加载方向对张紧式吸力锚极限承载力的影响分析

利用真空预压法在模型试验土池内制备了软黏土层，选择不同加载方向，进行力控制下张紧式吸力锚极限承载力模型试验，分析了加载方向对其破坏模式以及极限承载力的影响。结果表明，对于最佳系泊点受倾斜荷载作用的吸力锚，当加载方向从 40 °变化至 20 °时，尽管锚的水平位移和承载力明显增加，但锚始终表现为竖向拔出的破坏模式，且锚底以下土层的反向承载力是影响其极限承载力的关键因素。按照模型试验条件，分别通过塑性极限上限分析与极限平衡分析预测锚的极限承载力并与试验结果进行比较，发现如果将锚底的反向承载力系数取为常数，预测结果不能反映加载方向的变化对极限承载力的影响。因此，为了客观预测锚的极限承载力，依据模型试验结果，提出了一种反映加载方向对锚底反向承载力影响的修正关系。

Effects of loading direction on ultimate bearing capacity of suction anchors with taut mooring system

The soft clay stratum is prepared using the vacuum preloading method in a model test tank.Model tests on suction anchors with taut mooring system are conducted to study effects of different load directions on failure modes and the ultimate bearing capacities using the load-controlled method.The results show that the failure modes are still vertical pullout and the main factor affecting the ultimate bearing capacities is the reverse end-bearing resistance at the anchor tip although the lateral displacements and the ultimate bearing capacities obviously increase when the loading direction varies from 40 degree to 20 degree for the suction anchors with inclined loads at the optimal load attachment point.The ultimate bearing capacities associated with model tests are further predicted by the upper bound plasticity analysis and the limiting equilibrium analysis,which show that the predicted results do not reflect the effects of variations of loading direction on the ultimate bearing capacities if the reverse end-bearing resistance factor is taken as a constant.Therefore,a modified relation considering the effects of loading directions on the reverse end-bearing resistance is developed to correctly predict the ultimate bearing capacities.