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Subsidence over room and pillar retreat mining in a low coal seam

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International Journal of Mining Science and Technology 2019年第1期29卷 51-57页

作者： Andre Zingano Anderson Weiss Mining engineering Department University Federal of Rio Grande do Sul Carb.Do Cambuíinc.

The objective of this paper is to study the behavior of a low thick and low depth coal seam and the overburden rock mass. The mining method is room and pillar in retreat and partial pillar recovery. The excavation method is conventional drill and blast because of the small production. The partial pillar recovery is about 30% of the previous pillar size, 7 m × 7 m. The roof displacement was monitored during retreat operation; the surface movement was also monitored. The effect of the blasting vibration on the final pillar strength had been considered. Due to blasting, the pillar reduced about 20%. The consequence is more pillar deformation and roof vertical displacement. The pillar retreat and ground movement were simulated in a three-dimensional numerical model. This model was created to predict the surface subsidence and compare to the subsidence measured. This study showed that the remaining pillar and low seam reduce the subsidence that was predicted with conventional methods.

关键词： Subsidence Room-and-pillar mining Retreat mining Coal

Predict new cases of the coronavirus 19;in Michigan,*** other countries using Crow-AMSAA method

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Infectious Disease Modelling 2020年第1期5卷 459-477页

作者： Yanshuo Wang Data Mining and Reliability consultant LLLW LLC Inc.P.O Box 25124LansingMI48909USA

Statistical predictions are useful to predict events based on statistical *** data is useful to determine outcomes based on inputs and *** Crow-AMSAA method will be explored to predict new cases of Coronavirus 19(COVID19).This method is currently used within engineering reliability design to predict failures and evaluate the reliability *** author intents to use this model to predict the COVID19 cases by using daily reported data from Michigan,New York City,U.S.A and other *** piece wise Crow-AMSAA(CA)model fits the data very well for the infected cases and deaths at different phases during the start of the COVID19 *** slope b of the Crow-AMSAA line indicates the speed of the transmission or death *** traditional epidemiological model is based on the exponential distribution,but the Crow-AMSAA is the Non Homogeneous Poisson Process(NHPP)which can be used to modeling the complex problem like COVID19,especially when the various mitigation strategies such as social distance,isolation and locking down were implemented by the government at different places.

关键词： COVID19 Prediction Modeling Crow-AMSAA NHPP Infected cases Deaths

Estimating water deficit and its uncertainties in water-scarce area using integrated modeling approach

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Water Science and engineering 2012年第4期5卷 450-463页

作者： Shou-ke WEI Eawag the Swiss Federal Institute of Aquatic Science and Technology Department of Forest Resources Management University of British Columbia Emodlogic Technology inc.

Accurate assessment of water deficit and related uncertainties in water-scarce areas is strategically important in various fields of water resources management. This study developed a hybrid approach integrating conceptual water balance model and econometric regression to estimate water shortage and its related uncertainties in water-scarce areas. This hybrid approach was used to assess the agricultural water deficit of Beijing, an extremely water-scarce area in China. A predictive model of agricultural water demand was developed using the stepwise multiple regression method, and was validated by comparing the predicted values with observed data. Scenario analysis was employed to investigate the uncertainties of agricultural water shortage and agricultural water demand. This modeling approach can assist water administration in creating sustainable water allocation strategies in water-scarce areas.

关键词： water deficit hybrid model conceptual water balance model stepwise multipleregression method uncertainty Beo'ing

Laboratory characterization of temperature induced reflection cracks

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Journal of Traffic and Transportation engineering(English Edition) 2020年第5期7卷 668-677页

作者： Richard Y.Ji Tirupan Mandal Hao Yin William J.Hughes Technical Center Airport Technology R&D BranchFederal Aviation AdministrationAtlantic CityNJ 08234USA Gemini Technologies Inc.Atlantic CityNJ 08234USA

A hot-mix asphalt(HMA) overlay is one of the primary strategy for rehabilitating existing HMA pavements and Portland cement concrete(PCC) pavements. The current design program, FAARFIELD, does not address reflective cracking for asphalt-overlaid concrete pavements due to its mechanism complexity. The bending, shearing, and thermal are three crucial factors to successfully model reflective cracking. To implement this failure mode in flexible over rigid design procedure, a series of full-scale test pavements were constructed, instrumented, and tested in the condition of extreme cooling temperature at the FAA National Airport Pavement Test Facility. The purpose was to assess cooling effects on the propagation of reflection cracks for airport AC over PCC pavements. In preparation for reflective cracking phase VI test, the FAA is conducting laboratory experiment on field extracted hot mix asphalt(HMA) cores. In order to test these field HMA cores, the Texas Overlay Tester(OT) was customized to get data similar to the full-scale tests. This paper discusses finite element analysis on the full-scale testing, development of the customized Texas OT, and a laboratory testing suite using the customized Texas OT, inc.uding preliminary tests, instrumentation, experiment design, and test results. Data obtained from this research effort will be used to develop a rational testing procedure to simulate extreme cooling cycles through full-scale testing.

关键词： Reflection cracks Customized Texas overlay tester Overlay Strain properties Fracture properties

Real-Time Detection of Cracks on Concrete Bridge Decks Using Deep Learning in the Frequency Domain

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engineering 2021年第12期7卷 1786-1796页

作者： Qianyun Zhang Kaveh Barri Saeed K.Babanajad Amir H.Alavi Department of Civil and Environmental engineering University of PittsburghPittsburghPA 15261USA Wiss JanneyElstner Associates Inc.NorthbrookIL 60062USA Department of Computer Science and Information engineering Asia UniversityTaichungTaiwan 41354China

This paper presents a vision-based crack detection approach for concrete bridge decks using an integrated one-dimensional convolutional neural network(1D-CNN)and long short-term memory(LSTM)method in the image frequency *** so-called 1D-CNN-LSTM algorithm is trained using thousands of images of cracked and non-cracked concrete bridge *** order to improve the training efficiency,images are first transformed into the frequency domain during a preprocessing *** algorithm is then calibrated using the flattened frequency *** is used to improve the performance of the developed network for long sequence *** accuracy of the developed model is 99.05%,98.9%,and 99.25%,respectively,for training,validation,and testing *** implementation framework is further developed for future application of the trained model for large-scale *** proposed 1D-CNN-LSTM method exhibits superior performance in comparison with existing deep learning methods in terms of accuracy and computation *** fast implementation of the 1D-CNN-LSTM algorithm makes it a promising tool for real-time crack detection.

关键词： Crack detection Concrete bridge deck Deep learning Real-time

Tensile strength and failure behavior of rock-mortar interfaces: Direct and indirect measurements

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Journal of Rock Mechanics and Geotechnical engineering 2024年第1期16卷 41-55页

作者： Ghasem Shams Patrice Rivard Omid Moradian Civil engineering and Building engineering Department Universitéde SherbrookeSherbrookeQuébecCanada Department of Earth Sciences Swiss Federal Institute of Technology(ETH)ZurichSwitzerland Department of Civil and Environmental engineering Colorado School of MinesGoldenCOUSA

The tensile strength at the rock-concrete interface is one of the crucial factors controlling the failure mechanisms of structures,such as concrete gravity *** the critical importance of the failure mechanism and tensile strength of rock-concrete interfaces,understanding of these factors remains very *** study investigated the tensile strength and fracturing processes at rock-mortar interfaces subjected to direct and indirect tensile *** image correlation(DIC)and acoustic emission(AE)techniques were used to monitor the failure mechanisms of specimens subjected to direct tension and indirect loading(Brazilian tests).The results indicated that the direct tensile strength of the rock-mortar specimens was lower than their indirect tensile strength,with a direct/indirect tensile strength ratio of 65%.DIC strain field data and moment tensor inversions(MTI)of AE events indicated that a significant number of shear microcracks occurred in the specimens subjected to the Brazilian *** presence of these shear microcracks,which require more energy to break,resulted in a higher tensile strength during the Brazilian *** contrast,microcracks were predominantly tensile in specimens subjected to direct tension,leading to a lower tensile *** monitoring of the cracking processes in the rock-mortar interfaces revealed that they show AE precursors before failure under the Brazilian test,whereas they show a minimal number of AE events before failure under direct *** to different microcracking mechanisms,specimens tested under Brazilian tests showed lower roughness with flatter fracture surfaces than those tested under direct tension with jagged and rough fracture *** results of this study shed light on better understanding the micromechanics of damage in the rock-concrete interfaces for a safer design of engineering structures.

关键词： Rock-mortar Rock-concrete Moment tensor inversion(MTI) Acoustic emission(AE) Digital image correlation(DIC) Tensile strength Direct tensile test Brazilian test

Day-to-Day Market Power and Efficiency in Tradable Mobility Credits

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International Journal of Transportation Science and Technology 2015年第3期4卷 209-227页

作者： Ye Tian Yi-Chang Chiu Transportation System Analyst Metropia Inc.3701 Executive Center Dr.STE 209 Austin TX 78750 USA Associate Professor Department of Civil Engineering and Engineering MechanicsUniversity of ArizonaTucson85721USA

An active transportation and demand management framework focusing on tradable mobility credits(TMC)is integrated into an agent-based modeling and simulation(ABMS)*** this framework,it is conceived that an auction market within which mobility credits can be transferred between buyers and sellers is constructed in *** idea of ABMS is extensively inc.rporated to mimic system users’daily route choices as well as market-related micro-economical decision making process under TMC *** are able to form individual propensities towards available bid/ask choices by reinforcement learning *** integrated platform offers a brand new insight view of microscopic aspect of the daily operations of credit transfer market,which has hardly been obtained by prior analytical ***-to-day traffic dynamics and market dynamics can be ***,market MOEs,inc.uding convergence,stability,efficiency and relative market powers of buyers and sellers under different market policies are investigated.

关键词： tradable mobility credits simulation-based dynamic traffic assignment agent-based modelling and simulation auction willingness-to-pay willingness-to-accept microeconomics

Structural health monitoring of bridges in the State of Connecticut

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Earthquake engineering and engineering Vibration 2008年第4期7卷 427-437页

作者： Chengyin Liu Joshua Olund Alan Cardini Paul D＇Attilio Eric Feldblum John DeWolf SP-SELLS inc. Briarcliff Manor NY 10510 USA Department of Civil and Environmental engineering University of Connecticut 261 Glenbrook Rd Unit 2037 Storrs CT06269 USA DMJM Harris Boston MA 02110 USA Connecticut Department of Transportation 280 West Street Rocky Hill CT 06067 USA

A joint effort between the Connecticut Department of Transportation and the University of Connecticut has been underway for more than 20 years to utilize various structural monitoring approaches to assess different bridges in Connecticut. This has been done to determine the performance of existing bridges, refine techniques needed to evaluate different bridge components, and develop approaches that can be used to provide a continuous status of a bridge＇s structural integrity. This paper briefly introduces the background of these studies, with emphasis on recent research and the development of structural health monitoring concepts. This paper presents the results from three different bridge types： a post-tensioned curved concrete box girder bridge, a curved steel box-girder bridge, and a steel multi-girder bridge. The structural health monitoring approaches to be discussed have been successfully tested using field data collected during multi-year monitoring periods, and are based on vibrations, rotations and strains. The goal has been to develop cost-effective strategies to provide critical information needed to manage the State of Connecticut＇s bridge infrastructure.

关键词： structural integrity structural health monitoring field data vibrations

Studying Driving Risk Factors using Multi-Source Mobile Computing Data

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International Journal of Transportation Science and Technology 2015年第3期4卷 295-311页

作者： Xianbiao Hu Yi-Chang Chiu Yu-Luen Ma Lei Zhu Director of R&D MetropiaInc.TucsonAZUSA Associate Professor Department of Civil Engineering and Engineering MechanicsUniversity of ArizonaTucsonAZUSA Professor Katie School of Insurance and Financial ServicesIllinois State UniversityNormalIIUSA PhD student Department of Civil Engineering and Engineering MechanicsUniversity of ArizonaTucsonAZUSA

Traffic congestion can largely be attributed to the issues related with driving behavior,which may cause vehicle crash,stop-and-go traffic due to frequent lane changing behaviors,etc.,and makes the driving behavior research also of significance in the realm of traffic management and demand *** emergence and subsequent rapid advances with new information and communication technologies(ICT)now offers the capability of collecting high-fidelity and high-resolution trajectory data in a cost-effective *** this research,we use a smartphone app to collect data for the purpose of studying driving risk ***’s unique about the data in this research is its backend server also estimates traffic speed and volume for each link that the vehicle *** order words,the data collected with build-in GPS modules in the smartphone inc.ude not only the vehicle spatial-temporal dimension location,which could be used to correlate the network geography attributes and/or real-time traffic condition,but also the detailed information about the vehicle dynamics inc.uding speed,acceleration,and deceleration,whereby a driver’s control and maneuver of a vehicle can be analyzed in *** type of dataset combining both user trajectory and link speed/volume information is rarely seen in prior research,permitting a unique opportunity to link critical traffic congestion factors leading to driving behavior and crash *** this paper,the overall research framework used in this research is presented,which mainly inc.udes data collection,data processing,calibration and analysis methodology.A preliminary case study-inc.uding data summary statistics and correlation analysis-is also *** results of our study will further existing knowledge about driving exposure factors that are closely linked to crash risk,and provide the foundation for advanced forms of Usage Based Insurance.

关键词： Driving Risk Factors Smartphone Trajectory Data Information and Communication Technologies(ICT) Usage Based Insurance(UBI) Pay-As-You-Drive-And-You-Save(PAYDAYS)