Investigation on Geosynthetic Reinforced Two Layered Soil System

Use of geosynthetics for flexible pavements founded on expansive soil subgrade is one of feasible and economic solution to minimize the undulation and required pavement thickness. In this present investigation the effect of inclusion of the geosynthetic reinforcement on California Bearing Ratio (CBR) value of a two layered soil system with black cotton soil at bottom and granular soil at top as a buffer layer, with different thickness configuration and geotextiles of different physical and mechanical properties was studied by laboratory and field California bearing ratio tests. Thickness of flexible pavement over the two layer soil system of different thickness configurations was estimated for unreinforced and reinforced two layered soil system by the method suggested by United States Army Corps of Engineers and Indian Road Congress. The reduction (%) in the thickness of pavement due to inclusion of geotextiles has been observed in the investigation. The reduction in thickness of pavement can be achieved up to 53.53% depending upon the thickness configuration and the type of the geotextile used. The results have shown that the field CBR tests can yield the results in conformity with the values obtained in the laboratory test

Case Study of Failure of a R.C.C. Counterfort Retaining Wall

It is a fact that the retaining wall failures have occurred in the distant past as also in recent times and will recur inevitably in future. The reasons of failure are ultimately the errors of judgment to which no humans including the greatest of engineers are immune. Free flow of information on failure incidents is greatly inhibited in most of the cases by the natural tendency to avoid publicizing our mistakes although all human are prone to them. The present study through light on a failure of a recently constructed R.C.C. counter fort Retaining wall. The wall is located near Sangli city in Maharashtra state of India. The wall was constructed in 2003 and there was a heavy rainfall occurred in all over the Maharashtra state continuously in the year 2005 and 2006 subsequently in the catchments of river Krishna. The wall could not sustain the flood impact and there was a sliding, collapse and even rotational failure at some portion of wall was observed. Basically this wall was constructed to protect a village road about 1800m along a stream from flood water. Failure of any structure is usually not attributable to a single cause but in the present case at the prima-facie, it seems that the wall failed due to heavy flood and backwater in the stream from river Krishna and the improper design criteria. The other principle causes of the failure are found out and the remedial measures have been suggested. In this article, an attempt has been made by the authors to make an unbiased technological analysis of the data available, motivated by a desire to find ways of avoiding past mistakes and not sitting on judgment on them