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Distributed fiber optic sensors for tunnel monitoring:A state-of-the-art review

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Journal of Rock Mechanics and Geotechnical engineering 2024年第9期16卷 3841-3863页

作者： Xuehui Zhang Honghu Zhu Xi Jiang Wout Broere Geo-engineering Section Department of Geoscience and EngineeringDelft University of TechnologyDelft2628CNthe Netherlands School of Earth Sciences and engineering Nanjing UniversityNanjing210023China department of civil and Environmental engineering The Hong Kong Polytechnic UniversityKowloonHong KongChina

Distributed fiber optic sensors(DFOSs)possess the capability to measure strain and temperature variations over long distances,demonstrating outstanding potential for monitoring underground *** study presents a state-of-the-art review of the DFOS applications for monitoring and assessing the deformation behavior of typical tunnel infrastructure,including bored tunnels,conventional tunnels,as well as immersed and cut-and-cover *** systems based on Brillouin and Rayleigh scattering principles are both *** implementing DFOS monitoring,the fiber optic cable can be primarily installed along transverse and longitudinal directions to(1)measure distributed strains by continuously adhering the fiber to the structure’s surface or embedding it in the lining,or(2)measure point displacements by spot-anchoring it on the lining *** are four critical aspects of DFOS monitoring,including proper selection of the sensing fiber,selection of the measuring principle for the specific application,design of an effective sensor layout,and establishment of robust field sensor *** four issues are comprehensively discussed,and practical suggestions are provided for the implementation of DFOS in tunnel infrastructure monitoring.

关键词： Distributed fiber optic sensor(DFOS) Tunnel infrastructure Distributed strain sensing Point displacement monitoring Field instrumentation

Prediction of bearing capacity of pile foundation using deep learning approaches

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Frontiers of Structural and civil engineering 2024年第6期18卷 870-886页

作者： Manish KUMAR Divesh Ranjan KUMAR Jitendra KHATTI Pijush SAMUI Kamaldeep Singh GROVER department of civil engineering SRM Institute of Science and Technology Tiruchirappalli CampusTrichy 621105India department of civil engineering National Institute of Technology PatnaBihar 800005India department of civil engineering Faculty of EngineeringThammasat School of EngineeringThammasat UniversityBangkok10200Thailand department of civil engineering Rajasthan Technical UniversityKota 324010India

The accurate prediction of bearing capacity is crucial in ensuring the structural integrity and safety of pile *** research compares the Deep Neural Networks(DNN),Convolutional Neural Networks(CNN),Recurrent Neural Networks(RNN),Long Short-Term Memory(LSTM),and Bidirectional LSTM(BiLSTM)algorithms utilizing a data set of 257 dynamic pile load tests for the first ***,this research illustrates the multicollinearity effect on DNN,CNN,RNN,LSTM,and BiLSTM models’performance and accuracy for the first time.A comprehensive comparative analysis is conducted,employing various statistical performance parameters,rank analysis,and error matrix to evaluate the performance of these *** performance is further validated using external validation,and visual interpretation is provided using the regression error characteristics(REC)curve and Taylor *** from the comparative analysis reveal that the DNN(Coefficient of determination(R^(2))_(training(TR))=0.97,root mean squared error(RMSE)_(TR)=0.0413;R^(2)_(testing(TS))=0.9,RMSE_(TS)=0.08)followed by BiLSTM(R^(2)_(TR)=0.91,RMSE_(TR)=0.782;R^(2)_(TS)=0.89,RMSE_(TS)=0.0862)model demonstrates the highest performance *** is noted that the BiLSTM model is better than LSTM because the BiLSTM model,which increases the amount of information for the network,is a sequence processing model made up of two LSTMs,one of which takes the input in a forward manner,and the other in a backward *** prediction of pile-bearing capacity is strongly influenced by ram weight(having a considerable multicollinearity level),and the effect of the considerable multicollinearity level has been determined for the model based on the recurrent neural network *** this study,the recurrent neural network model has the least performance and accuracy in predicting the pile-bearing capacity.

关键词： deep learning algorithms high-strain dynamic pile test bearing capacity of the pile

Adaptation analysis and fusion correction method of CMIP6 precipitation simulation data on the Qinghai-Tibetan Plateau

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Journal of Mountain Science 2024年第2期21卷 555-573页

作者： PENG Hao QIN Dahui WANG Zegen ZHANG Menghan YANG Yanmei YONG Zhiwei School of civil engineering and Geomatics Southwest Petroleum UniversityChengdu 610500China School of geoscience and Technology Southwest Petroleum UniversityChengdu 610500China

In order to obtain more accurate precipitation data and better simulate the precipitation on the Tibetan Plateau,the simulation capability of 14 Coupled Model Intercomparison Project Phase 6(CMIP6)models of historical precipitation(1982-2014)on the Qinghai-Tibetan Plateau was evaluated in this *** indicate that all models exhibit an overestimation of precipitation through the analysis of the Taylor index,temporal and spatial statistical *** correct the overestimation,a fusion correction method combining the Backpropagation Neural Network Correction(BP)and Quantum Mapping(QM)correction,named BQ method,was *** this method,the historical precipitation of each model was corrected in space and time,*** correction results were then analyzed in time,space,and analysis of variance(ANOVA)with those corrected by the BP and QM methods,***,the fusion correction method results for each model were compared with the Climatic Research Unit(CRU)data for significance analysis to obtain the trends of precipitation increase and decrease for each *** results show that the IPSL-CM6A-LR model is relatively good in simulating historical precipitation on the Qinghai-Tibetan Plateau(R=0.7,RSME=0.15)among the uncorrected *** terms of time,the total precipitation corrected by the fusion method has the same interannual trend and the closest precipitation values to the CRU data;In terms of space,the annual average precipitation corrected by the fusion method has the smallest difference with the CRU data,and the total historical annual average precipitation is not significantly different from the CRU data,which is better than BP and ***,the correction effect of the fusion method on the historical precipitation of each model is better than that of the QM and BP *** precipitation in the central and northeastern parts of the plateau shows a significant increasing *** correlation coefficients between monthly

关键词： GCM CMIP6 Precipitation correction BP-QM fusion correction Spatio-temporal characteristics

Development of design charts to predict the dynamic response of pile supported machine foundations

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Frontiers of Structural and civil engineering 2024年第4期18卷 663-679页

作者： Deepthi SUDHI Sanjit BISWAS Bappaditya MANNA department of civil engineering National Institute TechnologyWarangal 506004India department of civil engineering Indian Institute of TechnologyDelhi 110016India

This paper proposes design charts for estimating imperative input parameters for continuum approach analysis of the nonlinear dynamic response of *** and analytical studies using continuum approach have been conducted on single and 2×2 grouped piles under coupled and vertical modes of vibration,for different dynamic forces and pile *** these design charts are derived from model piles,the charts have been validated for prototype pile foundations using scaling *** experimental responses of model piles are scaled up and these responses exhibit good agreement with analytical *** study also extends to estimation of the errors in computing frequency–amplitude responses with an increase in pile *** is found that,with an increase in pile length,the errors also *** effectiveness of the proposed design charts is also checked with data based on different field setups given in existing literature,and these charts are found to be ***,the developed design charts can be beneficial in estimating the input parameters for continuum approach analysis for determining the nonlinear responses of pile supported machine foundations.

关键词： pile foundation vertical vibration coupled vibration continuum approach soil-pile separation boundary zone parameters

Numerical manifold method for thermo-mechanical coupling simulation of fractured rock mass

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Journal of Rock Mechanics and Geotechnical engineering 2024年第6期16卷 1977-1992页

作者： Jiawei Liang Defu Tong Fei Tan Xiongwei Yi Junpeng Zou Jiahe Lv Faculty of engineering China University of GeosciencesWuhan430074China department of civil engineering Monash UniversityClaytonVIC3800Australia Badong National Observation and Research Station of Geohazards China University of GeoscienceWuhan430074China

As a calculation method based on the Galerkin variation,the numerical manifold method(NMM)adopts a double covering system,which can easily deal with discontinuous deformation problems and has a high calculation *** at the thermo-mechanical(TM)coupling problem of fractured rock masses,this study uses the NMM to simulate the processes of crack initiation and propagation in a rock mass under the influence of temperature field,deduces related system equations,and proposes a penalty function method to deal with boundary *** examples are employed to confirm the effectiveness and high accuracy of this *** the thermal stress analysis of a thick-walled cylinder(TWC),the simulation of cracking in the TWC under heating and cooling conditions,and the simulation of thermal cracking of the SwedishÄspöPillar Stability Experiment(APSE)rock column,the thermal stress,and TM coupling are *** numerical simulation results are in good agreement with the test data and other numerical results,thus verifying the effectiveness of the NMM in dealing with thermal stress and crack propagation problems of fractured rock masses.

关键词： Heat conduction Fractured rock mass Crack propagation Galerkin variation Numerical manifold method(NMM)

A stable one-point quadrature rule for three-dimensional numerical manifold method

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Science China(Technological Sciences) 2024年第5期67卷 1401-1416页

作者： ZHANG Ning ZHENG Hong YANG Liang WU WenAn YUAN Chi School of civil engineering Qinghai UniversityQinghai810016China Key Laboratory of Urban Security and Disaster engineering Ministry of EducationBeijing University of TechnologyBeijing100124China Faculty of engineering China University of GeoscienceWuhan430074China

We present a numerically stable one-point quadrature rule for the stiffness matrix and mass matrix of the three-dimensional numerical manifold method(3D NMM).The rule simplifies the integration over irregularly shaped manifold elements and overcomes locking issues,and it does not cause spurious modes in modal *** essential idea is to transfer the integral over a manifold element to a few moments to the element center,thereby deriving a one-point integration rule by the moments and making modifications to avoid locking *** the stiffness matrix,after the virtual work is decomposed into moments,higher-order moments are modified to overcome locking issues in nearly incompressible and bending-dominated *** the mass matrix,the consistent and lumped types are derived by *** particular,the lumped type has the clear advantage of *** proposed method is naturally suitable for 3D NMM meshes automatically generated from a regular *** tests justify the accuracy improvements and the stability of the proposed procedure.

关键词： three-dimensional numerical manifold method quadrature rule locking mass lumping

Parametric investigation on the novel and cost-effective nano fly ash impregnated geopolymer system for sustainable construction

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Frontiers of Structural and civil engineering 2024年第2期18卷 170-183页

作者： R.MOHANA S.M.Leela BHARATHI department of civil engineering Mepco Schlenk Engineering CollegeSivakasi 626123India

The hazardous environmental effects of greenhouse gas emissions and climate change demand alternative sources for cementitious materials in the construction *** development of geopolymer structures provides a way of producing 100%cement-free *** this research work,a novel and simple way of deriving nano particles from waste fly ash particles is *** effect of adding the synthesized nano fly ash particles as a filler medium in geopolymer mortars was investigated by considering strength and durability *** optimization was done by using regression analysis on the geopolymer mortar and the impact of adding nano fly ash particles was studied by varying different percentages of addition ranging from 0 to 7.5%by weight of binder *** the results,it was observed that 1%nano fly ash acted not only as a filler but also as nano-sized precursors of the polymerization process,resulting in denser geopolymer *** can explain the extraordinary gain in strength of 72.11 MPa as well as the denser core with negligible level of chloride ion penetration,making the material suitable for the development of structures susceptible to marine environment.

关键词： geopolymer nano fly ash chloride ion penetration durability polymerization fillers

Mechanical performance of cold mix asphalt containing cup lump rubber as a sustainable bio-modifier

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Journal of Traffic and Transportation engineering(English Edition) 2024年第3期11卷 424-440页

作者： Syed Abdul Ghafar Muhammad Naqiuddin Mohd Warid Norhidayah Abdul Hassan Zulfiqar Ali Jattak Ashraf Abdalla Mohammed Radwan Faculty of civil engineering Universiti Teknologi MalaysiaSkudai 81310Malaysia department of civil engineering Balochistan University of Information TechnologyEngineering&Management SciencesQuettaPakistan department of civil engineering Balochistan University of Engineering and TechnologyKhuzdarPakistan department of civil engineering Faculty of EngineeringUniversity of TripoliTripoliLibya

The road construction industry aims to contribute to the protection of already compromised *** mix asphalt(CMA)is a measure initiated by the road industry to protect the environment and preserve *** having additional benefits,CMA has attracted little attention due to its inferior ***'s performance is enhanced using a sustainable binder bio-modifier,natural cup lump rubber(CLR)is one of *** study evaluated the tensile properties,rutting,moisture susceptibility,and adhesion properties of CLR-modified CMA(CMA-CR).The tensile property was enhanced by 26%due to CLR ***-CR had excellent rutting resistance of less than 2 mm rut depth at 10,000 load cycles,showing 70%improvement compared with conventional *** susceptibility evaluation indicated that CMA-CR had tensile strength ratio(TSR)value of 104%,satisfying the minimum 80%requirement of AASHTO *** also retained more than 96%bitumen *** moisture damage resistance was improved by 12%and 10%in terms of TSR and stripping,*** durability results revealed that the CMA-CR mixture prevented higher mass loss,representing 14%improvement compared with conventional CMA.

关键词： Cup lump rubber Cup lump modified cold mix asphalt Moisture damage Tensile property Rutting Digital imaging

An ultra-thin bolt tension sensor and online monitoring system:For application in hydropower plant unit

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Frontiers of Structural and civil engineering 2024年第9期18卷 1388-1400页

作者： Shaoquan ZHANG Yanke TAN Hanbin GE Qilin ZHANG department of civil engineering Meijo UniversityNagoya 4688502Japan College of civil engineering Tongji UniversityShanghai 200092China

The condition of bolted connections significantly affects the structural ***,conventional bolt tension sensors fail to provide precise measurements due to their bulky size or inadequate *** study employs the piezoresistive effect of crystalline silicon material to fabricate an ultrathin *** sensor exhibits a linear relationship between pressure and voltage,an exceptional stability at varying temperatures,and a superior resistance to corrosion,making it adaptable and user-friendly for applications of high-strength bolt tension monitoring.A monitoring system,incorporating the proposed sensor,has also been *** system provides real-time display of bolt tension and enables the assessment of sensor and structural conditions,including bolt loosening or component *** efficacy of the proposed sensor and monitoring system was validated through a project carried out at the Xiluodu Hydropower *** to the results,the sensor and online monitoring system effectively gauged and proficiently conveyed and stored bolt tension *** addition,correlations were created between bolt tensions and essential unit parameters,such as water head,active power,and pressures at vital points,facilitating anomaly detection and early warning.

关键词： ultra-thin sensor high-strength bolt tension online monitoring system anomaly alarm hydro-generator units