Sanjer Bela Civil Engineering Site

  1)      What is meant by capillary rise in soil? How does it affect the pre-water pressure?   Capillary rise is the upward movement of water through the tiny pores (voids) in soil due to surface tension and adhesive forces between water and soil particles. This occurs above the water table , where the soil is unsaturated , but moisture is still present.   ü   Effect on Pore Water Pressure:   ·         In the capillary zone , pore water pressure is negative (also called suction or tension ). ·         This negative pressure increases the effective stress in the soil (since effective stress = total stress − pore pressure). ·         Result: Soils in the capillary zone can gain apparent strength due to suction.    

1)    What is meant by capillary rise in soil? How does it affect the pre-water pressure?   Capillary rise in soil refers to the upward movement of water through the soil pores due to capillary action, which is the result of surface tension and the adhesion of water molecules to soil particles. This phenomenon is especially significant in fine-grained soils (like silts and clays) because they have smaller pores that create stronger capillary forces.   Effect on Pore Water Pressure:   1)      Negative Pressure 2)      Increased inter granular pressure 3)      Enhanced effective stress 4)      Saturation effects