Evaluation of Dynamic Resistance for Application of Portable In-situ Device to Extra Target Depth

Abstract

The strength profiles of the subgrade must be assessed for the prediction and prevention of geo-hazards. This study aimed to evaluate the dynamic resistance (q(d)) for the application of an instrumented dynamic cone penetrometer (IDCP). An IDCP test and a cone penetration test (CPT) were conducted at an equivalent site up to the extra target depth. The dynamic cone penetration index (DCPI), N-value (N-IDCP), and q(d) were estimated from the IDCP test, and the static resistance (q(c)) was measured from the CPT. The test results show that the DCPI, N-IDCP, and q(c) can be used to detect the loose and hard layers; however, the N-IDCP might underestimate the strength profile in an extra target depth owing to the excessive energy loss. However, q(c) has a linearly proportional relationship with q(c), which considers the transferred driving energy at the cone tip. Thus, the q(d) estimated from the IDCP test can be used for reliable strength assessment at the extra target depth.