Dynamics process simulation of long run-out catastrophic landfill flowslide on December 20 th，2015 in Shenzhen, China
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摘要: 文章采用DAN3D数值方法对深圳人工堆填体滑坡运动过程进行了模拟研究，探讨了深圳“12.20”滑坡远程动力成灾过程。通过研究得到以下几点结论：（1）滑坡后破坏运动主要分为两个阶段：前一阶段为滑源区内运动，体现了高孔隙水压力下滑剪切；后一阶段为在流通区和堆积区内运动，体现了高饱和度滑体流动（涌动）剪切。（2）饱水渣土滑坡远程流化运动分析中，摩擦模型适合模拟孔隙水压力作用下的滑源区渣土体的失稳下滑运动过程；宾汉姆模型适合模拟非牛顿流体饱和渣土体的流化剪切过程；摩擦-宾汉姆组合模型更适用于该类型滑坡全过程的反演运动分析。（3）深圳滑坡后破坏运动速度变化主要经历了“启动-加速-持速-减速”的运动过程，高含水渣土的固-流转化致使滑坡远程运动，并造成巨大伤亡损失。（4）模拟结果显示：堆积区平均堆积厚度为11 m，堆积范围为0.4 km 2，最大运动速度为30 m/s，最大速度发生于距滑坡后缘620 m处，堆积范围、堆积厚度和运动速度同滑坡实际值基本一致。上述研究思路和方法对城市地质中渣土滑坡灾害的危险区划和渣土场科学选址评估具有一定借鉴意义。Abstract: In this paper, DAN3D numerical method is used to simulate the Shenzhen landfill landslide, and the dynamic disaster process is discussed. The conclusions are as follows: (1) the post failure movement of landslide was mainly divided into two stages: the previous stage was in the source area, which reflected the main body dynamic shear of high pore water pressure, and the latter stage is in the propagation area and accumulation area, which reflects the flow (surging) shear of the highly saturated sliding body. (2) In the analysis of the hydrodynamic movement of saturated soil landslide, the friction model is suitable for simulating the unstable sliding shear process under pore water pressure, and the Bingham model is suitable for simulating the fluidized shear process. The Friction-Bingham (FB) combined model is more suitable for the inversion or prediction of the whole process of the landslide. (3) the velocity change of the failure motion after the landslide in Shenzhen mainly goes through the process of starting-accelerating-holding-decelerating. The solid-flow conversion causes the huge casualty loss, in which the water is the key factor which the Shenzhen landslide dynamics causes the disaster. (4) The simulation result shows, the average stacking thickness is 11 m, the accumulation range is 0.4 km 2, the maximum velocity is 30 m/s, and the maximum velocity occurs at 620 m from the back edge of the landslide. The accumulation range, thickness and velocity are basically consistent with the actual value of the landslide. The above research ideas and methods can be used for reference in the hazard zoning of residual landslide in urban geology and the scientific site selection assessment of residual soil site.
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Key words:
- Shenzhen landslide /
- long run-out landslide /
- landfill /
- dynamic disaster /
- DAN3D /
- rheological model /
- numerical simulation
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