方溪面板坝面板缺陷渗流特性及静动力稳定性数值模拟研究

针对目前面板缺陷下的面板坝渗流特性及静动力稳定性研究较少的问题,以方溪面板坝为例,利用Geo-studio软件建立了面板及缺陷有限元计算模型,数值模拟了不同缺陷情况及不同库水位情况下的面板坝动静力渗透稳定性,得到了坝体内部浸润线变化及坝体上下游的静动力安全系数变化规律。计算结果表明,缺陷的产生使面板处出现了渗漏通道,较完整面板来说大大抬升了面板坝内部的浸润线,主要浸润线抬升部位在靠近面板处,在下游坝坡处浸润线区别则较小;缺陷尺寸越大且缺陷高程越高,浸润线的高程越高,坝体渗漏量越大,但缺陷尺寸的影响小于缺陷高程的影响;上游坝坡的静力安全系数整体上随库水位的升高而上升,下游坝坡则相反。库水位水平高于缺陷高程时,缺陷高程越高,缺陷尺寸越大,安全系数则越低,同时上游坝坡的静力安全系数大于下游坝坡的静力安全系数;缺陷面板遇上地震工况时,上下游坝坡整体安全系数明显下降,下游坝坡在部分工况下处于失稳状态。研究成果对于面板坝灾害防治有一定积极意义。

Numerical Simulation of Seepage Characteristics and Static and Dynamic Stability of Fangxi Concrete Face Dam

In view of the deficiency of the seepage and static dynamic stability of the face plate dam under the defect of the face plate, taking Fangxi face plate dam for an example, the face plate and the defect finite element calculation model were established by using the Geo-studio software. The stability of the dynamic and static force of the face plate dam under the condition of different defects and the different reservoir water levels was simulated, and the change of the infiltration line inside the dam body and the change of the static safety coefficient at the upstream and downstream of the dam body were obtained. The results show that the defect leads to leakage channel at the face plate, the infiltration line inside the panel dam is greatly raised for the more complete panel, and the main infiltration line lifting part. The larger the size of the defect, the higher the height of the defect, the higher the elevation of the infiltration line and the greater the leakage of the dam body, but the effect of the defect size is smaller than that of the defect height. As a whole, the static safety factor of the upstream dam slope increases with the increase of reservoir water level, while the downstream dam slope is opposite. When the reservoir water level is higher than the defect height, the higher the defect height, the larger the defect size and the lower the safety factor. At the same time, the static safety factor of the upstream dam slope is larger than that of the downstream dam slope. Under the condition of earthquake, the overall safety factor of the upstream and downstream dam slope decreases obviously, and the downstream dam slope part of the dam slope decreases obviously. It is in unstable state under different working conditions. The research result has positive meaning for disaster prevention of face plate dam.