软土基坑开挖引起地下连续墙水平变形的能量法

针对软土基坑开挖引起的地下连续墙水平变形计算问题,为克服以往解析方法的不足,提出了能量计算法。通过分析其典型变形模式,提出了适用于5种约束条件下的水平变形统一数学表达式;考虑地下连续墙非极限状态土压力,根据3种滑动面模型推导出相应的侧土压力表达式,进而建立整个围护系统总势能,利用最小势能原理,推导了地下连续墙水平变形的解析解。分别计算3种滑动面模型下的水平变形,并与基坑实测数据进行了对比验证,分析了各滑动面模型应用于地下连续墙水平变形计算的合理性。研究表明:对于内凸及复合式、悬臂式、踢脚式变形模式中,分别采用直线及对数螺线组合型、圆弧型、直线型滑动面较为合理,而三者对应的约束条件分别为两端固定、顶端自由底端固定、顶端固定底端平动。

Energy Method for Horizontal Deformation of Diaphragm Wall due to Soft Soil Foundation Pit Excavation

Aiming at the calculation of the horizontal deformation of the diaphragm wall caused by the excavation of the soft soil foundation pit and in order to overcome the shortcomings of the previous analytical methods, an energy calculation method was proposed. By analyzing the typical deformation modes, a unified mathematical expression for the horizontal deformation under five constraints was proposed. Considering the non-limit state earth pressure of the wall, the corresponding lateral earth pressure was derived according to three slip surface models; then the total potential energy of the enclosure structure system was established, and the analytical solution of the horizontal deformation of the diaphragm was derived by using the principle of minimum potential energy. The horizontal deformation was calculated by three slip surface models respectively and compared with the measured data of the several foundation pits. The rationality of each slip surface model applied to the horizontal deformation calculation of the diaphragm wall was analyzed. The results show that in the convex/compound, cantilever, and kick-in deformation modes, the straight and logarithmic spiral, circular, and linear sliding surfaces, respectively are more reasonable, and the corresponding constraints for the three are the two ends fixed, top free bottom fixed, and top fixed bottom translated.