong Tao, Naiming Xie, Liangyan Tao and Mingli Hu
The purpose of this paper is to summarize the advances in grey system theory research and various application achievements in science and engineering. At the same time, it…
Abstract
Purpose
The purpose of this paper is to summarize the advances in grey system theory research and various application achievements in science and engineering. At the same time, it commemorates the 40th anniversary of the birth of grey system theory and the 10th anniversary of Grey Systems–Theory and Application.
Design/methodology/approach
Firstly, the innovations of theoretical research in grey system theory were summarized and some of the widely recognized new results are briefly described. By searching and combing the research results of grey system theory in China national knowledge infrastructure (CNKI) database and Web of Science by Institute for Scientific Information (ISI), this paper shows the rapid development trend of grey system theory in the past 40 years, and the successful applications of grey system theory in the fields of social sciences, natural sciences and engineering technologies.
Findings
More than 227 thousands literature were found by input 10 phrases such as grey system, grey number and sequence operator etc. in CNKI database. After entering the new century, the number of grey system papers included in CNKI database is increasing rapidly. Since 2008, more than 10 thousands papers have been included per year and more than 15 thousands papers have been included per year since 2014. Grey system method and model are widely used in physics, chemistry, biology and other fields of natural science, as well as transportation, electric power, machinery and other fields of engineering technology, and a large number of valuable results have been achieved.
Practical implications
It can be seen that the grey system theory plays an important role in promoting China’s scientific and technological progress, innovation and development and high-level talent training from tens of thousands of literatures marked with important national science and technology projects and a large number of grey system literatures published by China’s double first-class universities and double first-class discipline construction universities.
Originality/value
Both innovations of theoretical research and practical application play important role in the growth of new theory. The innovations of theoretical research provide methods and tools for practical application, which is conducive to improve application efficiency and broaden application fields. A large number of practical applications needs have become the source of theoretical innovation and the solid background for the birth of theoretical innovation achievements.
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