Performance of Compacted Clayey Soil Stabilized Using Different Reinforcements
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2024-05-14
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Abstract
This study focuses on the use synthetic fibers and geotextile to improve the performance of soil supporting foundations. The research methodology was divided into two parts: the first part to assess the performance of the reinforced soil supporting the foundation through a comprehensive series of tests, including compaction tests, unconfined compression strength tests, CBR tests, and model footing load tests. The reinforcement materials used in this study include polypropylene fibers, glass fibers and woven geotextile. Fibers were randomly distributed within the soil, with five different ratios (0.6, 0.8, 1, 1.2, and 1.5%by weight of the soil) tested for their impact. The model footing load tests were conducted on a top layer reinforced with synthetic fibers at three thicknesses: 0.5B, 1.0B, and 1.5B (where B represents the width of the footing). Additionally, WG layers were added at varying distances and different parameters studied such as the optimum distance between the footing and the first reinforced layer, the number of layers. The second part included, experimental results of model footing tests conducted on soil reinforced with fibers and geotextile for shallow foundations was simulated with PLAXIS 3D.
The maximum dry density decreased from 1.852 g/cm³ to 1.65 g/cm³ and 1.75 g/cm³ after adding percentage up to 1.5% polypropylene fibers and glass fibers, respectively. While the optimum moisture content did not show a significant change decreased from 15% to 14.7% and 14.9 %. after adding percentage up to 1.5% polypropylene fibers and glass fibers, respectively. And the results showed that the compressive strength of the soil were significantly improved when PPF and GF were used as reinforcing materials. The UCS value increased from 122 kPa to 458 kPa and 249 kPa after adding the optimum percentage 1.2% polypropylene fibers and glass fibers, respectively.Additionally, the CBR value slightly increased about 63%, 42%, after adding the optimum percentage1.2% PPF and GF. Also, the test results showed that the inclusion of PPF, GF, and WG can significantly improve the soil bearing capacity and reduce settlement. Concerning of polypropylene fibers and glass fibers, ultimate bearing capacity (qu) was clearly increased as the thickness of the improved layer increased. The (qu) of the top layer reinforced with polypropylene fibers and glass fibers increases about 51% and 62% at thicknesses of 1.5B, respectively.
In the case of woven geotextile. It is concluded that the depth of the first layer effects on results. It is observed that BCR is initially increased up to the depth 0.35B and then gradually decreased, peaking at u/B = 0.35. The test results also showed that the BCR increased with increasing the number of reinforcement layers until a certain value three layers, the reinforcing effect becomes negligible.
The Finite element method with the help of Plaxis-3D software showed that polypropylene fibers, glass fibers and geotextiles can be successfully used to increase the bearing capacity of soil. The optimal design criteria were also explored which may increase the use of these materials in the construction of foundations on reinforced soils.