关键词: 近接工程, 有限土体, 土压力, 模型试验, 现场测试

Abstract: The distribution pattern of earth pressure in confined soil masses adjacent to newly excavated foundation pits near underground structures is a critical aspect of controlling the construction of retaining structures. Focusing on the three common failure modes of confined soil masses, this study qualitatively analyzes the influence of existing underground structures on the distribution of active earth pressure in confined soil masses based on the thin-layer element theory. Through a combination of model testing and field measurements, the rationality of the proposed earth pressure distribution pattern in confined soil masses is verified. The results indicate that: (1) the active earth pressure distribution in a newly excavated foundation pit adjacent to an existing underground structure and beneath semi-infinite soil masses takes on a nonlinear drum shape, with smaller values at the ends and a larger value in the middle. (2) The magnitude of increase in active earth pressure varies in the confined soil mass adjacent to the side walls of the existing underground structure, with transition points occurring at the top and bottom of the structure. (3) When the slip surface intersects the existing underground structure at its base, the distribution of soil pressure takes on a nonlinear B shape, with a sharp decrease in soil pressure at the base of the existing underground structure. (4) The earth pressure in confined soil masses increases with an increase in the area of the confined soil mass (greater depth of burial or closer proximity to the adjacent structure). The findings of this study offer new insights and qualitative analysis methods for exploring the distribution of active earth pressure in foundation pits adjacent to underground structures.

Key words: proximity engineering, confined soil mass, soil pressure, model test, on-site testing