长距离分洪隧洞输水模型试验相似性研究

针对长距离输水隧洞小比尺物理模型难以满足阻力相似的问题，依托陕西省某县城分洪隧洞工程，通过对进口闸室段过流能力及隧洞段输水能力进行分别验证，实现了在小比尺物理模型上进行隧洞过流能力的试验研究。基于隧洞段内可以形成均匀流的特点，采用明渠均匀流计算方法对模型实测结果进行了计算验证。结果表明：计算流量与模型实测流量的最小差值为11.71 m³/s，最小相对误差为1.93%；基于进口闸室段距离短、局部水头损失远大于沿程水头损失的特点，控制隧洞桩号0＋099.25 m处水深为隧洞正常水深，可直接验证其过流能力，进口闸室段过流量与实测过流量最大误差不超过1.78%；在30年一遇洪水时，推荐方案闸室和隧洞的过流能力相匹配且与模型实测值基本一致，隧洞的分洪流量达到863 m³/s，较设计分洪流量800 m³/s超泄了63 m³/s，超泄流量占设计过流量的7.88%，完全满足设计要求。

Experimental similarity of water delivery model tests of a long-distance flood diversion tunnel

Due to the problem that the small-scale physical model of the long-distance flood diversion tunnel is difficult to provide similar resistance conditions with the actual situation, we carried out a small-scale physical model test on the flow capacity of the inlet gate chamber section and the delivery capacity of the tunnel section of a flood diversion tunnel in a county of Shanxi Province. Based on the characteristics that uniform flow can be formed in the tunnel section, the calculation method of open-channel uniform flow is used to verify the measured results. The results show that the minimum difference between the calculated flow and the measured flow is 11.71 m³/s, and the relative error is 1.93%. Because the distance of the entrance gate chamber section is short and the local loss is far greater than the on-way resistance loss, the water depth at the stake number 0+099.25 m of the tunnel is controlled to the normal depth of the tunnel to directly verify its flow capacity; the results show that the maximum error of the calculated flow rate of the entrance gate chamber section does not exceed 1.78%. In the case of the flood once in 30 years, the flow capacity of the gate chamber and tunnel of the recommended scheme are basically consistent with the measured values. The flood diversion flow can reach as high as 863 m³/s, which is 63 m³/s higher than the designed overflow of 800 m³/s, accounting for 7.88% of the designed overflow, indicating that the recommended scheme can fully meet the design requirements.