RESEARCH ON DYNAMIC RESPONSE EFFECTS OF LOESS SLOP

This paper is based on dynamic shear modulus formula and correlative parameters of loess gained from three triaxial tests. The tests were acted by random seismic load. A subprogram of MSC.Marc was programmed. Finite element model acted by artificial earthquake wave was built to study dynamic response of loess slope. So, the displacement, velocity and stress transformation law of loess slope were analyzed when excellent frequency, amplitude and action direction of input seismic wave was changed. The results show that excellent frequency of slope displacement, velocity response time-history is much smaller than the input wave. A large number of high frequency wave was filtered when seismic wave transmit in slope soil. And dynamic response of loess slope was affected by the predominant frequency of seismic wave strongly. A giving slope was exceptional sensitive to certain seismic wave with predominant frequency. In addition, the changing of amplitude of seismic wave could alter the dynamic response amplitude of slope linearly, but couldn't transform the spectrum character of dynamic response of slope. The result also shows that the dynamic response time-history of slope contains more high frequency components when acting earthquake wave with certain action angle. Response amplitude of displacement and velocity reduced more quickly more close to the top when action angle increasing. Different effect law of stress response amplitude was shown in the top, middle and toe of slope. The changing of seismic wave acting direction affects dynamic response amplificatory coefficient also, which decreases with the increase of seismic wave acting angle when direction is un-vertical.