中文摘要：

以三峡库区兴山县二里半滑坡为例，分析了抗滑桩截面尺寸与抗滑桩各内力之间的关系，论述了截面尺寸与混凝土及锁口护壁费用、钢筋费用及单抗滑桩工程总费用之间的相互关系，提出了最优截面尺寸的概念。在此基础上考虑抗滑桩的结构要求，提出了确定合理的截面尺寸的方法：若最优截面宽度满足构造要求，则选取该截面作为设计截面；否则选取构造宽度下使工程造价最小的高度作为设计截面高度。

英文摘要：

The slope control design is usually concerned with three main parameters, interval, cross section dimension and anchoring length. At present, the pile interval has been discussed much, but seldom for the section dimension. As the pile section dimension affects the engineering safety and cost, it is necessary to find the optimum design method. Taking Erliban landslide in Xingshan County of the Three Gorges Reservoir Area as an example, the paper first introduces the conception of the optimum pile section dimension based on the analysis of the relationship between section dimension and the internal force as well as the relationships between section dimension and the expense of concrete, fore shaft and dado, steel bar and the total expense of a single pile. Then it suggests the reasonable method to determine the pile section dimension according to the pile structure requirement. When the optimum section dimension satisfies the pile structure requirement, it will be the design section; other wise, the dimension with the minimum cost will be the one. This result will be meaningful for landslide improvement.