互层土地基承载能力有限元分析

Study on Bearing Capacity of Multilayer Foundation Based on Finite Element Analysis

平台插桩前需要计算土层极限承载力以进行桩脚插深分析。实际工作中通常按均质土层的极限承载力公式计算,对复杂的互层土地基,目前的计算方法未考虑基础影响深度范围内所有土层的力学性质,其结果需要进行修正。应用有限元法对复杂互层土地基的承栽能力及破坏模式进行分析,可以反映综合地基承载力,无需进行修正。研究表明,对复杂的互层土地基,基础影响深度范围内土层的特性不同是造成地基破坏模式和承载能力差异的主要因素,应充分考虑3.5倍基础尺寸的深度范围内的所有土层的力学性质,这样得到的综合承载力与实际情况更为符合。

Ultimate bearing capacity of foundation should be calculated before penetration of Jack-up Rig to predict the penetration depth of Jack-up Rig footing. In actual work, it is calculated with the classical formula of ultimate bearing capacity which assumed soil as homogeneous foundation. However, for complex multilayer foundation, it is necessary to modify the calculation results be- cause the mechanical properties of soil in the range of affecting depth of foundation have not been considered. The Finite Element Method has been used to simulate the failure mode of foundation and calculate the comprehensive ultimate bearing capacity. With the Finite Element Method, it is not necessary to modify the calculation results because the mechanical properties of soil in the range of affecting depth of foundation have been considered. Results show that the difference of properties of soil within foundation affecting depth range is the main factor of different failure mode and different bearing capacity. Full consideration should be given to 3.5 times the base size within the depth of all the mechanical properties of soil, the comprehensive bearing capacity is more consistent with the actual situation.