水平动载下粉土地基中桶形基础承载力离心机实验研究

对动载作用下分层土中单桶基础动承载特性、四桶基础动承载特性进行了离心机实验模拟。结果表明,桶顶与粘土面相同时,有上覆粘土层条件下的桶基动力响应较无上覆粘土层条件下的孔压增长小,但沉陷大;桶顶与粘土层下的砂土面相同时比与粘土面相同时的响应大。桶基在动载后的静承载力得到提高。由于液化区的滤波和对动载的衰减作用,发生沉降的范围有限,离桶壁约一倍桶高距离。超孔隙水压从桶基边沿水平向逐渐衰减,从土面开始往下逐渐衰减到零。桶基周围砂土完全液化的厚度随载荷幅值的增加而增加,最大值约为桶高的40%。

RESPONSES OF SUCTION BUCKET IN FINE SAND UNDER HORIZONTAL DYNAMIC LOADING

The centrifugal experiments are carried out to study the dynamic responses of suction buckets in fine sand under horizontal loading.If there is a clay over-layer and the altitudes of bucket＇s top and the clay layer surface are the same,the settlements of bucket and sand layer are bigger than that without an over-layer,but the increment of pore pressure is on the contrary.The static bearing capacity of the bucket increases after experienced dynamic loading.With the increase of loading amplitude,the settlement of sand layer increases,but the effected area which have obvious deformation is limited（about one times the bucket＇s height）because of the filtering and decaying effects of the liquefaction zone on the vibration.The excess pore pressure decreases in horizontal direction from the side wall and in vertical direction from the surface of sand layer.The complete liquefaction thickness of the sand layer increases with the increase of load amplitude whose maximum is about 40% of the bucket＇s height.