中心岛法实用设计计算方法研究

在城市建设中越来越多的大面积深基坑采用中心岛顺作、周边预留土台逆作的开挖支护方式。该法不仅节约工程造价，而且节省大量工期，但目前仍缺乏简单、合理的设计计算方法。基于Rankine土压力理论，采用图解法得到中心岛被动土压力的分布模式，该土压力分布在单一土质条件下随埋深呈现为3段折线。根据上述土压力分布和基坑工程手册[1]有关悬臂结构的设计思路，提出中心岛法围护结构的设计计算方法，并提供一个算例。经算例验证该法简单实用，便于工程师使用。

Study of practical design and calculation method for central island method

For the urban construction, the method of “Central island by bottom-up and peripheral part by top-down” has been used more and more in large deep excavation of foundation pit. In the help of this method, construction cost and project time can be saved a lot. However, there is a lack of simple and reasonable calculation method for it. Central island distribution pattern of passive earth pressure are put forward in this article which is based on and Rankine's earth pressure theory. In the condition of single soil, the pattern was described in 3 polygonal lines with the corresponding depth. The practical method for central island method of retaining structures is proposed according to the above-mentioned distribution pattern and the design method of cantilever structure from excavation engineering handbook, and a case was given. It is proved by the example that the method was simple and practical, and convenient for using to the engineer.