The MRT Orange Line construction works in Bangkok are more complicated than works in earlier projects. As the tunnel alignment passes through the congested urban areas in the city, it either clashes with or passes beneath several existing structures. Underpinning works are then required. Assessment of movement of ground and structure plays an important role in the project. The rebound of piezometric pressure in sand layers that is being developed poses a major point of difficulty in the excavation and underground structure design and construction. Groundwater control measures become a crucial issue in MRT Orange Line project that leads to difficulties in deep MRT station excavations. To control base instability, various methods (e.g., cut-off wall, staged excavation) are introduced and presented in this article.