Numerical simulation of dynamic soil compaction with vibratory compaction equipment

Roller drums make use of various shapes and their dynamic compaction effect is achieved by different kinds of dynamic excitation systems. The bearing capacity of layered soil constructions can be measured during the soil compaction process. The finite element method has been applied for dynamic analyses using elastic models. For the realistic simulation of the dynamic compaction process it is necessary to integrate an inelastic material law for cyclic loads. Compaction with dynamic rollers takes place in different operating modes, which could be proven by the numerical simulations and the influence on continuously recorded control data could be clearly detected. 1 Dynamic Rollers for soil compaction Soil compaction with the help of vibratory compaction machinery, such as vibratory rollers and plates, works due to the static load of the whole machine, combined with dynamic forces. Integrated so-called exciter systems introduce dynamic forces into the compaction tool, which transmits the loads into the subgrade. Today, different kinds of exciter systems, such as adjustable or non-adjustable circular exciters, adjustable or non-adjustable directed exciters and oscillatory exciters, are implemented in vibratory rollers and their use results in different compaction effects in the subgrade. The dynamically excited drum delivers a rapid succession of impacts to the underlying surface from where the compressive and shear waves are transmitted through the material to set the particles in motion. This eliminates the internal friction periodically and facilitates the rearrangement of the particles into positions in combination with the static load which results in a low void ratio and a high density. The drum of a vibratory roller is excited by a rotating eccentric mass, which is attached to a shaft on the drum axis (Fig. 1). The rotating mass sets the drum in a circular translatory motion, i.e. the direction of the resulting force is corresponding with the position of the eccentric weight. Compaction is achieved mainly by transmitted compression waves in combination with the effective static drum load. Thus, the maximum resulting compaction force is intended to be almost vertical and in fact it is inclined