Accurate simulation for strength-degrading effects of geomaterials via a decoupling approach to treating tension-compression asymmetry

Abstract This study focuses on a new and high-efficiency approach in a unified sense of accurately simulating strength-degrading effects for geomaterials, including non-symmetric hardening-to-softening effects in tension and compression as well as non-symmetric tensile and compressive stiffness-degrading effects during unloading. It is intended to bypass both modeling and numerical complexities involved in existing approaches. To this goal, new elastoplastic equations are established with new numerical techniques. With a decoupling technique of treating tension-compression asymmetry, the foregoing complex effects are automatically incorporated as inherent response features of the new elastoplastic equations, thus bypassing usual modeling complexities. A new numerical technique of renormalizing piecewise spline functions is introduced to resolve the central yet tough issue of obtaining accurate and unified expressions for the tensile and compressive strength functions, thus bypassing usual numerical complexities and uncertainties in treating numerous unknown parameters and multiple ad hoc criteria. As such, the new approach is not only of wide applicability for various geomaterials but also of high computational efficiency with no more than three adjustable parameters. Toward validating the efficacy of the new approach, numerical examples for granite, salt rock, and sandstone-concrete combined body as well as plain concrete, high-performance concrete, and ultrahigh-performance concrete are presented by comparing model predictions with multiple data sets for strength-degrading effects in tension and compression.