Abstract: Underground structures frequently suffer from anti-floating failures that induce structural damage， subsequently triggering leakage and even structural collapse. This study addresses the structural damage caused by basement slab water pressure and foundation differential uplift. A three-dimensional finite element model incorporating raft slabs， column piers， and walls was established. Comparative analyses were conducted focusing on two typical working conditions： uniform water pressure and local differential uplift. The stress distribution patterns in raft slabs， evolutionary characteristics of structural displacement fields， and damage initiation and propagation paths were systematically investigated. The results demonstrated that under hydrostatic pressure， stress concentration effects occurred at the interface between raft slab bottoms and column piers， forming through-thickness damage zones that significantly compromised waterproofing performance. In local differential uplift scenarios， damage primarily propagated along the bottom edges of column piers at the boundaries between uplifted and non-uplifted zones. Comparative analysis revealed that global uplift exhibited more uniform stress distribution characteristics than local uplift. This study identified critical weak points in waterproofing systems， including column pier connection interfaces， raft slab edge regions， and wall roots. Enhancement measures were proposed， including arranging additional reinforcement layers， installing flexible waterstops， and optimizing structural stiffness distribution to improve anti-floating and waterproofing performance.