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等幅循环荷载的不排水三轴试验的结果表明,饱和南京细砂孔压比曲线的形状随循环周数比增大而发生规律性的变化。引入孔压增量比的概念,并定义有效动剪应力比和有效应力对数衰减率,发现孔压增量比的发展过程可分为下降段、平稳段和上升段;在平稳段和上升段,孔压增量比的累积量与有效动剪应力比的自然对数具有很好的线性关系,并推导出第N周的孔压增量比与第N-1周的有效应力比对数衰减率成正比,而与动应力幅值无关。据此建立的饱和南京细砂孔压增量模型,能够较好地描述等幅循环荷载作用引起的孔压比随循环周数的增大而增长的发展趋势。
The results of undrained triaxial tests with constant amplitude cyclic loading show that the shape of pore pressure ratio curve of saturated fine sand changes regularly with the increase of cyclic number ratio. The concept of pore pressure increment ratio is introduced and the effective dynamic shear stress ratio and logarithmic decrement of effective stress are defined. The development process of pore pressure increment ratio can be divided into descending, steady and rising sections. The linear logarithm of the cumulative logarithm of the ratio of pore pressure increment to the effective dynamic shear stress ratio and deduced the ratio of pore pressure increment at week N to the effective stress at week N-1 Number decay rate is proportional to, and dynamic stress amplitude has nothing to do. The saturated pressure increment model of fine sand in Nanjing based on this model can well describe the development trend of pore pressure ratio increasing with the number of cycles due to constant cyclic loading.