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Rate-dependent constitutive modelling blasting crack initiation and propagation in rock masses

国际煤炭科学技术学报（英文版） 2023年第6期10卷 102-119页

作者： Yongjun Zhang Meng Xu Sijia Liu Fei Liu Qingsong Wang School of Civil Engineering Qingdao University of TechnologyQingdao 266033China School of Civil Engineering Qingdao University of TechnologyQingdao 266033China China State Construction Engineering Corporation International Construction CO. LTD.Suzhou 215011China CRCC Plateau Tunnel Construction Technology and Equipment R&D Center China Railway 20th Bureau Group CorporationXi'an 710016China

This study examines the fracture mechanism of cracks and the final blasting effects on defective rock masses under blasting *** failure processes of jointed rock with two prefabricated joints are investigated through numerical simulations using a two-dimensional finite element ***,simulations are performed to analyze the blasting of granite specimens with various joint arrangements,focusing on the influence of front joint length,inclination angle,and blast hole distance on failure patterns,displacement,velocity,and stress at the joint *** numerical results provide a compre-hensive summary of various typical failure modes near blast holes and joints for the first ***,the simulation successfully captures the characteristics of the ring crack zone,wing cracks,and main crack deflection affected by the front ***,the results highlight the shielding effect of the front joint,which enhances damage in the medium between the borehole and the joint while exhibiting the opposite effect behind the joint in terms of stress wave ***,this study offers objective insights into the mechanics and failure characteristics of jointed rock masses under blasting loads and serves as a valuable reference for the design and optimization of blasting operations.

关键词： Blasting failure RHT model Double-jointed granite specimen Dynamic crack propagation Stress wave spreading

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Statistical assessment of the financial performance of shale-gas wells coupling stochastic and numerical simulation

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Petroleum Science 2024年第6期21卷 4497-4511页

作者： Andres Soage Luis Ramirez Ruben Juanes Luis Cueto-Felgueroso Ignasi Colominas Group of Numerical Methods in Engineering-GMNI Center for TechnologicalInnovation in Construction and Civil Engineering-CITEEC.Civil Engineering SchoolUniversity of a CorunaCampus of ElvinaA Coruna15008GaliciaSpain Department of Civil Engineering:Hydraulics Energy and Environment.Polytechnic University of MadridMadrid2006Spain Department of Civil and Environmental Engineering Massachusetts Institute of TechnologyCambridge02139MAUA Department of Earth Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridge239MAUSA

We present a new methodology to statistically determine the net present value(NPV)and internal rate of return(IRR)as financial estimators of shale gas *** method allows us to forecast,in a fully probabilistic setting,financial performance risk and to understand the importance of the different factors that impact *** methodology developed in this study combines,through Monte Carlo simulation,the computational modeling of gas production from shale gas wells with a stochastic simulation of gas price as a geometric Brownian motion(GMB).To illustrate the methodology's validity,we apply it to an analysis of investments in shale gas *** results show that gas price volatility is a key variable in the performance of an investment of this type,in such a way that at high volatilities,the potential return on an investment in shale gas increases significantly,but so do the risks of economic *** finding is consistent with the history of shale gas operations in which huge investment successes coexist with unexpected investment failures.

关键词： Gas volatility Shale gas Net presentvalue Internal ratereturn Stochastic model Financial estimator MonteCarlosimulation Kernel densityfunction

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Data augmentation-assisted muck image recognition during shield tunnelling

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Underground Space (new) 2025年第1期21卷 370-383页

作者： Yan, Tao Shen, Shui-Long Zhou, Annan Guangdong Engineering Research Center for Smart Construction and Maintenance of Infrastructures of Coastal Cities Department of Civil Engineering and Smart Cities College of Engineering Shantou University Guangdong Shantou515063 China Discipline of Civil and Infrastructure Engineering School of Engineering Royal Melbourne Institute of Technology MelbourneVIC3001 Australia

This paper proposed a framework for muck types identification based on data augmentation-assisted image recognition during shield tunnelling. The muck pictures were collected from the shield monitoring system above the conveyor belt. The data augmentation operations were then used to increase the quality of the original images. Furthermore, the Bayesian optimisation algorithm was employed to adjust the parameters of augmenters and highlight the features of the photos. The deep image recognition algorithms (AlexNet and GoogLeNet) were trained and enhanced by the augmentation images, which were used to establish the muck types identification models and assessed by the evaluation indices. Model efficiency was analysed through the performance and time cost of training and validation processes to select the optimal model for muck types identification. Results showed that the performance of identification models could be highly increased by data augmentation with Bayesian optimisation, and the enhanced GoogLeNet performed the highest efficiency for muck types identification. © 2024 Tongji University.

关键词： Belt conveyors

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Experimental Investigation of Wave-Current Loads on a Bridge Shuttle-Shaped Cap–Pile Foundation

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Fluid Dynamics & Materials Processing 2024年第7期20卷 1565-1592页

作者： Chenkai Hong Zhongda Lyu Fei Wang Zhuo Zhao Lei Wang College of Science and Technology Ningbo UniversityNingbo315300China Engineering Research Center of Industrial Construction in Civil Engineering of Zhejiang Province Ningbo University of TechnologyNingbo315211China

To scrutinize the characteristics of wave-current loads on a bridge shuttle-shaped cap–pile foundation,a 1:125 test model was considered in a laboratory *** inline,transverse and vertical wave–current forces acting on the shuttle-shaped cap-pile group model were measured considering both random waves and a combination of random waves with a *** experimental results have shown that the wave-current forces can be well correlated with the wave height,the wavelength,the current velocity,the incident direction and the water level in the marine *** increase in the current velocity can lead to a sharp increase in the inline and transverse wave-current forces,while the vertical wave-current force ***,the wave-current forces are particularly strong when a combination of high tide,strong wave and strong current is considered.

关键词： Shuttle-shaped cap-pile foundation wave-current force wave flume experiment sea-crossing bridge

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Numerical Simulation of Ground Movement Due to Tunneling

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Journal of The Institution of Engineers (India): Series A 2023年第3期104卷 653-663页

作者： El Raouf, Moamen Abd Bahloul, Khaled M. M. Civil Engineering Department Faculty of Engineering Al-Azhar University Qena Egypt Department of Construction Engineering October High Institute of Engineering and Technology Giza Egypt

The tunneling process results in ground movement. The prediction of ground movement can be achieved by using numerical analysis, analytical methods, and empirical methods. In the present paper, a parametric study via finite element program (Plaxis2D) was implemented to investigate the effect of some parameters like volume loss, the relative density of sand, and cover-to-diameter ratio (C/D). For the verification and judging of the reliability of the model results, the finite element results were compared with field measurements of the Greater Cairo Metro tunnel. Moreover, the model results were validated using the empirical formula (Peck, Proceedings of the 7th International Conference on Soil Mechanics and Foundation engineering, Mexico, pp 225–290, 1969). The results show that the numerical model results are fairly in agreement with the field measurements and empirical formula. The maximum value of the horizontal displacement occurred at the ground surface. Moreover, the horizontal displacement decreases, as the depth increases. The formula of peck gives an accurate value of the settlement and considers a reliable method for calculating the maximum settlement due to the tunneling process, especially in the preliminary stages of the project. The surface settlement calculated using volume loss = 0.5% is very close to real field observation. Furthermore, the width of the settlement trough increases, as the volume loss increases. © 2023, The Institution of Engineers (India).

关键词： Soil mechanics

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Efficient estimation of structural probability of failure with adaptive kriging and multi-layered hyperball-based importance sampling

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Journal of the Chinese Institute of Engineers, Transactions of the Chinese Institute of Engineers,Series A 2024年第1期47卷 108-119页

作者： Prayogo, Handy Yang, I-Tung Liao, Kuo-Wei Department of Civil and Construction Engineering National Taiwan University of Science and Technology Taipei Taiwan Department of Bioenvironmental Systems Engineering National Taiwan University Taipei Taiwan

The need for more resilient infrastructures entails an accurate and efficient structural reliability analysis. In recent years, Kriging-based meta-modeling has constantly been adopted to reduce the computational cost in estimating the probability of failure. Active learning models focus on most informative samples to increase computational efficiency. Nevertheless, the efficiency gained from the models may diminish when dealing with a rare event with a relatively small probability of failure. To resolve the difficulty, this study proposes a new method, Adaptive Kriging with Multi-layered Hyperball-based Importance Sampling (AK-MHIS), to estimate the structural probability of failure. AK-MHIS uses an adaptive multi-layered hyperball as its candidate sample pool with a new sample filtering mechanism and a more robust stopping condition for the active-learning phase. The performance of AK-MHIS method is validated in benchmark cases. The verification results confirm the superior performance of AK-MHIS to previous methods. © 2023 The Chinese Institute of Engineers.

关键词： Kriging

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Influence of Porosity on Vibration of Porous FG Plates Resting on an Arbitrarily Orthotropic Winkler-Pasternak Foundation by PDDO

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Acta Mechanica Solida Sinica 2025年第1期38卷 142-151页

作者： Yongyu Yang Xiaoqi Wang Hang Zhao Chao Wang Changzheng Cheng Raj Das Key Laboratory for Mechanics Engineering Research Center of Anhui Green Building and Digital ConstructionAnhui Polytechnic UniversityWuhu241000China College of Civil Engineering Hefei University of TechnologyHefei230000China School of Engineering RMIT UniversityMelbourneVIC3000Australia

This paper studies the vibration responses of porous functionally graded(FG)thin plates with four various types of porous distribution based on the physical neutral plane by employing the peridynamic differential operator(PDDO).It is assumed that density and elastic modulus continuously vary along the transverse direction following the power law distribution for porous FG *** governing differential equation of free vibration for a porous rectangular FG plate and its associated boundary conditions are expressed by a Lévy-type solution based on nonlinear von Karman plate *** frequencies and mode shapes are obtained after solving the characteristic equations established by *** results of the current method are validated through comparison with existing *** effects of geometric parameters,material properties,elastic foundation,porosity distribution,and boundary conditions on the frequency are investigated and discussed in *** highest fundamental dimensionless frequency occurs under SCSC boundary conditions,while the lowest is under SFSF boundary *** porous FG plate with the fourth pore type,featuring high density of porosity at the top and low at the bottom,exhibits the highest fundamental frequency under SSSS,SFSF,and SCSC boundary *** dimensionless frequency increases with an increase in the elastic foundation stiffness coefficient.

关键词： Vibration response Porous FG plate Orthotropic Winkler-Pasternak foundation PDDO

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Shake table tests to compare the seismic response of concrete frames with conventional and high-strength reinforcement

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Earthquake engineering and Structural Dynamics 2024年第1期53卷 89-115页

作者： Chin, Chih-Hsuan Cheng, Min-Yuan Lepage, Andrés Lequesne, Rémy D. Shih-Ho Engineering Co. Taoyuan Office Taiwan Department of Civil and Construction Engineering National Taiwan University of Science and Technology Taipei Taiwan Department of Civil Environmental and Architectural Engineering The University of Kansas Lawrence United States

Reported test results suggest reinforcement grade can have an important effect on the seismic displacement demands of reinforced concrete (RC) structures. Two one-story one-bay RC frames (Specimens C1 and H1) were mounted in parallel on the NCREE-Taiwan shake table and simultaneously subjected to 16 base motions, each representing a horizontal component of recorded earthquakes. The dynamic tests were followed by quasi-static large-amplitude cyclic testing. The specimens had the same nominal dimensions and base shear strengths with longitudinal reinforcement that was Grade 60 (60 ksi [420 MPa]) in C1 and Grade 100 (100 ksi [690 MPa]) in H1. Maximum drifts of H1 were 1.3 to 2.3 times larger than for C1. The lateral stiffness of H1 was consistently lower than C1, with stiffness ratios (H1 to C1) ranging from 0.78 after Run 1 to 0.45 after Run 16. Drift estimates using stiffness values based on gross-section properties provided a reasonable upper bound for C1 but were unconservative for H1. Drift estimates based on the secant-to-yield stiffnesses, which were inversely proportional to reinforcement grade, provided an upper bound for both specimens. Preliminary recommendations are made for accounting for these effects in design. © 2023 John Wiley & Sons Ltd.

关键词： Stiffness

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Dynamic civil facility degradation prediction for rare defects under imperfect maintenance

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Journal of Quality in Maintenance engineering 2024年第1期30卷 81-100页

作者： Leu, Sou-Sen Fu, Yen-Lin Wu, Pei-Lin National Taiwan University of Science and Technology Taipei Taiwan Department of Civil and Construction Engineering National Taiwan University of Science and Technology Taipei Taiwan

Purpose: This paper aims to develop a dynamic civil facility degradation prediction model to forecast the reliability performance tendency and remaining useful life under imperfect maintenance based on the inspection records and the maintenance actions. Design/methodology/approach: A real-time hidden Markov chain (HMM) model is proposed in this paper to predict the reliability performance tendency and remaining useful life under imperfect maintenance based on rare failure events. The model assumes a Poisson arrival pattern for facility failure events occurrence. HMM is further adopted to establish the transmission probabilities among stages. Finally, the simulation inference is conducted using Particle filter (PF) to estimate the most probable model parameters. Water seals at the spillway hydraulic gate in a Taiwan's reservoir are used to examine the appropriateness of the approach. Findings: The results of defect probabilities tendency from the real-time HMM model are highly consistent with the real defect trend pattern of civil facilities. The proposed facility degradation prediction model can provide the maintenance division with early warning of potential failure to establish a proper proactive maintenance plan, even under the condition of rare defects. Originality/value: This model is a new method of civil facility degradation prediction under imperfect maintenance, even with rare failure events. It overcomes several limitations of classical failure pattern prediction approaches and can reliably simulate the occurrence of rare defects under imperfect maintenance and the effect of inspection reliability caused by human error. Based on the degradation trend pattern prediction, effective maintenance management plans can be practically implemented to minimize the frequency of the occurrence and the consequence of civil facility failures. © 2023, Emerald Publishing Limited.

关键词： Defects

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Failure mechanism and infrared radiation characteristic of hard siltstone induced by stratification effect

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Journal of Mountain Science 2024年第3期21卷 1058-1074页

作者： CHENG Yun SONG Zhanping XU Zhiwei YANG Tengtian TIAN Xiaoxu School of Civil Engineering Yancheng Institute of TechnologyYancheng 224051China School of Civil Engineering Xi'an University of Architecture and TechnologyXi'an 710055China Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering Xi'an 710055China China Railway Construction Bridge Engineering Bureau Group Co. Ltd.Tianjin 300300China

The deformation in sedimentary rock induced by train loads has potential threat to the safe operation of tunnels. This study investigated the influence of stratification structure on the infrared radiation and temporal damage mechanism of hard siltstone. The uniaxial compression tests, coupled with acoustic emission(AE) and infrared radiation temperature(IRT) were conducted on siltstones with different stratification effects. The results revealed that the stratigraphic structure significantly affects the stress-strain response and strength degradation characteristics. The mechanical parameters exhibit anisotropy characteristics, and the stratification effect exhibits a negative correlation with the cracking stress and peak stress. The failure modes caused by the stratification effect show remarkable anisotropic features, including splitting failure(Ⅰ: 0°-22.50°, Ⅱ: 90°), composite failure(45°), and shearing failure(67.50°). The AE temporal sequences demonstrate a stepwise response characteristic to the loading stress level. The AE intensity indicates that the stress sensitivity of shearing failure and composite failure is generally greater than that of splitting failure. The IRT field has spatiotemporal migration and progressive dissimilation with stress loading and its dissimilation degree increases under higher stress levels. The stronger the stratification effect, the greater the dissimilation degree of the IRT field. The abnormal characteristic points of average infrared radiation temperature(AIRT) variance at local stress drop and peak stress can be used as early and late precursors to identify fracture instability. Theoretical analysis shows that the competitive relationship between compaction strengthening and fracturing damage intensifies the dissimilation of the infrared thermal field for an increasing stress level. The present study provides a theoretical reference for disaster warnings in hard sedimentary rock mass.

关键词： Hard siltstone Failure mechanism Stratification effect Infrared radiation characteristic Temporal-damage mechanism Dissimilation

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