强夯加固废弃铁矿渣路基的动应力扩散规律实验研究

Test study on soil dynamic stress diffusion of a waste iron slag embankment during dynamic consolidation

结合青临高速公路强夯加固废弃铁矿渣高填方路基工程,在实验段埋设48个土压力计,采用不同夯击能(2 000、2 250、2 500、2 800 kN.m)对设计夯点进行多次夯击,通过采集仪得到的数据,分析强夯时动应力的扩散规律。实验结果表明:强夯加固废弃铁矿渣路基的效果比较明显,强夯引起的动应力也很明显;锤底动应力的消散速度极快,加上余波仅有0.5 s左右的时间;不同夯击能引起的动应力不同,夯击能越大,动应力值也越大;动应力在竖向的影响距离远大于径向,锤底8 m仍有10 kPa以上的动应力;有效加固深度的临界动应力值为20 kPa;动应力在径向的衰减速度快于竖向,有效加固宽度约3 m;随着夯击次数的增加,在有效加固范围内动应力的增加比较明显,但在3击后基本保持稳定。实验结果可为今后相似条件下强夯加固工程施工参数的设计提供参考。

A large field test was conducted in the project of the Qing-Lin Expressway.Forty-eight soil pressure cells were embedded in the test section of the road.Different classes of tamping energy（2 000,2 250,2 500,2 800 kN·m） were used in this test.A dynamic strain gauge was used to record the dispersion and decay of the stress caused by dynamic compaction.The results showed that the reinforce effect on the waste iron slag embankment and the dynamic stress were both obvious.The dynamic stress decayed very fast and increased with the tamping energy.The vertical influence distance of dynamic stress was larger than that of the horizontal,and the dynamic stress was more than 10 kPa at 8 m under the rammer.The critical dynamic stress of the effective impacting depth was about 20 kPa.The decay speed of the horizontal dynamic stress was faster than that in the vertical.The effective horizontal impacting distance was about 3 m.With the compaction numbers increased,the dynamic stress in the reinforced range obviously increased and tended to be stable after about the third hit.