2018年10月11日,位于西藏江达县和四川白玉县交界处的金沙江沿岸发生了大型山体滑坡——白格滑坡,造成金沙江堵塞并形成堰塞湖;2018年11月3日该处发生二次滑坡,再次堵江并造成堰塞湖蓄水量增加。为了研究白格堰塞湖在人工挖槽泄流阶段对上游岸坡稳定性的影响,以堰塞体上游某天然岸坡为例,采用有限元软件PLAXIS研究了该边坡在水位下降过程中的变形特征及稳定性变化规律。结果表明:①随着堰塞湖水的逐渐泄流,坡体表面位移变形逐渐增大,坡体后缘部位最大位移达到8.5 cm,中部和前缘变形相对较小;②水位下降过程中,坡体后缘的塑性区向下扩展,但未形成贯通的塑性区,同时安全系数也逐渐减小,最终为1.16;③各降水阶段坡体的最不利滑裂面相同,滑弧剪出口位于滑坡体高程3 150 m处,距坡脚约250 m,确定了该岸坡潜在的滑坡形式为高位滑坡。研究成果对后期该区域滑坡灾害的预防和控制有一定参考价值。
Abstract
On October 11, 2018, a large-scale landslide (Baige landslide) took place along the Jinsha River at the junction of Jiangda County in Tibet and Baiyu County in Sichuan Province, which resulted in blockage of the Jinsha River and formed a barrier lake. On November 3, 2018, a second landslide occurred in this area, blocked the river again and raised the water storage capacity of the barrier lake. In order to study the influence of Baige barrier lake on the stability of upstream bank slope during the discharge of the barrier lake through artificial trench, we examined the deformation characteristics and stability variation law of a natural bank slope in the upstream of the barrier lake in the process of water level drawdown using finite element software PLAXIS. Results evinced that: (1) with the discharg of barrier lake, the deformation of slope surface gradually increased, and the maximum displacement at the back edge of the slope reached 8.5 cm, while the deformations in the middle and the front edge were relatively small; (2) in the process of water level descent, the plastic zone at the back edge of the slope expanded downward, yet with no plastic zone penetrated, and meanwhile the safety factor reduced gradually until reaching 1.16; (3) the most unfavorable slipping surface of slope at different stages of water level drawdown remained the same. The exit of the slipping arc located at elevation 3 150 m of the landslide body and about 250 m from the slope foot. Therefore, we conclude that the potential sliding form of the bank slope is a high-level landslide. The research results are of referential value for future prevention and control of landslide disasters in this region.
关键词
白格滑坡 /
岸坡稳定 /
堰塞湖 /
PLAXIS /
安全系数 /
塑性区
Key words
Baige landslide /
slope stability /
barrier lake /
PLAXIS /
safety factor /
plastic zone
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 刘才华, 陈从新, 冯夏庭. 库水位上升诱发边坡失稳机理研究[J]. 岩土力学, 2005, 26(5): 669-773.
[2] STIANSON J R, FREDLUND D G, CHAN D. Three-dimensional Slope Stability Based on Stresses from a Stress-deformation Analysis[J]. Canadian Geotechnical Journal, 2011, 48(6): 891－904.
[3] 崔 洁. 不同库水位升降速度对大坝边坡稳定性的影响研究[J]. 水利水电技术, 2017, 48(2):155-159.
[4] 唐晓松, 郑颖人, 邬爱清,等. 应用PLAXIS有限元程序进行渗流作用下的边坡稳定性分析[J]. 长江科学院院报, 2006, 23(4):13-16.
[5] 赵 川, 付成华, 欧阳朝军,等. 水位下降对某悬索桥桥基边坡稳定性影响分析[J]. 灾害学, 2016, 31(4):134-138.
[6] SAADA Z, MAGHOUS S, GARNIER D. Stability Analysis of Rock Slopes Subjected to Seepage Forces Using the Modified Hoek-Brown Criterion[J]. International Journal of Rock Mechanics & Mining Sciences, 2012, 55:45-54.
[7] VANDAMME J, ZOU Q. Investigation of Slope Instability Induced by Seepage and Erosion by a Particle Method[J]. Computers & Geotechnics, 2013, 48:9-20.
[8] JIANG Z M, XIONG X H, LING Z. Unsaturated Seepage Analysis of Slope under Rainfall Condition Based on FLAC3D[J]. Rock & Soil Mechanics, 2014, 35(3):855-861.
[9] NG C W W, SHI Q. A Numerical Investigation of the Stability of Unsaturated Soil Slopes Subjected to Transient Seepage[J]. Computers & Geotechnics, 1998, 22(1):1-28.
[10]SRIVASTAVA A, BABU G L S, HALDAR S. Influence of Spatial Variability of Permeability Property on Steady State Seepage Flow and Slope Stability Analysis[J]. Engineering Geology, 2010, 110(3): 93-101.
[11]YANG X L, YIN J H. Slope Equivalent Mohr-Coulomb Strength Parameters for Rock Masses Satisfying the Hoek-Brown Criterion[J]. Rock Mechanics & Rock Engineering, 2010, 43(4): 505-511.
[12]YANG C, FENG T G. Study on the Development of Plastic Zone Based on Strain Expressed Mohr-Coulomb Yield Condition[J]. Applied Mechanics & Materials, 2014, 580: 195-200.
[13]LANE P A, GRIFFITHS D V. Assessment of Stability of Slopes under Drawdown Conditions[J]. Journal of Geotechnical and Geo-environmental Engineering, 2000, 126(5): 443-450.
[14]刘华磊, 徐则民, 张 勇. 降雨条件下边坡裂缝的演化机制及对边坡稳定性影响:以云南省双柏县丁家坟滑坡为例[J]. 灾害学, 2011, 26(1): 26-29.
[15]ZIENKIEWICS O C, HUMPHESON C, LEWIS R W. Associated and Non-associated Visco-plasticity and Plasticity in Soil Mechanics[J]. Geotechnique, 1975, 25(4): 671-689.
PDF(4628 KB)
