The Influence of Water Level Fluctuation on the Bank Landslide Stability
-
摘要: 三峡水库正常蓄水后, 库水位在175~145m之间周期性波动, 滑坡地下水渗流状态将会发生较大的改变, 可能导致滑坡失稳.因此, 研究库水位周期性波动下滑坡的稳定性具有十分重要的意义.提出了土水特征曲线的多项式约束优化模型和采用饱和-非饱和渗流数值模型.以赵树岭滑坡为例, 利用有限元数值计算了库水位在175~145m之间波动下地下水渗流场, 将计算得到的孔隙水压力用于滑坡的极限平衡分析, 探讨了库水位上升和下降对库岸滑坡稳定性的影响.研究表明: 多项式优化模型可以很好地拟合非饱和土的土水特征曲线; 库水位上升时滑坡稳定性系数总体逐渐增大, 库水位下降时滑坡稳定性系数总体逐渐减小; 无论是库水位上升还是下降到库水位155m时, 其稳定性系数最小; 同一库水位下, 库水位上升时的稳定性系数比下降时的稳定性系数大.Abstract: The water level will periodically fluctuate between 145 and 175m since normal water level storage in Three Gorges reservoir, while the ground water seepage of landslide will be subject to great changes, which may lead to landslide instability. So it is of great significance to study the influence of water level fluctuatation on the bank landslide stability. In this paper, a polynomial constrained optimized model for soil-water characteristic curve is put forward and the saturated-unsaturated seepage flow numerical model is applied. In addition, Zhaoshuling landslide is taken as an example, water seepage fields are simulated by using finite element method with the water level fluctuation between 145 and 175m. The transient pore water pressures are used for limit equilibrium analyses of landslides with taking the effects of suction on shear strength of unsaturated soils into consideration. Then we discuss the effect of the fluctuation of water level in Three Gorges reservoir on the bank landslide stability. The result shows that a polynomial constrained optimized model may well fit the characteristic curve of soil and water of unsaturated soil. The stability coefficient increases gradually in general along with reservoir water level rise and the stability coefficient decreases gradually in general along with the fall of reservoir water level. However, when the reservoir water level reached 155m, whether it rises from 145m or falls from 175m, the stability coefficient is smallest; while the stability coefficient in period of reservoir water level rising from 145m to 175m is larger than that in period of falling from 175m to 145m.
-
图 3 约束优化与试验数据对比
Fig. 3. Contrast chart of holistic constrained optimization and test data
图 4 库水位上升(a) 和下降(b) 中地下水不同时刻的浸润线
Fig. 4. Groundwater infiltration lines for different time of reservoir water level raise (a) and (b) level drawdow
图 6 库水位变化过程中不同特征水位的稳定性系数
Fig. 6. Stability factor of different water level with reservoir water Level fluctuation
表 1 赵树岭滑坡的基质吸力(ϕ)、体积含水量(θ) 与相对渗透系数kr的关系表
Table 1. Relationship of matrix suction, water content and relative permeability coefficient on Zhaoshuling slope
-
[1] Fredlund, D. G., Xing, A., 1994. Equations for the soil-water characteristic curve. Can. Geotech. J. , 31: 521-532. doi: 10.1139/t94-061 [2] Hu, X. L., Tang, H. M., Ma S. Z., et al., 2006. Numerical simulation of the 3D landslide stability in Three Gorges area based on NMR. Earth Science—Journal of China University of Geosciences, 31 (2): 279-284 (in Chinesewith English abstract). [3] Jiang, G., Lin, L. S., Liu, Z. D., et al., 2001. Analysis method for slope stability considering unsaturated soil strength and its application. Chinese Journal of Rock Mechanics and Engineering, 20 (A01): 1070-1074 (in Chinese with English abstract). [4] Liu, C. H., Cheng, C. X., Feng, X. T., 2005. Study on mechanism of slope instability due to reservoir water level rise. Rock and Soil Mechanics, 26 (5): 669-773 (in Chinese with English abstract). [5] Liu, X. M., Zhao, H. L., Wang, L. J., 2001. Research on soilwater character of unsaturated pulverescent clay by experiment. Underground Space, 21 (5): 375-378 (in Chinese with English abstract). [6] Liu, X. X., Xia, Y. Y., Lian, C., et al., 2005. Research onmethod of landslide stability valuation during sudden drawdown of reservoir level. Rock and Soil Mechanics, 26 (5): 1427-1436 (in Chinese with English abstract). [7] Qi, G. Q., Huang, R. Q., 2004. A universal mathematical model of soil-water characteristic curve. Journal of Engineering Geology, 12 (2): 182-186 (in Chinese withEnglish abstract). [8] Tang, H. M., Ma, S. Z., Liu, Y. R., et al., 2002. Stability and control measures of Zhaoshuling landslide Badong County, Three Gorges reservoir. Earth Science—Journal of China University of Geosciences, 27 (5): 621-625 (in Chinese with English abstract). [9] Xu, Y. F., Dong, P., 2002. Fractal models for the soil-water characteristics of unsaturated soils. Rock and Soil Mechanics, 23 (4): 400-405 (in Chinese with English ab-stract). [10] Zhang, P. W., Liu, D. F., Huang, D. H., et al., 2003. Saturated-unsaturated unsteady seepage flow numerical simulation. Rock and Soil Mechanics, 24 (6): 927-930 (in Chinese with English abstract). [11] Zhang, W. J., Zhan, L. T., Ling, D. S., et al., 2006. Influence of reservoir water level fluctuations on stability of unsaturated soil banks. Journal of Zhejiang University (Engineering Science), 40 (8): 1365-1370, 1428 (in Chinese with English abstract). [12] 胡新丽, 唐辉明, 马淑芝, 等, 2006. 基于NMR的库区滑坡三维稳定性数值模拟. 地球科学——中国地质大学学报, 31 (2): 279-284. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200602019.htm [13] 蒋刚, 林鲁生, 刘祖德, 等, 2001. 考虑非饱和土强度的边坡稳定分析方法及应用. 岩石力学与工程学报, 20 (A01): 1070-1074. [14] 刘才华, 陈从新, 冯夏庭, 2005. 库水位上升诱发边坡失稳机理研究. 岩土力学, 26 (5): 669-773. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200505022.htm [15] 刘晓敏, 赵慧丽, 王连俊, 2001. 非饱和粉质粘土的土水特性试验研究. 地下空间, 21 (5): 375-378. https://www.cnki.com.cn/Article/CJFDTOTAL-BASE2001S1007.htm [16] 刘新喜, 夏元友, 练操, 等, 2005. 库水位骤降时的滑坡稳定性评价方法研究. 岩土力学, 26 (5): 1427-1436. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200509015.htm [17] 戚国庆, 黄润秋, 2004. 土水特征曲线的通用数学模型研究. 工程地质学报, 12 (2): 182-186. doi: 10.3969/j.issn.1004-9665.2004.02.012 [18] 唐辉明, 马淑芝, 刘佑荣, 等, 2002. 三峡工程库区巴东县赵树岭滑坡稳定性与防治对策研究. 地球科学——中国地质大学学报, 27 (5): 621-625. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200205023.htm [19] 徐永福, 董平, 2002. 非饱和土的水分特征曲线的分形模型. 岩土力学, 23 (4): 730-734. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200204002.htm [20] 张培文, 刘德富, 黄达海, 等, 2003. 饱和-非饱和非稳定渗流的数值模拟. 岩土力学, 24 (6): 927-930. doi: 10.3969/j.issn.1000-7598.2003.06.011 [21] 张文杰, 詹良通, 凌道盛, 等, 2006. 水位升降对库区非饱和土质岸坡稳定性的影响. 浙江大学学报(工学版), 40 (8): 1365-1370, 1428. doi: 10.3785/j.issn.1008-973X.2006.08.017 -
下载:
点击查看大图
图(6) / 表(1)
计量
- 文章访问数: 3722
- HTML全文浏览量: 98
- PDF下载量: 106
- 被引次数: 0
