流激振动作用下穿管堤防渗流分析

Seepage Analysis of Pipe-piercing Embankment Under Flow-induced Vibration

以广东省某穿管堤防为例,建立三维管道-堤防有限元模型来进行计算分析。根据现场实测振动响应数据进行荷载反演得到流激振动荷载,计算流激振动对管周土体的最大扰动范围,在该影响范围内进行流激振动荷载对穿管堤防渗流场的影响分析。结果表明:流激振动荷载作用下管周土体渗透系数增大,穿管堤防浸润线明显升高,且穿管导致堤防下游坡面渗流区域出现扩大现象;穿堤管道导致堤防最大渗流速度成倍增加,且中部穿管工况的堤防渗流速度与渗透力最大;管周土体孔隙压力随着管道埋深的加深而增大,在堤防下游坡面位置处有急剧下降趋势;对中部穿管工况进行防渗措施数量、尺寸敏感性分析可得,堤内管道全程布置外包混凝土为最优布置工况,正方形外包混凝土边壁至管壁的厚度选定为0.3D,正方形截渗环边壁至管壁的厚度以0.6D~0.75D为宜,截渗环的数量选定4个及以上为宜。

Taking a pipe-piercing dike in Guangdong Province as an example, a three-dimensional pipeline-dike finite element model is established for calculation and analysis. According to the field measured vibration response data, the flow-induced vibration load is obtained by load inversion, and the maximum disturbance range of flow-induced vibration to the soil around the pipe is calculated, and the influence of flow-induced vibration load on the seepage field of the dike is analyzed. The results show that under the action of flow-induced vibration load, the permeability coefficient of the soil around the pipe increases, the infiltration line of the dike increases obviously, and the pipe penetration leads to the expansion of the seepage area on the downstream slope of the dike, and the pipeline through the dike causes the maximum seepage velocity of the dike to increase exponentially, and the seepage velocity and seepage force of the dike under the pipe-piercing condition in the middle are the largest. The pore pressure of the soil around the pipe increases with the deepening of the buried depth of the pipeline, and there is a sharp downward trend at the position of the slope downstream of the dike;through the analysis of the number and size sensitivity of anti-seepage measures, it can be concluded that the optimal arrangement condition is that the outer concrete is arranged in the whole process of the dike, the size of the outer concrete is 2.1 D, the size of the cut-off ring is 2.2 D~2.5 D, and the number of the cut-off ring is 4 or more.