扎囊大桥桥址地区砂土液化问题研究

Study on Sand Liquefaction in the Site of Zhanang Bridge

以西藏扎囊大桥工程为例，在通过勘察、测试等手段掌握大量数据的基础上，对在建西藏山南地区雅鲁藏布江扎囊大桥桥址地区的砂土液化问题进行了研究。其结果表明：桥址区地基土的上、中部是饱和砂土层，其液化指数高达37．62～110．77，均远大于18，液化等级判定为严重；勘察探明，地基土下部为中密圆砾，承载力高，可作桥基基础持力层。

Taking the Zhanang Bridge Project in Tibet as an example, data obtained by way of survey and test, studied the sand liquefaction this paper, based on large amount of in the site of Zhanang Bridge on the Yarlung Zangbo River in the south mountainous area in Tibet. The result shows that the upper and middle part of the foundation soil in the site is saturated sand layer, with the liquefaction index up to 37.62- 110. 77 and far more than 18, thus the grade of liquefaction is judged as serious; and by surveys, the lower part of the founda- tion soil is proved to be medium-density cobble with high bearing capacity and may be used as the bearing layer for the bridge foundation.