力矩与水平荷载联合作用下裙板式基础破坏包络面研究

Failure envelope of skirted foundation subjected to moment and lateral load combined loading

联合采用swipe加载模式、固定位移比与固定荷载比加载模式,对于裙板式浅基础在水平荷载与力矩荷载的复合加载条件下的承载性能进行比较系统的平面应变有限元分析,主要探讨了裙板式基础埋深、地基土不排水强度的非均质性对于基础破坏包络面的影响,揭示了地基在水平和力矩荷载的不同组合条件下的失稳破坏机制。同时,对于两种swipe加载模式的有效性进行了比较。计算结果表明:对于非均质土,当裙板式基础埋深与宽度之比大于0.3时,破坏包络面产生正方向倾斜;当埋深与宽度之比小于0.3时,基础的破坏包络面出现负方向倾斜。而在均质土中,基础的破坏包络面没有出现负方向倾斜。

Combined with swipe loading method,fixed displacement ratio method and fixed load ratio method,the bearing capacity of shallow skirted foundations subjected to horizontal and moment combined loadings is explored through plane strain finite element numerical studies.The effect of embedment and soil strength nonhomogeneity on the failure envelope of skirted foundations is investigated;and the soil deformation mechanism under various combinations of horizontal and moment loads is shown.The validity of two types of swipe loading methods is compared.From the results,it is indicated that for nonhomogeneous soil,under the condition that the ratio of embedment depth to width is larger than 0.3,the failure envelope of skirted foundations is positively oblique;however the failure envelope is negatively oblique when the ratio of embedment depth to width is lower than 0.3.The phenomena of negative obliquity does not occur for skirted foundation in uniform soil.