Using natural Xiashu loess

a 1g large-scale shaking table model test with a scaling factor of 20 for a model slope with a height of 0.5 m and slope angle of 45°was carried out

and the mechanism of seismic behavior of Xiashu loess slopes was studied by means of investigating the dynamic properties

dynamic responses

and macroscopic deformations of the model slope.The experimental results showed that stable first and second order mode fundamental frequencies and damping ratios existed in Xiashu loess slopes

and that the first order mode fundamental frequency decreased gradually

while the first order mode damping ratio increased progressively with increasing input peak ground acceleration（PGA）.The PGA amplification factors near the toe of the model slope were less than those at other positions in the horizontal direction

and the values with 4.47 scaled El Centro earthquake record input were greater than those with full El Centro earthquake record and 4.47 scaled Kobe earthquake record.The PGA values were all greater than 1 in the range of the height of the model slope.Moreover

they gradually increased from bottom to top and approached the maximal magnitude at the crest.With the increase of the input PGA

the nonlin-earity of the soil gradually enhanced

and the slope also gradually tended to be the state of being out of safety.A few fissures and cracks occurred at toe and crest of the model slope after a series of seismic loading

which indicated that a（potential） slip surface

where the dynamic shear modulus of the soil was somewhat reduced

could have initiated in the soil through the toe of the model slope.