贺兰山云杉林根土复合体提高边坡稳定性分析

发布时间：2018-04-19 20:09

本文选题：边坡稳定性 + 土壤　；参考：《农业工程学报》2017年20期

【摘要】：为了研究贺兰山青海云杉林(Picea crassifolia)边坡根土复合体对边坡稳定性的影响,该文在直剪试验、三轴试验等获得的土壤参数基础上,建立了基于有限元理论的贺兰山青海云杉林边坡稳定性计算数值模型,并在5种坡度条件下(18.43°、21.80°、26.57°、33.69°、45.00°)计算了无林边坡和有林边坡的安全系数、最大塑性应变、最大位移、破坏时间及它们的增长率随坡度的变化规律,并计算了土壤强度参数摩擦角、黏聚力、剪胀角与安全系数的灰色关联度矩阵和平均关联度。结果表明:1)无林边坡与有林边坡的安全系数随坡度的变化规律是一致的,都以幂函数递减。有林边坡相对于无林边坡安全系数的增长率以指数函数增加,且坡度越陡根土复合体对边坡稳定性的提高作用越强;2)根土复合体的存在可以延长边坡的破坏时间,有林边坡的破坏时间均高于无林边坡,根土复合体提高边坡破坏时间的增长率随坡度的增大呈抛物线增加,且坡度越陡提高作用越明显。边坡破坏时有无塑性贯通区会明显改变最大塑性应变、最大位移、破坏时间的值;3)摩擦角、黏聚力、剪胀角3个土壤强度参数中,黏聚力是影响边坡稳定的主导因素,摩擦角、剪胀角的影响次之,此规律不受边坡坡度的影响,这是根土复合体可以显著影响边坡稳定性的根本原因之一。该文的研究结果对于解释森林根土复合体加固边坡作用的本质、推进边坡稳定性计算的数值模拟、防治贺兰山浅层滑坡及水土流失灾害都具有重要的意义。
[Abstract]:In order to study the effect of root soil complex on slope stability of Picea crassifolia slope in Helan Mountain, the soil parameters obtained by direct shear test and triaxial test were studied. A numerical model for calculating the slope stability of Picea crassifolia forest in Helan Mountain was established based on the finite element theory. The safety factor, maximum plastic strain, maximum displacement of the slope without forest, maximum plastic strain and maximum displacement were calculated under five kinds of slope conditions: 18.43 掳~ 21.80 掳~ 26.57 掳~ 33.69 掳~ 45.00 掳). The damage time and their growth rate vary with the slope. The grey correlation matrix and the average correlation degree between the friction angle, cohesion force, shear expansion angle and safety factor of soil strength parameters are calculated. The results show that the variation of safety coefficient with slope is consistent with that of forest slope, and both of them decrease with power function. The increase rate of safety factor of forest slope compared with that of non-forest slope increases with exponential function, and the steeper the slope is, the stronger the effect of the root soil complex on the slope stability is; (2) the existence of the root soil complex can prolong the failure time of the slope. The failure time of forest slope is higher than that of no forest slope. The increasing rate of root soil complex increasing slope failure time is parabola with the increase of slope, and the steeper the slope is, the more obvious the effect is. The maximum plastic strain, the maximum displacement, the value of the failure time, the friction angle, the cohesion force and the shear expansion angle are three soil strength parameters, the cohesive force is the main factor that affects the slope stability, and the friction angle is the main factor that affects the slope stability, among the three soil strength parameters: the maximum plastic strain, the maximum displacement, the failure time and the shear expansion angle. The influence of shear expansion angle is second, and this law is not affected by slope gradient, which is one of the fundamental reasons that root soil complex can significantly affect slope stability. The results of this paper are of great significance to explain the nature of forest root-soil complex strengthening slope, to promote the numerical simulation of slope stability calculation and to prevent shallow landslide and soil erosion disaster in Helan Mountain.
【作者单位】：宁夏大学农学院;北京林业大学水土保持学院;
【基金】：国家自然科学基金资助项目(31560232;31400616)
【分类号】：S714.7

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