Issue 53

A. Namdar, Frattura ed Integrità Strutturale, 53 (2020) 285-294; DOI: 10.3221/IGF-ESIS.23.22 291 of safe bearing capacity in soil mixture design. The shape of the histogram is skewed right. There is a large number of cases with low value of safe bearing capacity and few for high value. 0 500 1000 1500 2000 2500 3000 3500 0 2 4 6 8 10 12 14 16 18 Frequency Safe Bearing Capacity(kN/m 2 ) Safe Bearing Capacity(kN/m 2 ) Figure 4: The safe bearing capacity according to the number of occurrences. The internal angle of friction of soil has more influence on safe bearing capacity prediction. The increasing density, cohesive and internal angle of friction of mixed soil results in increasing the safe bearing capacity of the soil foundation, while the soil with higher moisture hurts the safe bearing capacity. The increase of optimum moisture content of the soil causes the reduction of density, cohesive and internal angle of friction of mixed soil and it results in the reduction of soil safe bearing capacity. The input, hidden and output layers of the ANN are constructed for assessing the effect of modification of soil mechanical properties in the prediction of the safe bearing capacity mechanism of the soil foundation. Tab. 2 shows the statistical analysis for examining the influence of each mechanical properties on safe bearing capacity. For the cover effect of each element of the mechanical properties in the prediction of the safe bearing capacity, R 2 and RMSE showed that the combination of all mechanical properties together enhances the accuracy of the safe bearing capacity prediction results. The mechanical properties interaction increases the safe bearing capacity of the mixed soil. According to Tab. 2, the value of the R 2 and RMSE for all mechanical properties effects on safe bearing capacity are 0.98 and 0.02, these values can provide a suitable accuracy for the prediction of safe bearing capacity of the mixed soil. The higher inaccuracy obtained when only the influence of the cohesive of the mixed soil is considered in the prediction of the safe bearing capacity. Mechanical properties R 2 RMSE Optimum Moisture Content 0.731 0.683 Density 0.597 0.293 Angle of friction 0.861 0.230 Cohesive of Soil 6.04E-4 10.97 All mechanical properties 0.98 0.02 Table 2: Statistical analysis for realizing the influence of each mechanical properties on safe bearing capacity. D ISCUSSION he mineralogy and the morphology of the soil interaction in the soil mixture process cause the distribution of the mechanical properties of the mixed soil and they lead to the development of the different levels of safe bearing capacity for each mixed soil. The moisture content of a mixed soil significantly affects the mineralogy and the morphology of the soil interaction. The optimum moisture content (%), density (kN/m 3 ), angle of friction (deg) and cohesive of soil (kN/m 2 ) never behave linearly in a group of mixed soils because of mechanical properties interaction. The T