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为探讨天津滨海新区典型软土的循环变形特性,采用不排水循环三轴试验,结合扰动状态概念,在考虑土体结构屈服压力基础上,提出了一种能考虑土体在循环荷载作用下结构逐渐破坏的扰动函数,建立了一种反映土体在循环荷载作用下土体结构破坏的塑性变形经验公式,并通过动三轴试验结果对所提经验公式进行了检验。分析结果表明:结构性软土在循环荷载作用下产生的累积塑性应变和振动次数的关系分为稳定型和破坏型2种典型情况;累积塑性应变随振动次数的增加而增大;相同的围压作用下,存在一个临界循环应力比,其上限值随着围压的增大而减小。可见,所提经验公式很好反映了土体在交通荷载下的变形特性。
In order to discuss the cyclic deformation characteristics of typical soft soils in Tianjin Binhai New Area, based on the undrained cyclic triaxial test and the concept of disturbance states, based on the yield pressure of soil structure, A kind of plastic deformation empirical formula which reflects the damage of soil mass under cyclic loading is established and the empirical formula is tested by moving triaxial test. The results show that the relationship between cumulative plastic strain and vibration frequency under cyclic loading can be divided into two typical cases: steady-state and failure-type. The cumulative plastic strain increases with the increase of vibration frequency. Under the action of pressure, there is a critical cyclic stress ratio, the upper limit of which decreases with the increase of confining pressure. Visible, the empirical formula provided a good reflection of the soil deformation under traffic load characteristics.