Anti-sliding stability of a gravity dam on complicated foundation with multiple structural planes

Anti-sliding stability of a dam foundation is one key problem that affects engineering safety. High gravity dams are typically built on complicated foundations, and maintaining their stabilities can be very challenging due to the formation of natural sliding paths from multiple weak structure planes. This paper presents two geomechanical model tests to study the stabilities of a foundation before and after reinforcement. By testing the original foundation, the resultant test results demonstrate that the stability safety factor is low and the associated weak structural planes are control factors therein. Subsequently, a sensibility analysis is performed to study the impacts of weak structural planes on foundation stability. Some reinforcement measures have been adopted accordingly, and the stability of the reinforced foundation is further studied in another model test. The second test indicates that the reinforcement effect is satisfactory in that, after reinforcement, the working performance and stability of the investigated foundation are greatly improved. These research results provide an important scientific basis for the evaluation of safety and reinforcement effectiveness in a gravity dam project.

► Stabilities of a foundation before and after reinforcement are studied by two model tests.
► Test results show that the stability of the original foundation is serious.
► Structural planes are found to be the primary control factors for stability.
► Different impacts of the structural planes are studied by a sensibility analysis.
► A concrete cutoff trench is verified to effectively improve the stability of the foundation.