An effort to implement a siphon drainage system requires a comprehensive knowledge of the factor affecting the performance of the drainage system to reduce the groundwater table in the landslide area. A long-term field experiment was conducted to evaluate the effectiveness of the siphon drainage system with vertical wells to maintain the stability of landslide masses in a volcanic hillslope in West Java. The groundwater levels in all wells and water discharged from each well were monitored and measured periodically. Results of a 1-year measurement of the groundwater level indicate that the siphon drainage system was generally effective in decreasing the groundwater level in the landslide masses to a maximum depth of 7 m with a maximum total drainage flow of 24 m³/day. The implemented siphon drainage system was also able to prevent the groundwater level from rising during a rainfall period. A series of slope stability analyses under a steady-unsteady state seepage condition indicates the siphon drainage increased the long-term stability of the landslide area significantly. Based on this study, factors affecting the effectiveness of long-term siphon drainage performance are thoroughly evaluated.

实施虹吸排水系统的工作需要全面了解影响排水系统性能的因素，以减少滑坡地区的地下水位。进行了长期的野外实验，以评估具有竖井的虹吸排水系统在西爪哇岛火山山坡上保持滑坡体稳定性的有效性。定期监测和测量所有井中的地下水位和从每个井中排出的水。一年的地下水位测量结果表明，虹吸排水系统通常可以有效地将滑坡体中的地下水位降低到最大深度7 m，最大总排水流量为24 m ³/天。实施的虹吸排水系统还能够防止降雨期间地下水位上升。在稳态-非稳态渗流条件下进行的一系列边坡稳定性分析表明，虹吸排水大大增加了滑坡区的长期稳定性。基于此研究，对影响长期虹吸排水性能的因素进行了全面评估。