Experimental Study On Small Strain Dynamic Characteristics Of Steel Slag Mixture Materialsfter Freezing And Thawing

With the development of the steel industry,the yield of steel slag is growing year by year.A great deal of steel slag not only forms a threat to natural environment,but also makes use of the occupation of land.For the time being,the recovery rate of steel slag in China is low.How to take effective measure to utilize them is a key point that scholars and experts research in China.In this paper,we investigate the mechanics characteristic of the soil which mixes with steel slag and sand,concrete and sand,providing the theoretical basis for the application of steel slag in terms of foundation treatment in the seasonal climate areas such as Northeast China Region.In order to simulate the freezing process of soils in the real environment.This experiment chooses a contant temperature refrigerator at-20 ? to make a one-way freezing to carry out the indoor test of frost heaving and thawing.In order to ensure the test target soil and soil under the same natural state,one-way freeze from top to bottom,which is convenient for taking out the specimen and reducing the disturbance and damage of the specimen,the experimenter make several cylindrical stainless steel of 50mm in diameter and 100mm in height.Soil dynamic shear modulus and damping radio are the most important dynamic characteristic paramenters,which are indispensable dynamic parameters to the soil and foundation seismic response analysis,and these are also essential content in the site seismic safety evaluation.We utilize the British GDS resonant column(RCA)test system to measure the dynamic shear modulus and damping ratio of target specimens by controlling different confining pressures,different curing ages,different mixratios and different freeze-thawing cycles.This experiment uses three different confining pressures(50kPa?100kPa?150kPa),two different curing ages(3days?7days),three different freeze-thaw cycles(1time?3times,?5times),three different mix ratios(Gs30?Gs40?Gs50),Gs30?Gs40?Gs50 represent steel slag content of solid material 30%?40%and 50%.To comparative analysis of the test are also designed two different mixing ratio of cement sand mixture change into respectively:Gc12 and Gc15.Gc12 and Gc15 represent cement content of solid material 12%and 15%.The experimental results show that the dynamic shear modulus increases with the increasing of confining pressure and increases with the increasing number of freeze-thaw cycles,and increases with the increasing of curing age.When the steel slag content is 40%,its dynamic shear modulus reaches the maximum value.When the steel slag content is 30%,its dynamic shear modulus is slightly larger than the dynamic shear modulus of 50%steel slag content.And the cement content is 15%,its dynamic shear modulus reaches the maximum value.The damping radio increases with the increasing of the number of freeze-thaw cycles.And decreases with the increasing of confining pressure and decreasing with the increase of curing age.When the steel slag content is 40%,its damping radio reaches the minimum value.And whe the cement content is 15%,its damping radio reaches the minimum value.