DIAGNOSTIC STUDY OF FAILED CANAL SLOPES

Abstract

Slopes either occur naturally or are engineered by humans. Slope may be artificial, as in cuttings, for embankments highways, railroads, earth dams, temporary excavations etc. Slopes can also be natural as hillside and valleys, coastal river cliffs and so on. In all this cases forces exist, which tend to cause the soil/rock to move from high points to low points. Slope stability problems have been faced throughout history when human being or nature has disrupted the delicate balance of natural slopes. A quantitative assessment of the stability of slope is clearly important when judgment is needed about whether the slope is stable or not and decision is to be made as consequence.. In the present work diagnostic study of failed canal slopes has been done. For the study failed slope of Ban Sagar Feeder Canal has been chosen. The study consists of five major aspects viz; field visit for site investigations, laboratory tests to asses representative shear strength parameters, back analysis of failed sections, stability analysis's of existing slopes and finally the remedial measures for the unstable sections. The Ban Sagar Feeder Canal (70 km ), proposed to carry the water from the Ban Sagar dam and discharge into the Adwa reservoir. In many reaches along the canal the slopes failed. The failures occurred mainly during and after the rainfall. The stability of existing profile is checked. For this, ten cross sections at different chainage have been taken. The back analysis was first carried to get the shear strength parameters. The stability analysis shows some sections are unstable. The stability of sections was studied for different pore pressure parameter. The remedial measures are suggested for the unstable sections.