冻融循环条件下纤维增强膨胀土力学性能演化规律研究OA

In response to the significant influence of water phase change on the engineering characteristics of expansive soil,this paper uses agricultural waste straw as an ecological reinforcement material to systematically explore the mechanical response mechanism of fiber-reinforced expansive soil under freeze-thaw cycles.By designing a multi factor control experiment and combining the Brazilian splitting test and unconfined compression test methods,the influence of reinforcement ratio(0%～2.0%)and freeze-thaw cycles(0～15 times)on the tensile and compressive properties of the specimen was quantitatively analyzed.The experimental results show that fiber reinforcement can significantly improve the ductility characteristics of soil.When the reinforcement rate reaches 2%,the failure strain of the specimen increases to 2.6 times that of the plain soil.After 15 freeze-thaw cycles,the tensile strength of the 0.5%reinforced sample decreased by 72.3%,and the compressive strength decreased by 63.5%.A strength prediction model considering freeze-thaw damage effects was established based on experimental data,revealing that fiber soil interface degradation is the main mechanism leading to mechanical performance degradation.