通过土工试验对不排水剪切条件下的饱和松散砂质土的工程特性进行了探讨 ,发现其在剪切时的应力 -应变关系呈现出加工软化特性 ,土体超过峰值强度后最终达到了变形的稳定状态 .基于稳定状态概念 ,将临界土力学理论与非线性应力 -应变关系相结合 ,建立了非线性应力 -应变 -临界状态本构模型 .采用香港钻石山地区全风化花岗岩残积土的不排水三轴试验结果 ,确定了有关模型参数 ,验证了所建议本构模型的合理性 Through the geotechnical test, the engineering characteristics of saturated loose sandy soil under undrained shear conditions are discussed. The stress-strain relationship of shear softened soil shows the characteristics of processing and softening. When the soil strength exceeds the peak value, the deformation finally reaches deformation Based on the concept of steady state, a nonlinear stress-strain-critical constitutive model is established by combining the theory of critical soil mechanics with the nonlinear stress-strain relationship.Using the weathered granite remnant soil in the Diamond Hill area of ​​Hong Kong, Drainage triaxial test results to determine the parameters of the model to verify the rationality of the proposed constitutive model