The Dynapac Seismic system (Seismic) is a compaction technology that that lets rollers determine the optimum frequency for any compacted material, monitoring the variations and constantly adjusting to changing conditions, automatically.
The conventional compaction theory considers the soil/ground and the drum as two separate systems. Conventional vibratory compactors deliver a rapid succession of impacts to the soil surface at a frequency that is either pre-set at a high or low amplitude or at a frequency that is adjusted manually.
The development of Seismic started with Dynapac’s engineering team challenging this theory with questions such as why waste valuable energy by letting the drum hit the soil randomly. All drum and soil combinations have their unique, natural frequencies. What if the drum of the machine could find the ground’s properties and use the natural frequency in the drum-soil system; and could it be possible to get the soil and drum to work together as one system, instead of the traditional two-system theory?
In order for Seismic compaction to be achieved, two specific conditions must be met: (1) the machine has to be able to read the stiffness properties of the ground in order to interact with it; once these values can be determined, the optimal frequency can be calculated; (2) subsequently, the machine has to automatically adjust its frequency to the varying ground properties at all times. The development of a special sensor and the improvement of the existing compaction meter on the drum make this technically possible.
Recognizing the dynamic characteristics of a certain soil just by looking at it is impossible. Operators have been able to adjust the frequency by themselves because rollers have had standard frequencies between 28 to 40 Hz (1,680 – 2,400 vpm) and indicators with recommendations to adjust frequencies manually depending on soil types. The Seismic eliminates the need for operators to set the frequency manually or guess what soil type or frequency should be used at any given time, because the system automatically detects the frequency of the soil characteristics, works together with it, and applies the correct amount of energy exactly when required.
Dynapac’s first step in letting a machine automatically decide compaction parameters was the introduction of ‘Active Bouncing Control’. If the compaction energy returns to the machine with the possibility of causing damage, vibration is actively shut off. This technology prevents unnecessary bouncing which saves the machine from downtime and secures a high second-hand value.
By working in sync with the ground’s natural properties, the machine’s compaction performance is maximized and less energy is required to achieve the same compaction results. At the system’s natural frequency the drum amplitude is enhanced significantly, because energy is automatically fed to the system at exactly the right time. This maximizes the contact force between the drum and the ground, as well as the compaction and energy efficiency.
With the frequency automatically optimized at all times, the Seismic reduces fuel consumption, eliminates unnecessary wear and tear, reduces the number of passes required to reach the optimum compaction, and reduces noise. According to Dynapac, the Seismic reduces vibration power and energy consumption by up to 30 % and lifetime fuel consumption by up to 10%. The Seismic will be included as a standard feature on CA1500-6500 rollers together with the Dynapac compaction meter.
