## 5 Conclusions  
This paper investigated the effects of several types of cohesive-frictional soil and geotextile reinforcement configurations on the bearing capacity via a laboratory test and numerical simulation. The reinforcement used in this study was a woven geotextilethat was manufactured from the high strength polyester (PET). The four reinforcement configurations studied were: (i) horizontal planar form of geotextile, (ii) full-wraparound ends of geotextile with foundation soils, (iii) full-wraparound ends of geotextile with filled-in sand, and (iv) full-wraparound ends of geotextile with filled-in sand and sand replaced foundation soil. The studied foundation soils were mixtures of fine sand and sodium bentonite at different replacement ratios of 0%, 20%, 40%, 60%, 80% and 100% by the dry weight of sand. The bearing capacity ratio (\(q_{b}/q_{0}\)) was used to illustrate the bearing capacity improvement due to the geotextile reinforcement, where \(q_{b}\) = bearing capacity of RSF and \(q_{b0}\) = the bearing capacity of unreinforced soil. The following conclusions can be drawn from this study. 1. For unreinforced soil, the \(q_{b0}\) decreased as the PI increased because of the reduction of soil shear strength. The \(q_{b0}\) can be predicted in terms of PI using a polynomial function: \(q_{b0}\) = 0.0011(PI)\({}^{2}\) \(-\) 0.658(PI) + 255.28 when 0% \(<\) PI \(<\) 314%. The \(q_{b0}\) with various PI is satisfactorily predicted by [PERSON] (1963)'s equation. The laboratory investigation showed that the effective values of influence parameters for planar geotextile reinforcement were U/B = 0.3, W/B = 3.0, H/B = 0.5, and N = 4. 2. For the horizontal planar form of geotextile reinforcement, when PI \(<\) 30, the \(q_{b}/q_{0}\) increased with the increase in N from 1 to 4. The high soil-geotextile interface shear resistance tended to prevent the movement of soil particles and increased the bearing capacity. On the other hand, when PI \(>\) 30% (B40, B60, B80 and B100), the \(q_{b}/q_{0}\) development was comparatively low with the additional N, because the soil movement highly occurred only on the first layer. 3. For the full-wraparound ends of geotextile with filled-in foundation soils, when PI \(<\) 118%, the \(q_{b}/q_{0}\) was improved in a range of 1.77 to 3.30 for B0, 1.45 to 1.90 for B20, and 1.44 to 1.75 for B40 when the N value increased from 2 to 4. Nevertheless, when PI \(>\) 118%, the \(q_{b}/q_{0}\) was lower than 1.25 for all N values. When compared to the horizontal planar form of geotextile, the \(q_{b}\) development in full-wraparound ends of geotextile was higher for the same foundation soils. 4. For the full-wraparound ends of geotextile with filled-in sand, the \(q_{b}/q_{0}\) value increased when the N increased from 2 to 4. For foundation soil with PI \(<\) 181%, the applied stress distributed through the foundation soil under the footing to the geotextiles effectively. However, the soil above the RSF was largely deformed with the low stiffness of soil with PI \(>\) 181% on the comparably stiffer RSF. With sand backfill under the footing, the \(q_{b}/q_{0}\) increased linearly with the increase of N from 2 to 4. The \(q_{b}/q_{0}\) varied from 1.35 to 3.34 for B20, 1.86 to 2.87 for B40, 1.66 to 2.91 for B60, 1.67 to 3.03 for B80, and 1.15 to 2.61 for B100. 5. The horizontal planar reinforced soils, the full-wraparound ends of geotextile with filled-in foundation soil, and the full wraparound ends of geotextile with filled-in sand, were recommended for foundation soils with PI \(<\) 30%, PI \(<\) 118%, and PI \(<\) 181%, respectively. The sand backfill above the full wraparound ends of geotextile with filled-in sand can help effectively transfer the applied stress to RSF, hence the significant improvement in \(q_{b}\). 6. It is kept in mind that the studied results are only valid for a woven geotextile. However, the knowledge gained from this research can be used as a guideline for further studies on different types of geosynthetics. Conceptualization and methodology, G.S. and P.S.