竖向荷载作用下砂土中裙式吸力基础承载特性

Bearing Capacity of Skirted Suction Caissons Under Vertical Loading in Sand

针对一种新型吸力基础形式——裙式吸力基础,采用有限元数值模拟方法和模型试验手段,以传统吸力基础为参照,得到基础荷载-沉降关系曲线,分析基础周围土体变形规律。研究表明:裙式吸力基础竖向承载力较传统吸力基础显著提高,吸力基础各部分承受的竖向荷载比例不同,基础顶板、主桶内外壁分担了约90%的竖向荷载,其余则由尖端部分和裙内外壁承担;随着桶体高径比增加,桶体内外壁所承受的摩阻力逐渐增加,而尖端阻力和裙内外壁侧阻力所占比例始终小于10%;基础周围土体隆起量随裙高的增加呈减小趋势,但随裙宽的增加不断增大;裙宽对竖向承载力的贡献要比裙高大得多,但裙高能有效限制土体隆起。

To increase the bearing behavior of conventional suction foundation, a modified type of the suction caisson,named as skirted suction caisson, was studied by using both the numerical method and model tests. Vertical loading-settlement curves and deformation of surrounding soil were obtained. It was shown that the skirted suction caisson can enhance the vertical bearing capacity due to adding the skirted structure. It was also found that the lid,inner and outer walls of the main bucket may provide 90% of the vertical loading,and the tip parts and inside and outside walls of the skirt account for 10%. Frictional resistance along the outer and inner walls of the main bucket increases with the increase of the ration of height to diameter. However, the resistance of tips and the outer and inner walls of the skirt accounts for less than 10% of the total resistance. Soil heave decreases with the increase of the skirt height,but increases with the increase of the e skirt width on the contrary. Contribution of skirt width to vertical bearing capacity is much greater than skirt height, but the skirt height reduces soil heave effectively.