Model And Numerical Experiment Study On Impact Of Flood On Rural Buildings

The flood disaster, one of the most common disasters, takes the first place of the nature disasters in damage. In the course of the flood impacting on the structure, although the impact time is short, the impact loading is strong and may cause the structure destroyed even collapsed. The flowing direction of the flood and the action range of the flood can't be forecasted. As a result, after the flood a lot of buildings were washed off. Therefore, based on the characteristics of the flood impacting, founding the impact loading model and researching the infection of the impact to the building is an important research work. In this paper, the impact loading of flood is studied based on the model and numerical experiment.The experiments are conducted in the large wave-current tank in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology. In this experiment, different heights of water with 0.6,0.9 and 1.2 meters are used to simulate the flood with different strengths. The distance between the building and the floodgate is 6 meter, the gradient of the hillside is 2 degree. The model scale of buildings is 1:6 and the structure models with different ratios of holes are designed to simulate the buildings at countries and villages.Based on the experimental results, the effects of heights of water and the ratios of holes on the impact loading are investigated. The impacting pressure and the flow loading of flood are studied respectively. First, the properties of the impacting pressure are discussed. The distributions of the impacting pressure on the surface of structure are studied. According to the different measuring points in the same direction, the pressure formulas of impacting pressure are fitted and the moment of bending and the resultant force are calculated. The rule of changes in the impact pressure, the bending moment and resultant force with different heights of water and ratios of holes are discussed. The experimental results are compared with the numerical results and it shows that the numerical model of impact loading is proper. Secondly, the relationship between impact loading, flow loading and hydrostatic pressure are compared. The distributions of the flow loading on the surface of structures are also studied. The rule of changes in the flow loading, the bending moment and resultant force with different heights of water and ratios of holes are also discussed.Finally, the finite element method is used to analyse the masonry structure model, and the contact element is used to simulate the mortar. Then, the stress and displacement nephogram, contact state and contact stresses of the wall in vulnerable positions under the impact pressure are analyzed. Both sides of the gable wall are easy to collapse under the impact pressure. The areas around the holes, junction of vertical and horizontal wall are weak zones and the stresses are greater than other wall under impact loading. Tangential contact stress and slip distance on the wall of the top of window, junction of vertical and horizontal wall and lower right corner of door, where mortar joint cracks easily, are the largest.