A Study on Duplication Method of Undisturbed Natural Clays in Laboratory

为了开发利用市售材料在实验室内复制原状天然粘土的方法，研究了高岭土与膨润土混合的人造粘土的物理性质、固结特性和剪切特性与混合条件的关系。从物理性质上发现，混合粘土的液限随混合粘土中膨润土含量的增加而线性增加，粘土，其增加率随混合水盐度的增加而减小。另一方面，在固结特性方面，发现混合土的压缩指数随混合土中膨润土含量的增加而线性增加，固结系数的对数随混合土中膨润土含量的增加而线性减小，而固结系数的对数随混合土中膨润土含量的增加而线性减小在剪切特性上还发现，随着混合粘土中膨润土含量的增加，剪切引起的超静孔隙水压力减小，抗剪强度增大，应变硬化程度增大，为了在实验室中重现老化效应，混合粘土在高温下从浆态再固结或仅在最后再固结阶段的二次压缩期间在高温下固化。结果，结果表明，高温固结或固化后的粘土试样的固结屈服应力比室温固结的粘土试样的固结屈服应力大，高温固结或固化后的粘土试样的固结屈服应力比室温固结的粘土试样的固结屈服应力大，高温固结或固化后的粘土试样的固结屈服应力比室温固结的粘土试样的固结屈服应力大，高温再固结过程和高温固化过程可以复制老化效应。

Relationships between physical properties, consolidation characteristics and shear characteristics and mixing conditions of artificial clays mixed a kaolin with a bentonite were investigated in order to develop the duplication method of undisturbed natural clays in laboratory by using marketed materials.As the results, it is found on physical properties that the liquid limit of mixed clays linearly increases with an increase of the bentonite content of the mixed clays and that the rate of its increase decreases with an increase of the salinity of the mixing water.On the other hand, the plastic limit is hardly influenced by the bentonite content of the mixed clays or the salinity of the mixing water.It is found on consolidation characteristics that the compression index of the mixed clays linearly increases and the logarithm of the coefficient of consolidation linearly decreases with an increase of the bentonite content of the mixed clays.It is also found on shear characteristics that the excess pore water pressure caused by shearing decreases, shear strength increases and the degree of the strain hardening increases with an increase of the bentonite content of the mixed clays.In order to duplicate the aging effect in laboratory, the mixed clays were reconsolidated at the high temperature from the slurry state or cured at high temperature only during the secondary compression of the last reconsolidation stage.As the results, it is found that the consolidation yield stress of the clay samples reconsolidated or cured at high temperature becomes large than that of the clay samples reconsolidated at room temperature and that the characteristics of the clay samples reconsolidated or cured at high temperature are similar to those of naturally aged clays.This implies that the high temperature reconsolidation procedure and the high temperature curing procedure can duplicate the aging effect.