The study of lateral dynamic response of pile foundation in the saturated sand has been concerned in the geotechnical field and the field of earthquake engineering.Especially

the lateral dynamic response of pile-groups is always one of the key research topics.Based on the shaking table test

through two different shaking table waveforms input and using the FBG grating sensing system

this paper studies the lateral dynamic response characteristics of single pile and pilegroups in the saturated sand and the pile-sand dynamic hysteretic p-ycurve of typical test points. The research results show that:the pore pressures of single pile and pile groups increase little in the initial stage of vibration

and then the pore pressure of single pile rises rapidly until later period with decreasing to 0.5

while the pore pressures of pile-groups rises slowly;The soil surface acceleration of single pile increases and then quickly reduces

and the amplified acceleration is slightly larger than the shaking table acceleration value in the single pile test.In the pile-groups test

the soil surface acceleration gradually increases and reaches the maximum immediately

the acceleration do not continue to enlarge but gradually decreased with increase of pore pressure ratio

until it coincides with the soil surface acceleration of single pile.The impact of liquefaction of saturated sand on acceleration and displacement of single pile slab is more obvious and lateral dynamic response sensitivity of pile-groups slab in liquefaction is lower than that of single pile;Under the same vibration and the slab input conditions

the pile-groups have better resistance to lateral force than the single pile after liquefaction.