On-site Engineering Research Articles

Research on Stability of an Open-Pit Mine Dump with Fiber Optic Monitoring

China has over 1500 open-pit mines and 5000 dumps consisting of waste rock from the mining process. Due to dump instability in an open-pit mine and its diverse foundations, landslides and mudslides frequently occur. Heaped loose waste rock and concentrated heavy rainfalls are the two important factors affecting slope stability of a dump. Using the high Dump II within the Nanfen Open-Pit Iron Mine with a slope height of 300 m as a case study, this paper first proposes a physical model similarity ratio according to the on-site engineering geological survey data. The governing principles of deformation in the shallow dump layers in terms of different heaped loads and rainfall were then determined using fiber optic sensing to conduct an experimental study on the monitoring of the dump stability with an indoor physical model. Experimental results confirm that the amount of rainfall and heaped load has a great impact on the landslide in a dump. With an increase in the amount of material heaped onto the pile, the place between two heaped load points is squeezed and slowly deformed. As rainfall begins, the deformation of the rock-soil mass is significant, and constantly increasing rainfall intensity is accompanied by a dangerous sliding surface. Finally, the FLAC3D method was used to simulate the deformation features in the shallow part of Dump II under different heaped load conditions and verify the experimental results of the indoor physical model. By comparing the physical model experiments and numerical simulation results, we propose monitoring the stability of Dump II using this fiber optic sensing technology and provide the scientific basis for stability monitoring of similar dumps to detect the early warning signs of mudslides or landslides.

Intelligent Approach Based on Random Forest for Safety Risk Prediction of Deep Foundation Pit in Subway Stations

The number of safety accidents caused by excavation of deep foundation pits in subway stations has been increasing rapidly in recent years. Thus, precisely predicting the safety risks for subway deep foundation pits bears importance. Existing methods, such as machine learning models, have been established for predicting such risks. However, these methods are unable to provide accurate results for deep foundation pits in subway stations due to small and unbalanced data samples. In this research, an intelligent model based on random forest (RF) was established for risk prediction of deep foundation pits in subway stations. To achieve such a goal, different types of monitoring data and risk level monitoring were introduced to the RF for training the model and estimating unknown relationships between monitoring values and safety risks of pits. An actual deep foundation pit in a subway station of the Wuhan Metro was used to demonstrate the applicability of the developed RF risk prediction model. The results showed that the superiority of the proposed RF risk prediction model can be used as a basis to implement a decision-making tool for predicting safety risks of subway foundation pits. The importance evaluation function of the model provides the ability to aid onsite engineers in determining the causes of safety risks, thus facilitating the implementation of emergency measures in advance.

Optimal design of the engineering parameters for the first global trial production of marine natural gas hydrates through solid fluidization

More than 90% of natural gas hydrates (hereinafter, hydrate for short) in the South China Sea are non-diagenetic ore bodies, so they cannot be exploited easily by means of the conventional methods. In this paper, the solid fluidization method, as one of the revolutionary technologies in efficient exploitation of non-diagenetic natural gas hydrates, was, for the first time, put forward by Academician Zhou Shouwei. And it is successfully applied in the Shenhu Area of the South China Sea based on the technologies, equipment and processes which rely on domestic independent intellectual property rights. During the production test of fluidization, the ore bodies of hydrates are broken by the jet at the bottom hole into fine particles and carried upward by the drilling fluid. When the phase equilibrium state is reached with the increase of temperature and the decrease of pressure affected by the operation parameters, which is different from conventional phase equilibrium state, the hydrates bearing solid particles are decomposed, and consequently liquid–solid flow in the annulus becomes complex gas–liquid–solid multiphase flow. Therefore, it is necessary to optimize the construction parameters design so as to meet the high-level requirements of well control safety. In this paper, the engineering parameters are optimally designed based on the engineering geological characteristics of the target block, combined with the analysis on complex multiphase flow in the wellbore. Then, a theoretical model and a numerical calculation method for the multiphase flow, temperature and pressure of complex media in wellbores and the phase equilibrium and decomposition of natural gas hydrates were established. And the multiphase flow in the wellbore during the production test of fluidization was analyzed under different operating parameters by means of numerical simulation, software emulation and experimental verification. And thus, the design optimization scheme of on-site engineering parameters of production test of marine natural gas hydrate fluidization was prepared. It is pointed out that the diameter of jet fluidization well section shall not be excessively large; and that it is necessary to increase the flow rate and density of drilling fluid and apply wellhead back pressure to ensure the cutting carrying safety and to mitigate well control risks. The results of this basic theoretical study can provide significant support to field operation and improvement of output in production tests.

Optimal design and dynamic control of construction dewatering with the consideration of dewatering process

Design optimization of construction dewatering has important values in protecting the surrounding environment and reducing the engineering cost. The existing dewatering design methods are mostly based on the optimization of pumping rate needed to maintain a stable water level, while the drop and rise of water level are not considered in the estimation of pumping rate and dewatering time. The dynamics process of construction dewatering is taken into account in this article. The method for calculating the total water yield and dewatering time from the initial groundwater level to the target water level is established. Then, the design optimization of well group dewatering is provided with the consideration of total water yield and dewatering time in dynamic dewatering process. Finally, the method for the calculation of total water yield and dewatering time when dewatering regions change is derived. The proposed method can realize design optimization and dynamic control of dewatering as the dewatering regions and water level changes in construction. The reliability of this method is verified in on-site engineering applications.

Design and Realization of Scaled Operations Monitoring and Management Platform of Electric Vehicles

Introduction the development of electric vehicles at home and abroad, depth analysis of the development characteristics and charging for electric service business model. Determine the functional requirements for the electric vehicles scaled operation monitoring management platform, and then presents a platform design ideas. Abstract layered architecture design of platform according to functional features, the platform is divided into the user layer, application layer, service layer and communication layer, followed concrete realization of every layer, while put forward plug-in design thinking as well as providing the data source service concept, in order to meet users to expand and upgrade requirements for the platform and continue extension of the platform services. Through on-site engineering applications, the platform has achieved satisfactory results.

Study on Splitting Tensile Strength of Shotcret Layer of High Temperature Tunnel

The high-temperature tunnel at Buren mouth - kongur Hydropower in West Kunlun Mountains of Xinjiang, China exist significant temperature differences phenomenon, which affects the stability of the shotcrete layer in tunnel. Combining with on-site engineering practice, the insulation heating device is designed. The laboratory splitting tensile strength test is carried out on polyester concrete, polypropylene concrete, polyacrylonitrile concrete and ordinary concrete with thermal heating device at 25°C-90°C. The splitting tensile strength changes of concretes affected by temperature difference are analyzed. The results supply a directly guidance to the design of the concrete sprayed layer structure of high-temperature tunnel.

Review: Ancient Building Technology. Volume 3: Construction, by G. R. H. Wright and Constructing the Ancient World: Architectural Techniques of the Greeks and Romans, by Carmelo G. Malacrino and Jay Hyams

G. R. H. Wright . Ancient Building Technology. Volume 3: Construction . Leiden: Koninklijke Brill NV, 2009, 325 pp., 415 b/w illus. $272, ISBN 9004177451 Carmelo G. Malacrino, trans. Jay Hyams . Constructing the Ancient World: Architectural Techniques of the Greeks and Romans . Los Angeles: J. Paul Getty Museum, 2010, 216 pp., 200 color illus. $50, ISBN 9781606060162 These two books devoted to the ancient art of building differ in aim and scope. G. R. H. Wright's book follows upon his two earlier volumes, focusing respectively on the historical context and building materials in the ancient world.1 Wright presents this third volume as a compendium of research on ancient construction, intended as a reference for specialists, particularly during fieldwork. Although Carmelo Malacrino's book also addresses scholars, it seeks a wider audience of nonspecialists, and will appeal to classical archaeologists, historians of art and architecture, and the general public with an interest in antiquity. While narrower in terms of the technical specialization of its intended audience, Wright's book features greater breadth in its balance of classical and nonclassical material. Including extensive treatment of the architecture of Egypt, Mesopotamia, Anatolia, the Levant, and Iran, it stretches chronologically from the Neolithic period to the Sassanians. Unlike Malacrino's book, which makes for a pleasant cover-to-cover read in addition to serving as a reference, Wright aims to facilitate reference by repeating information throughout chapters that are organized according to phases or techniques of construction, as well as by providing sections treating cultures and periods not covered by Malacrino. Both books are informative on a wide range of topics related to ancient construction, but because Wright had written an earlier volume devoted entirely to materials, his present book is not afforded the opportunity to give the kind of expansive treatment of the nature and production of building materials offered by Malacrino. The latter provides a whole chapter covering the full array of building stones used in Greek and Roman construction, including the different volcanic stones, limestones, and marbles presented in their historical and geographic contexts. Welcome information includes the varying prices of marble and colored stones during the Imperial era, as well as …

Application of Bayesian Method in Stochastic Analysis of Rock Slope Stability

The analysis of structural plane in rock slope is of vital importance to stability analysis of rock slope. In this paper, Bayesian method was adopted in the analysis of shear strength parameters along the fault in the West Slope of Upper Reservoir, Shisanling Pumped Storage Power Station. Full advantage was taken of the geological information outside the structural plane along with the practical experience of on-site engineers. The statistical estimation problem of small samples thus was successfully solved. The determination of sliding plane in rock slope is another key issue in the stability analysis of rock slope. The cracking process was utilized to track the most possible sliding plane in the slope. In consideration of the randomicity of both mechanical parameters of rock and structural plane and resistance of slide resistant piles, reliability index of slope stability was established with the aid of discretized dimensional reduction method of reliability and conditional probability.

Time series prediction of mining subsidence based on a SVM

In order to study dynamic laws of surface movements over coal mines due to mining activities, a dynamic prediction model of surface movements was established, based on the theory of support vector machines (SVM) and times-series analysis. An engineering application was used to verify the correctness of the model. Measurements from observation stations were analyzed and processed to obtain equal-time interval surface movement data and subjected to tests of stationary, zero means and normality. Then the data were used to train the SVM model. A time series model was established to predict mining subsidence by rational choices of embedding dimensions and SVM parameters. MAPE and WIA were used as indicators to evaluate the accuracy of the model and for generalization performance. In the end, the model was used to predict future surface movements. Data from observation stations in Huaibei coal mining area were used as an example. The results show that the maximum absolute error of subsidence is 9 mm, the maximum relative error 1.5%, the maximum absolute error of displacement 7 mm and the maximum relative error 1.8%. The accuracy and reliability of the model meet the requirements of on-site engineering. The results of the study provide a new approach to investigate the dynamics of surface movements.

Precision Construction in Japan - Utilization of Information and Communication Technology

Various information and communication technologies have been introduced to conventional construction methodologies to make them more advanced. Although these advanced methodologies are often referred to as “Intelligent construction” or “Smart construction” in Japan, we call them “Precision construction” here to make their purpose clearer. Precision construction generally has two different functions. One is to support machine control and the other is to support the flexible decision making of the on-site engineers. This paper introduces the present conditions and the foresight of precision construction in Japan.

Damage evaluation for water-based underbalanced drilling in low-permeability and tight sandstone gas reservoirs

Abstract With the characteristics such as small pore throats, strong water wetting, and well-developed fractures, the low-permeability and tight sandstone gas reservoir is liable to be damaged during operation, even in the underbalanced condition. At water-based under-balanced drilling, water blocking and stress sensitivity are the main damages for low-permeability and tight sandstone gas reservoirs. Such damages are evaluated by using Fractures Visualization Test System and Capillary Flow Porometer. The results indicate that low-permeability and tight gas reservoirs still have very strong water blocking damage in the process of underbalanced drilling, and the lower the initial permeability, the bigger the water blocking damage. Given certain effective stress, the lower underbalanced pressure is accompanied with more serious water blocking damage, and over-low underbalanced pressure can not protect formations. Given certain underbalanced pressure, the higher effective stress brings about more serious water blocking damage. Now, the water blocking damage evaluation in underbalanced condition is just under study. Next work should focus on the simulation of real in-situ operations in reservoir and applying the laboratory evaluation results into onsite engineering design.

Analytical model development of an eddy-current-based non-contacting steel plate conveyance system

A concise model for analyzing and predicting the quasi-static electromagnetic characteristics of an eddy-current-based non-contacting steel plate conveyance system has been developed. Confirmed by three-dimensional (3-D) finite element analysis (FEA), adequacy of the analytical model can be demonstrated. Such an effective approach, which can be conveniently used by the potential industries for preliminary system operational performance evaluations, will be essential for designers and on-site engineers.

An exploratory study of knowledge flows: A case study of Public Sector Procurement

The Knowledge Management discourse continues to develop in relation to both theory and practice. However, there is a paucity of empirical studies of Knowledge Management in the public sector. In this sector the flow of people-based knowledge (knowledge transfer) across processes and different organizational levels has more significance than that of the private sector. The aim of the paper is to explore the flow of knowledge (knowledge transfer), from document/contract preparation through to site implementation for a Public Sector Procurement Agency. A series of multi-level semi-structured interviews and secondary data is used. The findings show the need for an increased emphasis on lateral knowledge transfer and a diminishing of the traditional pyramidal approach to knowledge. Enabling influences included managing the development of experienced staff, appropriate ICT systems and collaborative teams. Barriers included over-reliance on consultants with consequent loss of experience and lack of empowerment of on-site engineers.

Dynamic mobile RFID-based supply chain control and management system in construction

Construction project control attempts to effectively obtain real-time information and enhance dynamic control and management via information sharing and analysis from involved participants of the projects to reduce construction conflicts and project delay. However, extending the construction project control system to job sites is considered inefficient since construction sites are unconventional practice. Integrating promising information technologies such as radio frequency identification (RFID) technology, mobile devices-PDA and web portals can help improve the effectiveness and convenience of information flow in construction supply chain control systems. Radio frequency identification is appropriate for various construction applications, and provides cost savings through increased speed and accuracy of data entry. This study demonstrates the effectiveness of a RFID-based supply chain management application called the mobile construction RFID-based dynamic supply chain management (M-ConRDSCM) system in construction projects, demonstrating that it responds efficiently and enhances the information flow among offices and sites in a construction supply chain environment. The M-ConRDSCM system is then applied to a selected case study involving a High-Tech factory building in Taiwan to verify the proposed methodology and demonstrate the effectiveness of information sharing of project control in the construction phase. The advantage of the M-ConRDSCM system lies not only in improving work efficiency for on-site engineers, but also in providing dynamic operation control and management to enable project participants to control the whole project. Moreover, this study presents a generic system architecture and its implementation.

Wireless networking in tunnelling projects

Emerging collaborative technologies and working methods often require tremendous engineering and organisational efforts for successful implementation of information and communication technologies (ICTs). According to a research conducted in Turkish construction industry, most of the problems that occur during the construction phase are due to lack of co-operation and communication between designers and contractors and lack of prompt expert decisions during on-site engineering. Similar to any major construction project, tunnelling project’s success is highly dependent on collaborative team work where communication and information exchange take place between project members. Distributed collaborative teamwork, as the case in most of the large scale construction projects as well as tunnelling projects, empowered by state of the art information and communication technology, promises more efficient work processes, reduced travelling needs, and increased opportunities for project communication. Following the fast development of mobile computing in recent years, many sectors have adopted mobile devices and wireless technologies enabling real-time information transfer thereby improving business processes. For some years, the feasibility of implementing wireless solutions to construction sites has been researched. Potentially, mobile and wireless technologies enable construction staff to be more flexible in terms of location and time. For better use of mobile collaboration in construction projects, mobile technologies and construction sector have to be examined in some detail to implant the most suitable technology for real-time information access and improved collaboration of distributed teams in construction. However, case studies in construction are very limited in number and scope. This paper discusses and proposes an implementation scenario of wireless networking in Marmaray; a multi-site tunnelling project in Istanbul. Benefits, possible problems and cost assessments are discussed.

Mobile Construction Supply Chain Management Using PDA and Bar Codes

Abstract: Construction project control aims to effectively obtain real‐time information and enhance dynamic control by utilizing information sharing and connecting involved participants of the projects to reduce construction conflicts and project delays. However, extending the construction project control system to job sites is not considered efficient because using notebooks in a harsh environment like a construction site is not particularly a conventional practice. Meanwhile, paper‐based documents of the site processes are ineffective and cannot get the quick response from the office and project control center. Integrating promising information technologies such as personal digital assistants (PDA), bar code scanning, and data entry mechanisms, can be extremely useful in improving the effectiveness and convenience of information flow in construction supply chain control systems. Bar code scanning is appropriate for several construction applications, providing cost savings through increased speed and accuracy of data entry. This article demonstrates the effectiveness of a bar‐code‐enabled PDA application, called the mobile construction supply chain management (M‐ConSCM) System, that responds efficiently and enhances the information flow between offices and sites in a construction supply chain environment. The advantage of the M‐ConSCM system lies not only in improving the efficiency of work for on‐site engineers, but also providing the Kanban‐like visual control system for project participants to control the whole project. Moreover, this article presents a generic system architecture and its implementation.

M&M 2002: Core Facility Management Session Maintaining Major Equipment in the Core Microscopy Facility

Abstract D. Sherman: This session centers on approaches to maintaining major equipment—primarily electron microscopes. I thought we ought to look at how effective it is to seivice with onsite engineers. So with that I would like to start us out with Pat McGinley from JEOL. Pat is a long—time JEOL employee. He started out as a service engineer in 1976 and is currently Vice President of Service and a member of the Board of Directors for JEOL USA.

COMPUTER GRAPHICS ANIMATION FOR CONSTRUCTION MANAGEMENT

Computer graphics animation systems provide the ability to integrate on-site engineers* expertise into design systems as well as construction management processes. Computer graphics animation improves coordination and communication among engineering, construction and client organizations. The expedited communication leads to a substantial improvement of quality and productivity in the AEC industry. Computer graphics animation makes it possible to move through the design objects and view the proposed facility interactively in virtual environment. In this way, all participants can work as a team beyond their specific interests. A collaborative work environment is created. The paper introduces the application of computer graphics animation as a tool for the construction management in terms of computer integrated construction, evaluates the role and proposes recommendations for the application. Several pilot trials have been implemented on a dam construction project, on a currently on-going industrial district readjustment project in Osaka, Japan, and on a highway reconstruction project in Kobe. * Member of JSCE, Konoike Construction Co.,Ltd. 3-6-1 Kitakyuhoji-machi, chuo-ku, Osaka 541, Japan ** Member of JSCE, Dr. of Eng. , Professor, Kumamoto University

Bellefonte Primary Containment Structure

Construction of the reactor building primary containment structure at the Bellefonte Nuclear Plant involved several specialized construction techniques. This two unit plant is one of the nine nuclear units at six different sites now under construction by the Tennessee Valley Authority (TVA). The post-Tensioned, cast-in-place interior steel lined containment structure is unique within TVA. Problems during construction were identified at weekly planning meetings, and options were discussed. Close coordination between craft supervisors and on-site engineering personnel drew together “hands-on” experience and technical background. Details of the construction techniques, problems, and solutions are presented.

Analytical Techniques for Evaluation of Oxidation Catalysts for the Abatement of Paint Bake Oven Emissions

The abatement of paint bake oven emissions using oxidation catalysts operated at low temperature (500°-600°F) offers significant energy savings relative to traditional incineration. Pilot testing in the field offers the advantage that the actual vapor stream is utilized to evaluate the catalyst. To this end, four low temperature catalysts based on three different substrates have been evaluated onsite for hydrocarbon solvent abatement efficiency. One of these experimental catalysts is effective in our pilot tests at 550°F even on an exhaust stream containing only 100 ppm (v/v-as propane) total hydrocarbons. In order to evaluate oxidation catalysts, a comprehensive program of vapor stream chemical analysis and catalyst surface analysis was necessary. Vapor stream chemical analysis included methane/nonmethane total hydrocarbon determination, gas chromatography- mass spectrometry and Fourier-transform infrared spectroscopy. Since it would not have been possible to pilot test each catalyst for a full year, methods of projecting effective lifetime after only a few weeks of on-site testing had to be utilized. The techniques employed were electron spectroscopy for chemical analysis, gas chemisorption, scanning electron microscopy, and x-ray fluorescence. This paper addresses the problems of on-site engineering and analysis, off-site chemical and physical analysis, and the performance of four different catalysts for the low temperature oxidation of enamel paint bake oven emissions.