Abstract: A reservoir employed trenchless horizontal directional drilling pipe installation method to construct a new bottom outlet. However, seepage issues emerged during the trial operation phase after the water storage resumed. Field excavation analysis indicated that the primary causes of seepage were non- standardized construction process control and insufficient pressure resistance of the PE pipe. PE pipe ruptured and collapsed when the external pressure exceeding the PE pipe′s strength, resulting in seepage. Based on this case, applicability of trenchless horizontal directional drilling pipe installation method constructing new bottom outlet is discussed. Considering its application to other reservoirs, it is concluded that trenchless horizontal directional drilling is feasible for constructing new bottom outlet in reservoir reinforcement projects, while continuous improvements in design and standardized construction practices are essential.

Key words: trenchless horizontal directional drilling, PE pipe, seepage

摘要： 某水库采用非开挖定向钻拉管新建放水底涵，但在恢复下闸蓄水后的试运行阶段便发生了渗水问题。现场开挖分析认为，渗水原因主要是施工过程管控不规范和PE管抗外压强度不足，在超PE管强度的外压下，PE管破损并发生空瘪后出现渗水问题。由此对非开挖定向钻拉管新建放水底涵在水库除险加固中的适用性进行思考分析，结合该项技术在其他水库的应用，认为采用非开挖定向钻法在水库除险加固中新建底涵是可行的，但仍需不断完善设计，规范施工。

关键词: 非开挖定向钻, PE管, 渗水