Granite Residual Soil Eroded By Acid Rain Static And Dynamic Mechanical Properties Study

Residual soil of weathered granite is widely distributed in the southeast coastal area of China,most of which are surface exposed and have special structural and mechanical properties.With the economic growth and radiation in the southeast of China,the traffic and transportation network continues to expand,and higher requirements are put forward for the safety and stability of engineering buildings.At the same time,the rapid development of economy and industry in Southeast China has also brought about environmental pollution in the form of acid rain,which has a long-term impact on building structures and soil.This article selects the guangdong zhaoqing district project,out of the clay of the granite residual soil under the influence of the acid rain for a long time for a series of basic physical test,triaxial consolidation drained shear and resonant column test,the granite residual soil in southeast area of mechanical properties and the p H value and influence of the acid rain time correlation is studied,and a variety of clayey soil model analysis of mechanical parameters,It provides reference for related engineering practice.The collected engineering soil was acidified into samples according to a certain p H value of acid solution and time,and its limit water content was determined.Considering the strength variation of the granite residual soil,the unconfined compressive strength test results show that the acid rain erosion causes great strength loss to the granite residual soil under the optimal water content.Triaxial consolidation drainage shear test was conducted on granite residual soil samples affected by different p H and erosion duration of acid rain.The results show that the maximum cohesion loss is 42.69%of the original standard remolded sample,and the maximum internal friction Angle loss is 19.12%.The variation curves of q_fand E₅₀of different types of samples with the increase of confining pressure show certain differences in the growth range and speed.The parameters of the test results were analyzed based on the Duncan-Chang E-B elastoplastic model,and the stress-strain curves were retrieved according to the parameters,which showed a good correlation with the original stress-strain curves.The results of the small-strain resonance column test show that the skeleton curve and hysteresis curve of the granite residual soil affected by acid rain erosion still have the characteristics of clay soil,and the relationship between shear strain and dynamic shear modulus follows the rule that the shear modulus decreases with the increase of shear strain.The dynamic shear modulus ratio G/G_maxand damping ratio D curves show the characteristics of log-log curves,which conform to the trend of dynamic shear modulus attenuation of clay soil.Based on the empirical formula of Hardin-Drnevich,G_max,G/G_max,D and D_maxwere fitted.When the fitting degree is above 90%,it can be considered that the model can well reflect the dynamic strength change of residual soil with the change of p H and time factors.The Martin-Davidenkov model and the selected empirical relationship can better fit the variation trend of G_maxand G/G_maxwith?,and the fitting law can be used as a reference for engineering.