水平荷载作用下张力腿平台吸力式基础的物理模拟

介绍了张力腿平台吸力式基础在水平静载和循环动荷载作用下的离心模型试验。通过水平静载离心试验获得了基础的水平承载力。利用电磁式激振器模拟动荷载,研究在动荷载作用下吸力式基础的动力响应,并比较了荷载强度和基础刚度对基础动力响应的影响。分析结果表明,在动荷载作用下,泥面下1～2 m深度内土体中孔压最大。当动荷载强度超过临界承载力时,基础周围土体有非常强的液化可能性。综合孔压变化和基础沉降规律分析基础有两种可能的破坏模式:振动最初1～2 h内的液化破坏和长时间激振后沉降过大引发的问题。将单桶连接成多桶基础,增大基础刚度,在相同动载强度下,周围孔压增长和激振沉降均小于承受相同荷载条件的单桶基础。

冰载荷作用下海洋平台桶基的离心模拟

吸力式基础从20世纪70年代开始应用于港口、防波堤和海岸灯塔等的建设上，从1994年开始被用于海洋平台基础。这种基础形式同样应用于我国渤海油田开发中。渤海湾每年冬季有三个月的冰期，海冰不仅使平台受到很大的水平静压力，而且海冰破碎撞击平台会引起平台结构强烈的振动。已测定的平台结构的振动频率是0．8Hz-1．0Hz。为了模拟在这种水平动载荷作用下基础的承载特性，清华大学开展了离心模型试验研究。本文介绍了动冰载荷作用下吸力式基础离心模型试验的结果，并进行了相应分析。

Development of a New Dynamic Lightweight Penetrometer for the Determination of Mechanical Properties of Fine-Grained Soils

Dynamic cone penetrometer is mainly used as an in situ device and laboratory application, in a mould, has rarely been reported due to the confining effect. In this study, a dynamic lightweight cone penetrometer that can be used in a CBR （California bearing ratio） mould in the laboratory as well as in the field, with similar results, was developed. The results show that the influence of the mould confinement can be eliminated when the hammer mass is 2.25 kg. A strong correlation was found between CBR values and the new dynamic lightweight penetrometer index, for six fine-grained soil samples, with different moisture contents, used in this study.