中文摘要：

坑中坑型深基坑工程日益普遍,但由于临近基坑挡土墙边的坑中局部深坑对大基坑的变形和稳定性产生影响,现今在坑中坑工程设计中选取大基坑计算深度时依然面临难题：若取外坑坑底是冒险,而取内坑的坑底又偏于保守。针对有支撑挡墙的坑中坑型深基坑的外坑围护墙体的设计,在考虑各种不同情况下的内坑与外坑相对位置、内坑开挖宽度和内坑开挖深度的基础上,提出了等效深度的概念和等效深度系数、等效影响角的参数,并论证了这种等效的可行性。同时,由于等效深度的确定将外坑围护墙体的设计问题等效为常规的基坑围护墙体设计,对坑中坑型深基坑工程外坑围护墙体设计、施工具有实际参考价值。

英文摘要：

Pit-in-pit excavation is becoming more and more popular,and concerns are increasing on the influence exerted by the interior pit.However,the calculating depth in design remains a puzzle,taking the exterior pit excavation depth is a risk,while the interior is conservative.This paper raises a concept of equivalent depth and two parameters called equivalent depth coefficient and equivalent impact angle based on analysis of various relative position of interior and exterior pit,width and depth of the former,whose feasibility is proved.The equivalent depth converts the pit-in-pit into normal excavation model,and the equivalent depth factor quantifies this kind of conversion.