基于可变元胞与跟驰理论的元胞自动机模型

为准确模拟桥址随机车流荷载，提出基于可变元胞与跟驰理论的元胞自动机(cellular automata, CA)模型。首先，重新定义元胞构成，提出以车辆为核心的动态可变元胞，并将精确的轴间距和轴重信息融入车辆元胞，实现车辆荷载的精确模拟；然后，引入跟驰理论，提出基于跟驰理论的状态演化规则，推导每辆车的专有加速度，实现车辆微观交互的模拟；最后，提出基于实测动态称重系统(weigh in motion, WIM)数据的发车规则，依据WIM数据，重构任意时段的实际车队，并建立基于车头时距的发车规则，重现车辆通过WIM时的运动状态。基于所提出的发车规则和动态演化规则，实现车辆从进入道路到驶离道路全过程时空位置的准确模拟，结合融入精确轴载的车辆元胞，实现随机车流荷载的模拟。基于实测WIM数据验证所提模型的可行性和先进性。结果表明：可变元胞可以精确模拟车辆荷载；提出的状态演化规则可以根据不同车辆的运动状态计算得到每辆车的专属加速度，准确模拟每辆车在自由行驶和跟驰行驶时的不同运动状态；新发车规则可以重构任意时段的实测车队，结合新状态演化规则，可以实现桥址任意时段随机车流的模拟。结合精细化车辆荷载模拟...

New cellular automata with based on transformable cell and car following theory

To reasonably simulate the stochastic traffic load on bridge site, a new cellular automata based on car following theory is proposed. Firstly, a new transformable cell which considers the vehicle as the core is proposed. The precise axle gap and axle weight are incorporated into the cell to fulfill the goal of precise vehicle load simulation. Then, the car following theory is introduced to propose the new transition rules, and the acceleration of each vehicle can be calculated based on the proposed transition rules. Finally, new boundary rules based on Weigh in Motion (WIM) is proposed. The vehicle sequence of any time period which matches the real one can be generated based on the WIM data, based on which the initial states of the vehicles to enter the road can be determined. Based on the proposed transition rules and the boundary rules, the spatiotemporal position of vehicles can be simulated, and the stochastic traffic load can be simulated with consideration of the new cell. The proposed model is validated using real WIM data, and the results indicate that the proposed new cell can precisely simulate the vehicle load. The proposed transition rules can compute the specific acceleration for each vehicle, and free driving and car following can be simulated. With simultaneously using the vehicle sequence generation method and the transition rules, the real traffic load of any time period can be reconstructed. The proposed CA model can be applied to simulate the stochastic traffic load of any time period on bridge site. With considering the precise axle load and reasonable traffic flow, the stochastic traffic load on bridge site can be successfully simulated.