湿度变化对黄土路堤边坡稳定性影响分析
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摘要
通过三轴压缩试验,分析不同含水率状态下压实黄土填料的强度变化特征,并计算评价了不同湿度、路堤高度、加筋条件下黄土边坡稳定性。结果表明:压实黄土填料强度随着含水率增加而下降,其中黏聚力与含水率呈负指数递减关系,内摩擦角与含水率呈线性递减关系,含水率对压实黄土的黏聚力影响更明显;随着路堤填料湿度上升,边坡稳定系数显著降低,当含水率从施工状态w_(opt)上升5%时,路堤高度10～40 m的边坡稳定性系数下降24.3%～37.9%;加筋层中使用的土工格栅抗拉强度越高,土工格栅层间距越小,路堤边坡稳定补强效果越明显。
The strength variation features of compacted loess filling in different cases of moisture content were analyzed through triaxial compression test; and the stability of loess slope in different cases of humidity, embankment height and reinforcement conditions were calculated and evaluated. The result shows that the strength of compacted loess filling decreases with the increment of moisture content, where in the cohesion relates to the moisture content with negative exponential decrease, the internal frictional angle relates to the moisture content with linear decrease, and the moisture content has more obvious impact; as the humidity of embankment filling increases, the coefficient of slope stability decreases greatly, i.e. when the moisture content increases by 5 % from w_(opt) in construction status, the stability coefficient of the embankment in 10～40 m high decreases by 24.3 %～37.9 %; the higher the tensile strength of the geogrid used in the reinforcement layer and the smaller the geogrid interval, the more obvious the reinforcement effect for the embankment slope stability.
The strength variation features of compacted loess filling in different cases of moisture content were analyzed through triaxial compression test; and the stability of loess slope in different cases of humidity, embankment height and reinforcement conditions were calculated and evaluated. The result shows that the strength of compacted loess filling decreases with the increment of moisture content, where in the cohesion relates to the moisture content with negative exponential decrease, the internal frictional angle relates to the moisture content with linear decrease, and the moisture content has more obvious impact; as the humidity of embankment filling increases, the coefficient of slope stability decreases greatly, i.e. when the moisture content increases by 5 % from w_(opt) in construction status, the stability coefficient of the embankment in 10～40 m high decreases by 24.3 %～37.9 %; the higher the tensile strength of the geogrid used in the reinforcement layer and the smaller the geogrid interval, the more obvious the reinforcement effect for the embankment slope stability.
引文
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[2] 邢鲜丽,李同录,李萍,等.黄土抗剪强度与含水率的变化规律[J].水文地质工程地质,2014,41(3):53-59,97.XING X L,LI T L,LI P,et al.Variation regularities of loess shear strength with the moisture content[J].Hydrogeology and Engineering Geology,2014,41(3):53-59,97.
[3] 景宏君,梁建红,李跃才,等.非饱和黄土渗透系数对其强度的影响[J].公路工程,2009,34(6):130-134,143.JING H J,LIANG J H,LI Y C,et al.Effects of unsaturated loess permeability coefficient by its strength[J].Highway Engineering,2009,34(6):130-134,143.
[4] 程小勇.含水量对黄土强度的影响试验研究[D].武汉:中国地质大学(武汉),2009.CHENG X Y.Experimental study of effects of loess strength on moisture[D].Wuhan:China University of Geosciences (Wuhan),2009.
[5] 付江.黄土高边坡开挖过程中的稳定性分析[J].路基工程,2018(3):162-166.FU J.Stability analysis of high loess slope in excavation process[J].Subgrade Engineering,2018(3):162-166.
[6] 叱干晓敏.考虑含水率变化对黄土结构强度影响的边坡稳定性分析[J].水利与建筑工程学报,2013,11(5):169-172.CHIGAN X M.Loess slope stability analysis based on considering effect of water content change on its structural strength[J].Journal of Water Resources and Architectural Engineering,2013,11(5):169-172.
[7] 徐名彬,陈国国.降雨对黄土边坡渗流及稳定性影响分析[J].路基工程,2015(5):115-117.XU M B,CHEN G G.Analysis on influence of rainfall on seepage and stability of loess slope[J].Subgrade Engineering,2015(5):115-117.
[8] 陶连金,张印涛,邹祖银,等.黄土加筋路堤的数值模拟及性能分析[J].公路交通科技,2006(12):32-36.TAO L J,ZHANG Y T,ZOU Z Y,et al.Performance analysis of a reinforcing loess embankment using numerical method[J].Journal of Highway and Transportation Research and Development,2006(12):32-36.
[9] 吴万平.《公路路基设计规范》释义手册[K].北京:人民交通出版社,2015.WU W P.Explanation Handbook of Specification for Design of Highway Subgrades[K].Beijing:China Communications Press,2015.