汶川地震区特大泥石流工程防治新技术探索

汶川地震在龙门山地区激发了大量的崩塌、滑坡,为泥石流的形成提供了丰富的松散固体物源,震后4年里泥石流非常活跃,暴发了数次特大规模泥石流.初步分析了2个典型泥石流防治工程失败的原因,发现对防治工程本身而言,主要因素在于目前大量采用的浆砌石结构抗冲击破坏能力弱.为了抵御特大泥石流的冲击破坏,初步提出了钢筋混凝土框架+浆砌石坝体式泥石流拦砂坝、预制钢筋混凝土箱体组装式拦砂坝的新型泥石流拦挡结构,以及复式断面泥石流排导槽、预制钢筋混凝土箱体组装式排导槽的新型泥石流排导结构,这些新结构可望在不大幅度增加工程投资的情况下,提高泥石流防治工程抗冲击破坏能力,缩短工程建设周期,保护流域生态环境,充分利用沟内现存材料.这些方法及其组合可望对特大泥石流进行有效的调控.

New Control Methods for Large Debris Flows in Wenchuan Earthquake Area

The Wenchuan earthquake induced a great mass of collapse and landslide in the Longmen mountain area, which provided abundant loose mass for the occurrence of debris flows. Thus several extra-large scale debris flows were broke in recent four years following the Wenchuan earthquake. Through analyzing the failure reasons of two typical debris flow prevention engineering, the main reason is related to that the stone masonry structure, which has been widely applied currently, has weak availability of resistance from debris flow. In order to resist the damaging of extra-large scale debris flows, we proposed new engineering structures for preventing debris flow, i.e. combination of check dam and drainage canal. The details of these new structures are as follows: check dam with the type of reinforced concrete frame + stone masonry dam body and prefabricated reinforced concrete cube boxes, drainage canal with the type of compound section and prefabricated reinforced concrete cube boxes. These new structures can improve the resistant abilities of check dams, decrease construction cycle, protect eco-environment of drainage area and make full use of existing materials in the gully without increasing investment. This new technology proposed in the present study can effectively control the extra-large scale debris flow in the Longmen mountain area.