超固结粘土的变形特性

本文介绍了用人工制备的超固结粘土试样进行的试验研究成果。试验证明:在临界状态“湿”边范围内,塑性应变增量的矢量与试样的初始状态无关。以等塑性体应变为硬化参数的屈服条件具有唯一性,塑性势函数等于屈服函数,流动法则为相适应的。在临界状态“干”边范围内,采用等塑性剪应变为硬化参数的屈服条件代替了一般以破坏条件为屈服条件的假定,从而能够反映超固结粘土的应变硬化一软化特性。最后得出了统一的屈服条件。

Deformation Properties of Over-consolidation Clay

In this paper the experimental results of artifical over-consolidated clay sampleswith three kinds of stress path-consolidated undrained, consolidated drained andconstant mean effective principle stress tests are presented. It was shown that according to their overconsolidated ratio the deformation properties of over-consolidated clay samples can be divided into &;quot;wet&;quot; and &;quot;dry&;quot; zones by critical state line. In the &;quot;wet&;quot; zone, the samples are in light over-consolidated state （Rp = l⁴） and their deformation properties are the same as those of the normally consolidated clay, i. e. the hardening parameter may be expressed in plastic volumtric strain; the direction of plastic strainincrement （Δν/Δετ）p is independent of stress path, and the plastic potentail functionequals to yield function. So, those conclusions concerning normally consolidated clay have been expanded. In the &;quot;dry&;quot; zone, the samples are in heavy over-consolidated state （Rp = 5¹6）, the hardening parameter expressed in plastic shear strain is more suitable than the yield function expressed in failure line. Finally the generalised formula of yield function and hardening rule are proposed.