玄武岩纤维加筋粉质黏土的静动力学特性试验研究

Experimental investigation on the static and dynamic characteristics of silty clay reinforced with basalt fiber

玄武岩纤维作为一种新型环保高性能土体加筋材料,在土体中所表现出的静、动力学特性不同于一般的土工合成材料。为深入研究玄武岩纤维加筋粉质黏土的静、动力学特性,进行三轴压缩试验和动三轴试验,分析玄武岩纤维掺入量以及土体含水率等因素对粉质黏土抗剪强度、剪切模量以及阻尼比的影响。研究结果表明:纤维的加入能显著提高土体的抗剪强度,而纤维对粉质黏土抗剪强度参数的影响主要体现在黏聚力的提高上,对内摩擦角的影响比较小;含水率在最优含水率18.5%时,土体的抗剪切强度达到最大值。在应变一定时,土体的动剪切模量随着纤维掺入量以及含水率的增大先增大后减小;阻尼比随着纤维掺入量的增大先减小后增大,而含水率对阻尼比的影响较小。总体而言,在最优含水率18.5%,最佳纤维掺入量0.2%情况下能显著改善粉质黏土的静、动力特性。本文的研究成果将为玄武岩纤维加筋土路基的设计提供依据。

Basalt fiber,a new type of environment protection and high-performance soil reinforcement material,shows different static and dynamic characteristics than general geosynthetics.In order to study the static and dynamic characteristics of silty clay reinforced with basalt fiber,triaxial compression test and cyclic triaxial test were carried out.The influences of the content of basalt fiber and soil moisture content on shear strength,shear modulus and damping ratio of silty clay were analyzed.The results show that the addition of basalt fiber can significantly improve shear strength of the soil.The influence of fiber on shear strength parameters of silty clay is mainly reflected in the increase of cohesion,whereas the influence on internal friction angle is relatively small.Shear strength of the soil reaches its maximum value at the moisture content level of 18.5%.When the strain remains constant,the shear modulus of the soil increases initially and then decreases with increasing basalt fiber content and moisture content.The damping ratio decreases initially and then increases with increasing basalt fiber content,while the moisture content has little effect on the damping ratio.In general,the static and dynamic characteristics of silty clay can be improved significantly under the combination of optimal moisture content of 18.5%and optimal basalt fiber content of 0.2%.The results could provide a basis for the design of subgrade soils reinforced with basalt fiber.