造林土质边坡浅层平面滑坡模型的初步研究

Model of assessing shallow planar landslide of forested soil side slope

造林土质边坡容易发生浅层平面滑坡。基于极限平衡理论,综合考虑土质边坡上林木根系的力学加固土壤作用和水文增加基质吸力效应,以及林木附加自重对边坡稳定的负面效应,建立了一个用来评价造林土质边坡浅层平面滑坡的分析模型。所有模型参数中土壤内摩擦角和边坡坡度的微弱变化能引起边坡安全系数较大浮动,而林木附加自重的变化对安全系数的影响较小。造林土质边坡浅层滑坡分析模型中林木根系对土壤的力学加固作用采用了修正的植物根系提高土壤抗剪强度的简单力学增强模型,相比以往类似边坡稳定性模型,分析模型显著提高了预测边坡稳定的准确性。

Forested soil side slope is prone to meet with shallow planar landslide. Based on the limit equilibrium theory, the paper tries to establish an analytical model to assess shallow planar landslide of the forested soil side slope, taking into account of the positive effects of mechanically reinforcing soil and hydrologically improving matric suction on slope by woody roots, as well as the negative effects of additional weight of trees. In all parameters of the model, minute variation of soil internal friction and slope gradient could bring enormous fluctuation of the results of safety factor, while changes of additional weight of trees had a little impact on safety factor. The mechanical action of soil reinforcement by roots, which was one component of the analytical model, adopted a modified simple mechanical model of improving shear strength by plant roots. Compared with previous similar models, the analytical model significantly improved the accuracy of forcasting slope stability.