Laboratory Simulation Experiment On Deterioration Of Cement-stabilized Soil In Seawater Environment

Cement stabilized soil in natural condition, as well as stabilization in corrosive site,will be influenced by environmental pollution such as acid rain, seawater invasion orindustrial pollution, and lead to deterioration of the structure. Especially in corrosivesite, the strength of soil stabilized by cement will increase, but at the same time, thestrength will decrease due to deterioration in the beginning of stabilization. This paperfocused in experimental work to study the strength of soil stabilized by cement incorrosive site which is represented by sea water. Laboratory tests were carried out tomeasure the strength distribution using micro cone penetration test. Also, elementanalysis test using Ion Chromatography to measure the distribution of Ca²⁺within thespecimen were conducted. This experimental works compare the effect of seawaterpressure to the strength of cement stabilized marine clay. Two conditions wereprepared. The first condition, two meters of seawater pressure applied to the specimenby using vertical pipe filled by seawater, and the other specimen has no pressureapplied. It is indicated that deterioration extend quickly under seawater environmentand deteriorated depth became deeper as the increase of pressure; and elementanalysis showed that calcium ion concentrations in deteriorated portion is lower thanin non deteriorated portion.Effects of curing time and cement content on deterioration of cement-stabilized soilwhich formed in marine soft soil site of Qingdao Jiaozhouwan Bay was studied withlaboratory simulation experiments. The deteriorated depth was defined according tothe features of penetration resistance and penetration depth curve. Results indicatedthat the deterioration expanded quickly under seawater environment, and thedeterioration depth became deeper with the increasing of curing time. With theincreasing of cement content, the strength of cement-stabilized soil increasedsignificantly, and meanwhile, the deterioration depth decreased significantly. Theconcentration of Ca²⁺and SO₄^2-in the cement-stabilized soil had a tendency of decreasing upwards，while the concentration of Mg²⁺gradually decreased with theincreasing of depth.