Author(s): Zhigang Wang; Dong Zhang; Hongwei Zhang; Weichen Ren

Linked Author(s): Zhigang Wang, Dong Zhang, Hongwei Zhang

Keywords: Ir-water bubbly flow; Urban deep-tunnel drainage system; Physical model test

Abstract: As the economical and social development, the sewage amount is becoming larger and larger. Moreover, in recent years, extreme weather events appear frequently, leading to severe urban flooding and then considerable economical damages. The urban deep-tunnel drainage system is an effective solution, which could transfer the stormwater down into the deep tunnels and storm it there, then pumped it into the rivers afterwards with a relatively small discharge. Clearly, it can effectively lower and delay the flood peak. However, during the operation of the urban deep-tunnel drainage system, the air may go into the system, especially the deep tunnels, which would be harmful to the safety of the system. In this paper, we systematically investigated the process of the air bubbles through physical model tests and found out that falling jet and swirling in the baffle drop shafts were the two main ways that could result in the air bubbles entering the deep tunnels. And adjusting the design of the inflow shafts and increasing the water level in the shaft could largely decrease or even avoid the air bubbles getting into the deep tunnels.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221357

Year: 2022