摘要
2008年,在"5.12"汶川地震后,随着降雨的发生,地震重灾区的中高山区较普遍地多次发生了泥石流灾害,尤其是对一些地震灾民安置点板房区造成了危害,累计造成人员伤亡(含失踪)达450余人,进一步加重了灾情。按照地震与泥石流暴发的时间顺序分类,区内的泥石流属后发型地震泥石流。其特征主要为:泥石流活动频率增高,暴发点多,规模大小不一,流体性质一般以粘性为主,密度值多在2.0～2.3 t/m3之间;泥石流的活动范围与降雨关系密切,活动范围还受地形因素控制,主要集中在龙门山等中高山区;泥石流危害形式有冲毁、淤埋、堵塞主河等多种形式。因此,在汶川地震重灾区这样的区域选址恢复重建,实质上是在工程地质条件复杂的不稳定区内选择相对稳定的安全岛,可供选择的场地极为有限。故恢复重建居民点时应因地制宜,尤其是岷江等江河峡谷区等地的居民点重建,宜保持当地居民传统的分散、多点居住的特点,而不宜于搞成规模较大的集中成片的居民点。这样既有助于场址的安全,又可以避免大规模泥石流、滑坡、崩塌、山洪等山地灾害发生时造成大量的人员伤亡。地震重灾区2008年的泥石流活动显示,龙门山及邻近的邛崃山等山区因汶川地震的影响,泥石流已进入强烈活动时期。其强烈活动时间,可能持续10～30 a,甚至更长。对此,要有足够的重视。在可能遭遇泥石流的区域开展的各种工程建设,一定要加强防范措施,防止泥石流危害。
On May 12, 2008, Wenchuan earthquake happened. In quake-hit area, with rainfall occurred after the earthquake, in middle-high mountain areas were common to many debris flow hazards happened, especially for some of the victims of the earthquake damage caused by the site, causing casualties （ including missing） of more than 450, further aggravated disasters by debris flow. According to the earthquake and debris flow activity of time sequence, the area of the classification of earthquake debris flow after earthquake. With increased frequency of debris flow activities, scale, the outbreak point size, with sticky fluid properties of characteristics; debris flow range of activities and rainfall close range, also terrain factors control, mainly concentrated in Longmenshan Mountains where is middle and high mountain areas, etc. ; debris flow hazards are destroyed, deposition and buried and damming river a variety of forms. Therefore, the worst-hit areas such regional location area, restoration and re- construction is essentially in unstable areas relatively stable and safe choice of venue selection is limited. So the restoration and reconstruction measures, especially residential construction of Minjiang River valley, and other simi- lar regions, the settlement of local residents in reconstruction, the dispersion, more traditional characteristic of living, and not to get into a larger scale of the settlement, sliced concentration is not only beneficial to site safety loca- tion, and can avoid large-scale debris flow, landslide, collapse, mountain torrent disaster when such large casualties. Earthquake -hit area in 2008, the activity of Longmenshan Mountains and adjacent Qionglaishan Mountains ar- eas, etc, due to earthquake debris flow has entered intense activity. The strong activity time, possibly continues 10 - 30 years, even longer time. Therefore, we should have enough attention to debris flow. In may encounter in the area of debris flow construction, and must strengthen prevent debris flow hazards prevention measures.
出处
《山地学报》
CSCD
北大核心
2009年第4期501-509,共9页
Mountain Research
基金
中国科学院知识创新工程重大项目专题:干旱河谷区土壤退化过程对植被的作用及水土保持技术研究(KZCX2-XB2-02-01-01)资助~~
关键词
汶川地震重灾区
泥石流灾害
活动特征
恢复重建
场地安全
Wenchuan quake-hit area
debris flow hazards
activity characteristics
restoration and reconstruction
site safety
