论文部分内容阅读
四川省4·20芦山7.0级地震具有震级高、破坏性强等特点,地震次生地质灾害以崩塌落石为主,滑坡不发育.与汶川5.12特大地震诱发的次生地质灾害相比,无论规模还是数量均显示较轻,但是处于地震影响区的宝兴县城却是个例外,县城周边山体因地形陡峻,表现出崩、滑灾害发育的特点.通过地震前、后对宝兴县城周边地质灾害现场地质调查显示:崩塌、滑坡和泥石流数量分别由地震前的3、1、3个(条)变为地震后的21、1、3个(条);地质灾害发育密度和模数分别由地震前的0.38个/km、0.34万m3/km变为地震后的2.02个/km、5.59万m3/km;地震后发育密度及模数分别是地震前的5.3和16.4倍;地震产生的边坡破坏效应显著.在此基础上,通过分段剖析可知:地震地质灾害主要发生在单薄山脊以及地形坡度陡峭处,岩质边坡以崩塌落石为主,松散层边坡则以滑坡为特征,但大型滑坡少见;地震对处于斜坡地带(非单薄山脊部位)大型松散堆积体等整体复活很少,只是局部陡缓交界部位存在坍滑或震动裂缝,整体稳定性较好,说明强震并不一定会诱发古滑坡等大型松散堆积体的整体复活.
The 4.40 Lushan MS 7.0 earthquake in Sichuan Province is characterized by high magnitude and strong destructiveness. The secondary geological disasters of earthquakes are mainly landslide and landslide, and the landslides are not developed.Compared with the secondary geological disasters induced by the Wenchuan 5.12 earthquake, Or the number showed a lighter, but in the earthquake-affected area of Baoxing County is an exception, because of steep terrain around the county, showing the characteristics of collapse and sliding disaster development.Before and after the earthquake on the site of geological disasters in Baoxing County Geological survey shows that the number of landslides, landslides and debris flow change from 3, 1 and 3 (strips) before the earthquake to 21, 1 and 3 after the earthquake respectively. The density and modulus of geological disasters are respectively 0.38 / km and 0.344 m3 / km, respectively, to 2.02 / km and 55900 m3 / km after the earthquake. The developmental densities and moduli after the earthquake were 5.3 and 16.4 times that before the earthquake respectively. The slope damage caused by the earthquake On the basis of this, it can be seen by the sectional analysis that the seismo-geological disasters mainly occur on the thinner ridges and the steep slope of the terrain, the rock slope is mainly the collapsing rockfall, the loose layer slope is characterized by the landslide, but the large Landslides rare; earthquake on the ground The overall revival of the large loose bulk bodies in the slope area (not only a thin ridge) is very small, but there are slump or vibration cracks in the local steep junction and the overall stability is good, indicating that strong earthquakes do not necessarily induce large loose The whole body of the resurrection.