Abstract: 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.

Key words: excavation of foundation pit, central island method, mound width remained, earth pressure distribution, design method