8.CONSOLIDATION

                   

Compaction:

          Compression is the process of expulsion of air from the voids by applying the load for short period of time. It is usually called as compaction.

Consolidation:

          Consolidation is the compression process by expulsion of water from saturated soil voids under a steady static and longtime pressure. Such a process of Consequent escape of pore water is called as consolidation. Consolidation rate is mainly depends upon the permeability of soil. The opposite process of consolidation is called swelling.

          Primary Consolidation:

          It is the compression of soil mass due to expulsion of water from the voids.

Secondary Consolidation:

          It is the compression of soil mass due to expulsion of highly viscous water and plastic re-adjustment of solid particles.

           1.Compression index  

                                            C_c = 0.007 (W_L - 10) for remoulded soil

                                             C_c = 0.009 ( W_L - 10) For Undisturbed soil

            2. Consolidation settlement    

             3.Co-efficient of volume change (mv) :

          It is the change in volume of soil per unit of initial volume due to unit increase in pressure.

  

           4.Co-efficient of consolidation      

           5..Time factor 

                              Here

                                t = Time of consolidation

                                d= Drainage path or thickness

                                  = H for single drainage

                                  = H/2 for double drainage

               6.Load Distribution Factors

                          Change in stress due to consolidation is calculated 
                  based on the load distribution factor.

                             For 1:2 load distribution, the stress is

For 1:1 load distribution, the stress is

See example problems on this topic:

Example problems

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