“半逆作法”施工的深基坑工程的设计应用探讨

Design and application of deep foundation pits by use of semi-reverse construction method

基坑工程施工过程存在不确定性,有时因工期需要,在工程实施一定阶段后,施工方法会存在由顺作法施工向逆作法或半逆作法形式的转变,特别是在部分围护体系已经施工完毕后,这就对基坑围护的设计方提出了更高的要求。结合苏州地区一深基坑工程实例,对施工顺序由"顺作法"改为"半逆作法"时围护设计中遇到的问题进行了探讨,并进行了计算分析。根据该工程现场施工状况及监测结果,在围护设计方案及施工方法进行了合理调整后,通过合理的施工组织安排,一方面将基坑施工对周边环境的影响均控制在了安全范围内,另一方面,也有效缩短了施工工期。此经验可为今后类似工程的实施提供一定的借鉴作用。

Uncertainties usually occur during the construction period of foundation pits.Sometimes for the need of construction period,after the project is implemented,the construction method will be transferred from the forward to reverse or semi-reverse method,especially after part of enclosure system has been completed.Then higher demands are proposed on the method for the enclosure design.Based on a deep excavation in Suzhou,the problem in enclosure design with the construction sequence being changed from the forward to semi-reverse construction method is discussed.The numerical analysis is also provided.Based on the site construction conditions and the measured results,with the reasonable enclosure design and construction method and the rational construction organization,the impact on the surrounding environment is controlled on safety range.The construction period is shortened.The experience can be used in the similar projects in the future.