Study On Electrical Resistivity Structure Parameters Of Loess During Consolidation

Loess is a kind of strong structural soil, in the south of China northwest,north China plain and the northeast region widely distributed, its uniquecomposition and structure feature makes the mechanics properties of loess andits closely related structure change, in these areas in the construction of projectsrelated to the loess engineering problems inevitably. Therefore, to study the stateof the structure of the loess, grasp its strength and deformation characteristics,perfect for foundation design theory and method, is particularly important. Theresistivity of loess mainly depends on some important structural parameters,such as porosity, pore shape, pore structure, degree of saturation and pore fluidresistivity, solid particle composition, particle shape, particle orientation and thecementation state, etc.The variation of AC resistivity structure parameters of undisturbed loessduring consolidation process were studied, including the average structure factor,the average shape factor and the anisotropic coefficient. Electrical resistivityparameters of undisturbed loess and remolded loess were compared. Effects ofthe current frequency on electrical resistivity were studied. The mechanisms ofvariation were explained according to structural change. And use the Image Pro Plus software analysis the qualitative and quantitative of microstructure imageof consolidation soil. The microscopic image analysis results and the exchangeof resistivity method of structure parameters is compared, the change rule ofauthentication exchange the applicability of the resistivity method.The resultsshow that:(1)The variation of undisturbed loess and remolded loess was different.(2)Vertical resistivity of undisturbed loess and remolded loess increase firstand then decrease with increasing pressure. Horizontal resistivity of undisturbedloess and remolded loess increases with the increase of pressure. The anisotropiccoefficient of undisturbed loess and remolded loess first decreases rapidly, thendecreases slowly and finally increases slightly with increasing pressure. Theaverage structure factor and the average shape factor of undisturbed loessdecrease first and then increase with increasing pressure. The average structurefactor and the average shape factor of remolded loess increase with increasingpressure.(3)The changing rules of structural parameters are similar under eachcurrent frequency, but the values are different.(4)A reasonable current test frequency range of electrical resistivity（50kHz~1MHz） is recommended.(5)With the help of image processing software such as IPP, microscopicimage parameters of the loess soil are calculated and analyzed, the changes ofthe loess soil’s pores before and after consolidation are studies．The loess structural before and after the consolidation is closely related to the pore with adiameter greater than16μm．(6)By studying the orientation characteristics of loess porosity and shapefeature, it is concluded that when consolidation pressure is1600kPa the loesssoil is treated, the weaker the orientation characteristics of the soil poreis．Directional indicators and shape indicators can be used as an important basisfor judging the consolidation effect．(7)By means of microscopic image of qualitative and quantitative analysisof the loess, observation of soil structural change. So as to verify the resistivitymethod to study the applicability of the loess structural changes in the process ofconsolidation.