砂土地基中吸力式沉箱的极限沉贯深度分析

吸力式沉箱是广泛应用于离岸结构物中的新型基础形式，贯入分析方法的研究是很重要的课题。分析了砂性土地基吸力贯入过程中的渗流状况，得出了筒内壁的压降比率与贯入深径比的关系公式，分析评估了抽吸作用对筒内壁压降比率的影响，提出了砂土地基中吸力贯入阻力和地基极限吸力的简便计算方法，给出了砂土地基中极限贯入深径比的计算公式，分析了各种砂土地基中的吸力贯入极限深径比。不计筒体自重和抽吸效应影响时，这一比值介于2.1～2.5之间。

Analysis of ultimate penetration depth of suction caissons in sand

Suction caissons have been widely used in offshore structures. Method of installation analysis is very important research subject. This paper provides the characteristic of the seepage field of the foundation during suction installation, and gives relationship between the ratio of the suction descending on the inside wall to the overall suction versus penetration depth-diameter ratio (?1).The pump effect on ?1 is also analyzed and evaluated. A simple and convenient calculating method of both suction caisson penetration resistance and ultimate suction in sand ground is proposed. An equation of ultimate penetration depth-diameter ratio (UPDR) calculating of suction caisson in sand is proposed. The UPDR in sand with density from loose to extremely dense is analyzed; and it is about 2.1 to 2.5 while the effort to UPDR of the deadweight of the structure and the pumping effort to UPDR are not included in it.