斜直组合桩支护深基坑开挖滑动面分析

Analysis of Sliding Surface of Deep Foundation Excavation Supported by Inclined and Straight Composite Piles

为研究基坑开挖过程中滑动面发展变化规律,文中结合具体工程实例提出软土地基下,不同开挖深度时的支护结构临界插入比的取值方法。结果表明,传统圆弧滑动法中,土体滑动面始终通过支护结构嵌固端底部这一假设并不合理。土体滑动面应随着支护结构插入比的增大而逐渐上移,经过支护结构嵌固端底部,并最终围护结构嵌固部分。对软土地基中,不同开挖深度、土体强度增长率和土体强度下的临界插入比数据进行拟合,得出对应的拟合曲线,并以此算出安全系数。实际工程中,考虑对应的安全系数将预测值放大后使用。

In order to study the development and changes of sliding surfaces during the excavation process of foundation pits,a method for determining the critical insertion ratio of support structures under soft soil foundation at different excavation depths is proposed based on specific engineering examples.The results indicate that in the traditional arc sliding method,the assumption that the sliding surface of the soil always passes through the bottom of the embedded end of the support structure is not reasonable.The soil sliding surface should gradually move up with the increase of the insertion ratio of the support structure,pass through the bottom of the embedded end of the support structure,and finally enclosure the embedded part.In soft ground foundation,the data of critical insertion ratio under different excavation depth,soil strength growth rate and soil strength are fitted to obtain the corresponding fitting curve and the safety factor.In the actual project,the corresponding safety factor is used to amplify the predicted value before using it.