An Experimental and Numerical Study of the Low‐Pressure Grouting of Granular Soils by Diluted Chemical Solutions

Abstract

The use of silicate solutions for the low‐pressure grouting of granular soils is one of the techniques applicable in geotechnical engineering to reduce the “natural” hydraulic conductivity of granular deposits. This provision was suggested as a possible mean to limit the leakage of water within some underground structures located in the urban area of Milan and caused by the increase of the water table level. These structures, in fact, were built during the 1970s, and in the early 1980s, without a proper waterproofing because of the low level of the water table at that time. An experimental and numerical study is presented here to evaluate the effectiveness of grouting treatments in reducing the hydraulic conductivity of granular soils. First, the experimental part of the study is summarized, which aims at providing an insight into the variation of the hydraulic conductivity of a granular soil during the grouting process. Then, the numerical modeling of this process is discussed and the main features of a two‐ and three‐dimensional finite element program, developed for the purposes of this study, are outlined. Finally, on the basis of a series of numerical analyses, some conclusions are drawn on the effectiveness of the proposed provision.