For braced excavations in deep deposits of soft clays or residual soils, the ground surface settlement behind the excavation is correlated with the extent of basal heave as well as the wall deflections and is also affected by the magnitude of the groundwater drawdown behind the retaining system. Reliability analysis based on a recently developed simplified logarithm regression model for estimation of the maximum ground surface settlement is presented. The first-order reliability method implemented with a variance reduction technique while considering soil spatial variability is employed to investigate the probability that certain ground surface settlement threshold is exceeded. This paper presents the effects of spatial averaging and the influence of several key design parameters including the stiffness of the wall system, the magnitude of the threshold ground surface settlement, the coefficient of variation of the soil properties, and the magnitude of the groundwater drawdown on the ground surface settlement. It is concluded that soil spatial variability results in a higher probability of failure (i.e., a lower reliability index), without considering it would result in an unreliable design. A larger characteristic length results in a lower probability of failure and a higher reliability index. When the spatial variability of both the c_u/σ'_v and E₅₀/c_u are considered, the influence on β is more significant.