陈强, 彭永良, 曹正正, 汪维. 2019: 循环荷载下兖石铁路路基膨胀土的动力特性试验研究. 工程地质学报, 27(4): 737-744. DOI: 10.13544/j.cnki.xq2019030
    引用本文: 陈强, 彭永良, 曹正正, 汪维. 2019: 循环荷载下兖石铁路路基膨胀土的动力特性试验研究. 工程地质学报, 27(4): 737-744. DOI: 10.13544/j.cnki.xq2019030
    CHEN Qiang, PENG Yongliang, CAO Zhengzheng, WANG Wei. 2019: EXPERIMENTAL STUDY ON DYNAMIC CHARACTERISTICS OF EXPANSIVE SOIL FROM YANZHOU-SHIJIUSUO RAILWAY ROADBED UNDER CYCLIC LOADING. JOURNAL OF ENGINEERING GEOLOGY, 27(4): 737-744. DOI: 10.13544/j.cnki.xq2019030
    Citation: CHEN Qiang, PENG Yongliang, CAO Zhengzheng, WANG Wei. 2019: EXPERIMENTAL STUDY ON DYNAMIC CHARACTERISTICS OF EXPANSIVE SOIL FROM YANZHOU-SHIJIUSUO RAILWAY ROADBED UNDER CYCLIC LOADING. JOURNAL OF ENGINEERING GEOLOGY, 27(4): 737-744. DOI: 10.13544/j.cnki.xq2019030

    循环荷载下兖石铁路路基膨胀土的动力特性试验研究

    EXPERIMENTAL STUDY ON DYNAMIC CHARACTERISTICS OF EXPANSIVE SOIL FROM YANZHOU-SHIJIUSUO RAILWAY ROADBED UNDER CYCLIC LOADING

    • 摘要: 采用兖(州)至石(臼所)铁路路基膨胀土,借助GDS动三轴仪,研究了含水率、振动频率、动应力幅值对膨胀土累计塑性应变、动强度以及临界动应力的影响。试验结果表明:以轴向累计应变达到5%作为破坏标准时,循环次数与累计塑性应变曲线关系呈现出稳定型、临界型、破坏型3种状态;动强度与临界动应力均随含水率的增大而显著降低,饱和状态下的临界动应力只有40 kPa,低于列车实际动荷载;临界动应力与饱和度之间存在一条临界状态线,可以判断试样处于稳定、临界、还是破坏状态。振动频率对土体动力特性的影响:在f=0.5~2 Hz内,动强度随频率的增加而增大,当频率继续增大到5 Hz时,膨胀土动强度显著提高;在f=0.5~5 Hz范围内,临界动应力随频率的增加而增大,近似呈线性关系。相关研究结果对揭示动荷载下膨胀土的力学特性,确保膨胀土地区铁路线的安全运营具有重要意义。

       

      Abstract: Dynamic triaxial test was carried out on the expansive soil from Yanzhou-Shijiusuo railway roadbed. It is to study the effects of water content, vibration frequency and dynamic stress on its cumulative plastic strain, dynamic strength and critical dynamic stress. The experimental results show that when the axial cumulative strain reaches 5%as the failure standard, the relationship between the number of cycles and the cumulative plastic strain curve shows three states:stable type, critical type and destructive type. Both the dynamic strength and the critical dynamic stress decrease significantly with the increase of water content. The critical dynamic stress in saturated state is only 40kPa, which is lower than the actual dynamic load of the train. We find that critical state line exists between the critical dynamic stress and saturation and can be used to judge whether the specimen is stable, critical or failure. The vibration frequency has the following effects on the dynamic characteristics of expansive soil. When frequency equals to 0.5~2Hz, the dynamic strength increases with the increase of frequency. When the frequency continues to increase to 5Hz, the dynamic strength of expansive soil increases significantly. When frequency equals to 0.5~5Hz, the critical dynamic stress increases with the increase of frequency, which is approximately linear. The related research results are of great significance to reveal the mechanical properties of expansive soil under dynamic loading and to ensure the safe operation of railway lines in expansive soil area.

       

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