岩石是人类应用最古老的工程结构材料之一,混凝土是现代土木、水利、交通等工程中应用最广泛的材料。它们大多处于复杂应力状态(多轴应力)下工作。强度理论研究材料在复杂应力状态下发生屈服和破坏的规律,并为工程结构设计提供必需的设计准则。因此,强度理论研究具有重要的理论意义、广泛的工程实际意义和巨大的经济意义。 Rock is one of the oldest engineering structural materials used by humans. Concrete is the most widely used material in modern civil engineering, water conservancy, and transportation projects. Most of them work in complex stress states (multiaxial stress). The strength theory studies the law of yield and failure of materials under complex stress conditions and provides the necessary design criteria for engineering structural design. Therefore, the study of strength theory has important theoretical significance, a wide range of engineering practical significance and great economic significance.