Control Effectiveness of Check Dams in Debris Flow Gully --A Case of Huashiban Gully in Earthquake Worst-Stricken Area, Beichuan County
详细信息
- 责任者：Zhou Haibo(Institute of Mountain Hazards and Environment ; Chinese Academy of Sciences ; Key Lab. of Mountain Hazards and Surface Process ; CAS ; Chengdu 610041 ; China) ; Chen Ningsheng
- 刊名：Journal of Mountain Research
- 出版年：2012
- 卷期：30(3)
- 页码：p.347-354
- issnNo：ISSN1008-2786
- isbnNo：CN51-1516/P
摘要
Check dam is one of the most effective structures to control debris flows. In Huashiban gully,control measures includes civil engineering works and biological works,where there are 13 check dams which make up cas- cade check dams, mainly distributing in the debris flow form-circulate region. The type of gravity dams are concrete structure, with both axial ends embedded in the bedrock for about 0.5 - 1 m. Based on the comparison of the differ- ences on gradient of the ditch, stability of the slope on both sides and erosion rate of debris flow between pre and post construction of the check dams, this paper shows the application of check dams on blocking and storing loss sol- id mass, stabilizing the ditch bed and bank slope, decreasing gradient of the gully, lowering debris flow velocity and its kinetic energy, and uplifting the base level of debris flow erosion in upstream. According to our research, check dams in Huashiban gully block solid mass 2.76 ×10^4m^3, only 0.50% of the total material source （575.1×10^4m^3） ,and 3.3% of the short-term activity soil source（85 ×10^4m^3） ,which indicate blocking is not the main func- tion. Check dams stabilize the bed 4.37 ×10^4m^3, accounting for 0.76% of the total material source, and 5.2% of the short-term activity content of debris flow. On the other hand,Check dams stabilize the slope 134.07×10^4m^3, accounting for 23.3% of the total material source,leading to the decreasing of debris flow source. Gradient of the deposition area has declined to 60% - 75%. For debris flows at the same frequency, the velocity,peak flux and erosion rate goes down, sediment transportation reduces by 35% -57%, and erosion base level in the upper ditch was uplifted by 0.3 - 0.5 m. On the whole, debris flows are translating from viscous flows to turbulent flows, and then high sand content flows.