中文摘要：

纤维与土体界面之间的相互作用对纤维加筋效果有着重要的影响,了解接触面之间力的产生和传递过程对合理有效地利用纤维改良土体的工程性质有着重要的意义。为了研究聚丙烯纤维在不同的土介质中筋/土界面间的微观力学作用机理,运用扫描电子显微镜（SEM）分别分析了纤维在素土、水泥土和石灰土中的表面形态学特征及接触面之间力的产生和传递过程。结果表明：纤维的加筋效果取决于筋/土界面作用强度,筋/土界面之间的力学作用主要有2种形式：黏接和摩擦;界面黏结力和摩擦力大小受土质条件和界面接触条件的影响;在纤维加筋素土中,筋/土界面作用力主要来自纤维表面与黏土颗粒的相互作用;在纤维加筋水泥土中,纤维主要与水泥水化产物发生作用,筋/土界面作用力以黏结力为主;在纤维加筋石灰土中,纤维表面发生严重的挤压变形,筋/土界面作用力以摩擦力为主。

英文摘要：

Interfacial interactions between fiber reinforcement and soil play an important role in reinforce benefit.Understanding the interfacial mechanical behavior is helpful to apply effectively the fiber reinforcement in geotechnical engineering practice.The objective of the present work is to study the interfacial micro-mechanical behavior of discrete polypropylene fiber reinforced soil.Three soil types（fiber reinforced raw soil,cement soil and lime soil）commonly used in the field were taken into account.The evolution of the interfacial microstructure and fiber surface morphology in these soil types were characterized by using scanning electron microscopy（SEM）.It was found that the bond strength between fibers and soil matrix and the associated interfacial friction are the dominant mechanism of fiber reinforced soil.They seem to be controlled by the soil properties and interface condition（microstructure,soil composition,fiber surface roughness etc.）.In fiber reinforced raw soil,the fiber surface is attached by many clay minerals.In fiber reinforced cement soil,the interfacial bond strength plays a main role in the interfacial mechanical behavior.In fiber reinforced lime soil,evident plastic deformation is observed on fiber surface,which greatly improved the interfacial friction.