Time-Dependent Material Properties of Shotcrete: Experimental and Numerical Study

Area of Science:

• Civil Engineering
• Materials Science
• Geotechnical Engineering

Background:

• Shotcrete is a critical material in underground construction, particularly in tunnels.
• Existing experimental data on shotcrete's mechanical properties, especially at early ages, is limited and outdated.
• Advanced constitutive models for shotcrete behavior require validation with recent, comprehensive experimental data.

Purpose of the Study:

• To present a new experimental program investigating the evolution of shotcrete properties.
• To evaluate and compare experimental results with existing literature data.
• To validate and assess the capabilities of three advanced constitutive models for shotcrete.

Main Methods:

• Conducting laboratory tests on shotcrete specimens from the Brenner Basetunnel site, starting at very young ages.
• Measuring Young's modulus, uniaxial compressive strength, shrinkage, and creep.
• Validating constitutive models (Meschke, Schädlich and Schweiger, Neuner et al.) using the generated test data.

Main Results:

• Comprehensive experimental data on shotcrete's early-age mechanical properties were obtained.
• The study identified discrepancies between new data and older literature values.
• The performance of advanced shotcrete models was assessed against the new experimental dataset.

Conclusions:

• The experimental program successfully closed the gap between outdated shotcrete data and advanced modeling capabilities.
• The validated models offer improved accuracy for predicting shotcrete behavior in underground structures.
• This research provides a crucial link for the reliable application of advanced shotcrete models in engineering practice.