critical path method: 

The critical path method (CPM) & project Evaluation and Review Technoque (PERT) are numerical techniques which construction management can use as an aid in planning , scheduling and controlling any project.

For details of critical path mehtod click here.

Basic Types Of soil:

A large part of the eath is covered with rocks and vellys.each of them is bieng made with the consolidation of the soil .there are different types of the soil to know about the soil types   click here.

Soil structures:

There are different types of soil structures possible but some of them are most common to know more about them   Click Here