Lateral mechanical behavior of composite ground due to adjacent excavation: centrifuge model test
Li Lianxiang1,2 Fu Qinghong1,2
1. Foundation Pit and Deep Foundation Engineering Research Center, Shandong University, Jinan 250061, China
2. School of Civil Engineering, Shandong University, Jinan 250061, China
Abstract： For deformations and internal forces of CFG piles in composite ground due to excavation of adjacent foundation pit, it is difficult to deal with such problems based on existing theories. A centrifuge model test has been carried out to study the change law of deformations and internal forces. Research results show that adjacent excavations may result in the increase of bending moment of CFG piles| the closer the CFG pile is to the foundation pit, the greater the increase of bending moment is. The excavation may also lead to ground surface settlement, but the settlements of soil and piles may not be synchronous. The CFG piles may penetrate upwards into the cushion layer, which provides the embedding and tie roles for the piles. The piles far from the foundation pit provide anchorage effect for those piles near the foundation pit through the friction between the loading gasbag and the cushion. The combined effects lead to the negative bending moment in those piles near the foundation pit. However, negative bending moments in the piles far from the foundation pit shall be small because in these locations, the differential settlement is generally small and the penetration phenomenon is not obvious. Earth pressure zone behind retaining wall can be divided into the decrease part and increase part. For the upper part, the earth pressure may decrease due to the unloading of soil, while for the lower part, the earth pressure may increase due to compression of retaining wall. The ground surface settlement caused by excavations has the form of exponential function, which is often called Peck’s curve. In the region with significant deformation, the horizontal displacement of retaining wall is basically linear, and the maximum value of displacement generally appears at the top of retaining wall in different stages. The magnitude and range of horizontal deformation of CFG pile due to excavation may decrease with the increase of its distance to the foundation pit.
李连祥 符庆宏. 临近基坑开挖复合地基侧向力学性状离心试验研究[J]. 土木工程学报, 2017, 50(6): 85-94.
Li Lianxiang Fu Qinghong. Lateral mechanical behavior of composite ground due to adjacent excavation: centrifuge model test. 土木工程学报, 2017, 50(6): 85-94.
