Study On The Mechanical Detection Method Of Heavy Metal Contaminated Soil

Soil is an important part of the earth’s ecological environment and the basic resource of agricultural production.With the rapid development of industry,the increase of various pollution sources makes heavy metal pollution of soil more aggravating.Due to soil heavy metal pollution has a serious impact on ecological environment、healthy life、quality of agricultural and livestock products,it has been widely concerned the detection methods and remediation technology of soil heavy metal pollution in recent years.Heavy metal pollution can change the mechanical parameters such as adsorption force and adhesion force between soil particles.Therefore,the study on the mechanical properties of heavy metal contaminated soil is expected to explore a method to detect heavy metal pollution in soil by using mechanical property parameters.Based on the practical situation of the soil heavy metal pollution(cadmium、plumbum、chromium、zinc),this paper conducts several experimental researches about mechanical detection to provide reference for the detection and remediation of heavy metal contaminated soil.The main contents and achievements of the study are as follows:(1)Experimental study on compressive mechanical properties of heavy metal contaminated soil.It has been studied the compressive mechanical properties of 5 kinds of soil samples including Control soil,lead,chromium,cadmium and zinc contaminated soil.Obtained the compressive stress-strain curves and mechanical properties of the 5 soils with different moisture content including compression limit load、compressive strength limit and compressive modulus of elasticity.Analyzed the effects and correlation of heavy metal pollution on soil compressive mechanical properties under different moisture content.It was found that the correlation between heavy metals contaminated soil and Control soil’s compressive mechanical properties was significant.(2)Experimental study on shear mechanical properties of heavy metal contaminated soil.Shear experiment soil samples were also prepared using the 5 soils mentioned above.Then to obtain shear load、displacement curve、Shear limit load、shear modulus of elasticity and shear strength.By carrying out the comparative analysis,statistical analysis and correlation analysis of the experimental data,it is known that heavy metal pollution has a significant effect on soil shear mechanical properties under different water content and there is a correlation between heavy metals contaminated soil and Control soil’s shear mechanical properties.(3)Experimental study on bending mechanical properties of heavy metal contaminated soil.In the bending experiment,three water content levels(9 %,12 %,15 %)and 4 heavy metal contaminated soils were used to make the samples to carry out static load three point bending experiment and obtain the bending load displacement curve、ultimate bending load、elasticity modulus、bending stiffness and bending strength.The results show that under the same moisture content,the bending strength、bending stiffness and elastic modulus are reduced by the content of heavy metals in the soil.Correlation analysis showed that there was a correlation between heavy metals contaminated soil and Control soil’s bending mechanical properties.(4)Experimental study on viscoelastic properties of heavy metal contaminated soil.Since agricultural soil is a kind of biological material with viscous property,we take soil with different moisture content and different heavy metal content as the research object to study the compressive creep and dynamic viscoelastic properties.Obtained the compression creep curve,used SAS essential nonlinear regression method to optimize the regression parameters and fitted the creep curve with Burgers viscoelastic model.Obtained modulus of elasticity at zero time、delayed modulus of elasticity、delay time、coefficient of viscosity、different frequency and different temperature scanning curves、loss modulus、loss tangent and storage modulus to fully express the viscoelastic properties of heavy metal contaminated soil.The correlation analysis shows that there is a significant correlation between heavy metals contaminated soil and Control soil’s viscoelastic properties.(5)Experimental study on dielectric properties of heavy metal contaminated soil.The heavy metal content has obvious influence on the dielectric properties of soil.This paper carried out four basic electrical parameters of impedance(Z),capacitance(Cs),resistance(Rs)and dielectric constant(ε~′)for 5 soil samples under different moisture content and different heavy metal content within the frequency range of100hz-1mhz.Analyzed the influence of heavy metal content of frequency moisture content on soil dielectric constant.(6)In this paper,the mechanism of heavy metal contaminated soil was briefly introduced.Based on the experimental results,the mechanical and dielectric properties of heavy metal contaminated soil’s discrimination model were established and validated...