The Possibility Of Blocking River Of Typicaldebris Flowin Wenchuan Earthquake Zone

After the Wenchuan earthquake, the landslide and debris flow is very strong inthe entire earthquake zone. On14August,2010,due to heavy rainfall21debris flowaround Yingxiu Town and40debris flow around Longchi Town outbreaks.Amongthem,the Hongchun gully outbreak a hug debris flow,which blocking the Mingjiangriver and resulting the catastrophe toon.At the same time, the Shaofang gully, theYinxingping gully,the Gaojia gully and the Chediguan gully are also outbreak debrisflow blockage Mingjiang River many times. That is a serious threat to the G213National Highway and Yingxiu to Wenchuan Highway.Frequent outbreaks of thedebris flow blocked the river after the earthquake, that’s a big problem to all ofus.This paper selects five typical debris flow gully to analysis the possibility of debrisflow blocking the river,to provide a reference for the characteristics of debris flowafter the qarthquake.There are11main impact parameters of derbis flow damming the river fromother scientists’s study.Them are mudslides weight,water weight,devris flow,waterflow,convergence angle,river width,river bend radius,the time,the gradient of thedebris flow,the gradient of the river and the frequency.The debris flow and the riverwidth have been used three times.The river flow has been used two times.Otherparameters have been only used once.Combinating the selected parameters of debrisflow in the study area,wo establish the identifical table.According to the importance of the impact parameters,we select the Heyiping ‘sflow formula,,Tangchuan’ experience formula, Zhangjinshan’s experience formula toanalysis the possibility of the debris flow blocking the river.Through thecalculation,the possibility of blocking the river from big to small in the study area is Hongchun gully,Chediguan gully,Yingxingping gully,Gaojia gully and Shaofanggully.The Tangchuan’s experience formula is more applicable to the Wenchuanearthquake area.The correction factor K ranges from1to1.5,we should be the value of1.5in the study area, but the inversiong result of K is1.The calculation results of theHeyiping and Zhangjinshan’s formula are too small,we can fix reasonable by quotingthe post-earthquake influence coefficient K.We use the qualitative and quantitative analysis to anlaly the possibility ofWenjia and Shuimo debris flow blocking river.We use the qualitative analysis toanaly the main factor of the debris flow blocking the river and amendment the table ofdebris flow blocking the river in the quake zone.We use Heyiping and Tangchuan’sformula to calculate the possibility.