Weiwei Sun¹, Hongping Min², Jianzhong Chen^1,*, 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… More >

Weidong Lei¹, Hai Zhou^1,*, 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… More >

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,… More >

Meng Wei^*, Ningxin Zhang, Yuan Tong, Yu Song

Intelligent Automation & Soft Computing, Vol.26, No.3, pp. 597-607, 2020, DOI:10.32604/iasc.2020.013938

Abstract The traditional radar signal detection mode of the analog digital converter (ADC) has a low prediction efficiency. Therefore, the advanced prediction model of the tunnel geological radar based on the cluster computing was designed. The completeness factor of the detection radar signal was calculated by the computer cluster effect, and then the information extraction and information integration of the radar pulse for the radar detection signal was determined. Moreover, the multi-order nonlinear regression forecasting model restructured the received signal. Thus, the prediction of the radar detection signal was achieved. In order to ensure the effectiveness More >

Peishuai Chen^1,2,3,*, Junjie Cao⁴, Weizhong Chen³, Weisheng Rao²

Structural Durability & Health Monitoring, Vol.14, No.2, pp. 147-163, 2020, DOI:10.32604/sdhm.2020.07619

Abstract Existing studies on the durability of subsea tunnel mainly focus on the concrete deterioration and steel corrosion, while there are few on the influence of mechanical properties deterioration of surrounding rock on the durability of subsea tunnel. To improve the accuracy of long-term stability prediction, seawater corrosion tests of intensely weathered surrounding rock of subsea tunnel are carried out. In this study, the strength characteristics of remolded samples of intensely weathered granite under different seawater concentrations are investigated, the strength attenuation equation under seawater corrosion is established, and the chemical damage evolution equation and model More >

Wei Liu^{1, 2, *}, Qianxiang Wu²

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.2, pp. 661-690, 2020, DOI:10.32604/cmes.2020.07764

Abstract A utility tunnel system consists of pipes and ancillary facilities. In this paper, a finite element model of a concrete utility tunnel with pipes inside is established. Several tunnel segments were built to simulate a real utility tunnel, while the pipe was fixed by springs on the brackets in the utility tunnel. Using the discrete soil spring element to simulate the soil-structure interaction, actual earthquake records were adopted as excitation to analyze the seismic responses of pipes in a utility tunnel. Moreover, the influences of different parameters, including soil type, earthquake records, and field apparent More >

Abierdi¹, Yuzhou Xiang², Haiyi Zhong², Xin Gu², Hanlong Liu^{2, 3}, Wengang Zhang^{2, 3, *}

CMC-Computers, Materials & Continua, Vol.63, No.2, pp. 825-844, 2020, DOI:10.32604/cmc.2020.07946

Abstract Tunnel excavation is a complicated loading-unloading-reloading process characterized by decreased radial stresses and increased axial stresses. An approach that considers only loading, is generally used in tunnel model testing. However, this approach is incapable of characterizing the unloading effects induced by excavation on surrounding rocks and hence presents radial and tangential stress paths during the failure process that are different from the actual stress state of tunnels. This paper carried out a comparative analysis using laboratory model testing and particle flow code (PFC^2D)-based numerical simulation, and shed light upon the crack propagation process and, microscopic stress More >

Yundong Han¹, Dawei Chen¹, Shaoqing Liu¹, Gang Xu²

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 1-19, 2020, DOI:10.32604/fdmp.2020.06525

Abstract A series of tests have been conducted using a Cryogenic Wind Tunnel to study the effect of Reynolds number (Re) on the aerodynamic force and surface pressure experienced by a high speed train. The test Reynolds number has been varied from 1 million to 10 million, which is the highest Reynolds number a wind tunnel has ever achieved for a train test. According to our results, the drag coefficient of the leading car decreases with higher Reynolds number for yaw angles up to 30º. The drag force coefficient drops about 0.06 when Re is raised… More >

Panpan Zhai^{1, 2}, Ping Xu^{1, 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 >

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 Thaulow^1,6, Jens Bollerslev^2,6, 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 >