Test study of pore water pressure during dynamic compaction at the subgrade of highway in the Yellow River flood area

摘要

The Yellow River flood area mainly consisted of silt and silty clay. Water level observing holes and pore water pressure gauges were embedded in the test section. The observation results showed that: The pore water pressure of 3m and 5m grew slowly at the beginning. With the increase of ramming strike and the total ramming strike energy, the fourth hit pore water pressure mutated and then grew slowly. The pore water pressure of 7m and 9m grew slowly all the time. Because of the well point dewatering, the excess pore water pressure dissipated very soon. 70-75% of the excess pore water pressure of the first pass dissipated 3 hours after ramming strike, then the excess pore water pressure dissipated slowly. The excess pore water pressure of 3m and 5m grew significantly, so the effective reinforcing depth of dynamic compaction was 5m.