# Experimental and Numerical Study in Dynamic Compaction of Weakly-Cohesive Soils
## 3 Experimental Tests  
The main objective of the compaction tests was to quantify the compaction effect in weakly cohesive soil. The experiments and practical investigations were carried out on the DN 2 national road (Bucharest-Urziceni, Romania) at the Movilita site (km 39 + 200). The following subgoals were assigned to meet the objective:  
* To check the characteristic parameters and the working regime of the compactor;
* To monitor the settlement achieved in the compaction process through determinations level topometric and geotechnical;
* To measure the increase in soil strength and stiffness by different in situ tests. The establishment of the compaction technological parameters was carried out based on an experimental polygon built with brought soil from the Movilita quarry (located on DN 2, at km 43 + 500, Romania). In this sense, it was necessary to determine the nature and physical-mechanical properties of the soil in its initial state before filling on the polygon, and therefore, in situ laboratory investigations became mandatory. The analysis of the granulometric composition (according to Romanian Regulation STAS 1913/5: Foundation land. Determination of granularity) of the soil brought from the quarry indicates 40% clay, 36% dust, and 24% sand. The results of the plasticity tests (according to Romanian Regulation STAS 1913/4: Foundation land. Determination of plasticity limits) are as follows: plasticity index, \(\mathrm{I_{p}}=20.04\%\); natural humidity, \(\mathrm{w}=11.5\%\); consistency index, \(\mathrm{I_{c}}=1.055\). The compressibility and consolidation characteristics of the soil based on oedometric tests (according to Romanian Regulation STAS 8942/1: Foundation land. Determination of the linear deformation modulus by field tests with the plate) show the following results: maximum density in the dry state, \(\rho_{\mathrm{dmax}}=1980\) kg/m\({}^{3}\); optimal compaction moisture, \(\mathrm{w_{opt}}=18.54\%\); consolidation time, \(\mathrm{t_{p}}=2\) h; the linear deformation modulus, \(\mathrm{E}=139.4\mathrm{e}^{5}\) N/m\({}^{2}\). Also, tracking the evolution of the compaction process begins with checking the characteristic parameters of the compactor and the working regime during compaction. To test the model in the vibration regime, experimental investigations were carried out in the ground channel (length L = 12 m, width l = 2.5 m, and thickness layer of soil filled h = 0.026 m), specially designed for the identical simulation of real working conditions. In this situation, the compaction was carried out with the double compactor type ABG-DD16 which has two vibrating rollers. The experimental tests for verifying the parameters of the vibratory working regime of the compactor consisted of the signal acquisition of the time variation of the drum vibration amplitude by processing the acceleration signals acquired with acceleration transducers located directly on the jacket of the vibratory roller in the vertical direction around its contact with the ground and on the upper chassis of the machine for both drums. The experimental plan of the in situ investigations is synthetically described in the diagram in Figure 6.  
The identification of the working regimes with vibrations consisted of checking the operation at nominal and maximum speeds of both the front drum vibrator and simultaneously (with both rollers active), as well as maintaining the frequency and amplitude of the roller vibrations at stable values over time to ensure a stable technological working regime.