Model study on geotextile reinforced railway subgrade

Abstract

The high speed trains in railway infrastructure impose high level of stress in the railway subgrade. In order to have high bearing capacity, for the construction of railway subgrade, high strength materials should be used. In the present study the railway subgrade with layers of geotextile is proposed. CBR test has been carried out at OMC and soaked conditions. Samples have been prepared by static compaction and the experiment has been carried out for five types of samples with reference to geotextile layer placement in the mould. A load vs. settlement curve has been plotted for each case mentioned above. Then a graph is drawn in order to study the variation of CBR value with number and location of geotextile layer. The purpose of CBR test has been to study the effect of location and number of geotextile layer on CBR value of subgrade soil. A model box of size 1 m × 1 m × 1 m has been constructed from steel sheets. A simple hydraulic jack loading system manually operated with a calibrated proving ring of capacity 5000 kN has been used for loading arrangement. The silty sand was placed in the box in three layers, each being 12 cm thick and compacted at OMC. The base course (aggregate size 20 mm) and sub-base course (aggregate size 40 mm) was of 7.5 cm each. The plate used for applying load is of mild steel with 20 cm diameter. Load is applied by jack and settlement was observed by dial gauge. The plate bearing test has been carried out on model subgrade section.