Research On The Developing Characteristics And Counter Measurement Of The Debris Flow In Che Diguan Gully Along The State Road Of G213

Debris flow which usually break out abruptly, is a geological hazard with a high danger, Because of the more frequent occurrence of the debris flow After the Wenchuan earthquake, this kind of geological hazard was back in a active era. Its formation condition of the debris flow in the research area is somehow different from the pre-earthquake’s, so our research needs more than the knowledge on debris flow before the earthquake. Therefore investigate the debris flow gullys in earthquake area and analyze their developing mechanism is of great importance on the research and hazard prevention of the debris flow. The debris flow in Che Diguan gully-a large typical gully in Wenchuan earthquake area-which locates in Yinxing, village, Wenchuan county, has a series of characteristics:a big watershed, a steep inclination, influenced by earthquake severely, rich supply of loose material and water resource and endangers a lot, etc. Through the field investigation of the debris flow in Che Diguan gully, its main features have been revealed:1. A degree of high risk. The Che Diguan Bridge on the highway of G213, Futang Tunnel under construction along the Duwen freeway, Minjiang River and the Hydropower station of Tai Pingyi upstream are all under great threat of the debris flow.2. A steep inclination of the gully & Easy activation of the loose material. The basin shape of the Che Diguan gully is like a tree leaf, while the dispersion is 2381.5m with a inclination of 302%o. The inclination from the upward of the Fei Shuiyan gully is steep while the downward is relatively gentle overall, which has a characteristic of alteration from steep-to-gentle in spatial. The gully is relatively straight in two dimensions, the width of the gully is narrow upstream while wide downstream with a characteristic of alteration from narrow-to-wide.3.64 points of loose material have been statisticsed by filed investigation, there are slope erosion provenance, collapse provenance and accumulation deposits in the gully. The static reserves of loose material are 7.43×106m3 and the dynamic reserves of loose material are 1.95×106m3. The loose materials increased substantially after the earthquake, and the risk of debris flow also increased greatly.4. According to the gully conditions and distribution feature of solid resource of the debris flow in Che Diguan gully, we use the comprehensive management project of "interception" supplemented by "protection, Drainage, sparse", that is fix the slope and the loose material(Foot Wall) in the middle+block and fix the loose material downstream+ diversion at the bridge site.5. In the early 2013, the management work in the debris flow gully has been completed. On July 10th in the same year, heavy rainfall occurs, large scale of debris flow broke out in Che Diguan gully, yet the counter measures played a very important role on disaster prevention, and protected the safety of Futang Tunnel and got the G213 section of the State Road rid of burial.