Development of a simulation device for impact roller

High-energy impact roller (IR) has been widely used to compact in-situ soils or fills for many kinds of earthworks. The IR applies high energy to the ground and densifies deeper soils than conventional rollers and plate-type compactors. But the transferring of IR energy into soil, the distributions of stress and displacement in soil while impacting and effect of the different masses and shapes of impact modules to the effectiveness of compaction are still unclear. This paper presents an impact roller simulation device to investigate the mechanism as well as the influencing factors on improvement of high-energy IR compaction. The device mainly consists of four parts including model box, model impact wheel, simplified buffering system and frame-towing system. The model impact wheels, as the key part of the device, are all 3-sided with different sizes and weights. The non-circular model impact wheels are towed with an electric motor through a steel rope and then roll on the surface of soil specimen, which is similar to the virtual process of IR compaction. Using this device, three laboratory compaction tests are carried out to verify the effectiveness of this device and investigate effects of impact wheel's sizes on the effectiveness of IR compaction. A Chinese electric cone penetrometer of 2.5 cm in diameter is used to verify the effectiveness of IR compaction. The results of laboratory compaction tests show that the impact roller simulation device is suitable for modeling IR compaction and it is easy to operate. The cone penetration data indicate that the effects of impact wheel's sizes on compaction are related to passes of IR compaction and that better effectiveness of IR compaction in shallow depth can be achieved by increasing the size of impact wheel.