吸力式沉箱基础抗拔破坏标准研究

Research on the Uplift Failure Criterion of Suction Caisson Foundation

为了得到吸力式沉箱基础的抗拔破坏标准,针对长径比为4的吸力式沉箱基础开展了倾斜抗拔承载力模型试验。试验中考虑了不同荷载作用角度的影响。试验结果表明:荷载作用角度较小时,吸力式沉箱基础的荷载-位移曲线可分为位移平缓段和突变段,且有明显的拐点。依据荷载-位移曲线上的拐点所对应的位移,提出了一个确定吸力式沉箱基础破坏位移的公式。对于荷载作用角度为90°的情况,吸力式沉箱基础被拔出前发生的位移非常小,无法用位移来判断吸力式沉箱基础是否发生破坏,建议从控制外荷载大小的角度预防其破坏的发生。

[ Abstract] To obtain the uplift failure criterion of suction caisson foundation, the model tests on inclined load- ing capacity of suction caisson are conducted by using models with L/D ratio of 4. The effect of loading angle is considered. The result shows that the load-displacement curves can be divided into two displacement segments, the gradual segment and the mutant segment, which have obvious inflection points in between when the loading angle is small. The damage displacement of suction caisson is obtained by proposing a formula based on the displacement corresponding to the inflection points. While the loading angle equals to 90 degree, the displacement changes little before suction caisson is pulled out. Therefore, displacement can not be used to decide if suction caisson foundation is damaged. It is suggested that load should be controlled to prevent the foundation from damaging.