A three-dimensional algorithm for estimating water-tightness of cement-treated ground with geometric imperfections

Jet-grouted cut-off walls (JGCOWs) and jet-grouted earth-plugs (JGEPs) are commonly used as artificial water barriers to impede ground water from seeping downstream of dams or into deep excavation pits. However, due to positioning errors and variability of column diameters, seepage passages may occasionally penetrate through the water barrier, thus undermining its water-tightness. A three-dimensional discretized algorithm (TDA) is proposed for quantitatively estimating the effect of the above geometrical imperfections on the water-tightness. With given random geometries of the treated ground, this algorithm is able to examine whether a water barrier is penetrated by seepage passages. It further quantitatively estimates the flow rate through the water barrier with the given random geometry. When compared with the results from 3-D random finite element analysis, it was found that the TDA results show strong correlations with FEM results, but at a remarkably reduced computational cost. The TDA generally gives a slightly more conservative estimation of flow rate than the FEM counterpart due to the lengthened seepage distance due to random corrugations in the penetrating untreated zones.