Distribution Of Active Earth Pressure Of Retaining Wall Considering Soil Arching

Retaining wall is the structure widely used in civil construction, water conservancy and hydropower, traffic engineering etc. construction. Retaining wall’s destruction, not only affects the foundation of engineering, but also may cause secondary disasters in the earthquake, thus the design of retaining wall need more accurate calculation of earth pressure theory as guidance. The current methods considering arching effect to calculate the earth pressure on retaining wall are confined to the calculation of earth pressure under a plane slip surface, and lack of theory analysis of soil arching shape, especially in the case of earthquakes, the existing theories ignored the impact of seismic coefficient to lateral earth pressure coefficient.In this paper, take vertical rigid retaining wall as the research object, considering arching effect, calculated the distribution of active earth pressure in static condition and seismic active earth pressure under earthquake.Firstly, considering arching effect, after analyzing the stress of the filling behind retaining wall, the equation of soil arching was obtained. By using the method of horizontal differential element, the formula of the distribution of active earth pressure were obtained, as well as the resultant force and its points of application. The influence of each parameter on calculation results is also analyzed. It is shown that the calculating results of proposed method are in consistence with the results of model test, and the height of the point of application of the resultant force is smaller than the result of Coulomb theory, so use the Coulomb theory to design retaining wall is dangerous. Then, considering soil-arching and assumed that soil arching took the form of circle and the inclination of slip surface behind retaining wall was a cycloid, an improved mathematical model was obtained to calculate the active earth pressure. The result was compared with the result calculated by the plane slip surface behind retaining wall as well as other methods, the influence of each parameter on calculation results is also analyzed. In this paper, it is first time combined curve slip surface and the soil arching effect to calculate the earth pressure, it has important theoretical significance. It is shown that when the ratio of the wall friction angle and the soil friction angle close to 1, the calculated value of resultant force is bigger than the value calculated by the Coulomb theory. In the case of earthquake, based on Mononobe-Okabe theory, considering arch effect and assuming that soil arching was in the form of circle, After analyzing the stress of the filling behind retaining wall, the equation of soil arching was obtained, as well as the lateral earth pressure coefficient, By using the method of horizontal differential element, an improved formula of the distribution of seismic active earth pressure resultant force and its points of application were obtained. The proposed method was compared with the existing methods and M-O theory, the influence of each parameter on calculation results is also analyzed. It shows that the resultant seismic earth pressure force is the same as that given by Mononobe-Okabe theory, the distribution of seismic earth pressure is non-linear. The distribution of seismic earth pressure is more sensitive to the change of horizontal seismic coefficient. When the earthquake coefficient is bigger, the resultant force point of application is far greater than the calculated value of M-O theory, so use the M-O theory to design retaining wall is dangerous. The results have a guiding role for the design of retaining wall.