砂土中带裙板防沉板基础水平向承载力的上限解

Upper Bound Solutions of Horizontal Bearing Capacity of Skirted Mudmat Foundation in Sand

作为深海油气工程中水下生产系统的重要基础形式,防沉板具有埋深浅、水下施工方便等优点.为了满足基础抗滑移的要求,可在防沉板底部设置裙板,裙板的存在增加了防沉板水平向承载力计算的难度.本文将带裙板防沉板基础简化为带裙板条形基础进行研究,通过开展砂土地基上防沉板基础水平向地基承载力模型试验,研究了防沉板基础在水平荷载下的承载规律.提出了一个能够反映裙板与基础内部土体共同作用的经验参数——水平向土体破坏率η,建立了适用于防沉板基础的水平向极限承载力分析的破坏机动场.通过极限分析上限定理推导了砂土地基上带裙板条形基础的水平向地基承载力的上限解,确定了η与H/B的拟合关系.

As an important foundation form for deepwater oil and gas engineering in the subsea production system,mudmat has many advantages,such as lower buried depth and convenient construction.To meet the requirements of foundation slip resistance,skirts can be installed at the bottom of the mudmat,whose existence,however,will increase the difficulty in calculating the vertical bearing capacity of the mudmat.The mudmat is simplified as the skirted strip foundation in this paper.The bearing capacity model tests of mudmat are carried out in sand to study the bearing rule of mudmat under horizontal load.A new empirical parameter,horizontal soil damage rate η,is defined to reveal the combined action between skirts and the inner soil of foundation.Failure velocity field is established to analyze the horizontal bearing capacity of skirted mudmat foundation.The upper value of the horizontal bearing capacity of skirted mudmat is obtained by the upper bound theorem of limit analysis.The fitting relationship between ηand H/B is obtained.