Experimental Study On Remodeling Red Clay Soil Resonant Column Under Different Parameters

The dynamic shear modulus and damping ratio of soil are two important parameters for characterizing soil dynamic properties and also the key to soil seismic response analysis and site safety assessment.At present,the research on the dynamic characteristics of undisturbed soil in the small strain range has been relatively mature at home and abroad.In actual engineering,the undisturbed soil is often treated by tamping and drainage consolidation to meet the strength requirements of the project construction,and the physical state of the soil such as water content and compactness is constantly changing with time;The dynamic characteristic parameters of different physical states also differ greatly.At present,there are few studies on the dynamic characteristics of non-unnatural soil under different physical conditions.The project carried out research on the dynamic characteristics of red loam under different physical conditions(water content,confining pressure,consolidation time,compaction work).According to the test results,the dynamic shear mode of red soil in small strain range was obtained.The variation of the quantity and the maximum damping ratio with the change of soil moisture content,consolidation time and confining pressure is an important supplement to the theory of soil mechanics remolding soil dynamic characteristics.Details are as follows:(1)The measured data conforms to the Hardin-Drnevich hyperbolic rule,and can be accurately fitted by the hyperbolic equation.The correlation coefficient is R?0.91,and the values of parameters a and b in the hyperbola are given.(2)When the confining pressure increases,the dynamic shear modulus of the red soil increases,and the maximum dynamic shear modulus of the sample has a good linear relationship with the confining pressure.The relationship between the dynamic shear modulus and the shear strain of the specimen under the confining pressure of 50 kPa and 350 kPa forms an envelope.The relationship between the dynamic shear modulus and the shear strain of the specimen is within the envelope when theconfining pressure is between 50 kPa and 350 kPa.The dynamic shear modulus ratio curve also showed a similar trend.(3)When the moisture content of red loam increases,the dynamic shear modulus and maximum dynamic shear modulus decrease first and then increase,and the maximum dynamic shear modulus of the soil reaches the minimum when the soil is at the optimal moisture content;The ratio decreases as the moisture content increases.(4)By studying the influence of consolidation time on the dynamic characteristics of remolded red loam,it is concluded that the consolidation time has an effect on the maximum dynamic shear modulus,dynamic shear modulus ratio and shear strain curve of red loam soil,and this effect There is regularity.Specifically,the maximum dynamic shear modulus of the sample increases with the increase of the consolidation time;the maximum damping ratio of the sample decreases with the increase of the consolidation time.(5)By controlling the number of times of compaction of the sample,the compaction work of the sample is different,so that the dynamic shear modulus and the damping ratio of the red soil in the small strain range are affected.The results show that the larger the compaction work is,the larger the maximum dynamic shear modulus is.The maximum damping ratio of most samples increases with the increase of compaction work.