A Five-Paper Research Programme
The Najd Fault System — the world's largest Proterozoic shear zone — runs NW–SE across western Saudi Arabia and directly controls the rock mass quality, joint fabric, and slope stability of every road cut in the region. Despite this, no quantitative framework currently exists to convert Najd structural observations into engineering-grade design parameters before a single borehole is drilled.
This five-paper programme, led by Prof. Abdullah Sabtan and Dr. Bader Sabtan, establishes that framework — from field measurement to a published regional guidance standard for KSA infrastructure.
Three phases converting field observations into a regional engineering standard. Expand any paper for a summary, or click “Explore” to open the full detail view.
Establish the geological signal and convert Najd fabric from observation into measurable structure.
Proves the structural signal statistically — two distinct joint families at all 5 sites. Every later paper depends on the credibility of this foundation.
The key engineering translation — turns “Najd influence” from qualitative statement into a variable that can be mapped, compared, and tested.
Translate structural fabric into road-cut decisions, support classes, and quantified failure probability.
Creates the practical chart: road alignment and slope dip direction become a fast screening tool for dangerous versus safer cuts.
Where the project becomes quantitatively defensible — shows how uncertainty moves through the entire engineering chain from measurement to design.
Scale the method from local road cuts to a regional screening framework for western Saudi infrastructure.
The capstone paper. Argues that Najd fabric assessment should become an early screening layer for roads, tunnels, and linear infrastructure across the Kingdom.
From fracture measurements to a quantified index, from an index to a road-cut decision chart, and from the chart to regional infrastructure risk guidance for western Saudi Arabia.
Establishes the bimodal Najd/Red Sea joint signature statistically and formalises the first measurable Najd Intensity Index. Both papers can proceed to submission immediately using data already collected.
Two statistically distinct joint families co-exist at all 5 sites — Najd (NW–SE, R̄≈0.98–1.00) and Red Sea (NE–SW). Site 2 shows Red Sea more coherent than Najd, indicating overprinting. Site 5 is a three-way mixture: Najd 39%, Red Sea 18%, unclassified 42%.
Formally defines the NII as a weighted composite of R̄, %Najd joints, joint frequency, Schmidt hammer R, and weathering grade W. Calibrates NII against GSI/RMR across 5 sites — filling the field's biggest gap: "Najd intensity" used qualitatively everywhere but never formally measured.
Converts the NII into a practical road alignment risk tool and a probabilistic slope stability model. These papers are the engineering core of the programme — moving from structural description to quantified design parameters and probability of failure.
Formalises the Red/Amber/Green classification based on Δθ — the angle between slope dip direction and dominant Najd joint dip direction. Derives threshold values statistically rather than by rule-of-thumb. Builds a decision matrix mapping (Δθ, slope height, weathering grade, NII) to required support level. Applied to 12 road-cut slopes in the Makkah region.
Takes the deterministic design chain — Schmidt → UCS → GSI → Hoek-Brown → Factor of Safety — and propagates uncertainty through every step using Monte Carlo simulation (n=1,000). Outputs P(failure) rather than a single FS value, showing how probability varies with NII and Δθ across all 5 sites.
The capstone paper synthesises the NII, Δθ zonation, and probabilistic framework into a unified regional guidance document. The goal is for Najd fabric assessment to become a mandatory pre-drilling screening step in KSA infrastructure planning — adopted into Saudi engineering standards.
Synthesises the NII, Δθ zonation system, and probabilistic FS framework into a unified regional guidance document for infrastructure planners across KSA. Argues for incorporating Najd fabric assessment as a mandatory pre-drilling screening step for road, tunnel, and linear infrastructure projects. This is the paper that gets cited by engineering standards bodies.
Target: Journal of Structural Geology — 3–5 months to submission
| Site | Najd R̄ | Najd μ | Red Sea R̄ | Rayleigh p | Note |
|---|---|---|---|---|---|
| Site 1 | ~0.99 | ~135° | Subordinate | < 0.05 | — |
| Site 2 | Lower | — | > Najd | < 0.05 | Red Sea overprint |
| Site 3 | ~0.98 | ~135° | Subordinate | < 0.05 | — |
| Site 4 | ~1.00 | ~135° | Subordinate | < 0.05 | — |
| Site 5 | 0.99 (39%) | — | 0.43 (18%) | 0.228 pooled | 42% unclassified · 3-way mixture |