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  • Open Access


    Analysis and Modeling of Propagation in Tunnel at 3.7 and 28 GHz

    Md Abdus Samad1,2, Dong-You Choi1,*

    CMC-Computers, Materials & Continua, Vol.71, No.2, pp. 3127-3143, 2022, DOI:10.32604/cmc.2022.023086

    Abstract In present-day society, train tunnels are extensively used as a means of transportation. Therefore, to ensure safety, streamlined train operations, and uninterrupted internet access inside train tunnels, reliable wave propagation modeling is required. We have experimented and measured wave propagation models in a 1674 m long straight train tunnel in South Korea. The measured path loss and the received signal strength were modeled with the Close-In (CI), Floating intercept (FI), CI model with a frequency-weighted path loss exponent (CIF), and alpha-beta-gamma (ABG) models, where the model parameters were determined using minimum mean square error (MMSE) methods. The measured and the… More >

  • Open Access


    ICMPTend: Internet Control Message Protocol Covert Tunnel Attack Intent Detector

    Tengfei Tu1,2, Wei Yin3, Hua Zhang1,2,*, Xingyu Zeng1, Xiaoxiang Deng1, Yuchen Zhou1, Xu Liu4

    CMC-Computers, Materials & Continua, Vol.71, No.2, pp. 2315-2331, 2022, DOI:10.32604/cmc.2022.022540

    Abstract The Internet Control Message Protocol (ICMP) covert tunnel refers to a network attack that encapsulates malicious data in the data part of the ICMP protocol for transmission. Its concealment is stronger and it is not easy to be discovered. Most detection methods are detecting the existence of channels instead of clarifying specific attack intentions. In this paper, we propose an ICMP covert tunnel attack intent detection framework ICMPTend, which includes five steps: data collection, feature dictionary construction, data preprocessing, model construction, and attack intent prediction. ICMPTend can detect a variety of attack intentions, such as shell attacks, sensitive directory access,… More >

  • Open Access


    Dynamic-Response Analysis of the Branch System of a Utility Tunnel Subjected to Near-Fault and Far-Field Ground Motions in Different Input Mechanisms

    Yuhang Jin1,2, Endong Guo1,2,*, Houli Wu1,2, peilei Yan1,2

    CMES-Computer Modeling in Engineering & Sciences, Vol.130, No.1, pp. 167-186, 2022, DOI:10.32604/cmes.2022.018113

    Abstract There are few studies on the dynamic-response mechanism of near-fault and far-field ground motions for large underground structures, especially for the branch joint of a utility tunnel (UT) and its internal pipeline. Based on the theory of a 3D viscous-spring artificial boundary, this paper deduced the equivalent nodal force when a P wave and an SV wave were vertically incident at the same time and transformed the ground motion into an equivalent nodal force using a self-developed MATLAB program, which was applied to an ABAQUS finite element model. Based on near-fault and far-field ground motions obtained from the NGA-WEST2 database,… More >

  • Open Access


    Analysis of the Stability and Mechanical Characteristics of the Jointed Surrounding Rock and Lining Structure of a Deeply Buried Hydraulic Tunnel

    Changchang Li1, Zuguo Mo2, Haibo Jiang1,*, Fengchun Yang1

    FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.1, pp. 29-39, 2022, DOI:10.32604/fdmp.2022.017947

    Abstract On-site monitoring and numerical simulation have been combined to analyze the stability of the jointed surrounding rock and the stress inside the lining structure of a sample deeply buried hydraulic tunnel. We show that the deformation around the tunnel was mainly concentrated in the range 51.37 mm∼66.73 mm, the tunnel circumference was dominated by shear failure, and the maximum plastic zone was about 3.90 m. When the shotcrete treatment was performed immediately after the excavation, the deformation of the surrounding rock was reduced by 58.94%∼76.31%, and the extension of the plastic zone was relatively limited, thereby leading to improvements in terms… More >

  • Open Access


    The Effect of Key Design Parameters on the Global Performance of Submerged Floating Tunnel under Target Wave and Earthquake Excitations

    Chungkuk Jin*, MooHyun Kim

    CMES-Computer Modeling in Engineering & Sciences, Vol.128, No.1, pp. 315-337, 2021, DOI:10.32604/cmes.2021.016494

    Abstract This study presents a practical design strategy for a large-size Submerged Floating Tunnel (SFT) under different target environments through global-performance simulations. A coupled time-domain simulation model for SFT is established to check hydro-elastic behaviors under the design random wave and earthquake excitations. The tunnel and mooring lines are modeled with a finite-element line model based on a series of lumped masses connected by axial, bending, and torsional springs, and thus the dynamic/structural deformability of the entire SFT is fully considered. The dummy-connection-mass method and constraint boundary conditions are employed to connect the tunnel and mooring lines in a convenient manner.… More >

  • Open Access


    Optimal Control of Slurry Pressure during Shield Tunnelling Based on Random Forest and Particle Swarm Optimization

    Weiping Luo1,2, Dajun Yuan1,2, Dalong Jin1,2,*, Ping Lu1,2, Jian Chen3

    CMES-Computer Modeling in Engineering & Sciences, Vol.128, No.1, pp. 109-127, 2021, DOI:10.32604/cmes.2021.015683

    Abstract The control of slurry pressure aiming to be consistent with the external water and earth pressure during shield tunnelling has great significance for face stability, especially in urban areas or underwater where the surrounding environment is very sensitive to the fluctuation of slurry pressure. In this study, an optimal control method for slurry pressure during shield tunnelling is developed, which is composed of an identifier and a controller. The established identifier based on the random forest (RF) can describe the complex non-linear relationship between slurry pressure and its influencing factors. The proposed controller based on particle swarm optimization (PSO) can… More >

  • Open Access


    Parameters Identification of Tunnel Jointed Surrounding Rock Based on Gaussian Process Regression Optimized by Difference Evolution Algorithm

    Annan Jiang*, Xinping Guo, Shuai Zheng, Mengfei Xu

    CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.3, pp. 1177-1199, 2021, DOI:10.32604/cmes.2021.014199

    Abstract Due to the geological body uncertainty, the identification of the surrounding rock parameters in the tunnel construction process is of great significance to the calculation of tunnel stability. The ubiquitous-joint model and three-dimensional numerical simulation have advantages in the parameter identification of surrounding rock with weak planes, but conventional methods have certain problems, such as a large number of parameters and large time consumption. To solve the problems, this study combines the orthogonal design, Gaussian process (GP) regression, and difference evolution (DE) optimization, and it constructs the parameters identification method of the jointed surrounding rock. The calculation process of parameters… More >

  • Open Access


    Numerical Analysis of Three-Layer Deep Tunnel Composite Structure

    Weiwei Sun1, Hongping Min2, Jianzhong Chen1,*, Chao Ruan2, Yanjun Zhang2, Lei Wang3

    CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.1, pp. 223-239, 2021, DOI:10.32604/cmes.2021.015208

    Abstract To date, with the increasing attention of countries to urban drainage system, more and more regions around the world have begun to build water conveyance tunnels, sewage pressure deep tunnels and so on. However, the sufficient bearing capacity and corrosion resistance of the structure, which can ensure the actual service life and safety of the tunnel, remain to be further improved. Glass Fiber Reinforced Plastics (GFRP) pipe, with light weight, high strength and corrosion resistance, has the potential to be applied to the deep tunnel structure. This paper proposed a new composite structure of deep tunnel lined with GFRP pipe,… More >

  • Open Access


    Development of TD-BEM Formulation for Dynamic Analysis for Twin-Parallel Circular Tunnels in an Elastic Semi-Innite Medium

    Weidong Lei1, Hai Zhou1,*, Hongjun Li2, Rui Chen1

    CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 577-597, 2021, DOI:10.32604/cmes.2021.011857

    Abstract In order to simulate the propagation process of subway vibration of parallel tunnels in semi-infinite rocks or soils, time domain boundary element method (TD-BEM) formulation for analyzing the dynamic response of twin-parallel circular tunnels in an elastic semi-infinite medium is developed in this paper. The time domain boundary integral equations of displacement and stress for the elastodynamic problem are presented based on Betti’s reciprocal work theorem, ignoring contributions from initial conditions and body forces. In the process of establishing time domain boundary integral equations, some virtual boundaries are constructed between finite boundaries and the free boundary to form a boundary… More >

  • Open Access


    Numerical Simulation of Fire-Smoke Diffusion Caused by Vehicles in a Tunnel

    Li Lei*, Wukai Chen, Huiling Li, Shuai Shi

    FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.5, pp. 837-856, 2020, DOI:10.32604/fdmp.2020.09631

    Abstract Urban tunnels are generally narrow and fire smoke can hardly diffuse. In the present study, numerical simulation is used to analyze the diffusion of high temperature smoke produced by fire inside a specific tunnel (the Kaiyuan tunnel). The results are compared with similar data relating to other tests to determine the validity of the numerical method. Moreover, the critical velocity obtained by numerical simulation of 5 MW, 20 MW, and 50 MW fires in curved and linear sections of the considered tunnel is compared with the values obtained using empirical formulas. The results show that, for the tunnel ventilation design,… More >

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