大型圧密装置による締固め不飽和土の圧密実験

The one dimensional compression tests of compacted soils under undrained and drained conditions were carried out using large consolidometer. The size of specimen is 30cm diameter and 10cm height. The soils used in the experiment are a clayey soil and mixed soils of the clayey soil and gravel which maximum diameter is 10 mm.
From this experiment, the following results are obtained.
(1) Under undrained condition, the pore pressure built up by compressive stress in clayey soil is little in dry side of optimum moisture content ω_<opt> and large in wet side of ω_<opt>.
When compressive stress is again applied after consolidation of clayey soil, the pore pressure built up under undrained condition is increased in dry side of ω_<opt> and decreased in wet side of ω_<opt> in comparison with the pore pressure at first time.
(2) The coefficient of consolidation c_v is obtained from compressive strain ε, pore water pressure u_w and pore air pressure u_a. The value of c_v for ε, u_w and u_a are mutually different and the values of c_v for u_w and u_a are greater than that for ε.
(3) The rate of secondary consolidation dε/d log t is about 1×<10>^^^<-3>～3×<10>^^^<-3> and this is equal to the value obtained by other many compacted soils with standard oedometer.
(4) The great pore pressure is remained after the colmpletion of primary consolidation of compressive strain ε.
(5) The mixture of gravel in clayey soil has effects on the decrease of void ratio and the increase of coefficient of consolidation.