黄土区施工开挖对渗流场的改变及边坡稳定性影响

The Construction and Excavation in Loess Area to the Change of Seepage Field and Its Influenee on Sloke Stability

邙山由第四系上更新统和中更新统黄土组成。在南水北调中线工程过黄河处,黄土中含有孔隙潜水,总干渠渠道开挖将形成数十米的高边坡,在地下水渗流作用下,边坡稳定性差。退水洞出口边坡为黄河南岸邙山自然边坡,自然状态下处于临界稳定状态。为保证退水洞的稳定,对出口边坡进行了治理。南水北调中线工程的实施,降低了轴线附近的地下水位,使得邙山黄土中的地下水渗流场发生了改变。分析地下水渗流场的改变及其对边坡稳定性的影响,为保证渠道边坡和退水洞出口边坡的长期稳定具有一定的指导意义。

Mangshan is made up of loess deposited in the upper and middle Pleistocene of Quaternary, where the middle route of south-to-north water transfer project passes by the Yellow River, the loess there stores the pore phreatic water. The slope, tens of meters high, was excavated along the channel, the seepage of ground water caused the instability of slope. The outlet slope of diversion tunnel at the south bank of Yellow River was in the critical stable state. To ensure its stability while constructed, some countermeasures were carried out in the outlet slope during construction of the project. The groundwater near the axis drained and its level declined as a result of the middle route of south-to-north water trans- fer project, which changed the groundwater seepage field in Mangshan loess. In the paper, the changes of groundwater seepage field and its effect on slope stability are analyzed, it has a certain guiding significance for maintaining the long- term stability of the slopes.