Study On Facility Scale And Layout Of Urban Rail Transit Station Based On Pedestrian Simulation

ABSTRACT:Traffic congestion has become the leading impediment for the sustainable development for metropolitans in China, and has begun to sprawl to second-tier cities. The characteristics of urban rail transit including high efficiency, low consumption, safety, environment-friendly, make it has great advantage in treating road traffic congestion, which has been demonstrated in Beijing, Shanghai. Due to the large sharing of floating population out of the overall residents in metropolitans in China, urban rail transit assumes high passenger load, and the pedestrian congestion in stations is serious, which is of great disservice to efficiency and safety. However, different from structure designing, the design of dimension and layout of the pedestrian facilities in rail station is based on rules of thumb, while simple calculation method in terms of static capacity is not able to reflect the complexity. Along with the development of computer aided modeling technology, pedestrian micro-simulation model became an effective tool in rail station facility designing eventually. However, the present models cannot reach the pedestrian density in congestion situation, and also fail to reflect the squeeze force under dense situation. Meanwhile, there are flaws in the present design approach for the dimension calculation and layout scheme for pedestrian facilities in rail station. To this end, this paper collected and analyzed the present work done on this topic. With the methodology of theory analyzing, model formulating, field study and computer programming, the following work was done and the corresponding conclusion was achieved.1) The pedestrian behavioral characteristics on various facilities in rail station was fully recorded and analyzed. The flow-density diagrams of different facilities, and the desired speed distribution were obtained, which supply data for simulation parameters calibration and validation. The attainable maximum capacities of facilities were got, which was compared with design capacities.2) The simulation model and analysis method applicable for station pedestrian simulation was concluded. Specifically, the basic theory of social force model and its various modified version is detailed. For the problems of this model, such as the high algorithm complexity, the differences in moving characteristics between particles acted by forces and pedestrian with high degree of self-control. The Gear’s predictor-corrector method and linked-list cell algorithm, and the perception-decision making-acting modeling approach of Agent, was introduced, the implementing framework of a space continuous particle model with object oriented programming technology was established.3) Based on the simulation framework of the space continuous particle model, the description of pedestrian figure was optimized. The implementing algorithm for linked-list cell method was designed taking the spatial discrete method in cellular agent model as reference. Using the agent modeling method, the behavior mechanism including pedestrian density scanning and space choice, variable interaction intensity between pedestrians pertained to density and panic index adjusting, were formulated, and the corresponding algorithm was designed. A cluster of parameters for the model was calibrated. With VC++programming platform, the aforementioned model and algorithm was integrated, and a simple version of simulation tool was developed. In terms of simulation result analysis of one-direction and bi-direction walkway, and evacuation simulation with the tool, the model is able to well perform self-organization phenomenon such as arc blocking at bottleneck and lane formation in walkway. The modified pedestrian figure description approach and the variable social force interaction intensity together allow applicability in simulation under both low density and congestion density condition, and the maximum pedestrian density drawn from field study can be reached. The pedestrian flow-density diagram from simulation in walkway fits well with that got by field study, while the optimized algorithm saves simulation time obviously. And also, the model established can reflect both the evacuation time and the squeeze force exerted by other pedestrians or obstacles.4) Although effected by operation quality to some extent, the level of service perceived by passengers in rail station, the density in particular, is fundamentally determined by design scheme. Therefore, domestic or abroad design manual on urban rail station were collected and compared. The differences of the design approach on platform, stairway and escalator, and concourse level were summarized. Aiming at these differences, typical stations were chosen as case study. The platform width calculation method, the stairway and escalator layout of long-train station, the layout scheme of fee collecting gates and evacuation testing method were evaluated with simulation tool. Based on the quantitative and qualitative analysis of the simulation results, the dimension calculation methods and layout schemes of various facilities were optimized, and modified platform width calculation method and evacuation test method under emergent situation were proposed.