Reliability assessment for serviceability limit states of stiffened deep cement mixing column-supported embankments

The reliability and deterministic analyses of wood-cored stiffened deep cement mixing and deep cement
mixing column-supported embankments (referred to as WSCSE and DCSE, respectively) considering
serviceability limit state requirements are presented in this paper. Random field theory was used to
simulate the spatial variability of soilcement mixing (SCM) material in which the adaptive Kriging
Monte Carlo simulation was adopted to estimate the failure probability of a columnsupported
embankment (CSE) system. A new method for stochastically generating random values of unconfined
compressive strength (qu) and the ratio (Ru) between the undrained elastic modulus and qu of SCM
material based on statistical correlation data is proposed. Reliability performance of CSEs concerning
changes in the mean (m), coefficient of variation (CoV), and vertical spatial correlation length (qv) of qu
and Ru are presented and discussed. The obtained results indicate that WSCSE can provide a significantly
higher reliability level and can tolerate more SCM material spatial variability than DCSE. Some performance
of DCSE and WSCSE, which can be considered satisfactory in a deterministic framework, cannot
guarantee an acceptable reliability level from a probabilistic viewpoint. This highlights the importance
and necessity of employing reliability analyses for the design of CSEs. Moreover, consideration of only m
and CoV of qu seems to be sufficient for reliability analysis of WSCSE while for DCSE, uncertainties
regarding the Ru (i.e. both m and CoV) and qv of qu cannot be ignored.