Numerical evaluation of clay disturbance during blade penetration in the flat dilatometer test

Abstract

This paper presents a study on the amplification of horizontal soil stresses during flat dilatometer test (DMT) blade penetration based on three-dimensional total and effective stress numerical analyses, while considering stress-flow coupling and large deformations. The focus here is on saturated clays, and the effect of soil stress history on the horizontal stress index is discussed in detail. The obtained results appear to be in good agreement with published and new field data, leading to the proposal of two new expressions for estimating the overconsolidation ratio and the earth pressure coefficient at rest directly from flat dilatometer tests in estuarine clays.

Site characterisation for the Ballina field testing facility

“…A range of K 0 profiles were obtained from each interpretation method, including independent estimations from a self-boring pressuremeter test (Gaone et al, 2016). Interpretation of push-in pressure cell (PiPCs) measurements showed good agreement with the lower bound profiles obtained using the expressions proposed by Lacasse & Lunne (1988) and Kouretzis et al (2015). Independent checks were made using similar expressions to those presented by the discussion contributors.…”

Site characterisation for the Ballina field testing facility

“…The Marchetti (1980) interpretation has been shown by Lacasse & Lunne (1988), Powell & Uglow (1988) and Cao et al (2015) to overestimate field measurements in soft clays. The numerical results of Kouretzis et al (2015) indicate that all of these methods overestimate K 0 when the K D value lies approximately between 2 and 7 for the parameters and model adopted in their study.…”

“…Profiles of the K 0 estimated from dilatometer test SDMT1 are shown in Fig. 11(c) Powell & Uglow (1988) and Marchetti (1980) are 28% and 70% higher than Kouretzis et al (2015), respectively. The Marchetti (1980) interpretation has been shown by Lacasse & Lunne (1988), Powell & Uglow (1988) and Cao et al (2015) to overestimate field measurements in soft clays.…”

“…Values of K 0 have also been estimated using the SDMT and CPTu. The SDMT has been interpreted using Marchetti (1980), Powell & Uglow (1988) and Kouretzis et al (2015). Profiles of the K 0 estimated from dilatometer test SDMT1 are shown in Fig.…”

“…Estimation of the yield pressure from SDMT data is based on the corrected first reading (P 0 ) and the equilibrium pore pressure (U 0 ) (Marchetti, 1980). Marchetti (1980), Powell & Uglow (1988) and Kouretzis et al (2015) interpretations for OCR have been adopted and yield pressures obtained by multiplying by the in situ vertical effective stress. CPT and SDMT estimations have been compared with data obtained by Pineda et al (2016a) from CRS compression tests estimated using the strain energy method proposed by Becker et al (1987).…”