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Journal of Central South University 2024年第6期31卷 2087-2101页

作者： GUO Feng-qi LI Shi-wei ZOU Jin-Feng School of civil engineering Central South UniversityChangsha 410075China

To address the seismic face stability challenges encountered in urban and subsea tunnel construction,an efficient probabilistic analysis framework for shield tunnel faces under seismic conditions is *** on the upper-bound theory of limit analysis,an improved three-dimensional discrete deterministic mechanism,accounting for the heterogeneous nature of soil media,is formulated to evaluate seismic face *** metamodel of failure probabilistic assessments for seismic tunnel faces is constructed by integrating the sparse polynomial chaos expansion method(SPCE)with the modified pseudo-dynamic approach(MPD).The improved deterministic model is validated by comparing with published literature and numerical simulations results,and the SPCE-MPD metamodel is examined with the traditional MCS *** on the SPCE-MPD metamodels,the seismic effects on face failure probability and reliability index are presented and the global sensitivity analysis(GSA)is involved to reflect the influence order of seismic action ***,the proposed approach is tested to be effective by a engineering case of the Chengdu outer ring *** results show that higher uncertainty of seismic response on face stability should be noticed in areas with intense earthquakes and variation of seismic wave velocity has the most profound influence on tunnel face stability.

关键词： reliability analysis shield tunnel face sparse polynomial chaos expansion modified pseudo-dynamic approach seismic stability assessment

Experimental study of the damage characteristics of rocks containing non-penetrating cracks under cyclic loading

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International Journal of Mining Science and Technology 2024年第2期34卷 197-210页

作者： Jun Xu Xiaochun Xiao Lu Ma Sen Luo Jiaxu Jin Baijian Wu School of Mechanics and engineering Liaoning Technical UniversityFuxin 123000China School of civil engineering Liaoning Technical UniversityFuxin 123000China department of engineering Mechanics Southeast UniversityNanjing 211189China

The damage evolution process of non-penetrating cracks often causes some unexpected engineering *** specimens containing non-penetrating crack(s)are used to study the damage evolution and characteristics under cyclic *** results show that under cyclic loading,the relationship between the number of non-penetrating crack(s)and the characteristic parameters(cyclic number,peak stress,peak strain,failure stress,and failure strain)of the pre-cracked specimens can be represented by a decreasing linear *** damage evolution equation is fitted by calibrating the accumulative plastic strain for each cycle,and the damage constitutive equation is proposed by the concept of effective ***,non-penetrating cracks are more likely to cause uneven stress distribution,damage accumulation,and local failure of *** local failure can change the stress distribution and relieve the inhibition of non-penetrating crack extension and eventually cause a dramatic destruction of the ***,the evolution process caused by non-penetrating cracks can be regarded as one of the important reasons for inducing *** results are expected to improve the understanding of the process of spalling formation and rockburst and can be used to analyze the stability of rocks or rock structures.

关键词： Damage characteristics Constitutive model Fissured rocks Non-penetrating crack Cyclic loading

Deep learning to develop zero-equation based turbulence model for CFD simulations of the built environment

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Building Simulation 2024年第3期17卷 399-414页

作者： Giovanni Calzolari Wei Liu Division of Sustainable Buildings Department of Civil and Architectural EngineeringKTH Royal Institute of TechnologyBrinnelvägen 23Stockholm11428Sweden

This study aims to improve the accuracy and speed of predictions for thermal comfort and air quality in built environments by creating a coupled framework between computational fluid dynamics(CFD)simulations and deep learning *** coupling approach is showcased by the development of a data-driven turbulence *** new turbulence model is built using a deep learning neural network,whose mapping structure is based on a zero-equation turbulence model for built environment simulations,and is coupled with the CFD software OpenFOAM to create a hybrid *** neural network is a standard shallow multi-layer *** number of hidden layers and nodes per layer was optimized using Bayesan optimization *** framework is trained on an indoor environment case study,as well as tested on an indoor office simulation and an outdoor building array *** show that the deep learning based turbulence model is more robust and faster than traditional two-equation Reynolds average Navier-Stokes(RANS)turbulence models,while maintaining a similar level of *** model also outperforms the standard algebraic zero-equation model due to its superior ability to generalize to various flow *** some challenges,namely the mapping constraint,the limited training dataset size and the source of generation of training data,the hybrid framework demonstrates the viability of the coupling technique and serves as a starting point for future development of more reliable and advanced models.

关键词： neural networks computational fluid dynamics(CFD) turbulence model OpenFOAM

Predictive active control of building structures using LQR and artificial intelligence

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Earthquake engineering and engineering Vibration 2024年第2期23卷 489-502页

作者： Nirmal S.Mehta Vishisht Bhaiya K.A.Patel Ehsan Noroozinejad Farsangi department of civil engineering SVNIT SuratGujarat 395007India Urban Transformations Research Centre Western Sydney UniversityNSWAustralia

This study presents a neural network-based model for predicting linear quadratic regulator(LQR)weighting matrices for achieving a target response *** on the expected weighting matrices,the LQR algorithm is used to determine the various responses of the *** responses are determined by numerically analyzing the governing equation of motion using the state-space *** training a neural network,four input parameters are considered:the time history of the ground motion,the percentage reduction in lateral displacement,lateral velocity,and lateral acceleration,Output parameters are LQR weighting *** study the effectiveness of an LQR-based neural network(LQRNN),the actual percentage reduction in the responses obtained from using LQRNN is compared with the target percentage ***,to investigate the efficacy of an active control system using LQRNN,the controlled responses of a system are compared to the corresponding uncontrolled *** trained neural network effectively predicts weighting parameters that can provide a percentage reduction in displacement,velocity,and acceleration close to the target percentage *** on the simulation study,it can be concluded that significant response reductions are observed in the active-controlled system using ***,the LQRNN algorithm can replace conventional LQR control with the use of an active control system.

关键词： active control system linear quadratic regulator artificial neural networks state-space approach response effectiveness factor resilience

Experimental and analytical investigation on friction resistance force between buried coated pressurized steel pipes and soil

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Frontiers of Structural and civil engineering 2024年第4期18卷 615-629页

作者： Shaurav ALAM Tanvir MANZUR John MATTHEWS Chris BARTLETT Erez ALLOUCHE Brent KEIL John KRAFT department of civil engineering and Construction engineering Technology Louisiana Tech UniversityRustonLA 71270USA department of civil engineering Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh Georgia Tech Research Institute AtlantaGA 30332USA Stantec Inc. Edmonton T5J0K4Canada North West Pipe Company VancouverWA 98684USA

This paper presents an analytical approach for estimating frictional resistance to pipe movement at soil and external pipe surface of buried coated pressurized steel pipes relative to the internal thrust *** proposed analytical method was developed based on 36 experiments,which involved three coating types(cement mortar(CM),polyurethane type-I(PT-I),prefabricated plastic tape(PPT))on pipes’surfaces,three different soils(pea-gravel(PG),sand(S),silty-clay(SC)),and four simulated over burden depths above the pipe’s *** showed frictional resistance decreased with increasing over burden depth above the pipe’s *** degree of frictional resistance at the pipe-soil interface was found to be in the order of PG>SC>S for all coating variations and overburden *** coated pipe buried in all three types of soil produced significantly higher frictional resistance as compared to other coating *** on experimental data,the developed analytical introduced a dimensionless factor“Z”,which included effects of types of coatings,soil,and overburden depths for simplified rapid *** showed that the method provided a better prediction of frictional resistance forces,in comparison to previous analytical methods,which were barely close in predicting friction resistance for different coating variations,soil types,and overburden *** resistance force values reported herein could be considered conservative.

关键词： friction resistance force thrust force coated pressurized steel pipe soil type overburden depth

Numerical analysis of moving train induced vibrations on tunnel,surrounding ground and structure

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Earthquake engineering and engineering Vibration 2024年第1期23卷 179-192页

作者： Swati Srivastav Sowmiya Chawla Swapnil Mishra department of Applied Geophysics Indian Institute of Technology(ISM)Dhanbad 826004India department of civil engineering Indian Institute of Technology(ISM)Dhanbad 826004India department of Mining engineering Indian Institute of Technology(ISM)Dhanbad 826004India

This study is focused on the effect of vibration induced by moving trains in tunnels on the surrounding ground and structures.A three-dimensional finite element model is established for a one-track railway tunnel and an adjacent twelve-storey building frame by using commercial software Midas GTS-NX(2019)and Midas *** study considered the moving load effect of a complete train,which varies with space as well as with *** effect of factors such as train speed,overburden pressure on the tunnel and variation in soil properties are studied in the time *** a result,the variations in horizontal and vertical acceleration for two different sites,i.e.,the free ground surface(without structure)and the area containing the structure,are ***,the displacement pattern of the raft foundation is plotted for different train *** lower speeds,the heaving phenomenon is negligible,but as the speed increases,both the heaving and differential settlement increase in the *** study demonstrates that the effect of moving train vibrations should be considered in the design of new nearby structures and proper ground improvement should be considered for existing structures.

关键词： moving train load tunnels vibration effect finite element method(FEM) wave propagation

Predicting moisture condensation risk on the radiant cooling floor of an office using integration of a genetic algorithm-back-propagation neural network with sensitivity analysis

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Energy and Built Environment 2024年第1期5卷 110-129页

作者： Meng Su Jiying Liu Moon Keun Kim Xiaozhou Wu School of Thermal engineering Shandong Jianzhu UniversityJinan 250101China department of civil engineering and Energy Technology Oslo Metropolitan UniversityOslo N-0130Norway School of civil engineering Dalian University of TechnologyDalianChina

Pre-dehumidification time(τ_(pre))and pre-dehumidification energy consumption(E_(pre))play important roles in preventing the condensation of moisture on the floors of rooms that use a radiant floor cooling(RFC)***,there are few theoretical or experimental studies that focus on these two important *** this study,an artificial neural network(ANN)was used to predict condensation risk for the integration of RFC systems with mixed ventilation(MV),stratum ventilation(SV),and displacement ventilation(DV)systems.A genetic algorithm-back-propagation(GA-BP)neural network model was established to predict τ_(pre) and E_(pre).Both training data and validation data were obtained from tests in a computational fluid dynamics(CFD)*** results show that the established GA-BP model can predict τ_(pre) and E_(pre) *** coefficient of determination(R^(2))of τ_(pre) and of E_(pre) were,respectively,0.973 and *** an RFC system integrated with an MV,SV,or DV system,the lowest values of τ_(pre) and E_(pre) were with the DV system,23.1 s and 0.237 kWh,respectively,for a 67.5 m^(3) ***,the best pre-dehumidification effect was with integration of the DV and RFC *** study showed that an ANN-based method can be used for predictive control for condensation prevention in RFC *** also provides a novel and effective method by which to assess the pre-dehumidification control of radiant floor surfaces.

关键词： Condensation prevention Radiant floor cooling Ventilation system genetic algorithm BP neural network

A modified smoothed particle hydrodynamics method considering residual stress for simulating failure and its application in layered rock mass

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Journal of Mountain Science 2024年第6期21卷 2091-2112页

作者： XIA Chengzhi SHI Zhenming KOU Huanjia department of Geotechnical engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground engineering of Ministry of Education Tongji UniversityShanghai 200092China

Residual strength is an indispensable factor in evaluating rock fracture,yet the current Smoothed Particle Hydrodynamics(SPH)framework rarely considers its influence when simulating *** improved cracking strategy considering residual stress in the base bond SPH method was proposed to simulate failures in layered rocks and slopes and verified by experimental results and other simulation methods(i.e.,the discrete element method).Modified Mohr–Coulomb failure criterion was applied to distinguish the mixed failure of tensile and *** fracture markψwas introduced to improve the kernel function after tensile damage,and the calculation of residual stress after the damage was derived after shear *** simulations were carried out to evaluate its performance under different stress and scale conditions and to verify its effectiveness in realistically reproducing crack initiation and propagation and coalescence,even fracture and *** results indicate that the improved cracking strategy precisely captures the fracture and failure pattern in layered rocks and rock *** residual stress of brittle tock is correctly captured by the improved SPH *** improved SPH method that considers residual strength shows an approximately 13%improvement in accuracy for the safety factor of anti-dip layered slopes compared to the method that does not consider residual strength,as validated against analytical *** infer that the improved SPH method is effective and shows promise for applications to continuous and discontinuous rock masses.

关键词： Smoothed particle hydrodynamics Cracking strategy Residual stress Layered rock Crack propagation

Structural build-up model for three-dimensional concrete printing based on kinetics theory

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Frontiers of Structural and civil engineering 2024年第7期18卷 998-1014页

作者： Prabhat Ranjan PREM P.S.AMBILY Shankar KUMAR Greeshma GIRIDHAR Dengwu JIAO Advanced Materials Laboratory CSIR-Structural Engineering Research CentreChennai 600113India department of Architecture and civil engineering City University of Hong KongHong Kong 999077China

The thixotropic structural build-up is crucial in extrusion-based three-dimensional(3D)concrete *** paper uses a theoretical model to predict the evolution of static and dynamic yield stress for printed *** model employs a structural kinetics framework to create a time-independent constitutive link between shear stress and shear *** model considers flocculation,deflocculation,and chemical hydration to anticipate structural *** reversible and irreversible contributions that occur throughout the build-up,breakdown,and hydration are defined based on the proposed structural ***,detailed parametric studies are conducted to evaluate the impact of model *** is revealed that the proposed model is in good agreement with the experimental results,and it effectively characterizes the structural build-up of 3D printable concrete.

关键词： structural build-up rheology thixotropy 3D printable concrete kinetics theory ultra high performance concrete

Deep bed filtration model for cake filtration and erosion

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 355-372页

作者： L.I.KUZMINA Y.V.OSIPOV A.R.PESTEREV department of Applied Mathematics HSE UniversityMoscow 101000Russia department of Computer Science and Applied Mathematics Moscow State University of Civil EngineeringMoscow 129337Russia

Many phenomena in nature and technology are associated with the filtration of suspensions and colloids in porous media. Two main types of particle deposition,namely, cake filtration at the inlet and deep bed filtration throughout the entire porous medium, are studied by different models. A unified approach for the transport and deposition of particles based on the deep bed filtration model is proposed. A variable suspension flow rate, proportional to the number of free pores at the inlet of the porous medium, is considered. To model cake filtration, this flow rate is introduced into the mass balance equation of deep bed filtration. For the cake filtration without deposit erosion,the suspension flow rate decreases to zero, and the suspension does not penetrate deep into the porous medium. In the case of the cake filtration with erosion, the suspension flow rate is nonzero, and the deposit is distributed throughout the entire porous medium. An exact solution is obtained for a constant filtration function. The method of characteristics is used to construct the asymptotics of the concentration front of suspended and retained particles for a filtration function in a general form. Explicit formulae are obtained for a linear filtration function. The properties of these solutions are studied in detail.

关键词： deep bed filtration cake filtration porous medium particle deposition and erosion analytical solution concentration front