ABSTRACT
Soils located above the groundwater table such as residual soils are generally unsaturated DQGSRVVHVVQHJDWLYHSRUHZDWHUSUHVVXUHV&OLPDWLFFKDQJHVLHHYDSRUDWLRQDQGLQ¿OWUDWLRQDQGWUDQVSLUDWLRQLQÀXHQFHWKHZDWHUFRQWHQWDQGWKHQHJDWLYHSRUHZDWHUSUHVVXUHRI the unsaturated soil, especially those located in the proximity of the ground surface. As a result, hydraulic properties, shear strength and volume of the soil change in response to cliPDWLFFKDQJHV7UDGLWLRQDOVRLOPHFKDQLFVSUDFWLFHVKDYHH[SHULHQFHGVLJQL¿FDQWFKDQJHV during the past few decades. Some of these changes are related to increased attention being given to the unsaturated soil zone above the ground water table. The computational capaELOLW\DYDLODEOH WR WKHJHRWHFKQLFDOHQJLQHHUKDVVWURQJO\ LQÀXHQFHG WKHHQJLQHHUV¶DELOLW\ WRDGGUHVV WKHVHFRPSOH[SUREOHPV7KHXQVDWXUDWHGVRLO]RQH LV VXEMHFWHG WRDÀX[ type boundary condition for many of the problems faced by the geotechnical engineers. Unsaturated soil mechanics has become a necessary tool for analyzing tzhe behavior of soils in this zone. This chapter presents some examples of unsaturated soil problems. Some basic physical relationships associated with unsaturated soil mechanics are outlined. Some H[DPSOHVRIODERUDWRU\DQG¿HOGWHVWVFDUULHGRXWRQXQVDWXUDWHGUHVLGXDOVRLODUHDOVRSUHsented.
