Analysis On The Permanent Displacement Of Gravity Retaining Wall Under Sesimic Loading

In the seismic design of gravity retaining walls, the active earth pressure and displacement information is a key factor to the success of this design. But due to the randomness of seismic load or the complexity between walls and the earth, it is still lack of accurate methods to calculate the residual displacement of retaining walls after the earthquake. Therefore, we mainly use the pseudo dynamic method and the kinematic method in this paper, and have proposed the calculation method of active earth pressure and residual displacement of retaining walls under seismic loads. Then, we analyzed the main influence parameters, the main conclusions are as following:Gravity retaining wall is key structure in geotechnical engineering, developing large scale shaking table tests and performance-based seismic design not only can reveal failure mechanism and laws of gravity retaining walls under seismic loads, perfect the seismic design theory and method, but also improve seismic competence and ability, and is of great significance to the development of seismic code. Therefore, the mainly works we have done in this paper are as follows:1. The magnitude and distribution of active earth pressure on retaining walls are greatly influenced by the magnitude of seismic horizontal acceleration. The greater the earthquake acceleration is, the greater the active earth pressure on the retaining walls will be, and the more obvious the nonlinear distribution along the wall will be; and the influence of seismic vertical acceleration component is relatively small. At the same time, the magnitude and distribution of the active earth pressure on the retaining walls will be greatly influenced by the size of the internal friction angle of the backfill. With the increase of the internal friction angle, the active earth pressure decreases and the amplitude is a little larger and the nonlinearity of the active earth pressure along the wall is more obvious; Compared with the effect of internal friction angle, the effect of the friction angle of the retaining wall is smaller. The active earth pressure will be reduced within a certain extent with the increase of the friction angle of the retaining walls.2. Compared to the traditional Mononobe-Okabe method, the active earth pressure calculated by the dynamic method is smaller, distribution of earth pressure is nonlinear. In the seismic design of gravity retaining walls, the Mononobe-Okabe method is conservative and safe; Because of considering the nonlinear characteristic and phase difference of seismic acceleration, the dynamic method is roughly consistent with the actual engineering.3. The retaining walls have a sliding yield acceleration and a rotational yield acceleration. When the peak acceleration of earthquake exceeds the sliding yield acceleration or the rotational yield acceleration of the retaining wall, it will slip or rotate around the toe of the wall.4. The magnitude of the peak value of the horizontal acceleration of earthquake has a great influence on the final displacement or rotation displacement of the retaining wall. With the increase of the peak value of earthquake acceleration, the cumulative slip displacement and rotational displacement of the retaining wall will increase. Therefore, the peak value of earthquake acceleration is an important parameter in the seismic design of retaining walls.5. The residual displacement of the retaining wall will increase with the increase of the vertical acceleration of the earthquake. The vertical acceleration of the earthquake has a negative effect on the seismic stability of retaining walls.6. The cumulative displacement of the retaining wall will increase with the increase of the surface load of filled soil.