Problems related to disposal of high level radioactive waste and municipal waste as well as CO2 storage are crucial environmental issues and therefore have attracted particular attentions in many countries. Nowadays, number of important achievements have made in these fields in terms of theoretical development, laboratory and field testing and numerical analysis. It appears now important for the actors including engineers, researchers and students to meet through a platform in order to exchange ideas and experiences. On the other hand, unsaturated soil mechanics has been well involved in these fields because of the different thermo-hydro-mechanical phenomena in relation to heat/water/gas/nuclide transfers in engineered/geological barriers in unsaturated state during both construction and exploitation stages. It is therefore interesting to include the topics of unsaturated soils in this platform. This is the goal of the International Symposium on Unsaturated Soil Mechanics and Waste Disposal-UNSAT-WASTE.
After the successful editions in 2005, 2009 and 2013, the fourth one will still be held in Shanghai, China, on July 14-16, 2017. The Symposium program consists of two main topics: unsaturated soil mechanics and waste disposal including nuclear and municipal waste repository as well as CO2 storage. All accepted papers will be included in the Symposium proceedings. Moreover, good papers will be selected for publication either in Engineering Geology or in Journal of Rock Mechanics and Geotechnical Engineering.
Some outstanding researchers and engineers over the world will be invited to deliver Keynote/invited lectures. We believe that their participation will greatly contribute to the success of the Symposium.

All accepted papers will be included in the Symposium proceedings. Moreover, good papers will be selected for publication either in Engineering Geology or in Journal of Rock Mechanics and Geotechnical Engineering.