基于非线性剪切梁方法的堤防液化判别分析研究

Liquefaction Evaluation and Analysis on a Levee Engineering Based on Nonlinear Shear Wedge Method

摘要:

很多河流的堤防工程修建在人口密集地区,失事后往往会造成严重后果,尤其是细粒土填筑而成的堤防,在地震作用下存在液化破坏的可能。采用合理方法对堤防进行液化判别,确定其在地震作用下的动力稳定性十分必要。针对某实际堤防工程,进行五种拟用筑堤土料动力特性试验研究,并基于试验成果,采用能够考虑地基-堤身相互作用的非线性剪切梁方法,对堤防的液化可能性进行判别。研究表明:提出的非线性剪切梁方法能够考虑地基和堤身间的相互作用,且简单实用、可操作性强;土体的相对密度、空隙比和颗粒粒径大小及其他粒分布特性对其抗地震液化能力影响较大;在设定运行工况下,Ⅷ度地震时除拟选粉质壤土外,其他四种土筑堤均有发生液化的可能,选用粉质壤土筑堤较合适。

Abstract:

Levee engineering is mostly built in densely-populated area,so the crash will always cause serious consequences especially for the levee filled by sandy soil which may develop into liquefaction under the action of earthquake.Therefore, the usage of reasonable methods of liquefaction on the levee to determine the dynamic stability under earthquake action is very necessary. This paper, in view of a practical levee engineering, conducted dynamic characteristic research on five kinds of materials to be used, basing on the research results of soil material dynamic characteristic test, and estimated liquefaction possibility of the levee by using the nonlinear shear wedge method which can consider the interaction between the levee and the foundation. Research shows that: the nonlinear shear wedge method can consider the interaction between the levee and the foundation, and is simple and practical; soil relative density, void ratio, particle size and particle distribution characteristics have a great influence on its ability to resist seismic liquefaction; in a set operation under the condition of 8 degree earthquake, only the silty loam levee will not lead to the occurrence of liquefaction, the other four materials exist the possibility of liquefaction, in conclusion, it is appropriate to select the silty loam to build the levee.