【摘要】 为研究低温状态下聚丙烯纤维(polypropylene fibers, PP)对膨胀土(expansive soil, ES)的力学改良效果，通过冻融循环试验和无侧限抗压强度试验，得到不同土样的应力-应变参数，基于室内试验数据，采用ABAQUS软件建立冻融循环后聚丙烯纤维加筋膨胀土(PP-ES)无侧限抗压强度试验的有限元模型，并对其数值模拟结果进行分析。结果表明：数值模拟结果与试验结果保持一致，利用ABAQUS软件建立的冻融循环纤维加筋土模型合理可行；随着冻融次数的增加，PP可在一定程度上抑制ES受冻融劣化的影响，有效增强ES冻融后的强度；当纤维掺量为0.3%时，在冻融循环1次后，对ES的强度提升幅度最大，达到57.80%。由基体和纤维应力分析得出，0.3%PP-ES抗冻融损伤性最优，对试件的增强效果最好，当纤维掺量大于0.3%时，对试样的影响以增韧为主。研究结果可为寒冷地区ES路基的纤维改良提供参考。更多还原

【Abstract】 In order to study the mechanical improvement effect of polypropylene fibers(PP) on expansive soil(ES) at low temperature, the stress-strain parameters of different soil samples were obtained by freeze-thaw cycling test and unconfined compressive strength test. Based on the indoor test data, a finite element model for the unconfined compressive strength test of PP-ES was established using ABAQUS software and the numerical simulation results were analysed. It shows that the numerical simulation results are consistent with the experimental results, and the freeze-thaw cycle fiber reinforced soil model established by using ABAQUS software is reasonable and feasible. With the increase of the number of freeze-thaw cycles, PP can suppress the influence of ES by freeze-thaw deterioration to a certain extent, and effectively enhance the strength of ES after freeze-thaw. When the content of fiber is 0.3%, the strength of ES increases to 57.80% after one freeze-thaw cycle. According to the stress analysis of matrix and fiber, 0.3%PP-ES has the best freeze-thaw damage resistance and the best reinforcement effect on the specimen. When the content of fiber is more than 0.3%, the effect on the sample is mainly toughening. The research results can provide reference for fiber improvement of ES subgrade in cold regions.更多还原