Friday, January 3, 2014

GATE, PSUs preparation- Soil Engineering ( notes)- Part 7

Hello there,
Welcome to the part 7 of the one liner notes useful for the preparation of GATE and other similar examinations.

  • In a triaxial compression test when drainage is allowed during the first stage(i.e. application of cell pressure) only and not during the second stage (i.e. application of deviator stress at constant cell pressure), the test is known as consolidated undrained test.
  • When a sample of sand is sheared under undrained condition, then volume of sample does not change.
  • The ratio of the undisturbed shear strength to the remoulded shear strength in the cohesive soils under undrained conditions is greater than 1.
  • Sensitivity of a soil can be defined as ratio of compressive strength of unconfined undisturbed soil to that of soil in a remoulded state.
  • Rankine's theory of earth pressure assumes that the back of the wall is vertical and smooth.
  • The major principal stress in an element of cohesion-less soil within the backfill of a retaining wall is vertical if the soil is in an active state of plastic equilibrium.
  • The effect of cohesion on a soil is to reduce the active earth pressure intensity but to increase the passive earth pressure intensity.
  • Co-efficient of earth pressure at rest is greater than the active earth pressure but less than passive earth pressure.
  • Total lateral earth pressure is proportional to square of depth of soil.
  • Cohesive soils are poor for back-fill because of large lateral pressure.
  • Base failure of a finite slope occurs when the soil below the toe is relatively soft and weak.
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1 comment:

  1. When a sample of sand is sheared under undrained condition the why volume down not change ,,,,please explain

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