SUCTION CHARACTERIZATION AND EFFECT OF DRYING - WETTING CYCLE ON DESILTING MATERIAL OF RESERVOIR: A REVIEW

Abstract: Desilting of reservoir and erosion both are major problems in the tropical country like India. The aim of this research work is to analyze the effect of drying-wetting cycle (WD Cycle) which plays an important role on erosion properties. To analyze the effect of drying-wetting cycle, suction is most important parameter. To evaluate its suction characteristics at variable moisture content using filter paper method were used as per ASTM D5298-10. Further, Total, metric and osmotic suction are evaluated for the Un-soaked sample at 10, 20C and 40C for different water content. The same methodology will be use to obtain suction, characteristics of soaked sample. The sample is prepared using same methodology and then soaked for 24 hrs. in tap water. SWCC curve were derived to get effect of weather cycle on desilting material of erosion. And from all the results of suction and SWCC curve it is concluded that in wetting cycle and in soaked condition suction is considerably less than Un-soaked sample and erodibility factor is less for soaked condition under wetting cycle as suction is less. Results also indicate that as temperature increase suction in desilting material is reduced. The value of suction in first WD Cycle varies from 570 kPa to 668 kPa and in third cycle it varies from 262 kPA to 357 kPa. The results indicate that in first weathering cycle during drying phase suction is more and then decreased and in wetting face it decreases sharply. After third WD cycle the material is susceptible to erosion as suction is reduced and shear parameters are reduced. And this effect cause erosion of canal bed and it is clear that as WD cycles increases the erosion of bed increases. The Manning’s coefficient is get affected by the present of suction. So, suction should be considered as parameter to determine the resistance coefficient of the channel. The Manning’s coefficient decreases with increasing rate of suction this study has been undertaken to investigate the determinants of stock returns in Karachi Stock Exchange (KSE) using two assets pricing models the classical Capital Asset Pricing Model and Arbitrage Pricing Theory model. To test the CAPM market return is used and macroeconomic variables are used to test the APT. The macroeconomic variables include inflation, oil prices, interest rate and exchange rate. For the very purpose monthly time series data has been arranged from Jan 2010 to Dec 2014. The analytical framework contains.