For braced excavations in deep deposits of soft clays or residual soils, the ground surface settlement behind the excavation is closely associated with the extent of basal heave as well as the wall deflections and is also greatly influenced by the groundwater drawdown behind the retaining wall. This paper presented a reliability analysis based on a recently developed simplified Logarithm Regression model for the maximum ground surface settlement estimation. The first-order reliability method (FORM) implemented with a variance reduction technique that considers the spatial variability of soil properties is employed to investigate the probability that certain threshold ground surface settlement is exceeded. Some useful conclusions regarding the effects of spatial averaging, and the influence of several key design parameters such as the wall system stiffness, the magnitude of the threshold ground surface settlement, the coefficient of variation of the soil properties, as well as the magnitude of groundwater drawdown are presented.