波浪荷载作用下饱和珊瑚砂动强度特性研究

分析了ＨＣＡ－１００空心圆柱扭剪仪加载限制条件，选择了符合实际波浪荷载作用的广义圆形应力路径实现方法和加载公式；利用空心圆柱扭剪仪模拟不同频率波浪荷载的广义圆形应力路径，研究了波浪荷载的加载频率和珊瑚砂相对密实度对饱和珊瑚砂动强度的影响规律。研究结果表明:广义圆形应力路径能够较好的模拟波浪荷载；试样破坏所需荷载循环次数随波浪荷载加载频率增加而增加，在低偏应力比条件下更为明显；相同加载频率下，饱和珊瑚砂动强度随破坏循环次数增加而减小；波浪荷载作用下饱和珊瑚砂动强度随荷载加载频率和珊瑚砂相对密实度增大而逐渐增大。根据不同荷载加载频率下饱和珊瑚砂对应的偏应力比与初始荷载加载频率为０．１Ｈｚ时的偏应力比之间的关系，建立了考虑荷载加载频率的饱和珊瑚砂动强度经验公式。

Dynamic Strength Characteristics of Saturated Coral Sand Under Wave Loading

This paper analyzed the loading limit conditions of HCA-100 hollow cylinder torsion shear apparatus and selected the generalized circular stress path method and loading formula.The generalized circular stress path of wave loads with different frequencies was simulated by HCA-100 hollow cylindrical torsion shear instrument.Thus the influences of wave loads frequency and relative density of coral sands on the dynamic strength of saturated coral sands were analyzed.The study results show that the wave load can be well simulated by the generalized circular stress path.The number of load cycles that resulted in specimen failure increase with the frequency of wave loads,and is more obvious under the condition of low deviator stress ratio.Under the same loading frequency,the dynamic strength of saturated coral sand decreases with the increase of the number of failure cycles.The dynamic strength of saturated coral sand increases with the increase of loading frequency and the relative compactness of coral sand under wave loading.Based on the relationship between the deviating stress ratio of coral sand under different loading frequencies and the deviating stress ratio at the initial loading frequency of 0.1 Hz,an empirical formula of dynamic strength of saturated coral sand considering the loading frequency is proposed.