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  • Open Access

    ARTICLE

    Elastoplastic Analysis of Circular Tunnel in Saturated Ground Under Different Load Conditions

    Panpan Zhai1, 2, Ping Xu1, 2, *

    CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 179-197, 2020, DOI:10.32604/cmc.2020.06474

    Abstract When a tunnel is excavated below the groundwater table, groundwater flows in through the excavated wall of the tunnel and seepage forces act on it. These forces significantly affect the ground reaction curve, which is defined as the relationship between the internal pressure and radial displacement of the tunnel wall. This study investigates analytical solutions for seepage forces acting on the lining of a circular tunnel under steady-state groundwater flow. Considering the tunnel’s construction or service period and boundary conditions, the direction of maximum principal stress changes, and the input stress of the Mohr-Coulomb criterion… More >

  • Open Access

    ARTICLE

    Progressive loss of bone mass in children with Fontan circulation

    Simone Goa Diab1, Kristin Godang2, Lil‐Sofie Ording Müller3, Runar Almaas4, Charlotte de Lange3, Leif Brunvand1, Kari Margrethe Hansen1, Anne Grethe Myhre5, Gaute Døhlen1, Erik Thaulow1,6, Jens Bollerslev2,6, Thomas Möller1

    Congenital Heart Disease, Vol.14, No.6, pp. 996-1004, 2019, DOI:10.1111/chd.12848

    Abstract Objective: We investigated bone mineral density (BMD) at different ages after the Fontan completion, and we evaluated the relationship between BMD, vitamin D levels, and pertinent patient variables.
    Methods: A cross‐sectional sample of 64 patients was examined with dual‐energy X‐ray absorptiometry (DXA) scans to determine BMD. Of these patients, 24 were also examined with BoneXpert software to determine bone mass density (BMX), expressed as the bone health index (BHI). Blood samples from all patients were analyzed. Patients were divided into three different age groups; A: 4‐9 years old (n = 22), B: 10‐15 years old (n =… More >

  • Open Access

    ABSTRACT

    Gas Sealing Behavior of Gasketed Segmental Joints in Shield Tunnels: An Experimental and Computational Study

    Wei Wu1,2,3, Yaji Jiao2,*, Hehua Zhu1,2,3, Rui Jin2

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.2, pp. 33-33, 2019, DOI:10.32604/icces.2019.05324

    Abstract When shield tunnels pass through gas-bearing strata, leakage may happen through the gasketed segmental joints, which puts threats on the safety during construction and operation process. Previous studies on sealing performance of the gasketed joints have focused on the waterproof behavior. However, differences in physical characteristics between liquid and gas, lead to different permeation properties. This paper presents a combined experimental and computational study to investigate the gas sealing behavior of the gasketed joints used for a shield tunnel project, i.e., Sutong GIL Utility Tunnel, which passes through soft soil strata rich in high-pressure biogas… More >

  • Open Access

    ABSTRACT

    Block Theory and Its Application to a Water-Conveyance Tunnel Project

    Zixin Zhang1,2,*, Shuaifeng Wang1,2, Xin Huang1,2

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.2, pp. 29-29, 2019, DOI:10.32604/icces.2019.04704

    Abstract Block theory is widely used in numerical simulation of rock engineering due to its concision and fast-calculation. The paper proposes block theory for TBM (tunnel boring machine) tunnels to extend the traditional block theory applicative for tunnels excavated by TBM. In the proposed method, TBM-block interaction forces are taken into consideration. Subsequently, an index is proposed to estimate the stability of the TBM tunnel based on safety factor at every given chainage of the tunnel. Finally, a real water-conveyance tunnel project is studied with block theory for TBM tunnels. The simulation results include the joint More >

  • Open Access

    ARTICLE

    Improved Particle Swarm Optimization for Selection of Shield Tunneling Parameter Values

    Gongyu Hou1, Zhedong Xu1,*, Xin Liu1, Cong Jin1

    CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.2, pp. 317-337, 2019, DOI:10.31614/cmes.2019.04693

    Abstract This article proposes an exponential adjustment inertia weight immune particle swarm optimization (EAIW-IPSO) to enhance the accuracy and reliability regarding the selection of shield tunneling parameter values. According to the iteration changes and the range of inertia weight in particle swarm optimization algorithm (PSO), the inertia weight is adjusted by the form of exponential function. Meanwhile, the self-regulation mechanism of the immune system is combined with the PSO. 12 benchmark functions and the realistic cases of shield tunneling parameter value selection are utilized to demonstrate the feasibility and accuracy of the proposed EAIW-IPSO algorithm. Comparison More >

  • Open Access

    ARTICLE

    NARX Network Based Driver Behavior Analysis and Prediction Using Time-series Modeling

    Ling Wu1, Haoxue Liu2, Tong Zhu2, Yueqi Hu3

    Intelligent Automation & Soft Computing, Vol.24, No.3, pp. 633-642, 2018, DOI:10.31209/2018.100000030

    Abstract The objective of the current study was to examine how experienced and inexperienced driver behaviour changed (including heart rate and longitudinal speeds) when approaching and exiting highway tunnels. Simultaneously, the NARX neural network was used to predict real-time speed with the heart rate regarded as the input variable. The results indicated that familiarity with the experimental route did decrease drivers’ mental stress but resulted in higher speed. The proposed NARX model could predict synchronous speed with high accuracy. These results of the present study concern how to establish the automated driver model in the simulation More >

  • Open Access

    ARTICLE

    A Study of the Suitable Measurement Location and Metrics for Assessing the Vibration Source Strength Based on the Field-Testing Data of Nanchang Underground Railway

    Ling Zhang1, 2, Xiaoyan Lei1, Jian Jiang2, Qingsong Feng1

    Sound & Vibration, Vol.52, No.5, pp. 22-27, 2018, DOI:10.32604/sv.2018.04058

    Abstract Underground railway vibration source strength is one of the key values used for environmental impact assessment and the evaluation of mitigation measure’s performance. However, currently there is no international standard of measuring the underground railway vibration source strength for such purposes. The available local standards and industrial guidelines do not agree on measurement locations as well as the metrics for presenting the source strength. This has caused many confusions. This paper aims to study the suitable measurement location and metrics using the data from a large scale field-testing carried out at the Nanchang underground railway… More >

  • Open Access

    ARTICLE

    Dynamic Pressures on Tunnel Roofs due to Vehicle Passages

    James D. Barnes1, Ethan R. Brush1, Mark S. Newmark1, Eric E. Ungar1, *

    Sound & Vibration, Vol.52, No.4, pp. 6-8, 2018, DOI:10.32604/sv.2018.03737

    Abstract Pressure and proximity measurements made in a tunnel indicate that a typical vehicle passage produced on the tunnel roof an initial pressure increase of small magnitude, followed by a sharp and more substantial drop in pressure below atmospheric. The magnitude of the pressure drop was found to increase with smaller clearances between the vehicle top and the tunnel roof, consistent with the Bernoulli relation and the vehicle speed. The dynamic pressures potentially may have significant effects on the vibration and noise environments on the lower floors of “air rights construction” buildings that span highways. More >

  • Open Access

    ARTICLE

    Information Monitoring Technology for Support Structure of Railway Tunnel During Operation

    Licai Zhao1,*, Shishuenn Chen

    Structural Durability & Health Monitoring, Vol.12, No.1, pp. 35-50, 2018, DOI:10.3970/sdhm.2018.012.035

    Abstract In the process of railway construction, because of the inconvenience of geological condition, water bursting and mud surging happen frequently, and the later deformation of support structure on the happening geology section would threaten the normal running of railway. The limit difference of deformation control value of the support structure section where geological accidents frequently happen, is small, and artificial half-automatic supervisory technology cannot get the health condition of tunnel in time, resulting many cars speed-down accidents due to deformation of support structure. Through design innovation, we introduce TGMIS in the later period of Yanzishan… More >

  • Open Access

    ARTICLE

    Comparison of extracardiac conduit and lateral tunnel for functional single-ventricle patients: A meta-analysis

    Zhiyong Lin, Hanwei Ge, Jiyang Xue, Guowei Wu, Jie Du, Xingti Hu, Qifeng Zhao

    Congenital Heart Disease, Vol.12, No.6, pp. 711-720, 2017, DOI:10.1111/chd.12503

    Abstract Objective: This study aims to assess and compare the early and long-term effects of extracardiac conduit (EC) and lateral tunnel (LT) in patients with a functional single ventricle through metaanalysis.
    Design: A systematic search was performed in PubMed, Embase, Cochrane Library, CNKI, VIP, CBM, and WanFang databases for papers that were published until August 1, 2016. Cochrane systematic review method was used for paper screening and information retrieve, and RevMan 5.3 software was applied for the meta-analysis.
    Results: Data for 10 studies with a total of 3814 patients were retrieved. The advantages of EC comparing to LT include:… More >

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