浙江遂昌苏村滑坡基本特征与成因机理分析

Sucun Landslide in Suichang County of Zejiang Province: Characteristices and Failure Mechanism

2016年9月28日17:28,浙江省遂昌县苏村发生一处中型岩质滑坡,约40万m3的岩土体从华上尖冲向桃源溪沟谷,摧毁了苏村部分居民住宅并形成长约523 m,宽约536 m的堰塞体,最大堆积厚度达到20 m,造成重大损失。该文以工程地质分析为基础,结合详细地质调查、三维扫描、遥感解译、室内试验等手段,分析了苏村滑坡的基本特征,并提出滑坡发生成因及机理的初步认识。结果表明:强降雨在I区促发碎裂基岩崩塌,在后缘形成长426 m、宽190 m的崩滑堆积体,滑动距离48 m,在锁固段两侧挤出第一次加速;中部坡度大于60°的顺层基岩在I区滑体冲击下,沿153 m的滑道加速推进,形成滑坡的第2次加速;滑坡中前缘平缓地带古滑体在上部滑体的冲击下,复活面积达3 553 m^2,滑距超过800 m,破坏性强;苏村滑坡发生大规模挤出楔裂型岩质滑坡,促发古滑坡复活形成堰塞湖,这对类似地质条件区域滑坡的判定及防治具有重要意义。

At 17： 28 of September 28,2015,a medium-sized landslide triggered by the heavy rainfall in Sucun,Suichang county of Zhejiang Province,causing heavy casualties and property loss. The volume of the instability rocks is about 4. 0 × 105 m3 and it runs form the Huashang ridge to the Taoyuanxi valleys. The mudstone barrier dam is 523 m long,536 m wide and the largest thickness of deposit is 15 m. On the basis of geologic analysis,combined with the detailed geologic investigation,3d scanning,remote sensing,laboratory test and other means,the basic features and mechanism of formation of Sucun landslide has analyzed in this paper,and put forward causes and mechanism of landslide by preliminary understanding. The results show that： There are two accelerations at Sucun landslide from the time. The heavy rainfall in the area I had contributed to cataclastic rock collapse,then accumulation near trailing fault of landslide. The deposit of collapse is 426 m and 190 m wide,it＇s sliding distance 48 m,for the first time of extrusion speed in beam mouth. Such deposits sailed down the middle bedding rock body slope which is 60 degrees and 153 m long,the speed accelerates quickly,this is the second slide speed; The ancient sliding body in the front flat has impact of the upper sliding body,resurrection area about 3533m^2,slide distance more than 800 m and destructive stronger. The Sucun landslide begins to mass extrusion wedge fracture rock slope,and it has promote the ancient landslide revivification and block up river channel to form barrier lake,which is of great significance that is the research about other similar geological condition of landslides and prevention.