Narrow Results

A new traffic flow model is proposed based on cellular automata and Naive Bayes theory to effectively describe the traffic flow velocity and flow state of the road. On the basis of NaSch model, the safety distance is fully considered in this model, and random deceleration and inflow rules of a vehicle are introduced. At the same time, vehicle acceleration, deceleration and lane change are optimized with Naive Bayes theory. Finally, experimental platform is used for numerical analysis, and the relationship between such parameters as average velocity of traffic flow, maximum velocity of traffic flow, number of inflow vehicles and random deceleration probability, etc. is studied in depth. The results show that the maximum velocity has a great effect on the traffic flow state, and when the vehicle inflow probability is lower, random deceleration probability has less effect on the average velocity and the number of vehicles waiting for inflow; on the contrary, the higher the random deceleration probability is, the more obvious the tendency of road congestion.

High-pile wharf is an important port structure and may suffer from accidental explosions or terrorist bombing attack during the service life. The reinforced concrete (RC) pile is one of the popular vertical load-bearing piles of high-pile wharf structure. As a main load-bearing member of the high-pile wharf structure, the damage of RC pile due to underwater explosive may cause subsequently progressive collapse of the whole structure. In this paper, the dynamic response and failure mode of RC pile in high-pile wharf structure under the near-field non-contact underwater explosion are investigated using a combined experimental and numerical study. First, a typical RC pile was designed and tested for the near-field non-contact underwater explosion. The failure mode and damage of the RC pile specimen were obtained and analyzed. Second, the numerical model of the RC pile under near-field non-contact underwater explosion was established by adopting the commercial software AUTODYN, and then validated based on experimental results. It was shown that the results from numerical model and experimental test compared very well in terms of the damage pattern and lateral displacement. Furthermore, the full-scale numerical model of the RC pile for the near-field non-contact underwater explosion was developed based on the validated numerical model to investigate the damage pattern and failure mode of RC pile under varied underwater explosives. Lastly, the safety distance for the RC pile for the underwater explosion loading with consideration of different explosive mass, the explosive depth and the concrete strength was suggested. The outcome of this study presented reference for analysis, assessment and design of the type of RC pile for high-pile wharf structure subjected to near-field non-contact underwater explosion.