Enhancement of Soft Soil Ground Using Synthetic China Nylon Cord Fiber

Structures constructed on soft and compressible soil are likely to be unstable due to possible failure of foundation by undrained shear yield of soil because of insufficient bearing capacity or unacceptably excessive settlement initiating violation of serviceability criteria. Therefore, it is imperative for civil engineers to use several kinds of ground improvement techniques to improve the soil’s stiffness and strength. This research introduces a specific ground improvement technique using China nylon cord fiber, collected from discarded tires, use as a reinforcement in soft soil. Such fibers are cheap and widely available locally. To study the effectiveness of such ground improve technique, firstly local soil is collected from the surrounding regions and a series of routine tests has been conducted to assess the engineering properties of the virgin soil. The experimental soil has been classified as ML, following the method of unified soil classification, ASTM. The fibers are gathered locally and fragmented into 10 mm, 20 mm, and 30 mm pieces. They are mixed with soil at 0.5%, 1%, 1.5%, and 2% by weight. The admixture-treated soil has been tested in the laboratory for assessing its compaction and penetration characteristics. As observed from Standard Proctor compaction tests, the optimum moisture content (OMC) and maximum dry density (MDD) of treated soil decrease in a nonlinear manner as the fiber content increases. Simultaneously, from California Bearing Ratio (CBR) tests, it has been found that a 20 mm length of 1% fiber mixed in soil yields the maximum value of CBR.