ISSN 1003-8035 CN 11-2852/P

    基于挡墙裂缝特征的滑坡活动性判识及降雨对滑坡稳定性影响的分析以贵州正安一处填方边坡为例

    Landslide identification based on characteristics of retaining wall fractures and rainfall stability analysis:A case study of fill slope in Zheng’an County, Guizhou Province

    • 摘要: 滑坡的变形特征以及机理是边坡稳定性分析和边坡破坏预警的关键。正安县芙蓉江镇某填方边坡挡墙在雨季产生了显著变形,挡土墙裂缝发育显著,为确定边坡的安全状态,对边坡的地质以及水文条件进行了调查,对挡墙以及周边地面裂缝特征进行了统计,并通过FLAC3D对非饱和降雨入渗后边坡的稳定性进行了计算。研究结果:(1)挡墙裂缝沿最大主应力的主平面发育,挡墙沿沟槽轴线对称沉降;(2)通过降雨强度为10 mm/d(小雨)和250 mm/d(暴雨)的入渗分析,小雨8 d和雨停后5 d安全系数分别降低14.5%和4.3%,暴雨1 d和雨停后2 d安全系数降幅分别为10%和3.5%;(3)分析了边坡的变形机理,认为填方加载和降雨后土体重度增加导致下滑力增加;降雨导致基质吸力、有效应力降低,而土体的抗剪强度和抗滑力降低;(4)根据挡墙裂缝特征和变形监测结果预测了边坡的主滑方向、几何边界和滑坡分区,后续边坡前沿鼓胀现象说明滑坡判识结果准确。

       

      Abstract: The deformation characteristics and mechanism of landslides are crucial for slope stability and slope failure warning. Significant deformation occurred in the retaining wall of a fill slope in Furongjiang Town, Zheng’an County, during the rainy season, with notable development of soil wall cracks. In order to determine the safety status of the slope, geological and hydrological conditions of the slope were investigated, and the characteristics of the retaining wall and surrounding ground cracks were statistically analyzed. The stability of the slope after unsaturated rainfall infiltration was calculated by FLAC3D. The results are as follows: (1) retaining wall cracks develop along the principal plane of maximum principal stress, and the retaining wall settle symmetrically along the axis of the groove; (2) Through the infiltration analysis of rainfall intensity of 10mm/d (light rain) and 250mm/d (heavy rain), the safety factors of light rain on 8 days and 5 days after rainfall cessation decreased by 14.5% and 4.3%, respectively, and the safety factors of heavy rain on 1 day and 2 days after rainfall cessation decreased by 10% and 3.5%, respectively. (3) The deformation mechanism of the slope was analyzed, indicating that the increase in gravitational force after filling and rainfall led to increased sliding force. Rainfall reduced matric suction and effective stress, resulting in decreased shear strength and sliding resistance of the soil. (4) Based on the characteristics of retaining wall cracks and deformation monitoring results, the main sliding direction, geometric boundaries, and landslide zones of the slope were predicted, and subsequent swelling phenomenon at the forefront of the slope confirmed the accuracy of the landslide identification results.

       

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