Influences of Deep Foundation Pit Excavation on the Stability of Adjacent Ancient Buildings

The excavation of deep foundation pits has a significant impact on the stability of adjacent buildings. On the basis of a deep foundation pit project in Xi'an, China, the deformation of a diaphragm wall and the settlement and deformation of an adjacent ancient building with and without MJS (Metro Jet System) pile reinforcement were studied through onsite monitoring and numerical simulation. The influence of the building's settlement difference on the shear strain of the building's walls was analyzed, and then the effect of MJS pile reinforcement was verified. The research results show that (1) the settlement difference serves as the primary cause of the shear strain of the building, and the shear strain rises with increasing settlement difference; (2) the maximum shear strain of the building occurs on both sides of the building's doors and windows and on the left and right corners of the building's walls; (3) the shear strain and settlement of the building without MJS pile reinforcement are significantly greater than those with MJS pile reinforcement; and (4) MJS pile support exhibits a better reinforcement effect within one times the excavation depth of the foundation pit. These research results have a certain guiding significance for enhancing the stability of foundation pits and ensuring the safety of adjacent buildings.