Accumulated settlement of X-shaped piled embankments under high-speed train loads
To explore the accumulated settlement of piled embankments under high-speed train loads,a large-scale X-shaped piled embankment model was established.A series of model tests were conducted,and the evolution of the cumulative settlement of X-shaped piled embankments was investigated.The results show that after 20 000 cycles of vibration,the accumulated settlement at the center of the adjacent four piles is the largest,followed by the track slab and then the pile top.Moreover,the"hang-up"effect in the square grid is significant.As the number of cyclic loading increases,the accumulated settlement at each measuring point continues to increase.When the loading frequency is≤15 Hz,after 10 000 cycles of vibration,the accumulated settlement curves at each measuring point gradually become gentle,and the rate of settlement gradually decreases.Furthermore,when the loading frequency is ≥25 Hz,the accumulated settlement curves on the track slab show little tendency to slow down with increasing cyclic loading times,and the rate of accumulated settlement growth is relatively fast.With an increasing loading frequency,the accumulated settlement at each measuring point gradually increases.The accumulated settlement reaches a maximum value at 25 Hz,and a"quasi-resonance"phenomenon occurs.In practical engineering,such situations can be avoided by increasing the stiffness of the embankment.As the loading amplitude increases,the accumulated settlement linearly monotonically increases.When the loading amplitude increases by 1 kN,the accumulated settlement on the track slab increases by an average 1.27 times.Finally,a prediction formula for accumulated settlement evolution considering factors such as the train speed and axle load was proposed through analysis and comparison.
万方数据
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