基于修正Davidenkov本构模型与Byrne孔压增量模型的有效应力算法及其验证

A New Effective Stress Method Using the Integration Algorithm of the Modified Davidenkov Constitutive Model and the Byrne Pore Pressure Increment Model,and Validation and Calibration

提出了Davidenkov本构模型的不规则加卸载修正准则,以代替扩展Masing法则中的"上大圈"准则,并通过南京细砂原状土样的共振柱试验,提出了考虑初始有效围压对初始剪切模量和参考剪应变的修正公式.利用ABAQUS显式开发模块,实现了基于不规则加卸载准则的修正Davidenkov本构模型与Byrne孔压增量模型的有效应力算法.对饱和南京细砂进行排水循环三轴试验,给出了南京细砂的Byrne孔压增量模型参数;对饱和南京细砂进行了不排水循环三轴试验和三维数值仿真的比较研究,发现该子程序能够较好地模拟南京细砂的振动孔压发展过程,合理地反映土体的液化特性,从而验证了本文提出的有效应力算法的合理性.

In this paper,the initial stress-strain skeleton curve was simulated by Davidenkov model, simplified loading and unloading rules were proposed in instead of the ＂upper boundary＂ rule of the extended Masing criteria. Through a large number of resonant column tests of undisturbed Nanjing fine sandy soil samples ,the fitting parameters of the small shear modulus and reference shear strain formulations including the effect of confining pressure has been given. A new effective stress method using the integration algorithm of the modified Davidenkov constitutive model and the Byrne pore water pressure increment model has been implemented in ABAQUS. Using the drained cyclic triaxial test data of the saturation Nanjing fine sand, the parameters of the Byrne pore model were given. The undrained cyclic triaxial tests and its three-dimensional numerical simulation for the saturation Nanjing fine sand has been performed, and the results of the measurement in tests and the calculation were coincide nearly. The results indicated the effective stress algorithm proposed in this paper can well simulate the pore pressure increasing process of the liquefiable sand, and the scientific rationality and validity of the integration algorithm were also verified.