土工合成材料作为一种经济环保、具备优异工程适应性的填筑材料,在地基加固等领域有着广泛的应用前景。针对中国西北黄土地区路基水毁病害问题,基于共振柱与微观试验,重点探究了筋材种类、加筋间距和围压等影响因素对动剪切模量的影响规律。结果表明:筋材的布置可有效提升复合体的动剪切模量,其中三向格栅加筋体系效果最优;归一化动剪切模量随剪应变的变化规律与原始衰减曲线具有一致性,呈非线性衰减,围压升高或加筋间距减小可延缓模量衰减、减弱滞回效应,提升其刚度特性;SEM分析表明,随着筋材的布置,颗粒间胶结接触形式呈现多样化特征,形成稳定的骨架结构,孔隙体积逐渐减小,颗粒定向排列程度提高。研究成果可为黄土路基抗震设计提供理论支撑。
As an economical, environmentally friendly filling material with excellent engineering adaptability, geosynthetics have a wide range of application prospects in urban infrastructure such as foundation reinforcement. In order to solve the problem of subgrade water damage in the loess region of Northwest China, this study focused on exploring the influence of influencing factors such as reinforcement type, reinforcement spacing and confining pressure on the dynamic shear modulus based on resonant column and microscopic experiments. The results show that: The incorporation of reinforcement can effectively improve the dynamic shear modulus of the composite, and the three-way grid reinforcement system has the best lifting effect. The variation of normalized dynamic shear modulus with shear strain is consistent with the original attenuation curve, showing nonlinear attenuation, and the increase of confining pressure or the decrease of reinforcement spacing can delay the modulus attenuation, weaken the hysteretic effect, and improve its stiffness characteristics. SEM analysis showed that with the arrangement of the reinforcements, the cementation contact forms between the particles showed diversified characteristics, forming a stable skeleton structure, the pore volume gradually decreased, and the degree of directional arrangement of particles increased. The study confirms that geosynthetics can optimize the dynamic characteristics of loess and provide important theoretical support for the seismic design of loess subgrade.
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