Application of Crosshole seismic tomography method in quality control and evaluation quality of Roller Compacted Concrete Dam

From the late years of 20th century up to now, in the world as well as in Vietnam, hydropower projects has been constructed very strongly, roller compacted concrete dams (RCC) have been built in almost countries. Recently, some RCC dams behaved abnormally such as permeability, crack, etc for a period of commercial operation which resulted in the fact that RCC quality changed adversely endangering to dam safety. The point is which geophysical method should be used to control, evaluate the RCC quality without affecting RCC dam integrity, contributing to the forecast of dam body stability and safety. Crosshole Seismic Tomography (CST) which is a Non-Destructive Testing (NDT) method is considered to be a good solution to solve this problem. In this article, the author shall discuss the advantages, preliminarily theoretical basis of the CST method and introduce some studied results performed by Power Engineering Consulting joint stock No.1 Co. (PECC1) in Vietnam.