关键词: 原状黄土, 循环三轴试验, 累积沉降, 列车荷载

Abstract:

The settlement after construction is the major research project for subgrade of dedicated passenger railway line, in which it is indispensable to keep the accumulated settlement under long-term train load repeatedly with a reasonable range. To discover the rule of loess foundation accumulated settlement under long-term train load repeatedly, a series of cyclic traxial texts were carried out for undisturbed loess; through anisotropic and long duration loading simulating the condition of constant loading of train load, the loess behavior of dynamic strength and cyclic stress-accumulated strain relationship under different confining pressures were obtained; and the cyclic stress-accumulated strain relationship at small cyclic stress were normalized. Results show that (1) The loess accumulated strain increases as time, and it can reach a relative stability value when the cyclic stress is less than critical stress, whereas it can't do. (2) The loess accumulated strains under different confining pressures increase with the increase of the cyclic stress; and the critical stress increases with the increase of confining pressure. (3) Under the same confining pressure and strain failure criterion, the dynamic strength decreases with the increase of cyclic number. (4) Under different confining pressures and the same cyclic number, when reach the same strain value, the cyclic stress increases with the increase of confining pressure. (5) When the cyclic stress is small, the loess accumulated strains under different confining pressures increase linearly with the cyclic stress.

Key words: undisturbed loess, cyclic triaxial test, accumulated settlement, train load