地形因子对坡脚型地震滑坡运动参数的影响研究

STUDY OF TOPOGRAPHY FACTORS INFLUENCE ON MOTION PARAMETERS FOR SEISMIC SLOPE-TOE LANDSLIDES

坡脚型滑坡是汶川地震诱发的一种典型的滑坡灾害。基于坡脚以上滑面长度(L′)、滑坡坡度(α)、坡脚角度(β)和滑坡堆积区的坡度(γ)4个影响坡脚型滑坡运动参数的地形因素,采用正交分析、极差、方差和回归分析等方法,研究地形因素对不同体积滑坡的最大垂直运动距离(Hmax)、最大水平运动距离(Lmax)、坡脚下的水平运动距离(L)和等效摩擦系数(Hmax/Lmax)的影响特征。研究结果表明:L′对体积1×104 m3≤V<1×106 m3滑坡的Hmax和Lmax的影响最大,也是Hmax和Lmax的显著性影响因子;对滑坡的Hmax/Lmax的影响最大,而和是滑坡的Hmax/Lmax的显著性影响因子;对体积V≥1×106 m3滑坡的Lmax和L影响最大,也是体积V≥1×105 m3滑坡的L显著性影响因子。在最大运动参数因子组合上,体积1×104 m3≤V<1×106 m3的坡脚型滑坡地形因子的作用较为一致,而对体积V≥1×106 m3滑坡的作用具有较大的差异性。研究结果为地形因子对坡脚型滑坡运动参数的影响特征和显著性作用提供依据,对坡脚型滑坡的防灾减灾具有实际意义。

Slope-toe landslide is a typical disaster induced by the Wenchuan earthquake. The influential factors of topography,including length of sliding surface above slope toe（L′）,landslide gradient（α）,angle of slope toe（β） and gradient of landslide accumulation（γ） were considered. The maximum vertical motion distance（Hmax）,maximum horizontal motion distance（Lmax）,horizontal motion distance under the slope toe（L） and equivalent fraction coefficient（Hmax/Lmax） were studied by the orthogonal,range,variance and regression analysis. The L′ is the most important and significant influence factor on Hmax and Lmax which the landslide volume is from 1×10^4 m^3 to 1×10^6m^3. Among the influence factors on Hmax/Lmax,the is the most important one and the and are the significant influence factors. The is the most important factor on Lmax and L of landslides with the volume more than 1×10^6m^3 and significant influence factor on L of landslides with volumes more than 1×10^5 m^3. The landslide volumes from 1×10^4 m^3 to 1×10^6 m^3,the topography factors play more consistent role on the factor combinations of the landslide maximum motion parameters,and it is different on the landslides with the volumes more than 1×10^6 m^3. These results could provide references for determining the influence and significant of topography factors on the motion parameters of slope-toe landslides,and it is a practical significance to the prevention and mitigation of slope-toe landslides.