Analytical solution and centrifugal test for the optimization of retaining wall insertion depth in narrow foundation pits
LIU Yangbin1，XIA Caichu1，XU Chen1，CHEN Xiaoxiang2
(1. Department of Geotechnical Engineering，Tongji University，Shanghai 200092，China；
2. PowerChina Fujian Electric Engineering Co.，Ltd.，Fuzhou，Fujian 350003，China)
Abstract：Compared with the wide foundation pit，the stability of the retaining wall of the narrow foundation pit is greatly improved due to its small excavation width. For narrow excavation engineering with a longitudinal length of several kilometers，optimization of the insertion depth of the retaining structure maybe bring significant economic benefits. Based on the narrow excavation of a cable tunnel in a city of Fujian province，the optimization of the insertion depth of the narrow excavation retaining structure was studied. The force and deformation characteristics of the retaining wall with different excavation widths were compared analytically. It is shown that with decreasing the excavation width，the horizontal additional load acting on the retaining wall，the internal force and deformation of the wall are greatly reduced. A new method for calculating the safety factor of anti-uplift stability of narrow excavation pits was put forward to improve the method proposed in the current specifications. The calculation results indicate that the safety factor obtained by the improved method is larger than that calculated by the current specification and that the insertion depth of the retaining wall calculated by the improved method can be reduced by 25%. For verification，centrifugal model tests were carried out. The test results show that，for narrow excavation pits，the calculation method of the critical insertion depth of the retaining structure provided by the code is indeed too conservative. Therefore，it is necessary to optimize the insertion depth of the retaining structure when designing a narrow excavation pit. The research can provide a theoretical basis for the optimal design of the retaining wall insertion depth of the narrow excavation pits.
刘炀镔1，夏才初1，徐 晨1，陈孝湘2. 窄基坑围护墙插入深度优化解析及离心试验研究[J]. 岩石力学与工程学报, 2020, 39(3): 593-607.
LIU Yangbin1，XIA Caichu1，XU Chen1，CHEN Xiaoxiang2. Analytical solution and centrifugal test for the optimization of retaining wall insertion depth in narrow foundation pits. , 2020, 39(3): 593-607.
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2020, Vol. 39 
