Can Ayday

Estimating rock mass properties using Monte Carlo simulation: Ankara andesites

In the paper, a previously introduced method (Sari, 2009) is applied to the problem of estimating the rock mass properties of Ankara andesites. For this purpose, appropriate closed form (parametric) distributions are described for intact rock and discontinuity parameters of the Ankara andesites at three distinct weathering grades. Then, these distributions are included as inputs in the Rock Mass Rating (RMR) classification system prepared in a spreadsheet model. A stochastic analysis is carried out to evaluate the influence of correlations between relevant distributions on the simulated RMR values. The model is also used in Monte Carlo simulations to estimate the possible ranges of the Hoek-Brown strength parameters of the rock under investigation. The proposed approach provides a straightforward and effective assessment of the variability of the rock mass properties. Hence, a wide array of mechanical characteristics can be adequately represented in any preliminary design consideration for a given rock mass.

Investigation of correlations between shear wave velocities and CPT data: a case study at Eskisehir in Turkey

Seismic waves result from fault movement during earthquakes. Depending on the features of the physical environment through which they pass, there are variations in the velocity and amplitude of body waves, which occur underground, and surface waves, which occur on the Earth’s surface. The ratio of shear wave velocity (Vs) to near-surface velocity is a parameter used widely in land use planning to predict the potential for amplified seismic shaking, especially in urban areas. The main objective of this study was to estimate Vs by using cone resistance (qc) and lateral friction (fs) for a study area at Eskisehir Graben, to help mitigate geotechnical earthquake engineering problems in civil engineering and land use planning. In geotechnical shallow soil research, certain geophysical methods are used for measuring Vs—a major form of seismic energy propagation—at the near surface. In this study, cone penetrometer data collected from seismic cone penetration tests (SCPT) includes qc, fs, and downhole Vs. S-type seismic energy waveforms, which are produced on the surface, were measured at different depths using an S-type geophone in the city center of Eskisehir via SCPT. With SCPT, qc, friction ratios (Rf), and Vs values were measured at 42 different test points. Rf properties are associated with soil thickness, and these were compared with dynamic soil properties (Vs) using a standard statistical method; we calculated correlations amongst Vs, qc, and Rf measured from cone penetration tests.