Experimental Study on Cemented Soil in Sulfate Radical Corrosive solution

The cemented soil is a widely used method to stabilize the weak soil.It would be working in polluted environment,and be influenced by environmental pollution such as acid rain,seawater invasion or industrial pollution,which may lead to deterioration of the structure.In order to simulate and study the erosion effect process including as the changes of corrosive degree of surface,compression strength of cemented soil samples and SO_(4)^(2-)concentration of corrosive solutions,a series of tests are conducted on the cemented soil blocks cured in different concentrations of MgSO_(4),H_(2)SO_(4)and Na_(2)SO_(4)solutions.The test results show that the corrosive degree of the sample surface increases while the compression strength decreases with the increase of the corrosive solution concentration at the same erosion time,and that the corrosive degree increases with the corrosive time.The influence of inorganic compound solutions on the cemented soil follows the order of Na_(2)SO_(4)>MgSO_(4)>H_(2)SO_(4).By analyzing the mechanism,the corrosive type of H_(2)SO_(4)and MgSO_(4)solutions to cemented soil is a composite type of resolving and crystallizing combination,and Na_(2)SO_(4)solution to cemented soil is a composite type of dissolving and crystallizing combination.

Experimental study on geosynthetic-reinforced sand fill over marine clay with or without deep cement mixed soil columns under different loadings

Geosynthetics and deep cement mixed(DCM)soil columns have been widely used to improve soft soil grounds in many countries and regions.This paper presents an experimental study on a geosynthetic-reinforced sand fill over marine clay with or without DCM columns under different loadings.Two tests were conducted on the sand fill reinforced with fixed-end and free-end geosynthetics over marine clay under three-stage local loading to investigate the effects of the boundary conditions of geosynthetic reinforcement on reducing settlements.It is observed that the fixed-end geosynthetic sheet is more effective in reducing settlements than the free-end condition under identical local loading.Another test was conducted on the fixed-end geosynthetic-reinforced sand fill over the marine clay improved by DCM columns under single-stage uniform loading.The vertical stresses on the marine clay and on the DCM columns,as well as the tensile strains of the geosynthetic sheet in the overlying sand fill,were measured.The results revealed that the stress concentration ratio increases with an increase in consolidation settlements,and the maximum tensile strain of the geosynthetic sheet occurs near the edge rather than at the center of the top surface of the DCM columns.