Reiknforcement effect arising from confining dilatancy and its evaluation

本研究旨在揭示土工合成材料的加固机理。重点研究了剪切作用下土工合成材料的围合效果。围合效应被解释为钢筋的力学相互作用，从而防止压实土的膨胀变形。首先，研究人员试图通过一系列土工合成加筋土结构的有限元模拟来解释土工合成加筋土的机理，其中土被建模为考虑压实土的剪胀特性的弹塑性材料。然而，为了提高数值模拟在实际设计工作中的实用性，作者意识到，应该从土本身的力学特性的角度更准确地理解土与加固之间的力学相互作用，即加固机制。然后，对压实（通常是非饱和）砂土进行了一系列的室内试验。并在实验室进行了模型试验。压实的土样（直径30厘米，高40厘米）由土工合成材料包裹。试件放置在单轴加载装置上，经受压剪作用。测量了剪切过程中对土工合成材料产生的广泛应力。

This research aims at revealing the reinforcement mechanism by geosynthetics. The attention is paid to confining effect by the geosynthetics under shearing. The confining effect is interpreted as the mechanical interaction such that the reinforcement works so as to prevent dilative deformation of compacted soils. The investigators, first, try to explain the geosynthetic-reinforcement mechanism throughout a series of finite element simulations for geosynthetic-reinforced soil structures, in which the soils are modeled as elasto-plastic materials considering dilatancy characteristics of compacted soils. However, in order to heighten the usefulness of such a numerical simulation in the practical design work, the authors realized that the mechanical interaction between soils and reinforcement, that is, the reinforcement mechanism, should be more precisely understood from a viewpoint of mechanical characteristics of soils itself. Then, a series of laboratory tests for compacted (usually unsaturated) sandy soils is carried out. And some model tests in the laboratory are also performed. Compacted soil specimens (30 cm in diameter and 40 cm in height) are wrapped by geosynthetics. The specimens are laid on the uniaxial loading apparatus and are subjected to compressive shear. The extensive stresses working to the geosynthetics are measured during shear.