{"id":3548,"date":"2024-09-05T18:09:28","date_gmt":"2024-09-05T12:39:28","guid":{"rendered":"https:\/\/study.madeeasy.in\/?p=3548"},"modified":"2025-08-13T13:15:24","modified_gmt":"2025-08-13T07:45:24","slug":"preconsolidation-pressure","status":"publish","type":"post","link":"https:\/\/www.madeeasy.in\/study\/ce\/soil-mechanics-foundation-engineering\/preconsolidation-pressure","title":{"rendered":"Preconsolidation Pressure"},"content":{"rendered":"

The maximum pressure to which an overconsolidated soil had been subjected in the past is known as the preconsolidation pressure or over-consolidation pressure (\u03c3c<\/sub>) . When a soil specimen is taken from a natural deposit, the weight of the overlying material (over-burden) is removed. This causes an expansion of the soil due to a reduction in pressure. Thus the specimen is generally pre-consolidated or over-consolidated. When the specimen is loaded in the consolidation test, the initial portion AB of the compresion curve ABCD is actually a recompression curve. Consequently, the initial portion AB is relatively flat. It is followed by a straight line CD with a steep slope which indicates the compression of a virgin (normally consolidated) soil.<\/p>\n

In the transition range BC, the slope gradually changes. The preconsolidation pressure (\u03c3c<\/sub>) falls in this range. It can be obtained using the method given by Casagrade.<\/p>\n

\"Pre<\/p>\n

The procedure consists of the following steps:<\/h2>\n
    \n
  1. Determine the point E on the curve where the curvature is maximum, i.e., the radius of curvature is minimum.<\/li>\n
  2. Draw the tangent EF to the curve at E.<\/li>\n
  3. Draw horizontal line EG at E.<\/li>\n
  4. Bisect the angle between the tangent EF and the horizontal EG, and draw the bisector EH.<\/li>\n
  5. Produce back the straight line portion CD of the curve and determine the point of intersection P of the bisector EH and the backward extension of CD.<\/li>\n
  6. Draw the vertical PJ through P which cuts the log \u03c3 -axis at J. The point J indicates the preconsolidation pressure \u03c3c .<\/li>\n
  7. The vertical PJ cuts the curve at point K. The portion ABK of the curve represents the recompression curve and the portion KCD as the virgin compression curve.<\/li>\n<\/ol>\n

    Length of Drainage Path<\/h3>\n