Abstract：Construction sequences and support parameters have strong influence on stability of giant underground caverns. Based on 3D fracture and damage FEM and fundamental principles of dynamic construction mechanics，numerical simulations are conducted to obtain the optimal construction sequences for the caverns constructed in high dipping laminar strata of Longtan hydropower station，China. The size of the powerhouse caverns is the largest in the world. The optimal construction sequences of the caverns are obtained by comparing the damaged zone of surrounding rock mass with displacements of key points around the caverns. The numerical methods and some conclusions from the research work are useful for the design and construction of analogous rock engineering.
