General dynamic drainage consolidation laboratory test

as tamping impact energy is not enough

some basic mechanical responses of soft soil in the actual project are difficult to excite

and relative features of soil are difficult to find. Through the self-developed multi-directional high energy electromagnetic force impact test system which can provide high impact energy produced by electromagnetic force and therefore could simulate the tamping energy acted in practice engineering

static and dynamic drainage consolidation model test for muck

is carried out. The experimental study obtains the response characteristics of pore pressure of this ultra-soft soil as follows: the time that upper pore pressure increases sharply to the maximum

which is very short (only 6 ms) at impact instant

and after the peak it drops rapidly to a certain value; in the initial twice tamping

the curve of pore water pressure at middle deep position shows bimodal type

the time interval between the two peak increases with the increase of tamping times gradually

and finally disappeared; each tamping

instantaneous earth pressure in the middle position shows a sharp growth and rapid decrease

and growth magnitude with the increase of tamping times shows a trend of decrease

but earth pressure value after tamping several days later is still greater than the value before tamping each time; after each tamping dissipating

the final value of pore pressure is less than the initial pore pressure

which signifies that under the certain condition of drainage

such ultra-soft soil foundation can be

indeed

acted by dynamic loading; the action mechanism of residual stress produced by dynamic tamping for soil consolidation exists

and it plays a main role for settlement

but for certain static loading

corresponding mechanism is little; the disturbance effect of inserting drainage board could not be ignored

but the disturbance effect decreases with soft soil embedded depth.