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The Cellular Traffic Capacity Model of Toll Station Square

Bai Yuning, Wang Kaixuan, Yi Lei, Peng Bo

Archives of Transport

2023

Vol. 67, iss. 3

35--47

Traffic capacity is an important index to measure the operation efficiency of expressway toll stations. In order to provide relevant theoretical support for accurately evaluating the congestion degree and service level of toll stations, this paper establishes a traffic capacity calculation model for the square in front of expressway toll stations based on the traditional cellular transmission method. Firstly, by dividing the square in front of the station into regular cells, the process of calculating the traffic capacity is simplified; Secondly, the capacity model of the square in front of the station is established based on cellular transmission, and a large amount of data is collected through the monitoring videos of several toll stations. The theoretical capacity of the square in front of the station is calculated by using the important parameters of the model calibrated by the measured data under different lengths of the square in front of the station and the configuration of toll lanes. Then, the simulation platform of VISSIM software is used, and many experiments are carried out with relevant measured data to verify the accuracy of the model in multiple scenarios. Finally, the simulation value of the capacity of the square in front of the station is obtained, and the error is calculated by using the simulation value and the calculation value. The results show that the error of the verification result is 5.19%, and the error is within the allowable range, which shows that the model is accurate and feasible. The theoretical capacity calculated by the capacity model of the square in front of the toll station established in this paper is compared with the actual capacity, which can be used as a standard to judge the congestion degree of the square in front of the toll station and further provide a theoretical reference for evacuation of congestion.

Study of calculation method of pure mode II stress intensity factor of fine-grained concrete using different numerical models

Zhou Changlin, Peng Bo, Deng An, Gao Xiaofeng, Li Yaojia, Zhou Lei, Zhu Zheming

Journal of Theoretical and Applied Mechanics

2021

Vol. 59 nr 2

251--264

Measuring and calculating methods of critical stress intensity factors (SIFs) have become hot topics which attracted large attention recently. In this work, anti-symmetrical four-point bending tests of cracked fine-grained concrete specimens were conducted experimentally and numerically by using a computer-controlled universal testing machine and ABAQUS code. A comparative study of the calculation method of pure mode II stress intensity factor of a fine-grained concrete was performed by utilizing the conventional finite element method (FEM) in two and three dimensions as well as the extended finite element method (XFEM) in three dimensions. The results show that in three-dimensional models, the crack mode is closest to the pure mode II at the center of specimen thickness. Pure mode II stress intensity factors obtained by SEAM2D and XFEM3D are 1.013 and 1.0617 times that by SEAM3D, respectively. Pure mode II stress intensity factors of the fine-grained concrete obtained by the conventional FEM are more stable than that by XFEM. The number of mesh circles has slight influence on the calculation results of pure mode II stress intensity factor.