摘要
该文采用规范法进行液化地基的液化指数计算及液化等级判定,并考虑机场进行大面积填挖方引起地势设计标高变化的工况,对规范公式进行修正并计算,讨论了基于标贯试验的液化指数计算的起算标高。通过对采用标贯击数计算液化指数标贯临界值以及液化指数的公式进行深度修正,求取其与填挖方深度的函数关系,并引用北京某机场液化地基标贯实测数据进行验证对比,结论为该修正方式与增加上覆非液化土层厚度可减小液化指数及等级的震后调查结论矛盾,应采用天然地面标高进行计算。液化地基处理措施及深度的控制采用规范初步判别标准,上覆非液化土层厚度考虑了填挖方引起的增减。对液化地基处理方式及深度不做要求,仅对处理后的效果采用标贯试验进行验证,并采用初步判别标准作为处理效果的评价标准。
The specification method was adopted in this thesis, to calculate the liquefaction index and liquefaction grade of liquefaction foundation. Considering design elevation of topography changes caused by large area filling and excavation in airport terrain, specification formula was modified and put into use, furthermore, exploring the original data about the calculation of liquefaction index based on standard pen- etration test（SPT）. The critical point of liquefaction index was estimated by SPT blow count, and depth modification was taken in the formula of liquefaction index, in order to find the function relationship be- tween the liquefaction index and the depth of the filling and digging. The measured data about liquefied foundation SPT in an airport of Beijing was validated in round robin comparison. It was found that the modification method was different from some post-earthquake statistics that the adding overlaying none-liq- uefied soil thickness may decrease liquefaction index and grade. The conclusion was, the natural ground level should be chosen as basic data. Treatment measures and depth of liquefaction foundation should use preliminary discriminant standards of specification method, and the changes from filling and digging should also be considered in overlaying none-liquefied soil thickness. There＇s no regulation on treatment measures and the depth standard of liquefied foundation, but to use SPT to verify the result and apply a preliminary discrimination standards as an evaluation standard of treatment effect.
出处
《勘察科学技术》
2014年第5期29-33,共5页
Site Investigation Science and Technology
关键词
规范法
液化
等级判别
地基处理
specification method
liquefaction
grade discrimination
foundation treatment
