GIS环境下大区域工程场地地震液化势的二维概率评价方法

Probabilistic Estimation of Seismic Liquefaction Potential for Large Region Site Based on Two-Dimensional GIS Technique

用具有概率意义的饱和砂土抗液化强度经验公式来对大区域场地进行地震液化势二维概率评价;在GIS软件ArcGIS的支持下,将取样钻孔处的液化势评价结果等价于数字高程模型(Digital Elevation Model,DEM)中的高程,利用ArcGIS空间分析模块中的Kriging插值法估计大区域场地的地震液化范围。研究表明:将Kriging法应用于岩土工程地质特征的统计推断,有助于揭示勘探孔以外的地层信息,对于大区域场地地震液化范围的判别是一个较好的手段;利用ArcGIS空间分析模块中的Kriging法,通过已勘察点的信息(液化势)来估计未勘测点的土层液化势,能够较好地区划出场地地震液化势的空间分布特征。

The empirical equation of cyclic resistance ratio CRR of saturated sands with different probability level is utilized to evaluate the earthquake-induced sand liquefaction for 2D large region site.By GIS technique,the evaluation values of seismic liquefaction potential at the observation boreholes can be adopted as the elevation in digital elevation model and then the identification of liquefaction locality for 2D large region site can also be estimated based on Kriging interpolation method.The research shows that： The Kriging interpolation is an effective method to estimate the latent distribution of the site liquefaction potential beyond the observation boreholes.So it is a preferable way to evaluate the possible liquefaction range for 2D large site.Based on ArcGIS software,the Kriging method embedded in the ＂Spatial Analysis＂ extension module can be utilized to evaluate the liquefaction potential of the unidentified points by the evaluated liquefaction potential results of the reconnaissance boreholes.Thus the 2D distribution map of the latent liquefaction potential for the large region site can be generated.