Abstract:

he soils under the foundation of building or within the slope are usually in complex initial stress state before subjected to cyclic loading induced by earthquake or other dynamic loadings; after reforming the DTC-199 torsional cyclic load triaxial apparatus, the dynamic strength of compacted loess can be tested under this consolidation stress conditions. Results show that the initial angle α0 of principal stress has a considerable influence on the dynamic strength of compacted loess when other initial consolidation stress conditions are fixed; the initial coefficient b0 of intermediate principal stress has little influence on the dynamic strength of compacted loess; with the increase of α0, dynamic strength reduces gradually and it reaches minimum when α0 is 90o; maximum reduction range is about 40 % . The initial coefficient of intermediate principal stress has interval effects and amplification effect on the dynamic strength of compacted loess. When b0 increases from 0 to 0.5, the dynamic strength increases; and when b0 increases from 0.5 to 1, the dynamic strength decreases; the rate of increasing is less than rate reduction about 5 %.

Key words: compacted loess, dynamic strength, initial angle of principal stress, initial coefficient of intermediate principal stress