低温状态下纤维加筋膨胀土数值模拟试验
首发时间:2022-12-28
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PP掺量为0.3%,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PP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膨胀土路基的纤维改良提供参考。
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Numerical simulation of fiber-reinforced expansive soil at low temperature
Abstract:In order to study the mechanical improvement effect of PP fibers 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, and based on the indoor test data, the ABAQUS software was used to establish a finite element model of PP-ES after freeze-thaw cycling. 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. The results show that the numerical simulation results are consistent with the experimental results, and the freeze-thaw cycle fibre 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. 57.80%. From the matrix and fibre stress analysis, it was concluded that 0.3% PP-ES had the best resistance to freeze-thaw damage and the best strengthening effect on the specimens, and when the PP doping amount was greater than 0.3%, the effect on the specimens was mainly toughening. The results of the study can provide a reference for the fibre improvement of expanded soil roadbeds in cold areas.
Keywords: geotechnical engineering expansive soil freeze-thaw cycle compressive strength
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