A novel vibro-penetration test (VPT) for the investigation of cohesionless soils in the field

• Published in: Soil dynamics and earthquake engineering (1984) 2019-11, Vol.126, p.105760, Article 105760
• Main Authors: Cudmani, Roberto, Manthey, Sven
• Format: Article
• Language: English
• Subjects: Acceleration; Calibration chamber tests; Cohesion; Cohesionless soils; Field investigation; Finite element analysis; Harmonic excitation; Hypoplasticity; Parameters; Penetration resistance; Penetration tests; Soil dynamics; Soil investigations; Soil mechanics; State variable; Test procedures; Vertical forces; Vibratory driving; Vibro-penetration test
• ISSN: 0267-7261; 1879-341X
• DOI: 10.1016/j.soildyn.2019.105760

A novel dynamic penetration testing method for the investigation of cohesionless soils based on the principles of vibratory driving has been developed. During the so-called vibro-penetration test (VPT), a vertical harmonic excitation force drives a rod with a conical tip into the ground. The penetration resistance is defined as the number of excitation cycles Nz10 required for 0.10 m penetration with a reference driving energy. In order to evaluate Nz10, the tip and shaft resistance, the tip acceleration and the depth of the penetrometer tip are recorded during driving and the data are evaluated according to a proposed vibro-penetration model. Experimental and numerical investigations are carried out to investigate the soil response, validate the mechanical model and evaluate the influence of the density, the effective stresses and the machine parameters on the vibro-penetration resistance. The results show that the Nz10 – values are reproducible, correlate unambiguously with the state variables but depend on the machine parameters to some extent. In comparison with the CPT, the VPT shows similar sounding records. However, the required equipment is much lighter, the execution faster and in-situ investigations of medium dense to dense cohesionless soils at large depths are feasible. •Novel Vibro-Penetration Test (VPT) based on the principles of vibratory driving.•The penetration resistance Nz10 is defined considering a reference energy.•The actual energy delivered at the tip is calculated each cycle.•Experimental and numerical investigations for validation and evaluation of the VPT.•Demonstration of the VPT and comparison with CPT results in the field.