PINE NEEDLE REINFORCED SOIL FOR ROAD EMBANKMENT SLOPE PROTECTION-A LABORATORY STUDY

Abstract

A great interest in the research of naturally available materials had been evoked due to the lack of resources that are environment friendly. Randomly distributed fibre-reinforced soils have recently been a source of attraction for Engineers. The present work emphasizes on soil stabilization using pine needles. The pine needles are available as scrap material in abundance in hilly areas and therefore can be used for soil stabilization purpose taking into account both cost as well as easy availability of material. The present work therefore includes pine needle reinforced soil for road embankment slope protection and possible executive problems of using pine needles as natural fibers in soil reinforcement. This research work have been divided into four stages firstly collection of materials, secondly determination of physical and chemical properties of the materials, thirdly preparation of various mix designations considering different percentages of pine needles with and without adding fly ash, and finally GEO STUDIO software is used to carry out the slope stability analysis. In Geo STUDIO also a particular module called GEOSLOPE or SLOPE/W is used for analysis of stability of slope. The essential attributes like C,& 4 values are obtained by triaxial test. Whereas I values are obtained through the OMC & MDD obtained through proctor test. Also CBR test was conducted in order to check the load carrying capacity of the soil as well as suitability of the - soil for subgrade. It has been observed that the addition of pine needle & fly ash both individually and collectively to the soil results in a decrease in the CBR values of soil mixes. Soil engineering properties like angle of internal friction and cohesion increases considerably on admixing of pine needle irrespective of aspect ratio. However, the increase of internal friction and - cohesion was more pronounced for 53 aspect ratio in comparison to 27 aspect ratio. It can be stated from the results of the slope stability analysis of 5m, lOm & 1 5m high road embankment that the inclusion of pine needles and fly ash yields stable slopes with FOS? 1.5. The analysis of slope configuration designed also infers that the factor of safety (FOS) increases irrespective of height with the increase in pine needles and fly ash under both saturated as well as dry conditions.