Model tests on influences of excavation of foundation pits on bending moment and deformation of pile foundation of adjacent buildings

Model tests are carried out based on an example of the excavation of an underground foundation pit on Shangfu-Fubei Road in Tianshui City. The horizontal displacement and bending moment of the pile groups during the excavation of the foundation pit are studied. The influence laws of depth-to-width ratio of the foundation pit, buried depth of the toe of the diaphragm wall and the distance from the foundation pit on the pile foundation of adjacent buildings are investigated. The test results show that the deformation of the foundation pile is affected by the depth-to-width ratio of the foundation pit and the upper load, and the larger the depth-to-width ratio of the foundation pit, the more influences by the upper load. The influences of excavation of the foundation pit on the surrounding buildings decreases as the excavation distance increases. As the distance from the excavation surface increases, the maximum bending moment of the piles has a tendency to move upward, and the maximum value is always smaller than that of the pile closer to the foundation pit at the same depth. As the buried depth of the toe of the diaphragm wall increases, the protective effect of the diaphragm wall on the pile foundation of the buildings is strengthened. In the foundation with pile groups, the front-row piles have a good isolation effect on the back-row ones. The model tests fully consider the influences of various factors on the pile foundation of the neighboring buildings during the excavation of the foundation pit, and can provide a reference for similar projects. © 2021, Editorial Office of Chinese Journal of Geotechnical Engineering. All right reserved.