论文部分内容阅读
按照在最佳系泊点受倾斜荷载作用的张紧式吸力锚的破坏机制,建议了利用软土不排水循环剪切强度计算软土中吸力锚循环承载力的极限平衡分析方法。该方法考虑了平均系泊荷载在土中引起的平均剪应力对土体循环剪切强度、进而对锚循环承载力的影响。为了说明该方法的可行性,进行了大量张紧式吸力锚在平均系泊荷载与循环荷载共同作用下的承载力模型试验。依据试验结果确定了锚被竖向拔出土层时系泊点的位移破坏标准,并据此确定了与不同模型试验条件对应的循环承载力。进而利用循环三轴试验确定的土层不排水循环强度随平均应力的变化关系和实测的土层剪切强度,通过极限平衡分析计算了与模型试验对应的循环承载力。计算与模型试验结果比较表明,对于张紧式吸力锚被竖向拔出土层的破坏模式,计算结果比模型试验结果偏大,平均偏大1.9%,绝大多数偏差在10%以内。因此,对于软土中的张紧式吸力锚,如果采用该方法计算与竖向拔出土层破坏模式相应的循环承载力时,将结果减小10%是恰当的。
According to the failure mechanism of tensioned suction anchor subjected to inclined load at the optimal mooring point, the limit equilibrium analysis method for calculating the bearing capacity of suction anchor in soft soil based on undrained cyclic shear strength of soft soil is proposed. The method considers the influence of average shearing stress of average mooring load on soil cyclic shear strength, and then on the bearing capacity of anchor. In order to demonstrate the feasibility of this method, a large number of tensioned suction anchors were tested in a bearing capacity model with average mooring load and cyclic loading. Based on the test results, the displacement failure criterion of mooring points when the anchor was pulled out of the soil vertically was determined, and the cyclic loading capacity corresponding to the different model test conditions was determined. Furthermore, the cyclic bearing capacity corresponding to the model test was calculated by the limit equilibrium analysis using the relationship between the undrained cyclic strength of the undrained soil with the average stress and the shear strength of the soil determined by the cyclic triaxial test. The comparison between the calculation and the model test results shows that the calculation results are larger than the model test results for the failure mode of the tensioned suction anchor vertically pulled out of the soil layer, with an average 1.9% larger and the majority of the deviation less than 10%. Therefore, for the tensioned suction anchor in soft soil, it is appropriate to reduce the result by 10% if this method is used to calculate the cyclic loading corresponding to the vertical failure mode of soil withdrawal.