Study On The Unloading Strength And Creep Properties Of Long-term K₀-consolidated Artifical Frozen Clay Under High Pressure

In freeze sinking project in deep alluvium, the safety of the frozen soil wall, shaft lining,even the success of the entire project depend on the interaction between frozen soil wall andshaft lining.Therefore, based on the test mode of “long-term、high pressure K0consolidation—freezing—constant axial pressure and unloading confining pressure”, the tests for frozen clay collectedfrom deep alluvium were carried out to investigate the deformation、strength and creep propertyfor frozen clay under unloading path systematically, and the law for strength and deformationbehaviour of frozen clay affected by temperature、consolidation stress and consolidation timewas revealed.First, long-term、high pressure K0consolidation tests were carried out on the remolded deep clay to obtain the K0values and curves of axial deformation-time of different consolidation stress(8MPa、10MPa、12MPa、14MPa、16MPa) and different consolidation time(1d、3d、7d、14d、28d) during the whole consolidation process.Secend, the test of freezing under high pressure were carried, drawing the frost-heave capacity of different freezing temperature under different axial load and the law of thefrost-heave ratio affected by consolidation stress and temeperature.And then, triaxial unloading tests were carried out on frozen clay, obtaining the curves ofstress-strain, strength value and failure strain for frozen soil sample of different temperature anddifferent consolidation condition; The results of single factor cycle tests draw the law of thestrength, deformation behavior and failure strain affected by temperature、consolidation stressand consolidation time, in the meanwhile, the curves of stress-strain were fitted withDuncan-Chang model. Through orthogonal tests, drawing the conclusion that the temperature isthe main factor affect the strength of frozen clay, consolidation time followed and the stress isthe least.At last, according to the strength of frozen soil sample obtained by triaxial unloading tests,triaxial unloading creep tests were carried out to get creep curves that fitted to get the fittingparameters and then analysis the relationship between creep properties and temperature,consolidation time and consolidation stress.