In the process of soft foundation treatment using dynamic drainage consolidation

the growth and dissipation of pore water pressure play the decisive role. It is not only primary bases to control the construction schedule

but also is an important parameter to ascertain the strengthening depth and evaluate the reinforcement effect. So the model test

it simulated an expressway site conditions

is carried out with test apparatus designed by ourselves. In order to comprehend the variation of pore water pressure under different parameter combination

these parameters include tamping times; tamping energy; hammer weight; hammer bottom’s area and fall distance

the test is divided into several groups. These tests include the pore water pressure of the same or different depths under different or the same tamping times

the pore water pressure of the same depth with different combinations between tamping energy and hammer weight and so on. Research shows that

when keeping tamping energy invariant

increasing tamping times will slower dissipation of pore water pressure. And increasing hammer weight will be more effective than increasing fall distance. The high tamping energy can make pore water pressure has bigger amplitude

and the corresponding reinforcement range will increase. In order to speed up dissipation of pore pressure

construction procedure should adopt the method of “multiple tamping

and successive increase tamping energy”.