克里金估计方法在场地液化势评估中的应用

    APPLICATION OF KRIGING ESTIMATION METHODS IN SITE LIQUEFACTION POTENTIAL ASSESSMENT

    • 摘要: 评估场地液化势是在可液化场地实施抗液化工程措施的重要前提,其主要方法是利用基于原位测试钻孔数据的经验公式,通过空间差值方法评估整个场地的液化势。地质统计学中的克里金理论是进行土体参数空间差值的一种有效手段,该理论主要包括普通克里金(OK)、简单克里金(SK)和指示克里金(IK)等。本研究以中国台湾某沿海工业园区的可液化场地为例,基于液化潜力指数(LPI)和液化概率(PL)两种液化评估指标,分别采用IKLPI、OKLPI和OKPL法评估场地液化势,并对3种方法的有效性和准确性进行对比分析,探讨克里金估计方法在场地液化势评估中的应用成效。结果表明:在1999年的集集地震水平下,3种方法估计得到的液化区划图存在一定差异,液化区划图受液化势指标和制图方法的影响,且前者的影响更大,其估计方差呈现以测点为中心,随距离增加而增大的变化趋势;结合两个测点附近观测到的液化现象,发现OKLPI和OKPL法的估计结果与现场液化程度较一致,体现了这两种方法的可靠性;通过交叉验证表明,3种方法的预测误差较小,均能较好地还原原始实测数据的变化趋势。因此,本研究推荐OKLPI法对本场地进行液化势评估。

       

      Abstract: Liquefaction assessment is an important prerequisite for implementing liquefaction mitigation measures. Kriging theory in geostatistics is an effective tool for spatial interpolation of parameters,which mainly includes ordinary Kriging(OK),simple Kriging(SK) and indicator Kriging(IK). A liquefiable site in a coastal industrial park in Taiwan,China was adopted as a case study. The liquefaction potential index(LPI)as well as liquefaction probability(PL)were used to describe the degree of liquefaction. The effectiveness of three Kriging estimation methods,IKLPI,OKLPI and OKPL methods,on the liquefaction assessment were explored. The results show that under the 1999 Chi-Chi earthquake,the liquefaction maps of estimated mean value by the three methods are different. The liquefaction maps are affected by the evaluation index as well as the mapping method,and the former factor has a greater impact. It is found from the liquefaction maps of estimated variance that the variance increases consistently with the increase of distance to the test data. By comparing the results of three evaluation methods with the liquefaction observations,the OKLPI and OKPL methods are consistent with the field observations,indicating a reliable evaluation. The cross validation results show that the prediction errors of the three methods are small,and they can well reflect the variation trend of the test data. Overall, the OKLPI method is recommended to evaluate the liquefaction potential of the site.

       

    /

    返回文章
    返回