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膨胀土路堑开挖一段时间后边坡坍滑是路基施工中常见现象且与坡高、坡率无直接联系。为探求其变形破坏演化过程以便实施有效工程处治,采用FLAC对广西百隆路百色膨胀土堑坡开挖过程进行模拟,获得新开挖边坡的位移、应力、应变变化规律;通过强度折减法计算得到的安全系数随挖深增大而减小,但此时边坡是稳定的。此外采用FLAC热力学模块模拟边坡大气影响深度内的湿度场,再次分析获得经历干湿循环作用后其相应的位移、应力、应变变化规律,即边坡的失稳过程。对比工程实体修建时的现场观察与数值分析结果,发现两者基本吻合,由此总结并提出开挖膨胀土堑坡坍滑的4阶段变化规律及合理实施柔性支护的建议。
After a period of expansive soil cutting, slope collapse is a common phenomenon in subgrade construction and has no direct relation with slope height and slope rate. In order to explore its deformation and failure evolution process in order to carry out effective engineering treatment, FLAC was used to simulate the excavation process of Baise expansive soil cutting slope on BaiLong Road in Guangxi Province to obtain the displacement, stress and strain variation of the newly excavated slope. The calculated safety factor decreases with increasing digging depth, but the slope is stable at this time. In addition, the FLAC thermodynamic module was used to simulate the humidity field within the depth of the impact of the slope atmosphere, and the corresponding laws of displacement, stress and strain after wetting and drying cycles were analyzed again, that is, the instability of the slope. Comparing the results of on-site observation and numerical analysis of the construction entity, it is found that the two are in good agreement with each other. Based on the results, the four-stage variation law of slump of excavation expansive soil slope and the suggestion of reasonable support are proposed.