基于广义非线性强度准则下地基承载力的计算

Calculation of the Foundation Bearing Capacity Based on the Generalized Non-linear Strength Theory

Mohr-Coulomb理论应用于土体分析时的两大缺陷,即未考虑中主应力的影响,也未考虑土体材料的SD效应,因而对于土体材料的潜能未充分考虑。为了考虑上述两种效应,本文基于广义非线性强度准则(GNST)及平面强度理论,推导出了可应用于砂土及粘土类材料的平面应变破坏条件。将上述推导结果应用于地基承载力的计算,推导出了基于GNST准则的地基承载力计算公式。通过与实际载荷试验数据比较,本文计算结果与实验数据吻合较好。表明推导出来的α公式对于计算砂土的强度特性是可行的,同时也可应用于其他平面应变问题有同样的参考意义。

There were two inperfeetions in using Mohr-Coulomb theory to analyze the stress of soil, that is, the influence of both the intermediate principal stress and the SD effect of soil materials were not considered, the potential strength of soil was misestimated. In order to consider above two effects, based on the generalized non-linear strength theory （ GNST } and a stress condition in plane strain state, the failure criterion for the plane strain for sand and clay materials were proposed. The formula was applied to the calculation of the bearing capacity of foundation. By compa- ring the calculation result with test data, the computed results by proposed method were perfectly consistent using the GNST criterion parameter α. The validity of the proposed formula of bearing capacity of foundations and the calcula- tion of strength characteristics of soil were verified. The failure criterion in plane strain can serve as reference to other plane strain problems.