Application of Geogrids on the Geotechnical Properties of Subgrade Materials under Soaked Condition

Abstract

Highway construction is one of the main engineering design and construction in civil engineering in many countries all over the world. Existing studies have shown that civil engineers engaging in highway construction have several challenges during road construction especially as it is related to the topography of the site ,inadequate subgrade soil and high water table, inspite of this challenges ,the application of geogrids as a geotechnical property is imperative to improve the subgrade of soils with soaked condition.

Soil samples were labeled (A, B& C) at random. These samples were taken to the Laboratory for experiments to identify and determine the Grain size analysis, atterberg, compaction and California bearing ratio by placing the geo-grids at varying depths and in single layer under soaked conditions (48hrs) to determine the strength of the soil samples. The geogrids were introduced in three independent single layers i.e. 2/5, 3/5 and 4/5 the distance from the base of the mould. Samples A, B&C (3%, 9% &6%) respectively, shows that the strength of subgrade is considerably increased by introducing geo-grids reinforcement in the soil. It is found that geo-grids placed at 3/5 the distance from the base showed higher CBR value(15.1%,14% & 12.2%) than when placed at 2/5 (12.8%,11% & 8.8%) and 4/5(11%, 10% & 8.3%) distances from the base.

The differences in the behavior of the soil under soaked conditions improve on increasing the number of layers of geo-grids. As a subgrade stabilizer it has shown great effect of improvement. It can be used to improve poor lateritic materials due to its low maintenance, corrosion resistance and increment in the service life of road pavement. This application of geogrids is a means to improve the strength of basic engineering and geotechnical properties of poor subgrade soils under soaked condition. This  will reduce land wastage, uneconomical design of road construction. Geo-grids should be employed as a modernized form of improving road construction on poor subgrade materials.

Keywords: geogrids, CBR, highway construction, soaked conditions, reinforcement, subgrade.