Use of Penetration Methods for Evaluation of Ground Bearing Capacity

Abstract

Reliable off - road trafficability assessment hinges on in - situ penetration testing that captures depth - dependent soil strength across moisture states and translates it into operational pass/fail decisions. We present a field - deployable workflow centred on c one (static) and dynamic penetration methods. In the static branch, Cone Penetration Tests (CPT) advance a conical probe at a constant 20 mm s⁻¹, logging cone resistance (q₍c₎) and sleeve friction (f₍s₎) continuously or at 10 – 20 cm intervals; in the dynami c branch, DPL/DPM/DPH/DPSH tests derive specific dynamic resistance from standardized hammer blows with friction corrections at 1 m steps. From penetration records we compute Cone Index (CI) and Remoulding Index (RI) and derive the Rating Cone Index (RCI = CI·RI) for dry, moist, wet conditions, anchored to laboratory - verified USCS classes. We compile RCI look - ups for dominant soils (e.g., SM: 119 → 72 → 25 for dry→moist→wet) and demonstrate the operational rule by comparing RCI with Vehicle Cone Index (VCI₁ , VCI₅₀): at the Živanice site (USCS SM, moist ≈ 51 %), RCI₂ ≈ 72, thus vehicle classes with VCI ≤ 72 are passable, whereas higher - demand classes are not. Penetration methods deliver continuous or quasi - continuous strength profiles, outperforming point sam pling for heterogeneity detection, but show reduced reliability in gravelly/stony and organic horizons and in impermeable cla ys exhibiting a “rubber effect,” and are sensitive to moisture stratification. The workflow (CPT/DPT → CI, RI → RCI → RCI ≥ VCI dec ision) supports rapid, reproducible trafficability mapping and provides clear guidance on when to pair penetration testing wi th core drilling or auxiliary geotechnical probes.