Improving Study On Social Force Model Of Pedestrian Movement Behavior On Ladder Sections

Since the 21 st century, the urbanization process was constantly accelerated, the urbanization level was significantly increased, the city scale is unceasingly expanded, the form、function and structure of architecture is intend to diversification, residents activities is increasingly frequent and centralization. According to incomplete statistics, thousands of people around the world get hurt or die because of crowd accident every year, crowd accident not only caused casualties and economic losses, but also has a detrimental effect on the construction of city and the development of social. Therefore, ensure the safety of pedestrian in travel activities has been gradually developed into a social issue.In group activities, pedestrian movement behavior has an important effect on the safety of pedestrians, it is not only has certain regularity, but also has great randomness. It is difficult to implement pedestrian movement experiment, and the experiment is almost impossible of the risk section. So, the research by model was widely adopted. The social force model was established on the basis of pedestrian individual, and the dynamic interaction between pedestrians and environment has been considered, therefore, the description of pedestrian movement phenomenon is more reliable. Therefore, this paper adopts the social force model to research movement characteristics of pedestrian.The ladder section was more and more rifeness in modern cities, especially mountain cities. It has a certain gradient, and was composed of several step, the movement behavior of pedestrian was more complex on ladder sections than plane section. In addition, the ladder section was accident-prone location, it is an important part of the dangerous section, therefore, it is necessary to research movement characteristics of pedestrian on the ladder section.First, the characteristics of pedestrian traffic were introduced from macro and micro two aspects. The characteristics of pedestrian freedom movement was analyzed from four aspects, including the freedom of movement speed, the characteristics of macroscopic parameters, the trajectory of pedestrian movement and the desired speed. A large amount of data investigation data was analyzed by MATLAB and SPSS, The factors that affected speed was analyzed form gender, gradient, length three aspects, and the relational model was established between desired speed, slope, and length, the theory system of pedestrian traffic flow was enriched and improved.Second, the fundamentals of the model were introduced, and the current research literatures were systematically reviewed from seven aspects, including the improvements of the model structure and its expressions, the affection of the relative velocity and different direction, the analysis of the requirement space, the optimization of the algorithm, the selection of parameters, the application of the model. The stress distribution of pedestrian was analyzed, the inclined force component of the gravity was introduced into the model. the parameter and algorithm of the model were optimized on the basis of considering the influence of steps, the improved model of could apply to the ladder was established.Finally, the initial model and the improved model were used to instance simulation by MATLAB. In order to verify the improved model was rationality or not, the simulation results and the actual movement were compared from three aspects, including the relationship between speed and length, the relationship between speed and gradient, the trajectory of pedestrian movement.Pedestrian movement phenomenon on ladder sections could be effectively described by the improved model, and the theoretical basis was provided in the planning and design of pedestrian traffic facilities.