Study on the Control Discharge Characteristics of the Tangential Intake Structure of the Deep Tunnel Storage System in Korea

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Oh Jun-Oh, Park Jea-Hyeon, Park Chang Geun

Tuesday 30 june 2015

12:30 - 12:33h at Africa (level 0)

Themes: (T) Water engineering, (ST) Experimental facilities and instrumentation, Poster pitches

Parallel session: Poster pitches: 5F. Engineering - Instrument

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Due to the change of the rapid urbanization and the characteristics of the precipitation, specially the storage capacity of the urban watershed has been decreased, so the flood mitigation policy using the deep tunnel system has been used for decades in some countries. In the case of Japan, the underground storage tunnels such as the Sinwogi, the Naniwa, the Yodo, the Otsu have been used as the flood protection structures. In Korea, the interest of these underground facilities has been increased because of increasing of the flood damage in the metropolitan areas, and the deep tunnel systems has been applied at Shinwol area in Seoul as the flood protection policy. In this study, the hydraulic characteristics of the vortex type intake structure of the deep tunnel was analyzed through the hydraulic model experiments specially for the tangential intake structure including the design factors such as drop shaft diameter (D), inflow channel width (B), inflow channel length (L), inflow channel angle (_), join angle inflow channel and drop shaft (_). Yu(2009) etc. suggested the control discharge formula for the the tangential intake structure, which indicate the proper design guideline. In our research The 4 cases hydraulic model experiment has fulfilled, and compared with the theoretically calculated data and experimental data of Qc and yc respectively. Experimental results were compared and analyzed divided into three ranges according to the ratio of the measured and calculated control discharge (Qc(m)/Qc(p)), and the design factor ratios such as e/B z/L, L/B, z/B, the e/z. The each factor ratios in these three ranges were analyzed by sensitivity analysis. In the case of less than 0.8, Qc(m)/Qc(p) have been mainly determined by e, z, _, which are influence factors on contorl discharge, If Qc(m)/Qc(p) is 1.2 or more, the influence of _ is negligible, but e and z have a significant affects on the control discharge. In the case that Qc (m)/Qc(p) is increasing from 0.8 to 1.2, the effect of _ is decreased. The Yu’s proposed control discharge equation(2009) shows the approaching channel length(L) is negligible in the case of same e/B, but the experiment data shows the approaching channel length(L) is very important factor, so the factors of the control discharge equation should be revised by the adjustment of the weighted factors through the more researches.