用液化度概念评价岩土结构地震液化变形的探讨

地震液化研究的核心是变形。在很多情况下地基虽未达到完全液化,然而饱和砂土由于超静水压的上升而造成的软化,使得地基及其上部结构发生较大变形。由于工程设计人员很难预测变形大小,因此引入液化度概念来间接表征岩土结构的变形。针对目前液化程度评价方法的缺点,给出采用液化度概念的原由,对液化度的概念进行了明确的定义并给出其计算方法。接着,通过分析1995年日本阪神大地震中沉箱结构液化变形,例证液化度评价岩土结构变形的重要意义。最后,提出用液化度评价岩土结构变形的研究思路,分析不同影响因素并建立它们之间经验的函数关系,提出工程设计中可通过不同影响因素的组合来优化地基处理范围,达到经济合理的效果。

Discussion on Assessment of Earth-structure Liquefaction Deformation Based on the Concept of Degree of Liquefaction

Deformation of earth-structures is a key problem in studies of soil liquefaction due to earthquake.In many situations,relatively larger deformation of foundation and upper structures occurs before soils fully liquefy because excessive pore water pressures generated in saturated soils have softened the soil strength.However,it is difficult to predict such a deformation for practical engineers,so the concept of degree of liquefaction is introduced in this paper for assessing earth-structure deformations.Considering the disadvantages of existing methods of assessing liquefaction,the background of the concept is given,and the definition and computation methods of this concept are provided.Then,the importance of the concept is displayed by analyzing the deformation of the quay wall of caisson type in Kobe during the 1995 Great Hanshin earthquake.Finally,different influence factors are analyzed,and the relationship is produced between degree of liquefaction and earth-structure deformation.Furthermore by analyzing different influencing factors,the disposal areas subject to liquefaction destruction can be reasonably and economically optimized in engineering design.