Experimental Study on Mechanical Properties of Soil mixed with Deformable Particles

研究了利用膨胀塑料废弃物制备的可变形颗粒混合土的力学性能。首先，利用一维固结试验的结果，对土骨架中含有可变形颗粒的土的一维压缩机理进行了研究。因此，在变形颗粒混合土的情况下，除了由刚性颗粒骨架重新排列引起的普通体积压缩外，构件的两种额外压缩结构构型。其中一种是可变形颗粒本身的体积压缩，另一种是可变形颗粒变形引起的孔相进一步减少。然后，利用x射线CT进行微观观察，评估可变形颗粒的体积压缩。因此，定量地证实了上述额外成分分类的有效性。同时，利用双孔仪进行了三轴压缩试验，试图单独测量可变形颗粒本身压缩的体积压缩应变和孔隙空间缩小量。然而，不可能单独估计这两种额外类型的成分，因为水会进入膨胀塑料颗粒表面的孔隙空间。因此，在本研究的后期，对土壤的蠕变特性和渗透保水性进行了研究，以便将这种膨胀塑料废弃物实际应用于轻质土工材料中。结果表明，蠕变引起的沉降量与塑料废弃物的掺量成正比。在物理性能方面，明确了将该塑料废弃物与土壤混合，除具有轻质效果外，还能提高透水性和保水性。

In this study, mechanical properties, such as deformability, of deformable particle mixed soil using expanded plastic wastes were investigated. At first, one-dimensional compression mechanism of soil which containing deformable particles in the soil skeleton was examined using the results of one-dimensional consolidation tests. As a result, two extra types of compression structural configurations of the components in addition to the ordinary volumetric compression caused by the rearrengement of a rigid particle skeleton as in the case of the deformable particle mixed soil. One of them was the volumetric compression of the deformable particle itself and the other was a further pore phase reduction caused by the deformation of the deformable particles. Then, microscopic observation using X-ray CT was carried out to evaluate the volumetric compression of deformable particles. Consequently, it was quantitatively confirmed that above-mentioned classification of extra components was valid. And in parallel, triaxial compression tests using double cell apparatus were conducted to attempt the individual measurement of volumetric compressive strain into the compression of deformable particle itself and the amount of pore space reduction. However, it was impossible to estimate these two extra types of components individually, because of the existence of the water getting into the pore spaces of expanded plastic particle's surfaces. Therefore, the latter term of this study, creep property and permeability & water retentivity of soils were investigated, for the purpose of the actual application of this expanded plastic wastes into the lightweight geomaterials. As a result, the amount of settlement caused by creep was in proportion to the mixing ratio of the plastic wastes. And as for the physical properties, it was clarified that the permeability and water retentivity were improved in addition to lightening effect, in case of mixing this plastic wastes with soil.