The tunnel boring technique poses significant demands on the stability of the tunnel tube, which depends on various factors including the time-dependent strength and stiffness development of the annular gap filling material. To conduct a finite element analysis of the material behavior, reliable material parameters such as modulus of elasticity or stiffness modulus are often lacking, requiring assumptions to be made. These assumptions are typically based on the relationships between material parameters in concrete technology, which can be inaccurate for annular gap filling materials as their consolidation and hardening behavior differs from that of standard concretes. Hence, it is crucial to model the time-dependent behavior of the annular gap filling material in a nuanced manner to maintain the stability of the tunnel tube. To optimize the effective and durable use of two-component mortars, determining relevant material properties in the laboratory at an early stage is vital. This study presents the determination of soil mechanical parameters “cohesion and constrained modulus” as supplementary material parameters for two-component mortars.