Failure mechanism of unsaturated landslide dam under seepage loading – Model tests and corresponding numerical simulations
Failure mechanism of unsaturated landslide dam under seepage loading – Model tests and corresponding numerical simulations
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DOI：
10.1016/j.sandf.2018.05.012
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发表时间：
2018-10
影响因子：
3.7
通讯作者：
Xianyu Xiong;Zhenming Shi;Shenggong Guan;Feng Zhang
中科院分区：
文献类型：
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作者：
Xianyu Xiong;Zhenming Shi;Shenggong Guan;Feng Zhang
滑坡坝由于其岩土材料的快速破裂、滑动和堆积，其结构往往比原状土更脆弱，更易受到渗流荷载的影响。此外，由于LD中的天然填充岩土材料大多处于非饱和状态，为了准确模拟LD的破坏机理，需要采用一种能够统一描述非饱和/饱和状态下土体力学行为、合理确定材料参数的本构模型。本文对三种不同地基材料制备的模型LD进行了保水试验和水槽试验。采用非饱和土本构模型进行数值模拟。根据保水试验和三轴试验结果，合理确定了LD材料的参数。利用这些参数，进行土-水-气耦合有限元分析，模拟水槽试验的模型LD。计算结果与试验结果的对比表明，本文所采用的数值方法对于描述模型LD在渗透荷载作用下的不同破坏机理具有满意的精度。结果表明，材料性质的LD，特别是强度和非饱和和饱和状态之间的空隙比的差异，起着重要的作用。此外，还通过数值试验研究了水头上升速率对水流特性的影响。本研究的目的是通过综合的方法来了解此类滑坡的破坏机理，为滑坡减灾过程中的决策提供科学依据。
Due to the rapid cracking, sliding and packing of its geomaterials, a landslide dam (LD) is usually weaker in structure than the undisturbed ground and is more vulnerable to seepage loading. In addition, since the naturally packed geomaterials of an LD are mostly in an unsaturated state, it is necessary to use a suitable constitutive model that can describe the mechanical behaviour of the soils under an unsaturated/saturated state in a unified way and whose material parameters can be determined in a rational way in order to accurately simulate the failure mechanism of the LD. In this paper, water retention tests and flume tests were conducted on model LDs prepared with three different ground materials. An unsaturated soil constitutive model was selected for the corresponding numerical simulations. Based on the results of water retention tests and triaxial tests, the parameters of the LD materials were properly determined. Using these parameters, soil-water-air coupling finite element analyses were conducted to simulate the flume tests on the model LDs. By comparing the calculated results with the test results, it was found that the numerical method used in this paper has satisfactory accuracy for describing the different failure mechanisms of the model LDs under seepage loading. The results indicate that the material properties of the LDs, especially the strength and the difference in void ratio between the unsaturated and the saturated states, play important roles. In addition, the influence of the rate of the rise in water head was also investigated by numerical tests. The purpose of this research is to provide a scientific basis for decision-making in the disaster mitigation process of LDs with a comprehensive method for understanding the failure mechanism of these LDs.