Dynamic Compaction with Rollers
Near-surface compaction plays an important role for the construction of various civil engineering structures such as dams and embankments for roads and railways. Dynamic roller compaction has become the common method of near-surface compaction since dynamic rollers are much more efficient than common static rollers. Eccentric masses in a dynamic roller drum cause vibrations which are transmitted to the grains of the soil to be compacted. For a short term the the static grain to grain friction decreases to the much smaller dynamic friction, which abets the rearrangement of the grains and therefore the change in packing from loose to dense.
There are two common methods for the excitation of a dynamic drum. Most dynamic rollers have vibrating drums. The eccentric masses are shafted concentrically to the drum axis resulting in a high vertical loading (front drum on the left of the image). The torsional motion of an oscillatory drum is caused by two opposed, rotating eccentric masses, which shafts are mounted eccentrically to the drum axis. Soil is dynamically loaded horizontally by the drum motion (rear drum on the right of the image) and statically loaded by the dead weight of the drum and roller in vertical direction. Mainly tangential forces are transmitted in the soil by shear waves.
Within this research project the fundamental behavior of the interaction between the drum of a dynamic roller and the ground are investigated. Besides experimental field tests with extensive measurements a theoretical modeling and numerical simulation of the interaction system drum - subgrade are performed.
Univ.Ass. Dipl.-Ing. Dr.techn. Johannes Pistrol, BSc