| Retaining wall is widely used in the lifeline engineering such as traffic, bridges, building foundation, water conservancy, port and so on. The concrete, brick and stone materials used to build gravity retaining walls usually can be fined locally. The gravity retaining wall has better adaptability with its simple forms and its easy construction. Therefore, the gravity retaining wall is widely used in all kinds of real project. China is located between the world’s most active Pacific seismic zone and the Himalayas-Mediterranean seismic belt. In recent years, it shows that China is in the earthquake active period and a series of destructive earthquakes happened. Many retaining walls was damaged in the strong earthquake and so the research on seismic performance of retaining walls is of great significance. The gravity retaining wall has the most simple of the mechanical behavior than other types of retaining structure. A thorough study of the seismic behavior of gravity retaining walls can help us to understand better other more complex type of retaining structure, and its research methods and research results can be popularized to the seismic research of other type of retaining structure. Therefore, the seismic researches of gravity retaining walls have important engineering meaning and theoretical research significance.The present research is supported by the National Mega-project of Natural Science Foundation of China Function "Failure mechanism and seismic safety evaluation of the nuclear power plant engineering structure under seism action"(No.51138001), the earthquake industry special funds for scientific research projects "Study on key techniques of nuclear power plant’s seismic design-Study on the earthquake response of the structures features and failure mechanism of nuclear power plant’s draining structures(No.201208013)" and the natural science fund plan of Liaoning province "Study on earthquake response of nuclear power plant’s draining shield tunnel under complex ocean foundation conditions". Based on the domestic and foreign research results, this paper studied the displacement mode and failure mechanism of the upright retaining wall under severe earthquake by the use of combined the shaking table test and the numerical simulation. The main contents of this study are as follows:(1) The computation theory and the calculation method of PFC2D are systematically presented. Then, the clump theory in PFC2D and the common process of solving problem using granular flow method are elaborated in detail. (2) According to the basic types, two groups of shaking table model test of a retaining wall were designed carefully. The displacement mode and failure mechanism of model were study by using the Digital Particle Image Velocimetry technology. Then, a PFC numerical simulation of the shaking table test was proceeded by means of PFC2D and its fish language re-development and the microscopic parameters were calibrated, which made the numerical simulation based on reliable parameters.(3) Based on the relationship between physical test parameters and numerical micro-parameters, the full scale numerical model of retaining wall were established and a thorough study of the seismic behavior of gravity retaining walls was completed through observing the displacement of the retaining wall, the damage rule of backfill and the change rule of active earth pressure. Then the important influencing factors of retaining wall’s seismic performance, the interface friction coefficient between the retaining wall and the foundation, the size of the wall body, the thickness of the foundation and vertical seismic load, were studied by PFC numerical computation.(4) A numerical model of a retaining wall adding anchor rods was created. The numerical simulation results show that anchor rods suppressed the displacement deformation of retaining wall and enhanced the seismic stability of retaining wall. |
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