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Liu X.,China University of Petroleum - Beijing | Zhang H.,China University of Petroleum - Beijing | Li M.,China University of Petroleum - Beijing | Xia M.,China University of Petroleum - Beijing | And 4 more authors.
Journal of Natural Gas Science and Engineering

The reverse fault is one of main threats faced by high strength gas pipelines, for the potential of leading to buckling failure in the pipe. A 3D finite element model was established in this study, in which the pipe was modeled by shell elements and the pipe-soil interaction relationship by spring elements. A suitable equivalent boundary condition is introduced at the ends of the pipe to simulate the remote end and reduce the model dimension. The mechanical behavior of the buckling process of the pipe was studied. 10 high strength pipe steel materials of 3 different APL 5L grades (X80, X90, X100) were taken into consideration to analyze the influences of the yield strength and the strain hardening parameter of the pipe steel material on the buckling behavior. Results show that, when buckling occurs in high strength steel gas pipelines under reverse fault displacement, the Mises stress in the buckling position of the pipe is about 1.1 times the yield strength of the pipe steel. The critical fault displacement and axial stress increase with the increase of the yield strength, and decrease with the increase of the hardening parameter, while both the yield strength and the hardening parameter have a small influence on the critical axial strain. © 2016 Elsevier B.V. Source

Du H.-Y.,Harbin Institute of Technology | Zeng Q.-S.,Harbin Institute of Technology | Li F.,Beijing Capital International Airport Co. | Yuan D.-C.,Northeast Forestry University
Journal of Harbin Institute of Technology (New Series)

This paper investigates the modified function projective synchronization, which means that the drive system and the response system are synchronized up to a desired scale matrix of function. By the active control scheme, a general method for modified function projective synchronization is proposed. Numerical simulations on chaotic Rössler system and hyper-chaotic Chen system are presented to verify the effectiveness of the proposed scheme. Source

Meng X.,Beijing University of Technology | Jiao S.,Beijing University of Technology | Liu J.,Beijing Capital International Airport Co. | Cao X.,Beijing University of Technology
Chinese Journal of Environmental Engineering

To study the removal performance of slow sand filter for di(2-ethylhexyl) phthalate (DEHP) in secondary effluent from wastewater treatment, a pilot scale slow sand filter with 0.4~0.6 mm granular diameter quartz sands as 800 mm depth filter bed was operated as an advanced wastewater treatment unit. Results showed that the turbidity, chemical oxygen demand and color in effluent of the slow sand filter were far below Water Quality Standard for Urban Miscellaneous Water Consumption: Urban Recycling Water (GB/T18920-2002).When DEHP in influent of slow sand filter was 6.1~62.8 μg/L, DEHP in effluent was declined to 1.7~7.3 μg/L.When a shock concentration of DEHP 282.8 μg/L in influent was applied to the slow sand filter, DEHP in the effluent was below 10 μg/L. The excellent performances of the slow sand filter for DEHP removal from wastewater were contributed by biofilm adsorption, filtration and biodegradation in the bed of the slow sand filter. Source

Du H.,Harbin University of Science and Technology | Lu N.,Harbin University of Science and Technology | Li F.,Beijing Capital International Airport Co.
Proceedings of 2012 International Conference on Measurement, Information and Control, MIC 2012

This Paper investigates the modified function projective synchronization (MFPS) of two different chaotic systems with parameter perturbations. The parameter perturbations are assumed to appear in both drive and response systems, which perturbed about the nominal parameter values. Based on the robust control techniques, the robust control law is proposed, which is able to overcome random uncertainties of all model parameters. Corresponding numerical simulations are performed to verify the analytical results. © 2012 IEEE. Source

Hou G.,China University of Mining and Technology | Liu H.,Beijing Capital International Airport Co. | Li J.,China University of Mining and Technology | Gao R.,China University of Mining and Technology | And 2 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering

During the actual construction process of subway tunnel, the surrounding rock is in a complex process of loading and unloading. Meanwhile, the excavation and support are completed in multiple steps. During this process, the previous excavation step will influence the subsequent excavation. Based on the characteristics of underground engineering, that is, loads are applied first, then excavation is conducted, and supports are provided at last, the actual construction process of subway tunnel under excavation unloading effect was described and simulated. The excavation unloading effect during the process of subway tunnel construction was analyzed in detail; and the 4-stage simulation method was put forward, which can simulate the excavation unloading effect during the construction process of subway tunnel. Taking the tunnel in Xisanqi-Qinghe section of Beijing metro line No. 8 as engineering background, the actual process of shield construction of subway tunnel and the excavation unloading effect were simulated. The effects of excavation face supporting pressure, supporting time and filled grouting on excavation and support of metro tunnel were studied, with and without consideration of the excavation unloading effect. The surrounding rock-support working mechanism of metro shield tunnel was obtained based on the excavation unloading effect. Source

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