研究目的:提出综合交通枢纽超深、超大、体形复杂基坑实施方案确定原则与思路,解决多级基坑围护体系和大空间支撑体系参数确定方法。
研究结论:综合交通枢纽内基坑方案确定首先要采用总体研究的思路;施工方案的选择和各项技术参数的确定应采用数值模拟和规范计算相结合的分析模式;多级式基坑支护参数的确定没有规范要求,应根据基坑卸载平台宽度(B)、深坑深度(H)之间的比例关系,以及施工方法和降水条件等综合确定;大空间支撑体系布置和支撑参数的确定应采用等效刚度概念和刚度均匀布置的原则,并应考虑环境温度变化、支撑立柱隆沉、施工荷载作用等的综合影响。
Research purposes: The principles and the thoughts on the met}lod for construction of big,deep and complex foundation pit for integrated transport hub are offered,and the methods for determining the parameters of building exterior—protected system and large—space bracing system for multi—step foundation pit aye discussed.
Research conclusions: The construction scheme of the foundation pit for integrated transport hub should be determined in accordance with the overall thoughts.The construction scheme and the relative parameters should be chosen with numerical simulation and calculations.As there is no criterion for determining the parameters for the exterior—protected construction for the multi—step foundation pit,80 the parameters for the exterior—protected for such foundation pit should be determined in accordance with the ratio of unloaded width(B)and foundation pit depth(H),the construction method and dewatering condition.For arranging the large—space bracing system and determining its parameters,the concept and principle of equivalent stiffness and even stiffness should be followed and the influence factom of the change of environment temperature,heave and settlement of the bracing column and construction loads should be considered.