Experimental Study On Influence Of Organic Matter Pore Fluid On Physical And Mechanical Properties Of Soil

There are different forms of organic matter in soil and their interactions with soil is also different.This research chose Fuzhou natural soil as research object,contrasted the changing characteristics of clay contaminated in different degrees by adding dissolved organic matter?glycine,fulvic acid,Sodium humate?and discussed the effect rule and action mechanism of mechanics property of clay by organic matter.The main research contents and conclusions are as follows:?1?The physical and mechanical properties of soil and interaction mechanism were studied by selecting fulvic acid,glycine and sodium humate as soluble organic matter pore fluid.The existence of pore fluid of organic matter was studied and found that the density,viscosity and absorbability of the pore fluid of organic matter increased with the increase of the concentration of organic matter,and the viscosity and adsorption of sodium humate solution at the same concentration were greater than that of the amino acetic acid solution.Through a series of tests,it is found that adding organic matter will increase the liquid limit of soil,sodium humate solution had the most significant effect on the liquid limit,when the concentration of glycine was greater than 5%,the liquid limit of the soil almost did not change.The three kinds of organic solution can increase the plastic limit of soil,but increase slightly.?2?The addition of organic solution to the soil makes the soil more resistant to compression and slightly increases the yielding pressure,when w0/w_L=1.25 the effect of organic matter is obvious,but it is relatively small impact on clay when w0/w_L?1.75.The soil with sodium humate solution has greater compression resistance than the other organic soil.Based on the analysis,it can be concluded that the one-dimensional compression curves of the higher initial water content samples are above the lower initial water content samples,and the greater the initial moisture content,the smaller the reconstituted yield stress.For the permeability coefficient,the permeability coefficient of soil decreases slightly with the addition of organic solution,and the greater the concentration of organic solution,the smaller the permeability coefficient.?3?Zeng combined with Burland and Hong theory,the prediction formula of remolded soil compression curve?VCL?was established,and the predicted results were compared with the experimental results it will find that after adding organic matter pore fluid,the compression curve of organic soil is located above the predicted compression curve,and the smaller the initial moisture content,the greater the deviation between them.When the viscosity of the organic soil pore fluid is similar to that of water,the osmotic coefficient of organic soil can be predicted by Zeng's prediction formula 1gkV?-8.89+4.891g e-5.121g w_L,however,when the difference between the viscous coefficient of the pore fluid and the water is large,the error predicted by this formula is larger,so we need to modify the viscosity coefficient.?4?As the pore fluid of organic matter increases the liquid limit of soil,the undrained shear strength of soil can be increased by adding organic solution when the water content is constant,and compared with the influence ability of various organic matter,sodium humate is greater than amino acetic acid than fulvic acid.The unconsolidated undrained shear strength of the sample after adding organic solution can be predicted by Hong's prediction formula Cu=1.4/?w/w_L?^4.5?w_L<150%?.