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ISSN 1000-0585
CN 11-1848/P
Started in 1982
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  • Table of Content
      , Volume 61 Issue 7 Previous Issue    Next Issue
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    Editorial
    Review
    Closed-loop control theory of intelligent construction
    FAN Qixiang, LIN Peng, WEI Pengcheng, Ning Zeyu, LI Guo
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 660-670.   DOI: 10.16511/j.cnki.qhdxxb.2020.26.023
    Abstract   HTML   PDF (3211KB) ( 493 )
    Intelligent construction is one of the most popular research directions in the field of infrastructure engineering for various fields including hydropower and civil engineering projects. Intelligent construction has been used in China in recent years and is essential for the future development of engineering systems and project management. This study defines intelligent construction as the integration of sensors, communication systems, data systems, construction methods and project management to perceive, analyze and control the safety, quality, environmental effects, schedule and construction costs. This article then describes the main characteristics of intelligent construction systems. Current experience shows that the general closed-loop control theory of intelligent construction including perception, analysis, control and continuous optimization leads to current construction activities forming new construction activities from quantitative descriptions and learning from existing activities. This intelligent behavior provides better control of the construction process. Finally, the integration of intelligent construction methods with management decisions leads to new value creation with new intelligent construction methods needed to further develop construction techniques.
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    Research Article
    Intelligent closed-loop control of concrete moisture levels
    FAN Qixiang, DUAN Yahui, WANG Yezhen, WANG Xiaohai, YANG Simeng, KANG Xusheng
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 671-680.   DOI: 10.16511/j.cnki.qhdxxb.2020.26.038
    Abstract   HTML   PDF (4457KB) ( 168 )
    The concrete moisture content must be maintained after curing. The cement particles in concrete cannot fully hydrate and transform to a stable crystalline form if the concrete is not well hydrated. In addition, moisture loss may result in shrinkage, deformation and cracks, which will affect the structure durability. Concrete specifications and experience have shown that the concrete surface humidity should be no less than 95% during curing. Humidity diffusion theory was used to develop a mathematical model for the concrete moisture conservation with the third type of boundary condition at the surface. Information technology and mechanical control theory were then used to develop an intelligent control method for the concrete moisture conservation. An intelligent control system was then developed to automatically collect the temperature, humidity and wind speed near the concrete surface and to then calculate the concrete surface humidity. The intelligent control system provides real-time feedback warnings and intelligently controls a spray tube which reduces labor costs and ensures the concrete quality. The intelligent control equipment can be flexibly adapted to various large, complex engineering projects.
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    Moving-average calculations for real-time concrete temperature monitoring
    NING Zeyu, LIN Peng, PENG Haoyang, WANG Zhilin, CHEN Wenfu, TAN Yaosheng, ZHOU Tiangang
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 681-687.   DOI: 10.16511/j.cnki.qhdxxb.2020.26.40
    Abstract   HTML   PDF (4814KB) ( 128 )
    Real-time temperature monitoring data quality is important for intelligent concrete cooling control. This paper presents a moving-average method for real-time concrete temperature monitoring data which extends the traditional moving average to multiple dimensions including time, space, and quality. Dynamic analyses of the raw data average in the intelligent concrete cooling control system provide temperature data that characterize the conditions at a given moment, spatial location, or object, which significantly reduces the effects of systematic and random errors in the raw data and reduces data distortion caused by instrument failures, sudden environmental changes and other effects. This method then reduces the impact of data errors on subsequent data calculations, simulations, and analyses. Analysis of real-time concrete temperature monitoring data from the Baihetan and Wudongde arch dams shows the advantages of this method for improving the monitoring system, data quality, and decision-making ability of management personnel. The results then provide a reference for concrete temperature control system design and quality evaluations.
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    Overtime warning of concrete pouring interval based on object detection model
    MEI Jie, LI Qingbin, CHEN Wenfu, WU Kun, TAN Yaosheng, LIU Chunfeng, WANG Dongmin, HU Yu
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 688-693.   DOI: 10.16511/j.cnki.qhdxxb.2021.26.016
    Abstract   HTML   PDF (14601KB) ( 468 )
    Timely, comprehensive and accurate access to the status and progress of various activities on the construction site is essential for quality control, progress tracking and productivity analysis, and is also necessary for the full realization of fine management and intelligent construction. At present, the progress recording and quality control under the concrete pouring construction scenario are still mostly done manually, leading to problems such as insufficient timeliness, misreporting and omission. In this study, the semantic segmentation and object detection technology in the field of deep learning computer vision are applied to the field of engineering construction. Real-time construction progress is obtained by identifying formwork cover ratios and the unloading event of the bucket, and the overtime warning of layer coverage time with second-level accuracy is realized.
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    Intelligent construction methods for the Baihetan super high arch dam
    TAN Yaosheng, FAN Qixiang, WANG Zhilin, CHEN Wenfu, GUO Zengguang, LIN Ende, LIN Peng, ZHOU Tiangang, ZHOU Mengxia, LIU Chunfeng, GONG Pan, PEI Lei
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 694-704.   DOI: 10.16511/j.cnki.qhdxxb.2021.26.005
    Abstract   HTML   PDF (18906KB) ( 390 )
    Construction projects are making use of modern information technology methods such as big data and artificial intelligence to improve project construction. The Xiluodu Hydropower Project is a pioneer application of intelligent construction methods for high arch dams. However, the rapid advances in information, sensing and data processing methods require further development of intelligent dam construction methods. Intelligent dam construction methods are introduced here as applied to the Baihetan Hydropower Project, a 300-meter ultra-high arch dam, with extensive monitoring measurements, real analyses, intelligent decision making and feedback control. This paper describes the intelligent construction system and its implementation with a focus on key construction processes and business processes including whole-process concrete placement monitoring, concrete leveling and vibrating monitoring, intelligent water-cooling, intelligent spraying and intelligent grouting. This paper then further describes the close-loop control of these intelligent methods and their functions.
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    Three-dimensional seepage field simulations to evaluate seepage control for the Baihetan dam
    CHEN Zhiheng, RONG Guan, TAN Yaosheng, ZHANG Ziyang, WANG Kexiang, LUO Guanjun
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 705-713,723.   DOI: 10.16511/j.cnki.qhdxxb.2021.26.002
    Abstract   HTML   PDF (22574KB) ( 328 )
    A three-dimensional finite element model of the geological and hydrogeological conditions of the Baihetan dam was developed to analyze the seepage control schemes. The model was used to model the seepage distribution characteristics of the dam foundation such as the soaking surface, the gross head, the hydraulic gradient and the seepage flow to analyze the seepage stability of weak intercalation. The analysis used steady seepage theory and accurate simulations of the drainage holes to simulate the seepage field for normal operation conditions. The results show that the dam foundation grouting curtain effectively prevents reservoir water leakage from upstream and effectively stops possible leakage channels. Drainage hole arrays significantly reduce the surrounding soaking surface area and drain leakage water from the dam foundation and abutments on both sides. There are large hydraulic gradients at the intersections of the bedding fault zone, fractural fault zone and grouting curtain and at the drainage holes, with small hydraulic gradients at other locations. The results show that the seepage control design scheme can effectively control the seepage and that the anti-seepage drainage design is reasonable.
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    Key techniques for dam construction simulations
    LIU Youzhi, ZHANG Guoxin, TAN Yaosheng, LIU Chunfeng, GONG Pan, PEI Lei
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 714-723.   DOI: 10.16511/j.cnki.qhdxxb.2021.26.004
    Abstract   HTML   PDF (8474KB) ( 182 )
    The Wudongde and Baihetan arch dams are two super high arch dams under construction at the same time in China. The dam site is located in the windy, dry, hot Jinsha River valley. The dams are made of low-heat cement. This project models the temperature control and crack prevention during the pouring process, the dam and foundation deformation control with water storage, and the safety of long-term operation. This article focuses on the key technical issues involved in simulating the dam construction process with the intelligent construction system used for these dams, the key problems in the simulation dam construction process, and the key points in creating dam construction simulations. The experience gained in developing these two engineering dam simulation was used to identify the problems that need to be solved for future projects.
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    Intelligent spray control for the concrete curing of mass concrete bins
    YANG Ning, LIU Yi, QIAO Yu, TAN Yaosheng, ZHU Zhenyang
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 724-729.   DOI: 10.16511/j.cnki.qhdxxb.2021.26.008
    Abstract   HTML   PDF (3962KB) ( 148 )
    The external environment around hydropower projects is very complex. Many dam sites have complex, variable meteorological conditions, such as strong winds, dry heat and intense sunshine. The particular climate and geographical conditions require changes to the conventional monitoring method for individual concrete dam surfaces to provide high-quality dam construction. The concrete environment, especially the temperature, needs to be carefully controlled during construction to reduce the occurrence of harmful cracks. This paper describes an automatic control system for mass concrete climate control. Experimental data was used to develop a model that related the outside environmental temperature and the equipment characteristics to the concrete surface conditions with another model to relate the temperatures inside the concrete to the concrete surface temperature. These two models were then used to design intelligent spray equipment for use during the pouring process that adjusts the spray intensity based on the pouring requirements and the ambient temperature to automatically control the concrete climate to give the correct concrete temperature and humidity ranges.
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    Engineering application and factors affecting infrared temperature measurements of mass concrete surfaces
    QIAO Yu, YANG Ning, TAN Peng, PENG Haoyang, WU Wei, ZHOU Dajian, WANG Xiaonan
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 730-737.   DOI: 10.16511/j.cnki.qhdxxb.2021.26.017
    Abstract   HTML   PDF (9155KB) ( 112 )
    Dam concrete pouring needs accurate non-contact infrared temperature measurements and temperature control. This paper presents an infrared temperature measurement algorithm for dam concrete surfaces based on concrete surface temperature measurements for various ambient temperatures at various distances. The algorithm was then applied to an infrared concrete temperature measurement system for super-high arch dams in complex environments. The tests show that this system provides accurate, real-time, and on-line temperature monitoring of the concrete production, transport and pouring at a site test in the Wudongde Hydropower Station. The system provides continuous boundary conditions including the temperatures for analyzing the dam characteristics. The study results provide a reference for on-line temperature monitoring of similar engineering systems.
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    Three-dimensional temperature field analyses based on massive optical fiber temperature monitoring data in concrete dams
    ZHOU Huawei, ZHAO Chunju, CHEN Wenfu, ZHOU Yihong, TAN Yaosheng, LIU Quan, PAN Zhiguo, YOU Hao, LIANG Zhipeng, WANG Fang, GONG Pan
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 738-746.   DOI: 10.16511/j.cnki.qhdxxb.2020.26.043
    Abstract   HTML   PDF (18701KB) ( 145 )
    Optical fibers were embedded in a large concrete dam during construction for real-time temperature measurements to enable reconstruction of the three-dimensional temperature distribution in the Baihetan dam. A three-dimensional temperature analysis was developed to manage the fiber optic measurements and predict the construction quality through real-time data acquisition, analysis and processing of the massive temperature data sets to monitor the temperature changes. The results show that the system provides efficient analyses of the massive amounts of temperature data and accurately analyzes the temperature distribution characteristics in concrete dams. This system can be directly applied for temperature monitoring and analysis of other concrete dam projects. The system can also be extended to the management and analysis of massive data sets for other projects.
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    Thermal parameter inversion for various materials of super high arch dams based on the hybrid particle swarm optimization method
    WANG Feng, ZHOU Yihong, ZHAO Chunju, ZHOU Huawei, CHEN Wenfu, TAN Yaosheng, LIANG Zhipeng, PAN Zhiguo, WANG Fang
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 747-755.   DOI: 10.16511/j.cnki.qhdxxb.2020.26.044
    Abstract   HTML   PDF (5872KB) ( 111 )
    Concrete thermal parameters during construction and laboratory tests can differ, so the particle swarm optimization (PSO) algorithm and optical fiber temperature monitoring data were used to identify the thermal parameters of the concrete for super high arch dams at low winter temperatures. Traditional PSO algorithms can easily fall into local extrema, so a swarm intelligence-hybrid particle swarm optimization (HPSO) model was developed in this study using a concave function weight decreasing strategy to avoid local extrema. HPSO combines PSO with genetic algorithm cross and mutation operations. These more effectively balance the algorithm global and local search abilities. HPSO was used for thermal parameter inversion searches of various strength concretes and concretes with various gradations with cooling water and a specified environmental temperature. The model considers the influences of multi-stage water flows and water temperature variations along the cooling water pipe. Examples show the effectiveness of the intelligent identification system and the quick convergence of HPSO. The inversion results clarify the relationship between the thermal parameters and the temperature changes.
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    Intelligent scheduling for high arch dams
    WANG Fei, LIU Jinfei, YIN Xishuang, TAN Yaosheng, ZHOU Tiangang, YANG Zhiyue, FENG Bo, YANG Xiaolong
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 756-767.   DOI: 10.16511/j.cnki.qhdxxb.2021.26.003
    Abstract   HTML   PDF (17447KB) ( 381 )
    The construction of arch dams is often affected by severe natural environmental conditions and the complex construction processes which slow construction progress. Construction scheduling simulations provide effective management tools for arch dam construction progress planning. Intelligent construction methods based on the Internet of Things (IoT) have been used in the construction of hydropower stations such as the Xiluodu, Wudongde and Baihetan high arch dams. During these projects, arch dam construction management has gradually evolved from simple manual interactions to intelligent systems. However, the simulation parameters often do not accurately reflect the actual construction state, so the simulation resources do not accurately match the actual conditions and schedule optimization, construction resource allocation, project coupling, and multi-party collaboration can be at very different states. Intelligent scheduling simulations based on the Internet of Things have been developed to improve construction scheduling for high arch dams. Finally, this paper summarizes the key technologies for intelligent schedule simulations and identifies key directions for future intelligent schedule simulations.
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    Intelligent concrete transport methods for super-high arch dams
    XU Jianjiang, CHEN Wenfu, TAN Yaosheng, GAO Shikui, ZHOU Tiangang, ZHOU Mengxia, LIU Chunfeng, LIANG Cheng, LI Xiangqian
    Journal of Tsinghua University(Science and Technology). 2021, 61 (7): 768-776.   DOI: 10.16511/j.cnki.qhdxxb.2021.26.007
    Abstract   HTML   PDF (9365KB) ( 153 )
    Proper concrete transport at super-high arch dams is important for maintaining good concrete properties for dam integrity. This study used the Baihetan project as an example to analyze the problems of isolated information, difficult linkage control and safety control of cable crane groups for concrete transport when building super-high arch dams. The construction was further complicated by a double platform construction layout and the difficulties of concrete transport management with multiple, simultaneous pours. This paper presents a model of the concrete transport linkages and cable crane groups efficiency and safety characteristics with an intelligent management and control system. The system provides real-time analysis, feedback warnings and dynamic tracking in the intelligent management and control platform for the concrete transport. The platform has been successfully applied in the Baihetan project to provide digital control of the concrete transport efficiency and safety to effectively improve the traditional construction management that deals with poor linkage analyses, slow feedback, and poor process control. The research results can be used for similar projects.
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