Experimental Analysis Of Dynamic Characteristics Of Reconstituted Saline Soil In Songnen Plain

Roadbeds constructed on saline-alkali soil in the seasonal frozen soil region are prone to damage such as frost heave and thaw settlement under the influence of traffic loads and freezethaw cycles.The Songnen Plain is located in the seasonal frozen soil region of Northeast China and contains a large amount of carbonate saline-alkali soil.Due to its location at the intersection of the Binxian Fault and the Keshan-Daan Fault,the region experiences frequent seismic activity.With the implementation of the revitalization strategy for the Northeast’s old industrial base,the engineering construction process in the Northeast region has accelerated.The special nature of vehicle and train vibration loads,earthquake loads,damage to the soil caused by freeze-thaw cycles,and the salinization of the soil itself collectively affect the engineering properties of the soil in the Songnen Plain.Therefore,comprehensive research on the dynamic characteristics of soil under the influence of freeze-thaw cycles,earthquake loads,and salinization is of great significance for the smooth progress of engineering construction in the seasonal frozen soil region of Northeast China.This article chooses to study saline soil in Zhao Yuan County,Daqing City,in the central part of the Songnen Plain,which has typical salinization,freeze-thaw cycles,and seismic activity.The study investigated the effects of freeze-thaw cycles,salt content,moisture content,dynamic stress amplitude,effective confining pressure,and load frequency on the dynamic parameters of remolded saline soil.The grey correlation analysis method was used to analyze the correlation between each factor and the dynamic shear modulus and damping ratio of remolded saline soil.A GBRF regression prediction model was established for the dynamic shear modulus and damping ratio of remolded saline soil in the Songnen Plain.The following are some specific aspects:1.GDS dynamic triaxial tests were conducted on remolded saline soil with different salt content and freeze-thaw cycles to study the coupling effect of salt content and freeze-thaw cycles on the dynamic parameters.The results showed that the effect of freeze-thaw cycles on the dynamic shear modulus in low-salt soil is mainly reflected in the first six cycles,while it is more sensitive to the effect of freeze-thaw cycles in high-salt soil.The damping ratio in lowsalt soil tends to stabilize after six freeze-thaw cycles,while it tends to stabilize after nine freeze-thaw cycles in high-salt soil.2.The effects of moisture content,dynamic stress amplitude,effective confining pressure,and load frequency on the dynamic parameters were tested by GDS dynamic triaxial tests.The results showed that the dynamic shear modulus increases with the increase of dynamic stress amplitude,effective confining pressure,and load frequency,and increases first and then decreases with the increase of moisture content.The damping ratio decreases with the increase of effective confining pressure and load frequency,increases with the increase of dynamic stress amplitude,and changes opposite to the dynamic shear modulus with the change of moisture content.3.The grey correlation analysis method was used to analyze the correlation between the influencing factors of the dynamic characteristics of remolded saline soil.Based on the correlation analysis results,it was found that moisture content should be a key factor to consider in the design and construction of saline soil in the Songnen Plain.A GBRF regression prediction model for the dynamic shear modulus and damping ratio of remolded saline soil was established using Python,and the predicted values of the model were in good agreement with the experimental values.It is believed that the established prediction model can complete the prediction of the dynamic parameters of saline soil in the Songnen Plain.