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以南京片状细砂为研究对象,采用英国WFI动静多功能三轴仪,研究饱和南京片状细砂在循环荷载作用下静偏应力水平、循环应力水平对其不排水动力特性的影响。把振动孔压的发展与应力路径相联系,分析了循环荷载作用下不同阶段南京片状细砂所处的初始压密状态、压缩状态和膨胀状态的发生和发展过程;根据静偏应力与循环偏应力的大小,视有无偏应力反向,将南京片状细砂的破坏模式可分为循环活动性和塑性应变累积破坏;同时,针对振动孔压上升使得南京片状细砂出现动剪切模量软化现象,研究了每一次循环过程中滞回曲线的卸载段及再加载段的割线动剪切模量Gsec和最大割线模量Gmax的变化规律,发现Gsec和Gsec/Gmax与循环应变εs之间的关系可用指数函数描述。
Using the flake fine sand in Nanjing as the research object, this paper studied the effect of static deviatoric stress level and cyclic stress level on the dynamic characteristics of undrained saturated sand with saturated Nanjing flake fine sand under the action of cyclic load. The development of vibrating pore pressure is related to the stress path. The occurrence and development of the initial compressive state, the compression state and the expanded state of Nanjing flake fine sand under different cyclic loadings are analyzed. According to the relationship between static deviatoric stress and circulation The magnitude of deviatoric stress depends on the non-deviatoric stress reversal. The failure mode of Nanjing flaky fine sand can be divided into cyclic activity and plastic strain cumulative damage. At the same time, in view of the increase of vibration pore pressure, The results show that the relationship between Gsec and Gsec / Gmax and the maximum secant modulus Gmax are similar to that of the unloaded section and the reloaded section in each cycle. The relationship between cyclic strain εs can be described exponentially.