分淮入沂整治工程典型堤段垂直防渗体防渗效果分析与评价

随着堤防加固技术的进步,垂直防渗加固在众多堤防中得到广泛应用。但由于地质条件的复杂性及工程的隐蔽性,在垂直防渗工程完成后,其防渗效果难以检测与评价。依托分淮入沂整治工程,通过数值模拟方法分析了垂直防渗体的存在、防渗体铺设深度、防渗体完整性及防渗体缺陷位置等对堤防渗流场的影响,以溢出点水力梯度为评价指标,通过与土层允许水力梯度的比较来评价垂直防渗体的防渗效果。结果表明:堤岸经垂直防渗处理后在防渗体后的水头明显下降;防渗体进入堤防黏土层比防渗体未插入黏土层有更好的防渗效果;垂直防渗体存在缺陷时,会引起防渗体后浸润线明显抬升;在溢出点处所有工况的水力梯度都小于允许水力梯度,整个防渗工程防渗效果显著。

Effectiveness of Vertical Anti-seepage Body in Typical Levee Segment ofHuaihe River Drainage Project: Analysis and Evaluation

Despite wide application of vertical anti-seepage reinforcement in embankments, the effectiveness of anti-seepage is difficult to be detected and evaluated after the anti-seepage project is finished due to the complexity of geological conditions and concealment of project. In this paper we analyzed the effects of vertical anti-seepage body, the depth, damage location, and integrity of anti-seepage body on the seepage field of levee by numerical simulation taking the regulation project of diverting Huaihe River into Xinyi River as a case study. We further examined the effectiveness of anti-seepage body by comparing the hydraulic gradient of spill point with the allowable hydraulic gradient of soil. Results show that the head behind the anti-seepage body decreased markedly after the vertical seepage control treatment was carried out on the levee. The bottom of anti-seepage body inserting into the clay layer of levee had better impervious effect than that of anti-seepage body not inserting into clay layer. In the presence of defectives, the infiltration line rose obviously behind the anti-seepage body. The hydraulic gradient in all conditions at the spill point was smaller than the allowable hydraulic gradient, indicating evident seepage control effect.