THE 6TH AUGUST 2009 FIELD URGENT INVESTIGATION ON THE GEOHAZARD OF THE ROCK FALL DAMMINGIN HOUZIYAN, SHUNHE, HANYUAN, SICHUAN

A large rock fall in Houziyan, Shunhe, Hanyuan happened on 23:30 pm, August 6, 2009, completely damming Daduhe River for 4.5 hours, forming a ten kilometer long dammed reservoir and inundating road S306. Sichuan Bureau of land and mineral resources invited expert group headed by Prof. Huang Runqiu to have a field investigation on August 7. Based on the analysis of the topography, texture of the slope and induced factors and with help of Laser scanning, the expert group provided a scheme for removing risk rockmass step by step, No. A rock block about 10000 m3 was successfully removed by exploding at 19: 10 of August 8, which provide a base for new S306 and recovery of the old S306.