ZHANG Zi-xian,LIU Jia-chun.Effects of Silt and Hydraulic Uncertainty on Discharge Capacity of Storm Sewer[J].China Water & Wastewater,2021,37(15 15):115.
Effects of Silt and Hydraulic Uncertainty on Discharge Capacity of Storm Sewer
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第37卷
Number:
15 15
Page:
115
Column:
Date of publication:
2021-08-01
- Keywords:
- storm sewer; silt depth; allowable deviation of pipe diameter; hydraulic uncertainty; discharge capacity
- Abstract:
- Effects of silt and hydraulic uncertainty on the discharge capacity of storm sewer were investigated, and the formula for calculating the change rate of storm sewer discharge capacity after silt deposition was derived. Under the condition of the allowable silt depth before and after dredging in Technical Specification for Operation, Maintenance and Security of Sewers & Channels and Pumping Stations in City and Town (CJJ 68-2016), the discharge capacity of the existing storm sewer decreased by more than 20% and nearly 15%, respectively. The formulas for calculating the change rate of new storm sewer discharge capacity in the case of the diameter and roughness change separately and simultaneously were derived, respectively. For new storm pipes with diameter of 100-1 500 mm, the change rate of the corresponding discharge capacity was between -19.9% and -1.8% under the condition of allowable negative deviation of pipe diameter stipulated in Concrete and Reinforced Concrete Sewer Pipes (GB/T 11836-2009). When the allowable negative deviation of pipe diameter combined with the common variation of roughness or the allowable pipe silt depth appeared, the decreasing range of the discharge capacity became larger, and the maximum value reached 40%. The results showed that the current hydraulic design method could not realize the expected function of storm sewer. Therefore, it was suggested to reduce the allowable silt depth and strengthen the maintenance and management for existing storm sewers, revise the allowable negative deviation of pipe diameter and improve the hydraulic design method for new storm sewers.
Last Update:
2021-08-01