Recent content by HENRYZAU

Footing width should be provided for bearing capacity check

For sandy material use effective unit weight, for clayey material unit weight "doesn't matter" it's the undrained shear strength Cu or Su that matters.

I would go for 4xD as a minimum, but the excavation-induced lateral deflection effects on the existing piles may be more critical.

EireChch, See attached paper by Ewers & Allman in 2000. Key conclusion from this paper: "Cα was found to be dependent on the current vertical effective stress and the preconsolidation pressure. The magnitude of Cα was relatively small at pressures below the preconsolidation pressure and...

For global slope stability, a minimum FS of 1.2 may be adopted if there is no sensitive structure/utility nearby. If there is, ground movement/impact on adjacent structure/utility is likely the governing factors, FS may be 1.5 or higher.

Your Ca of 1.2% is likely for normally consolidated soft clay/silt. Natural soil normally has a yield stress/preconsolidation more than its initial effective vertical stress (YSR/OCR > 1.0 depending on its stress history/ageing/cementation etc.), which means without loading the creep rate of...

Drained or undrained conditions is normally related to saturated clays (drained condition is always assumed for sands due to high permeability although fine sand under earthquake can also behave as undrained). For soils above ground water table, unsaturated soil mechanics should be applied. To...

I have seen on many cases the prediction was way off. So I tend to trust my judgement rather than the driverability analysis done by an inexperienced engineer (GIGO). You need experience & expertise to get it close to reality. Tricky for driven piles terminating in soils, highly variable rock...

To OP, Plaxis is a true 2-D plane strain model while Wallap is a pseudo 2-D model or a subgrade reaction model; which option did you use in Wallap? with soil arching or not? Are you comparing the total strut load or per meter run in two programs? your excavation width? 13m is strut horizontal...

Borehole is a rather crude method for soft clay, I would go CPTu or DMT thru the embankment (predrilling may be required) and in virgin ground nearby (not affected by the embankment load), then compare the yield stress of the soft clay before and after the embankment and work out how much...

To OP, HSS model would improve the prediction on base heave compared to HS model.

use Generalized Hardening Soil Model - links: https://www.plaxis.com/support/models/udsm-generalized-hardening-soil-model/

None of the dynamic formula is reliable unless it's calibrated via pile load test (static or high-strain dynamic)on a site.

human909 (Structural), I referred to the OP' comment below: "Due to limit in overburden pressure after certain length the increase in length does not contribute much in capacity." The referenced paper is attached as well...

Refer to Fellenius 1995 paper, critical depth does not exist.