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| Protection effect analysis of isolated piles for deep foundation pit on existing tunnel outside the pit |
| XU Changjie1, ZHU Huailong1, LONG Libo2, JIANG Yalong1, HU Qi3
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Protection effect analysis of isolated piles for deep foundation pit onexisting tunnel outside the pitXU Changjie1, ZHU Huailong1, LONG Libo2, JIANG Yalong1, HU Qi3(1. Jiangxi key laboratory of infrastructure safety control in geotechnical engineering, East China Jiaotong University, Nanchang 330013, Jiangxi, China;
2. Shanghai Jiangong Second Constrution Group Co., Ltd, Shanghai 200080, China;
3. Hangzhou Dongtong Geotechnical Technology Co., Ltd, Hangzhou 310020, Zhejiang, China |
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Abstract The isolated pile technique was adopted in a practical foundation project in Nanchang. Based on this project, numerical modeling simulations built with ABAQUS were combined with the observed data to study the protection effect of isolated piles on adjacent subway tunnel when the foundation pit was proceeded. The influences of horizontal location as well as buried depth of the isolated piles on internal stress and diameter variation of lining in existing tunnel during excavation were studied, based on the analysis on several sets of numerical models. A significant influence of the horizontal location on internal stress of the lining has been observed, a shorten gap of the isolated piles to the tunnel implied an improved protection effect. In addition, the deformation of the lining could be greatly suppressed by setting the isolated piles and more prominent effect on horizontal deformation compared with that on vertical direction. A further analysis indicated that the buried isolated piles performed better than the exposed ones. In general, the buried isolated piles with shortened pile length could be used in practical engineering to reduce the project cost.
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Received: 15 December 2018
Published: 22 February 2019
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