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The full catalogue

Every analysis. Every test.No black boxes.

213 code-checked analyses and 47 lab-test workflows — each one carries its governing standard in the output and is covered by the golden test suite (4,569+ automated engine tests, green on every build). 149 of those suites benchmark results value-by-value against published worked examples, and we are extending that engine by engine. This is exactly what you get, the day you sign up.

Flagship engines

Not a drawer of lookup calculators — real solvers.

Most of the catalogue is a standards calc. But a handful are full numerical engines we wrote ourselves — finite-element solvers, a double-hardening constitutive model, rigorous limit analysis — the work that usually costs a separate five-figure specialist seat. Each is validated against its published benchmark.

Full 2-D finite-element suite

Our own solvers — bearing capacity & load–settlement (Prandtl-validated), slope strength-reduction (critical FoS, no assumed surface), seepage flow-nets, consolidation and 2-D deformation. Not a wrapper: the element assembly, Newton solve and yield return-mapping are ours, benchmarked against the published cases.

Replaces
2-D / 3-D FE analysis suites · thousands / yr per seat

Hardening-Soil constitutive model

The double-hardening Hardening-Soil model on a stress point (calibrate against your lab curves) AND in a boundary-value problem — stress-dependent stiffness, shear + cap hardening, K₀ⁿᶜ and OCR. It drives the nonlinear confined & layered settlement engines.

Replaces
Constitutive-calibration + settlement seats · ~$2,000 / yr

Rigorous limit analysis

Two-sided bounds on the collapse load by linear programming — a statically-admissible lower bound (always safe) AND a kinematically-admissible upper bound — so the true failure load is provably bracketed. Immune to the stress singularity that trips displacement FE at a footing edge.

Replaces
A dedicated limit-analysis seat

Laterally-loaded piles (p-y)

The p-y finite-difference solver for a single pile (deflection, moment, shear down the shaft), t-z / q-w axial load-transfer, group p-multipliers, and the pile-head stiffness matrix — plus RC M–φ and P–M interaction for the section itself.

Replaces
Deep-foundation p-y / group seats · ~$1,200–2,000 each

Mechanistic-empirical pavements

Multilayer layered-elastic response (Burmister), a rigid-slab plate-on-Winkler FE with Westergaard stresses, time-stepping M-E distress (fatigue, rutting, IRI, JPCP cracking/faulting) and FAARFIELD-style airfield CDF — the mechanistic core, not a nomograph.

Replaces
Mechanistic-empirical + airfield pavement seats

Nonlinear seismic site response

Time-domain nonlinear 1-D response with Masing hysteresis (the strain / stress / G-Gmax profiles down the column) and a 2-D FE site-response solver for basins and ridges — the amplification a 1-D column analysis misses.

Replaces
DEEPSOIL / SHAKE workflow
Engineering analyses · 213

213 analyses, every result cites its clause.

Don’t take our word for it. Each analysis is pinned to a published worked example and re-checked on every build. Download the validation traceability matrix — source, inputs, textbook value, our computed value, and the measured deviation, for a PE to audit line by line.

Shallow foundations & settlement

42

Bearing, settlement and raft systems on soil.

Bearing capacity
Terzaghi-Vesic-Hansen · EC7 · IS 6403
Given

Strip 2 m, Df 1.5 m, c′ 10 kPa, φ′ 30°, γ 18 kN/m³

Result

q_ult ≈ 1,210 kPa → q_safe ≈ 400 kPa (FoS 3), every N-factor cited

Settlement (elastic + consolidation)
Schmertmann · EC7 · IS 8009
Given

q 150 kPa, B 2 m, Es 25 MPa, 4 m NC clay

Result

Immediate 8 mm + consolidation 22 mm = 30 mm

Differential settlement & angular distortion
Skempton-MacDonald 1956 · Bjerrum 1963 · IS 1904
Given

Footings 30 / 12 / 22 / 8 mm on a 6 × 6 m grid

Result

Governing β = 1/333, tilt 1/520, within framed 1/300 ✓

Schmertmann CPT settlement
Schmertmann 1978 · CFEM
Given

q 120 kPa over a qc profile, B 2.5 m, 30-yr

Result

s ≈ 19 mm with depth + creep correction

Consolidation time-rate
Terzaghi 1-D · IS 8009
Given

Cv 3 m²/yr, H_dr 2 m, U 90 %

Result

t ≈ 1.1 yr (Tv 0.848)

Degree of consolidation (U ↔ Tv)
Terzaghi 1-D · IS 8009
Given

Tv 0.2; target U 90 %

Result

U 50.5 % at Tv 0.2; Tv 0.848 needed for U 90 %

Finite-strain (large-strain) consolidation — Gibson
Gibson, England & Hussey 1967 · CONDES-class · soft soil / slurry / tailings
Given

Phosphate-clay slurry H₀ 9.6 m, e₀ 14.8, power-law e-σ′ / k-e (Townsend-McVay 1990)

Result

Ultimate settlement 5.32 m by the nonlinear PDE — within 2.2% of the published CONDES/FSConsol symposium result (5.44 m); log-linear or power-law constitutive

Finite-strain consolidation — layered (multi-material)
Gibson 1967 · per-layer C_c / C_k / e₀ / k₀ · σ′-continuous interface
Given

Soft slurry (C_c 2.4, e₀ 5) over stiffer clay (C_c 0.8, e₀ 3), H₀ 6 m

Result

Interface flux in the continuous σ′ gradient (harmonic-mean k) — e jumps at the boundary, σ′ continuous; reduces exactly to the single-material engine within a layer

Coupled consolidation (Biot u–p)
Biot 1941 / Terzaghi 1943
Given

E 5 MPa, ν 0.3, k 1e-4 m/day, 5 m layer double-drained, σ 100 kPa

Result

Settlement 74 mm (σ·H/E_oed), c_v ≈ 0.069 m²/day derived from k & E_oed, t₉₀ ≈ 77 days — coupled poroelastic solve, U–Tv matches Terzaghi

Consolidation under a footing — 3-D coupled Biot FE
Biot 1941 · Zienkiewicz §3.2 u–p · 20-node hex Q2–Q1 · Terzaghi + Skempton-Bjerrum cross-check
Given

6×6 m loaded area, q 100 kPa, 10 m clay, E′ 5 MPa, ν′ 0.3, k 1e-8 m/s, top drainage

Result

Final 93.3 mm (62.0 immediate + 31.3 consolidation); computed Skempton-Bjerrum μ 0.41; t₅₀ 3.1 days against 33.2 by 1-D Terzaghi — 10.7× faster because water escapes sideways. Collapses to q·H/E_oed exactly when the far field is set to 0

Combined footing
Bowles §9 · Das §4
Given

2 columns 800 + 1200 kN at 4 m, qa 150 kPa

Result

L 6.4 m, resultant centred (e 0), B 2.1 m

Raft sizing
ACI 336.2R · EC7 · IS 2950
Given

Σ load 24 MN, qa 150 kPa

Result

Raft 13 × 13 m, q 142 kPa < qa ✓

Raft on Winkler springs
ACI 336.2R · Bowles §9 · IS 2950
Given

k 30 MN/m³, 0.5 m slab, 8 columns

Result

Max settlement 18 mm, M_max 420 kN·m/m

Beam on elastic foundation
Hetényi 1946
Given

EI, k 20 MN/m³, point load 200 kN

Result

λ 0.62 /m, y_max 4.1 mm, M_max 81 kN·m

Subgrade reaction (soil springs)
Bowles · Vesić · IS 2950
Given

B 2 m, Es 20 MPa, ν 0.3

Result

k_s ≈ 11.8 MN/m³ (Vesić) for the STAAD / ETABS hand-off

Plate load test
ASTM D1195 / D1196 · IS 1888
Given

0.3 m plate, 12 mm settlement at 220 kPa

Result

Safe BP 147 kPa, scaled to the footing width

Machine foundation (block dynamics)
ACI 351 · DIN 4024 · Richart · IS 2974
Given

A 6 m², 20 t block, Cu 4×10⁴ kN/m³, 25 Hz

Result

f_n 17.4 Hz, ratio 1.43 — clear of resonance ✓

Foundation analysis (SPT → SBC table)
AASHTO · EC7 · IS 6403/8009
Given

SPT profile, Df 2 m, silty sand, B = 1 → 3 m

Result

Allowable pressure per size = min(shear, settlement), governing mode flagged

Probabilistic bearing capacity
Monte-Carlo · Eurocode 7 · IS 6403
Given

N 21, φ′ COV 0.12, B 2 m, Df 8 m, demand 250 kPa

Result

Characteristic SBC (P05), reliability 96 %, β 1.8

Two-layer bearing capacity
Meyerhof-Hanna 1978 · Das §4
Given

Dense sand φ 40° (1.5 m) over soft clay c_u 30, B 1.5 m

Result

q_ult 459 kPa by punching shear (q₂/q₁ 0.11, Ks 2.5)

Footing on / near a slope
Meyerhof 1957 · Vesić-Hansen
Given

B 2 m, Df 1 m, φ′ 30°, slope 20° at the crest

Result

q_ult 529 kPa — 51 % of level-ground capacity retained

Settlement on sand (Burland-Burbidge)
Burland & Burbidge 1985 · BS 8004
Given

q′ 100 kPa, B 3 m, average SPT N̄ 12, normal sand

Result

Immediate 11.4 mm, with creep 14.8 mm (z_I 2.28 m)

Immediate (elastic) settlement
Bowles · Steinbrenner
Given

q 150 kPa, 3 m square, Es 20 MPa, ν 0.3, H 6 m

Result

Centre 17.6 mm (Steinbrenner I_s 0.43, F1/F2 closed-form)

Vertical stress increase (Boussinesq / Westergaard)
Newmark · Westergaard
Given

q 100 kPa, 1 × 1 m, z 1 m, centre, ν 0

Result

Δσ_z 33.6 kPa (Boussinesq) vs 21.6 kPa (Westergaard, layered)

Stress under a circular area
Boussinesq · tank / silo
Given

q 100 kPa, R 2 m, z 3 m (centre)

Result

I 0.424 → Δσ_z 42.4 kPa

Stress under a strip load
Boussinesq · wall footing / road
Given

q 100 kPa, B 2 m, z 1 m (centreline)

Result

I 0.818 → Δσ_z 81.8 kPa (vs 66.7 by 2:1)

Stress under a line load
Boussinesq 2-D · wall / rail
Given

Q 100 kN/m, x 0, z 2 m

Result

Δσ_z 31.8 kPa (I 0.637); σ_x = τ = 0 on the centreline

Secondary compression (creep)
Mesri · Cα/Cc
Given

Cα 0.04, e_p 1.0, H 4 m, t₁ 2 yr → t₂ 50 yr

Result

Cαε 0.02 → creep S_s 112 mm over 1.4 log-cycles

Skempton-Bjerrum settlement correction
Skempton-Bjerrum 1957 · Scott
Given

S_oed 100 mm, A 0.7, α 0.7, S_imm 15 mm

Result

μ 0.91 → field S_c 91 mm, total 106 mm

Eccentric footing pressure (kern)
Meyerhof 1953 · IS 1904
Given

Q 1000 kN, M 100 kN·m, 2 × 2 m

Result

e 0.1 m < B/6 → q 325 / 175 kPa, no uplift, B′ 1.8 m

Layered elastic settlement (IS 8009)
Newmark · Fox · EC7 · IS 8009
Given

22.4 × 4.5 m raft, p 140, soil 0.5 m Es 49.5 + rock 8.5 m Es 248.7

Result

σz = 4·p·I_B per layer → 3.9 mm total (rigidity × depth corrected)

Flotation / uplift check
EN 1997-1 UPL · buoyancy
Given

Basement 20 × 30 m, base 5 m, water table 1 m

Result

Uplift 23,544 kN, FoS 2.55, EN 1997-1 UPL util 0.44

Compensated (floating) foundation
Bowles · Skempton-Bjerrum · EC7 · IS 2950
Given

q_gross 200 kPa, Df 5 m, γ 18 kN/m³

Result

relief 90 kPa → net 110 kPa, 45 % compensated (settlement governs)

Overlay design (Benkelman / IRC 81)
Add-on
IRC 81:1997 · BBD
Given

Deflections 1.2/1.4/1.0/1.6/1.3 mm, major road

Result

x̄ 1.30, σ 0.224 → Dc 1.747 mm (read overlay off the IRC 81 curve)

FE bearing capacity & load–settlement
Add-on
Prandtl 1921 · viscoplastic Mohr–Coulomb FE
Given

Strip 2 m, sᵤ 20 kPa, φ 0 (undrained)

Result

q_ult = 102.9 kPa (Prandtl 5.14·sᵤ to 0.1%) + the full load–settlement curve & collapse mechanism

Limit-analysis bearing bracket (lower + upper bound)
Sloan 1988/1995 · FE limit analysis (LP)
Given

Strip 2 m, cᵤ 50 kPa, φ 0 (undrained)

Result

Rigorous two-sided bound 4.07·cᵤ ≤ q_exact ≤ 6.00·cᵤ, bracketing the exact Prandtl 5.14·cᵤ — singularity-immune

Footing bearing capacity — 2-D elasto-plastic FE (HS/MC)
Prandtl 1921 · Vesić 1973 · Hardening-Soil (Schanz-Vermeer-Bonnier 1999) · B-bar FE
Given

Strip B 2 m, c′ 10, φ 25°, E_ref 30 MPa, m 0.5

Result

Full load–settlement curve + q_ult from a meshed plane-strain continuum (general-stress Mohr-Coulomb strength + HS stress-dependent stiffness, B-bar anti-locking), cross-checked live against the closed-form Vesić N-factors — a PLAXIS/RS2-class footing BVP

Footing bearing capacity — 3-D elasto-plastic continuum FE
Skempton 1951 · Vesić 1973 · viscoplastic Mohr-Coulomb · 20-node hex FE
Given

Square B 2 m, sᵤ 50 kPa, φ 0 (undrained)

Result

q_ult + full load–settlement curve from a true 3-D continuum (quarter-symmetry, 20-node serendipity hexahedra, viscoplastic Mohr-Coulomb) capturing the square/circular shape effect (s_c≈1.2) a 2-D model cannot — cross-checked live against Skempton/Vesić; heavy solve on Modal — a PLAXIS-3D/RS3-class footing BVP

Hardening-Soil footing — load–settlement (2-D double-hardening FE)
Schanz-Vermeer-Bonnier 1999 · Vesić 1973 / Prandtl 1921 · B-bar FE
Given

Strip B 2 m, D_f 1 m, c′ 10, φ′ 30°, E₅₀ʳᵉᶠ 30 MPa, m 0.5

Result

The FULL load–settlement curve from the true HS constitutive law integrated at every Gauss point (hyperbolic pre-failure response, stress-dependent E(σ₃), per-point plastic shear hardening γ^p) + q_ult cross-checked live against the Vesić closed form — 28 cited literature anchors: Prandtl 5.14·sᵤ reproduced from above with q_ult/sᵤ constant to 0.7 % over an 8× strength range, Vesić c·N_c + q₀·N_q matched to ~2–5 % over a 20× surcharge range, and monotone mesh convergence to the exact limit

Hardening-Soil model — SoilTest (triaxial + oedometer)
Schanz-Vermeer-Bonnier 1999 · Duncan-Chang
Given

E₅₀ʳᵉᶠ 30 MPa, m 0.5, c′ 1, φ 35°, σ₃ 100 kPa

Result

Stress-dependent E₅₀/E_ur, hyperbolic q–ε₁ to q_f 273 kPa (secant = E₅₀ exactly at half-strength) + oedometer E_oed — calibrate HS parameters against your lab curves

Hardening-Soil confined (1-D) nonlinear settlement
Hardening-Soil oedometer · Schanz-Vermeer-Bonnier 1999
Given

5 m NC clay, Δq 100 kPa, σ′v0 50 kPa, E_oedʳᵉᶠ 4 MPa, m 0.9, φ 25°

Result

Nonlinear settlement 135 mm with stress-dependent stiffness (secant E_oed 3.8 MPa) — vs 233 mm from a fixed initial modulus; OCR 2 halves it (stiff E_ur reload)

Hardening-Soil layered (multilayer) settlement
Hardening-Soil per layer · Terzaghi sub-layer summation
Given

3-layer profile (soft 3 m / firm 4 m / stiff 5 m), Δq 120 kPa, WT 2 m

Result

Total 253 mm; each sub-layer an oedometer at its own σ′v0 + HS params + OCR, auto sub-discretised (discretisation-independent) — soft shallow layer contributes 189 mm (the dominant stratum for ground improvement)

Deep foundations — piles & wells

24

Bored, driven and well foundations, capacity to load test.

Pile capacity (bored / driven) + uplift
AASHTO LRFD · EC7 · IS 2911
Given

600 mm bored, 15 m, c_u 50 kPa

Result

Q_ult ≈ 1,850 kN → Q_safe 740 kN (FoS 2.5); tension T_safe from shaft + self-weight

RC moment–curvature (M–φ) section
Add-on
Hognestad 1951 · ACI 318 §22.2 · IS 456
Given

1 m bored pile, M30, 8000 mm² steel

Result

M_n, M_cr, M_y + the COMPUTED cracked-EI (not a 0.35–0.7 guess) for the p-y solver

RC axial–moment (P–M) interaction
Add-on
ACI 318 §22.4 · IS 456 cl.39 · fibre integration
Given

1 m bored pile, M30, 8000 mm² steel

Result

Full P–M failure envelope: squash 19,860 kN, balance, pure-bending M_n — check any (M, P) demand

Rigid pile-cap group (V-H-M)
Add-on
Poulos-Davis · Hrennikoff
Given

3×3 group, s 2 m, V 300 kN, M 1200 kN·m

Result

Per-pile axial 133 kN (leeward) to −67 kN (uplift), cap stiffness — statics-validated

Helical (screw) pile
ICC-ES AC358 · Hoyt-Clemence · Perko
Given

3 helices 0.3 m at 5/4/3 m, φ 32°, γ′ 10

Result

Σ plate bearing 197 kN + shaft → Q_ult 214 kN; torque-checked

Drilled shaft (bored pile) axial
FHWA GEC-10 · O'Neill-Reese 1999
Given

1 m × 15 m, c_u 100 kPa (α-method)

Result

Side 2180 kN + base 707 kN → Q_ult 2884 kN

Micropile (Types A-D)
FHWA-NHI-05-039
Given

0.2 m bond, 8 m, α 150 kPa, 3000 mm² steel

Result

Bond allow 302 kN vs structural 957 kN → 302 kN governs

Wave-equation drivability
Smith 1960 · FHWA GEC-12
Given

20 m steel pile, 50 kN ram, 100 kJ, Rᵤ 1500 kN

Result

Set 24 mm → 41 blows/m, σ_c 253 MPa (bearing graph)

Pile-cap / footing punching shear
ACI 318 · EC2 · IS 456
Given

P 1500 kN, 0.4 m column, d 0.5 m, M25, q 240 kPa

Result

τv 0.73 MPa ≤ τc 1.25 MPa → util 0.58 ✓

Pile-group settlement (interaction)
Poulos-Davis · Randolph-Wroth
Given

3×3 group, d 0.5 m, L 15 m, s 1.5 m, w_single 8 mm

Result

r_m 26 m → Rs 5.6 → group settlement 45 mm

Pile group efficiency
Converse-Labarre · Feld · IS 2911
Given

9 piles, 3 d c/c spacing

Result

η 0.74 (Converse-Labarre) → group 12.3 MN

Lateral pile (p-y curves)
Reese-Matlock · API RP 2GEO
Given

600 mm, soft clay ε50 0.02, 150 kN head

Result

Groundline 5.5 mm, M_max −258 kN·m (FDM)

Lateral pile capacity (Broms ULS)
Broms 1964 · Tomlinson
Given

0.5 m pile, e 1 m, My 200 kN·m, clay cu 50 kPa

Result

Hu 101 kN, hinge at 1.2 m (long-pile yield-governed)

Driven pile dynamics (Hiley)
Tomlinson · IS 2911-1 App B
Given

30 kN ram, 1.2 m drop, 5 mm/blow set

Result

R_u 1,731 kN → safe 692 kN

Pile downdrag (negative friction)
FHWA NHI-05-039 · EC7 · IS 2911
Given

Fill over soft clay, neutral plane 9 m

Result

Drag load 380 kN added at the neutral plane

Pile-raft (Poulos PDR)
Poulos 1991/2001
Given

Raft + 16 piles, 30 MN

Result

α_pr 0.7, settlement 24 mm, 62 % carried by piles

Pile load test (Davisson)
ASTM D1143 · Davisson · IS 2911-4
Given

500 mm × 15 m, maintained-load curve

Result

Safe 1,333 kN (IS ⅔ @ 12 mm), Davisson ult 2,209 kN

Well foundation
IRC 45:1972 · IRC 78
Given

6 m well, 6 m grip, H 1,500 kN, M 9,000 kN·m

Result

K_p 6.11, elastic demand 98 > capacity 64 → revise

Pile-group settlement (equivalent raft)
Tomlinson · Terzaghi-Peck
Given

Group 3 × 3 m, 12 m friction piles, Q 4 MN, m_v 0.2

Result

Settlement 133 mm (raft at 8 m, 2:1 spread Δσ′ 111 kPa)

Single-pile settlement (Vesić)
Vesić 1977 · FHWA · Das §9
Given

Q 500 kN (40 % point), 15 m × 0.5 m, q_p 4 MPa

Result

Head settlement 5.7 mm = 1.4 (elastic) + 4.0 (point) + 0.4 (shaft)

Axial pile load–settlement (t-z/q-w)
Add-on
Coyle-Reese 1966 · API RP 2GEO · Reese-O’Neill
Given

0.6 m × 15 m bored pile, clay s_u 60 kPa, 900 kN working

Result

Q_ult 2,150 kN (shaft 72 %), 7.4 mm at working load

Lateral pile group (p-multiplier)
Add-on
Reese & Van Impe Ch 8 · AASHTO §10.7.2.4 · Mokwa-Duncan
Given

3×2 group of 0.6 m piles at 3D in sand, 1,200 kN cap load

Result

9.8 mm cap deflection, Gₑ 0.66; leading row governs at 468 kN·m

Pile-head stiffness matrix (K22/K23/K33)
Add-on
p-y beam-column (Reese) · Maxwell-Betti
Given

0.6 m × 15 m free-head pile in sand, 200 kN operating shear

Result

K22 3.1×10⁴ kN/m, K33 1.4×10⁵ kN·m/rad, coupling K23; symmetric to <1%

Steel pile section M–φ (pipe / solid)
Add-on
AISC 360 §F · Timoshenko · fibre integration
Given

Ø600 pipe, 20 mm wall, fy 355 MPa

Result

My 1,816 kN·m, Mp 2,389 kN·m (= fy·Z), shape factor 1.32

Slopes & embankments

25

Soil and rock slope stability, seismic displacement.

Slope stability (Bishop · Spencer · M-P)
Duncan & Wright · Bishop/Spencer · IS 7894
Given

12 m slope, 1.5:1, c′ 15 kPa, φ′ 28°, r_u 0.3

Result

FoS 1.38 (Spencer), critical circle located

Infinite slope
Duncan-Wright · EM 1110-2-1902
Given

β 20°, z 2 m, c′ 5 kPa, φ′ 30°, full seepage

Result

FoS 1.12 (parallel seepage)

Rock slope stability (planar / wedge / toppling)
Wyllie & Mah · Markland · Goodman-Bray
Given

30 m face 60°, joint dips 35°, c 50 kPa, φ 30°

Result

FoS 1.28 dry → 0.88 with water + seismic

Rockfall trajectory + catchment
Ritchie 1963 · Pierson/ODOT-FHWA · lumped-mass / RocFall
Given

30 m face 60°, 1000 kg block, μ 0.40, Rₙ 0.35, Rₜ 0.85

Result

runout 16.9 m, max bounce 2.1 m, 227 kJ at the toe; Ritchie ditch 8.7 m × 1.8 m

Rapid (sudden) drawdown — upstream slope
Duncan-Wright-Wong 3-stage · USACE EM 1110-2-1902 App. G
Given

15 m dam, 1:2.5 upstream, c' 5 kPa, φ' 28°, R-env φR 20°, pool 13 m → 0

Result

FoS drops from the full-reservoir value to the after-drawdown value (3rd/undrained stage governs); Duncan-Wright-Wong τff interpolation

Barton-Bandis rock-joint strength
Barton & Choubey 1977 · Barton-Bandis 1990
Given

JRC 10, JCS 50 MPa, φr 30°, σn′ 500 kPa

Result

φpeak 50° (i = 20° dilation), τ = 596 kPa — nonlinear envelope

Duncan-Chang hyperbolic model
Duncan & Chang 1970 · Duncan et al. 1980
Given

K 300, n 0.5, c′ 10, φ′ 30°, Rf 0.9, σ₃ 100 kPa

Result

(σ₁−σ₃)f 234.6 kPa, Ei 30.2 MPa, hyperbolic q(ε) → qult 260.7 kPa

Modified Cam-Clay (NC undrained)
Roscoe-Burland 1968 · Muir Wood · Wroth 1984
Given

φcs 25.4° (M 1.0), λ 0.16, κ 0.03, p′₀ 200 kPa

Result

su 57.0 kPa (su/p′₀ 0.285), critical state p′ 114, q 114 kPa

HS-Small small-strain stiffness
Benz 2007 · Hardin-Drnevich
Given

G₀ 100 MPa, γ₀.₇ 2e-4, Gur 25 MPa

Result

Gs = 72.2 MPa (0.722·G₀) at γ₀.₇; decays G₀→Gur with strain

Drucker-Prager cone
Drucker-Prager 1952 · de Souza Neto §8.3
Given

c' 10, φ' 30°, σ₃ 100 kPa

Result

triaxial failure 234.6 kPa (= Mohr-Coulomb), α 0.231, k 12.0 kPa

von Mises (J2) yield
von Mises 1913 · Simo & Hughes
Given

σ 200/100/100 kPa, σy 150 kPa

Result

q = 100 kPa (√3J₂) < σy → elastic, FoS 1.50

NGI-ADP anisotropic undrained
Grimstad-Andresen-Jostad 2012
Given

suA 60, suP/suA 0.4, suDSS/suA 0.6

Result

suA 60, suP 24, suDSS 36 kPa; isotropic q = 2suA = 120 kPa

Soft-Soil-Creep parameters
Vermeer & Neher 1999
Given

Cc 0.3, Cs 0.05, Cα 0.01, e₀ 1.0, φcv 25°

Result

λ* 0.065, κ* 0.022, μ* 0.00217, M 0.984, creep 0.5%/decade

Seismic slope displacement
Bray & Travasarou 2007 · Newmark
Given

ky 0.1 g, Ts 0.3 s, Sa 0.5 g, Mw 7.5

Result

D₅₀ 18.5 cm (16–84%: 9.6–35.8 cm)

Probabilistic slope (reliability)
Duncan 2000 · FOSM + Monte-Carlo · USACE
Given

β 25°, c′ 10±30%, φ′ 28±10%, γ 19

Result

μ_FoS 1.60, reliability index β, Pf (FOSM ≈ Monte-Carlo)

Multi-layer site response (SHAKE)
Kramer Ch.7 · Schnabel-Lysmer-Seed
Given

30 m soil column over Vs 600 rock

Result

Transfer function → T₀ + peak amplification (eq-linear)

Seismic design spectrum
ASCE 7-16 · EC8 · IS 1893
Given

Zone IV, medium soil, T 0.5 s, R 5

Result

Sa/g 2.50 → Ah 0.06 (ZPA 0.12 g)

Seismic design spectrum (code-based)
ASCE/SEI 7-16 · EN 1998-1 (EC8) · IS 1893
Given

ASCE 7-16, site B, Sₛ 1.5, S₁ 0.6, Vs30 800

Result

SDS 0.90 g (Sa @ 0.2 s), SD1 0.32 g (Sa @ 1.0 s) — pick any code (IS / ASCE / EC8), no region gate

Field-vane correction (Bjerrum μ)
Bjerrum 1973 · IS 2720-30
Given

s_u,vane 50 kPa, PI 40 %

Result

μ 0.835 → design s_u 41.7 kPa

Embankment basal stability
IRC:75 · Ladd · Terzaghi
Given

6 m fill on soft clay c_u 20 kPa

Result

FoS 1.31 (Ladd) — sets the stage-construction band

Embankment benching
IRC:75 · MoRTH
Given

Side-hill fill, 1 m benches

Result

Interface FoS 1.45

Newmark seismic displacement
Newmark · Jibson 2007
Given

PGA 0.24 g, yield k_y 0.12 g

Result

Permanent slip 4.6 cm

FE slope stability (strength reduction)
Add-on
Zienkiewicz SRM · Griffiths & Lane 1999
Given

10 m slope 2:1, c′ 15 kPa, φ′ 25°, γ 19

Result

FoS by φ-c reduction on a finite-element mesh (no assumed slip surface)

3-D FE slope stability (strength reduction)
Griffiths & Marquez 2007 · 20-node hex viscoplastic
Given

10 m slope 2:1, c′ 10 kPa, φ′ 20°, γ 20, finite width B/H = 1

Result

F₃D by 3-D φ-c reduction — the failure mechanism emerges (no assumed slip surface); end restraint gives F₃D ≈ 1.15·F₂D, converging to the 2-D value as the slide widens

3-D DEM slope stability (Scoops3D)
USGS Scoops3D TM 14-A1 · Bishop/Ordinary column method
Given

A real terrain grid (DEM), multi-material soil, thousands of spherical trial surfaces

Result

the 3-D-critical failure mass anywhere on the terrain — F₃D, the sphere, its volume/area/footprint — reproducing the parametric slope-3d circle on a planar slope (validated to within the 3-D end-restraint credit)

Retaining & excavation

16

Walls, cuts and embedded support systems.

Earth pressure (active / passive / seismic)
Rankine · Coulomb · Mononobe-Okabe · IS 14458 · EN 1997-1 · AS 4678
Given

5 m wall, φ′ 32°, kh 0.1

Result

Ka 0.31, Pa 56 kN/m; Kae 0.41 (Mononobe-Okabe)

Earth pressure at rest (K0)
Jaky · Mayne-Kulhawy (OCR)
Given

φ′ 30°, OCR 4, γ 18, H 5 m

Result

K0 1.00 (vs 0.50 NC), at-rest thrust 225 kN/m

Retaining wall
Bowles · IS 14458 · AS 4678
Given

5 m cantilever, 10 kPa surcharge

Result

FoS overturn 2.4, slide 1.7, resultant in kern ✓

Sheet pile wall
CIRIA C580 · BS 8002 · Bowles §14 · AS 4678
Given

Cantilever 6 m retained, φ′ 30°

Result

Embedment 4.2 m, M_max 185 kN·m/m

Braced excavation
Terzaghi-Peck · Peck 1969
Given

8 m cut in soft clay

Result

Strut loads from apparent pressure; base-heave FoS 1.4

Basal heave (excavation)
Bjerrum & Eide 1956 · Terzaghi 1943 · Skempton Nc
Given

10 m cut, 15×30 m, s_u 40 kPa, γ 18, q 10

Result

N_c 6.41 → FoS 1.35 (Bjerrum-Eide) — deepen toe / improve clay

Excavation-induced settlement
Clough & O'Rourke 1990 · Hsieh-Ou 1998
Given

He 10 m, δh,max 30 mm (sand), building at 5 m

Result

δv,max 30 mm, trough to 20 m, 22.5 mm at building (1/667)

Ground anchor / tieback
BS 8081 · PTI · Littlejohn
Given

0.15 m hole, 8 m bond, c_u 100 kPa, α 0.4

Result

τ 40 kPa → T_ult 151 kN, allowable 75 kN (FoS 2)

Embedded wall — soil-structure interaction
Add-on
Beam on elastic foundation · CIRIA C760 · Padfield-Mair
Given

6 m propped wall, prop at 1.5 m

Result

Deflection 13 mm, M_max 156 kN·m/m, prop 80 kN/m, passive 38% mobilised

Staged embedded retaining wall
EN 1997-1 (EC7) · CIRIA C760 · subgrade reaction
Given

6 m dig, Ø600 diaphragm wall, 6 m embedment, prop at 1.5 m

Result

Deflection 4 mm, M_max 132 kN·m/m, prop 88 kN/m, passive 40% mobilised; LEM cross-check agrees (≥ 3.58 m)

Contiguous pile wall
CIRIA C760 · IS 14458 · IS 456
Given

9 m retained, 600 mm piles

Result

Embedment 5.1 m, M 420 kN·m, deflection 22 mm

Secant pile wall
CIRIA C760 · DIN 4126
Given

10 m, 750 mm secant

Result

Embedment 5.6 m, water cut-off achieved ✓

MSE wall
FHWA NHI-10-024 · BS 8006 · IS 14458 · AS 4678
Given

8 m, geogrid at 0.6 m spacing

Result

T_max 24 kN/m, pullout FoS 1.6, sliding 1.8

Soil nail wall
FHWA-IF-03-017 (GEC-7)
Given

9 m cut, nails on a 1.5 m grid

Result

Global FoS 1.5, nail tension 95 kN

Soil-structure interface (Goodman joint)
Goodman-Taylor-Brekke 1968 · R_inter reduction · Potyondy 1961
Given

φ 35°, R_inter 0.67 (concrete/sand), σ′_n 100 kPa

Result

δ 25.1°, τ_max 46.9 kPa — only 67% of the soil strength; the reduced wall/shaft friction to design with

Staged excavation — FE heave & basal stability
K0 staged FE · Smith-Griffiths §6 · Terzaghi/Bjerrum-Eide basal heave
Given

Wide cut, cᵤ 30 kPa, γ 18, excavate to 8 m in 6 lifts

Result

Base heave builds 18→62 mm per lift then basal-heave collapse near 6.7 m (N≈4.8, conservative vs Prandtl 5.14) — the staged deformation a closed-form check can’t give

Seepage & dewatering

13

Flow nets, FE seepage, drains and dam seepage.

Seepage & dewatering
Flow net · Thiem · Terzaghi
Given

Δh 6 m, 4-well system

Result

Q 1,150 m³/day (Thiem), drawdown to formation

FE seepage (2-D)
Add-on
Finite element · Laplace
Given

Zoned dam, k profile

Result

Phreatic line + exit gradient 0.42 < critical

FE unconfined seepage (phreatic surface)
Add-on
Free-surface FE · Dupuit-Charny
Given

L 30 m, h₁ 12 m, h₂ 3 m, k 10⁻⁵

Result

Phreatic line + q within ~5 % of the exact Dupuit q, seepage face located

Earth-dam seepage
Casagrande · EM 1110-2-1901
Given

Homogeneous 20 m dam

Result

Casagrande line, q 1.8×10⁻⁵ m³/s per m

In-situ permeability
Hvorslev · BS 5930 · IS 5529
Given

Falling-head in cased borehole

Result

k 3.2×10⁻⁶ m/s (Hvorslev)

Percolation test
USEPA · IS 2470
Given

30 min for a 25 mm drop

Result

Perc rate → soak-field sizing

Vertical drains (PVD)
Barron · Hansbo · Carrillo
Given

PVD 1 m grid, Cv 2 m²/yr

Result

90 % consolidation in ~4 months (Hansbo)

Vacuum preloading
Kjellman · Indraratna · Hansbo PVD
Given

70 kPa vacuum, 8 m clay, PVD 1.5 m, 0.5 yr

Result

63 kPa eff. (replaces 3.5 m fill) → 657 mm primary, U 74 %

Multi-layer consolidation
Terzaghi 1-D · IS 8009-1
Given

2-layer NC profile, Δσ 40/30, cv 1.5/2.0

Result

Total 190 mm; U 95.6 % at 2 yr (settlement-weighted)

Asaoka settlement prediction
Asaoka 1978 · observational
Given

Plate readings 100…433 mm at equal Δt

Result

Final 500 mm, U 86.6 %, 67 mm remaining

Seepage under structures (Lane & Bligh)
Lane 1935 · Bligh · creep theory
Given

Head 2 m, ΣL_v 14 m, ΣL_h 30 m, fine sand

Result

Lane C_w 12 ≥ 7 ✓, Bligh C_B 22 ≥ 15 ✓ — safe against piping

Permeability from grain size
Hazen 1892 · Kozeny-Carman
Given

D10 0.2 mm, void ratio 0.7, 20 °C

Result

k 4×10⁻⁴ m/s (Hazen), 4.3×10⁻⁴ m/s (Kozeny-Carman)

Quick condition / hydraulic heave
Terzaghi · critical gradient
Given

Gs 2.65, e 0.65, Δh 3 m over L 6 m

Result

i_cr 1.00, i_e 0.50 → FoS 2.0 against boiling (γ′ 9.81)

Seismic & liquefaction

44

Triggering, settlement and lateral spread.

Seismic site classification
ASCE 7-16 · EC8 · IS 1893
Given

Vs30 / SPT profile to 30 m

Result

Site class D → design response spectrum

Seismic site response
Kramer Ch.7 · 1-D SH wave · IS 1893 · EC8
Given

H 30 m, Vs 200 m/s, ξ 5 %, rock Vs 760

Result

T₀ 0.60 s, peak amplification ×3.6, surface PGA from rock

Nonlinear time-domain site response
DEEPSOIL-class · Masing hysteresis · Newmark integration · Kramer Ch.7
Given

H 30 m, Vs 200 m/s, τ_max 80 kPa, rock PGA 0.02 → 0.4 g

Result

Weak motion amplifies ×1.8; strong motion DE-amplifies to ×0.8 (soil softens + hysteretic damping) — the nonlinearity equivalent-linear misses

2-D site response — basin amplification (SH-wave FE)
QUAD4M-class · antiplane SH FE · Lysmer absorbing base · Bard & Bouchon 1985
Given

Sediment basin, H 30 m, soil Vs 200 / rock Vs 760 m/s, ξ 5%

Result

2-D basin focusing amplifies the surface ×1.8 MORE than a 1-D column (Mexico City / Kobe effect) — validated to 2-D/1-D = 1.00 on a flat profile

2-D topographic amplification — ridge crest (SH-wave FE)
Trifunac 1973 · Eurocode 8 Part 5 Annex A (S_T) · homogeneous SH FE
Given

Ridge H 20 m, half-width 50 m (slope ~22°), Vs 500 m/s

Result

Crest topographic factor S_T ≈ 1.4 — the hilltop shakes 40% harder than flat ground, purely from geometry (validated flat S_T = 1.00, bounded < Trifunac 2)

Coupled effective-stress liquefaction — 1-D site response
Dobry 1985 / Matasovic-Vucetic 1993 · DEEPSOIL v7 Eq. 4.10 + 4.30/4.31 · Carlton 2014
Given

H 15 m, Vs 140 m/s, WT 1 m, FC 5 %, bedrock PGA 0.30 g, 2 Hz, 12 s, v = 1

Result

Liquefaction at t = 3.37 s, peak r_u 0.992. AFTER triggering the surface peak collapses to 0.024 g against the 0.156 g a total-stress solve on identical inputs gives (−84.8 %), the late-window RMS to 3.5 %, and the site period lengthens 1.23× — the recorded Port Island / Wildlife Array de-amplification signature that a total-stress site response plus a separate triggering check structurally CANNOT produce. Before triggering the two runs agree, so the coupling is shown to act only where the physics says it should; both are reported side by side

Liquefaction triggering
Boulanger-Idriss 2014 · NCEER · IS 1893
Given

N 15, FC 5 %, σ′v 66 kPa, PGA 0.24 g, M 7.5

Result

CRR 0.186, CSR 0.257 → FoS 0.72 → liquefiable

CPT liquefaction triggering (Boulanger-Idriss)
B-I 2014 · UCD/CGM-14-01
Given

qc 5 MPa, FC 10 %, σ′v 60 kPa, z 5 m, amax 0.3 g, Mw 7.0

Result

qc1Ncs 73, CRR 0.134, CSR 0.307 → FoS 0.47 (liquefies)

Vs liquefaction triggering (Andrus-Stokoe)
Andrus-Stokoe 2000 · Youd 2001
Given

Vs 180 m/s, FC 10 %, σ′v 80 kPa, z 5 m, amax 0.3 g, Mw 7.0

Result

Vs1 190, CRR 0.193, CSR 0.234 → FoS 0.98 (marginal)

Tunnel settlement trough (Peck)
Peck 1969 · O’Reilly-New
Given

D 6 m, axis 15 m, volume loss 1 %, K 0.5 (clay)

Result

i 7.5 m, Smax 15.0 mm, 6.2 mm at 10 m offset, slope 1.2 mm/m

Slope stability number (Taylor)
Taylor 1937 · friction-circle
Given

Ns 0.18, c 20 kPa, γ 18 kN/m³, H 6 m

Result

c_d 19.4 kPa → FoS 1.03, critical height 6.2 m

Dam seismic deformation (Makdisi-Seed)
Makdisi-Seed 1978 · Kramer
Given

H 30 m, Vs 250 m/s, ky 0.1 g, kmax 0.2 g, norm 0.05 s

Result

T0 0.31 s, ky/kmax 0.5 → crest displacement 31 mm

Cement / lime stabilisation (IRC SP:89)
IRC SP:89 · MoRTH §400
Given

4 % cement, γd 2000 kg/m³, 7-day UCS 5.0 MPa, CTB

Result

binder 80 kg/m³, target 4.5–7.0 MPa → accepted

Rural road pavement (IRC SP:72)
Add-on
IRC SP:72-2015
Given

CVPD 100, CBR 5 %, total 350 mm (curve C)

Result

curve C → base 225 mm + sub-base 125 mm, bituminous surfacing

Airfield strength (ACN-PCN)
Add-on
ICAO Annex 14 · Doc 9157
Given

Aircraft ACN 45, pavement PCN 50, flexible

Result

ratio 0.90 ≤ 1 → unrestricted operations

Airfield thickness design (FAA closed-form)
Add-on
FAA AC 150/5320-6D · Corps CBR / Westergaard
Given

Flexible: ESWL 30000 lb, p 100 psi, CBR 8, 5000 coverages

Result

Corps CBR → 19.2 in cover (α 1.001); rigid slab via Westergaard edge

MEPDG fatigue cracking (flexible)
Add-on
AASHTO MEPDG · NCHRP 1-37A
Given

εt 70 µε, E 500 ksi, Hac 6 in, Va 7 %, Vbe 11 %, N 1e7

Result

C 0.415, Nf 1.01e9 → damage 0.99 % → 0.59 % area cracking

Layered-elastic pavement response (Burmister)
Add-on
Burmister 1945 · Huang 2e · KENLAYER/WESLEA-class
Given

3-layer AC/base/subgrade, E 500/25/7.5 ksi, h 4/8 in, q 100 psi, a 5 in

Result

εt 346 µε (fatigue) · εv 942 µε (rutting) · deflection 0.71 mm — exact-Boussinesq-validated

Asphalt Institute M-E flexible design check
Add-on
Asphalt Institute MS-1 · Burmister strains
Given

3-layer section, εt 346 µε, εc 942 µε, E 500 ksi, 1e5 ESALs

Result

Nf 2.65e5 (fatigue) · Nr 4.82e4 (rutting govern) → rutting CDF 2.07 — thicken

Aircraft landing-gear pavement response (multi-wheel)
Add-on
FAA AC 150/5320-6E · Burmister LET
Given

3-layer section, dual wheel at 20 in spacing, q 100 psi, a 5 in

Result

single-wheel 942 µε → dual-gear 1132 µε subgrade strain (1.20× amplification)

FAARFIELD subgrade CDF design check
Add-on
FAA AC 150/5320-6E · DOT-57714 failure model
Given

dual gear 150 kN/wheel, 1.4 MPa, 125 mm AC / 400 mm base, 1200 dep/yr × 20 yr

Result

subgrade strain → coverages-to-failure (verified Bleasdale) → CDF vs 1.0 adequacy

FAARFIELD aircraft-mix CDF design check
Add-on
FAA AC 150/5320-6E · cumulative damage (mix)
Given

narrow-body (130 kN, 3000 dep/yr) + wide-body (250 kN dual-tandem, 400 dep/yr), 20 yr

Result

Σ-aircraft CDF; the heavy wide-body governs despite fewer departures

FAARFIELD HMA fatigue CDF (RDEC)
Add-on
Carpenter-Shen RDEC · FAA HMA CDF
Given

125 mm AC, εt from Burmister, S 3447 MPa, Va 7 %, Vb 11 %, 1200 dep/yr × 20 yr

Result

PV → Nf (0.4801·PV⁻⁰·⁹⁰⁰⁷) → HMA CDF vs 1.0 (secondary to the governing subgrade CDF)

MEPDG IRI (ride quality / smoothness)
Add-on
AASHTO MEPDG Eq. 5-15a
Given

IRI₀ 63, RD 0.3 in, FC 5 %, TC 200 ft/mi, age 10 yr, wet frost-prone subgrade

Result

site factor 368 → IRI 84 in/mi (1.33 m/km) — good ride

JPCP transverse cracking (rigid)
Add-on
AASHTO MEPDG Eq. 5-16/17 · Westergaard
Given

250 mm slab, MR 4.5 MPa, k 30 MPa/m, 9 kip wheel, 5e7 reps

Result

Westergaard edge stress → σ/MR → Nf → ~20 % slabs cracked

Rigid slab structural response (FE + Westergaard)
Add-on
Plate-on-Winkler FE · Westergaard (1926/48) · Ioannides 1985
Given

250 mm slab, E 28 GPa, k 30 MPa/m, 40 kN wheel @ 0.7 MPa, edge load, MR 4.5

Result

ℓ 1056 mm · σ_edge 1.44 MPa (FoS 3.1) · FE deflection 0.64 mm · corner 0.38 mm

Climate-zone EICM inputs (MEPDG)
Köppen-Geiger · AASHTO MEPDG §3
Given

Cold continental (Dfa) zone, Northern hemisphere

Result

Monthly temps −9→21 °C, precip 600 mm, freezing index 450 °C·days — feeds the distress drivers

JPCP cracking time-stepping (rigid MEPDG)
Add-on
AASHTO MEPDG §5 · monthly Miner · Bradbury curling
Given

280 mm slab, MR 4.5, k 40, 5×10⁷ reps, 20 yr

Result

Month-by-month load + curling → 6.6 % slabs cracked (within terminal); ΔT=0 matches the single-pass check

Airfield thickness design (FAARFIELD, CDF=1)
Add-on
FAA AC 150/5320-6 · iterate to CDF=1
Given

3-aircraft mix (B737/A320/B777), 20 yr, 60 MPa subgrade

Result

Required AC 335 mm; B777-300 governs (heaviest gear dominates the subgrade CDF)

FAARFIELD flexible design (full LEAF)
FAA AC 150/5320-6G · FAAModulus + Bleasdale · Appendix H
Given

4" P-401 / 8" P-403 / 12" P-209 / design P-154, CBR 5, 4-aircraft mix (B737-800/A321/EMB195/CRJ700), 20 yr

Result

FAAModulus sublayer moduli + Bleasdale failure → P-154 = 10.6 in (FAARFIELD 10.1); A321-200 governs

FAARFIELD rigid design (PCC slab)
FAA AC 150/5320-6G Ch.4 · Westergaard edge + Rollings SCI · Appendix H
Given

P-501 R=600 psi, k=100 pci, 4-aircraft mix, 20 yr

Result

Westergaard edge stress + Rollings SCI failure → slab = 17.9 in (FAARFIELD FE 17.14); A321-200 governs

Axle-load spectra (NALS → ESALs)
Add-on
AASHTO fourth-power · MEPDG §3
Given

Single-axle spectrum 40–120 kN, 1M axles

Result

Truck factor 1.54 → 1.54M ESALs; heavy tail dominates

Pavement-ME performance (time-stepping)
Add-on
AASHTO Pavement-ME / MEPDG · monthly EICM
Given

150 mm AC / 300 mm base / 60 MPa subgrade, 1e6 axles/yr, 20 yr, moderate climate

Result

month-by-month → total rut 21 mm (AC 15 + subgrade 5), fatigue 22 %, IRI 1.66 m/km (NCDOT-validated band)

JPCP IRI (rigid ride quality)
Add-on
AASHTO MEPDG Eq. 5-32a
Given

IRI₀ 63, 10 % cracked, 5 % spalled, 2 in/mi faulting, age 20 yr

Result

site factor + distress → IRI 79 in/mi (good ride)

JPCP joint spalling (rigid)
Add-on
AASHTO MEPDG Eq. 5-33a
Given

age 20 yr, 6 % air, f'c 28 MPa, 50 freeze-thaw/yr, 250 mm slab, w/c 0.45

Result

durability scaling factor → ~5 % joints spalled (feeds JPCP IRI)

JPCP joint load transfer & faulting potential
Add-on
AASHTO MEPDG Eq. 5-20d/22/23a · Westergaard
Given

250 mm slab, aggregate base, undowelled, erodibility 3, curling 0.024 in

Result

joint LTE 52 % · DE 0.079 lb/in · curling faulting potential 0.126 in

CRCP punchouts (rigid)
Add-on
AASHTO MEPDG Eq. 5-26
Given

accumulated transverse fatigue damage DIPO = 1, crack spacing 48 in

Result

PO = 216.8421/(1+33.158·1^-0.589) → 6.4 punchouts/mi

MEPDG thermal cracking (TCMODEL)
Add-on
AASHTO MEPDG Eq. 5-11 · Paris law
Given

mild climate ΔT 25 °C vs cold ΔT 60 °C, 150 mm AC

Result

mild ~6 ft/mi (negligible) → cold ~200 ft/mi (severe) low-temp cracking

MEPDG asphalt rutting (climate-integrated)
Add-on
AASHTO MEPDG Eq. 5-1a · EICM-lite
Given

150 mm AC, hot climate (mean 20 °C ± 18), 1e7 reps, β1r 0.5

Result

monthly-incremental asphalt rut ~0.6 in — realistic (single-shot gives absurd 0.5 in/sublayer)

MEPDG subgrade rutting (Tseng-Lytton)
Add-on
AASHTO MEPDG Eq. 5-2a · FHWA NHI-05-037
Given

fine subgrade MR 60 MPa, Wc 15 %, 1e7 reps over 1.5 m compressible depth

Result

εo/εr 71, depth-integrated subgrade rut ~0.2 in (wetter subgrade → more)

Concrete durability (IS 456 exposure)
EN 206 · ACI 318 · IS 456
Given

SO3 0.6 %, SO4 1.5 g/L, Cl 500 mg/L, pH 6.5

Result

Class 3 (Severe) → SRPC, 330 kg/m³, w/c 0.50, cover 50 mm

Liquefaction settlement
Tokimatsu-Seed · Ishihara-Yoshimine
Given

FoS profile, Dr 50 %

Result

Post-liquefaction settlement 92 mm

Lateral spread
Youd-Hansen-Bartlett 2002
Given

Free-face 5 m, T15 3 m

Result

Ground displacement 0.9 m

Post-liquefaction residual strength
Olson-Stark 2002 · Seed-Harder
Given

(N1)60cs 8, σ′v0 100 kPa, driving shear 12 kPa

Result

Sr/σ′v0 0.09 → Sr 9 kPa, flow-slide FoS 0.75 < 1 (mitigate)

Ground improvement

3

Stone columns, vibro and deep mixing.

Stone columns
Priebe 1995 · IS 15284-1 · FHWA NHI-08-082
Given

0.8 m columns, 2 m grid, a_s 0.13

Result

n 2.8 (Priebe) → settlement reduced to 38 %

Vibro-compaction
Mitchell 1981 · Brown 1977
Given

Loose sand Dr 45 %

Result

Dr → 75 % at 2.6 m probe spacing

Deep soil mixing
FHWA-RD-99-138 · Bruce 2000
Given

0.8 m columns, a_s 0.25

Result

Composite stiffness → settlement to 45 %

Pavements

5

Flexible and rigid pavement design.

Flexible pavement (IRC 37)
Add-on
IRC 37:2018 · IITPAVE
Given

50 msa, subgrade CBR 8 %, 90 % reliability

Result

BC 50 + DBM 130 + 553 granular = 733 mm; ε checked

Rigid pavement (IRC 58)
Add-on
IRC 58:2015 · Westergaard
Given

30 MSA, 98-pctile axle stress

Result

Slab 280 mm, fatigue + erosion < 100 %

Flexible pavement (AASHTO 93)
Add-on
AASHTO 1993 Part II
Given

W18 5×10⁶, MR 10 ksi

Result

SN 4.2 → layer thicknesses

Rigid pavement (AASHTO 93)
Add-on
AASHTO 1993 Part III · Eq 3.1
Given

W18 30×10⁶, S′c 4.5 MPa, k 40 MPa/m, J 3.2, R 90 %

Result

PCC slab D ≈ 302 mm (serviceability ΔPSI 2.0)

DCP subgrade strength
ASTM D6951 · IRC SP-72
Given

8 mm/blow penetration rate

Result

CBR ≈ 14 % → subgrade acceptance band

In-situ investigation

36

CPT, DMT, pressuremeter and field tests.

Site investigation plan
ASTM D420 · BS 5930 · EC7-2 · IS 1892
Given

Building footprint, 8 m grid

Result

12 boreholes, depths to 1.5 × B below founding

Phase relations (weight-volume)
Index · γ, e, n, Sr
Given

Gs 2.70, γd 16 kN/m³, w 12 %

Result

e 0.655, n 0.396, Sr 49 %, γ 17.9 / γsat 19.9 / γ′ 10.1 kN/m³

Soil classification (USCS / IS / AASHTO)
ASTM D2487 · IS 1498 · Casagrande
Given

70 % fines, LL 45, PL 22 (PI 23)

Result

USCS CL (lean clay), AASHTO A-7-6, above the A-line

Consistency & activity (Atterberg)
Skempton · IS 2720-5
Given

w 30, LL 45, PL 22, clay 30 %

Result

PI 23, I_L 0.35 (medium/firm), activity 0.77 (normal)

Stress path invariants (p-q / s-t)
MIT s-t · Cambridge p-q
Given

σ1 150, σ3 50 kPa, c′ 0, φ′ 30°

Result

p 83.3, q 100, s 100, t 50, η = M = 1.2 — at failure

Layered-soil permeability (k_h, k_v)
Parallel / series · anisotropy
Given

3 layers: 2 m@1e-5, 3 m@1e-7, 1 m@1e-6 m/s

Result

k_h 3.6×10⁻⁶, k_v 1.9×10⁻⁷ m/s, anisotropy 18.5×

Flow-net seepage quantity
Casagrande · q = k·H·N_f/N_d
Given

k 1e-5 m/s, H 4 m, N_f 4, N_d 12, 50 m wide

Result

q 1.33×10⁻⁵ m³/s/m → 57.6 m³/day total, exit gradient 0.22

Construction dewatering (well system)
Equivalent-well · Sichardt · Thiem / Dupuit
Given

40 × 20 m pit, k 1e-4 m/s, drawdown 5 m, H 12 m, 10 wells

Result

r_e 16 m, R 150 m → 1,151 m³/day total (115 per well), drawdown cone plotted

Pumping test (Cooper-Jacob)
Cooper-Jacob 1946 · ASTM D4105
Given

Q 1000 m³/day, r 30 m, Δs 0.5 m/cycle, t₀ 0.01 day, b 10 m

Result

T 367 m²/day, S 0.0092, k 36.6 m/day

Granular filter design (Terzaghi)
Terzaghi / USACE EM 1110-2-1901
Given

Base D15/D85 0.05/0.5 mm, filter D15/D50/D85 0.6/2/8 mm

Result

Retention 1.2 ≤ 4 ✓, permeability 12 ≥ 4 ✓ → filter acceptable

Gradation indices (Cu, Cc)
ASTM D2487 · well / poorly graded
Given

D10 0.1, D30 0.3, D60 0.6 mm (sand)

Result

C_u 6.0, C_c 1.5 → well graded

Capillary rise & suction
Hazen · Terzaghi · h_c = C/(e·D10)
Given

D10 0.2 mm, e 0.6, C 0.3 cm²

Result

h_c 0.25 m (25 cm), suction 2.45 kPa

Darcy flow & seepage velocity
Darcy 1856 · v = k·i
Given

k 1e-5 m/s, Δh 3 m over L 10 m, n 0.4, A 2 m²

Result

i 0.30, v 3×10⁻⁶, v_s 7.5×10⁻⁶ m/s, Q 6×10⁻⁶ m³/s

Effective stress at depth
Terzaghi · σ′ = σ − u
Given

z 5 m, WT 2 m, γ 18 / γ_sat 20 kN/m³

Result

σ_v 96, u 29.4, σ′_v 66.6 kPa (full profile plotted)

Mohr-Coulomb failure
Coulomb · Mohr circle
Given

σ3 50 kPa, c 10 kPa, φ 30°

Result

σ1f 184.6 kPa, q_u 34.6, plane 60°, circle tangent to envelope

Pore-pressure parameters (A, B)
Skempton 1954 · Bishop-Henkel
Given

Δσ₁ 200, Δσ₃ 50 kPa, A 0.5, B 1.0

Result

Δu 125 kPa (contractive), Ā 0.5, Δσ′₁ 75 / Δσ′₃ −75 kPa

CPT interpretation
Robertson 1990 · IS 4968
Given

qc / fs depth profile

Result

SBT zones, φ′ 36° (Kulhawy-Mayne), Dr, su

CPTu dissipation → ch
Teh & Houlsby 1991
Given

t50 100 s, 10 cm² cone, Ir 100, u2

Result

ch 246 m²/yr (T50* 0.245); kh from mv

Critical State Line (triaxial p'-q)
Schofield-Wroth · BS 1377-8
Given

3 CD tests σ'3 100/200/300, σ'1 3× σ'3

Result

M 1.20 → φ' 30°, c' 0 (R² 1.0)

CPT soil behaviour type index Ic
Robertson 2009 · SBTn
Given

z 5 m, qt 5 MPa, fs 50 kPa, γ 20, GWT 0

Result

iterated n 0.64 → Ic 2.01 (SBT 6, sand-like)

Embankment load stress (Osterberg)
Osterberg 1957 · trapezoidal fill
Given

H 5 m, γ 20, crest a 5 m, 2H:1V, z 10 m

Result

q 100 kPa, I 0.395 → Δσv 79 kPa (centreline)

Deadman (tie-rod) anchor capacity
Teng 1962 · passive block
Given

γ 18, φ 30°, surface deadman h 2 m, T 40 kN/m

Result

Kp−Ka 2.67 → T_ult 96 kN/m, FoS 2.4 (OK)

PVD spacing designer (preload)
Hansbo · invert radial U
Given

ch 2 m²/yr, U 90% in 6 mo, dw 66 mm, s 2, kh/ks 2

Result

required triangular spacing ≈ 1.05 m (n ≈ 17)

Strut / waler buckling check
Perry-Robertson · AISC · IS 800
Given

KL/r 100, fy 250, class b, Ae 6000 mm²

Result

χ 0.52 → fcd 118 MPa → Nd 709 kN

RC section design (IS 456 flexure)
ACI 318 · EC2 · IS 456
Given

Mu 225 kN·m, b 300, d 500, M25, Fe415

Result

Mu,lim 259 → Ast 1495 mm² (singly OK)

Pile buckling + P-δ
Davisson-Robinson 1965
Given

N 1000 kN, Lu 3 m, EI 40 MN·m², clay kh 10 MN/m³

Result

zf 1.98 m → Pcr 3982 kN → δ 1.34 (FoS 4.0)

SPT N correction
ASTM D1586 · IS 2131:2025
Given

Field N 19/23/33, σ′v 144–198 kPa, Peck Cn

Result

Design N 17/19/26 with overburden + dilatancy + N60

SPT correlations (multi-method)
Stroud · Schultze · Bowles · IS 6403
Given

Corrected N 21, silty sand, σ′v 160 kPa

Result

φ′, cu, Es, Dr, γ, qc — min/mean/max envelope + recommended

Flat dilatometer (DMT)
Marchetti · ISSMGE TC16 (2001)
Given

p0 300, p1 800, u0 50, σ′v 100 kPa

Result

ID 2.0 (sand), KD 2.5, M 20.9 MPa, φ′ 33.5°

Ménard pressuremeter (PMT)
NF P94-261 Annexes D + H
Given

ple* 1.0 MPa, EM 10 MPa, 2 m square in sand

Result

kp 1.28, q_net 1,285 kPa, settlement 7.5 mm

Field density
ASTM D1556/D6938 · IS 2720-28/29
Given

Sand-replacement on a compacted layer

Result

γ_d 17.8 kN/m³ → 96 % of MDD ✓

Resistivity (ERT)
ASTM G57 · NACE · AWWA · IS 3043
Given

Wenner array, 4 spacings

Result

ρ 22 Ω·m → soil corrosivity class

Compression index (Cc, Cr)
Skempton · Terzaghi-Peck · Nagaraj
Given

LL 50, w_n 35, e0 0.95, Gs 2.70

Result

Cc 0.29 (mean of 5 correlations), Cr 0.06

Frost penetration depth
Stefan · Modified Berggren
Given

k 1.5 W/m·°C, ρd 1700, w 15 %, F 600 °C·days

Result

Frost line 1.22 m (Modified Berggren, λ 0.9)

Coefficient of consolidation (oedometer)
Casagrande · Taylor · IS 2720-15
Given

t₅₀ 10 min, H_dr 10 mm, m_v 0.2 (Casagrande)

Result

c_v 1.04 m²/yr (3.3×10⁻⁸ m²/s), k 6.4×10⁻¹¹ m/s

Preconsolidation σ′p / OCR
Becker work method · Casagrande · IS 2720-15
Given

e–log σ′ curve, break at 100 kPa, σ′v0 50

Result

σ′p 100 kPa, OCR 2.0, Cc 0.25, Cr 0.05

Rock & tunnelling

2

Rock-mass classification and tunnel support.

Rock mass classification
RMR89 · Q · GSI · Hoek-Brown 2002
Given

σci 50 MPa, mi 10, GSI 45, RQD 70

Result

RMR 62 (class II), Q 8.3, mb 1.40, s 0.0022

Tunnel ground reaction (convergence-confinement)
Duncan Fama · Hoek
Given

r0 5 m, p0 10 MPa, c 1 MPa, φ 30°, unsupported

Result

p_cr 4.13 MPa, plastic radius 9.2 m, convergence 77 mm

Problem soils

3

Expansive and collapsible ground.

Expansive soil (swell)
ASTM D4546 · IS 1498 · IS 2720-40/41
Given

FSI 80 %, PI 45, swell pressure 220 kPa

Result

Severity high → under-reamed piles / CNS layer

Expansive heave magnitude
ASTM D4546 · IS 9214
Given

2 m active zone, Cs 0.08, p_s 200 kPa, σ'_final 50

Result

ΔH 50.7 mm (high) — surcharge 200 kPa to suppress

Collapse potential
ASTM D5333 · Jennings & Knight
Given

h0 20 mm, 19 → 17.5 mm on wetting at 200 kPa

Result

I_c 7.5 % → moderately severe collapse

Lab tests · 47

47 lab workflows, signed and chained.

Classification & index

8
Water content
IS 2720-2 / ASTM D2216
Given

Result

Atterberg limits
IS 2720-5 / ASTM D4318
Given

Casagrande LL + rolled PL

Result

LL 42, PL 20 → PI 22, USCS CL

Sieve analysis
IS 2720-4 / ASTM D6913
Given

Mass retained per sieve

Result

Cu 8, Cc 1.2 → well-graded sand (SW)

Hydrometer
ASTM D7928 / IS 2720-4
Given

Hydrometer readings vs time

Result

18 % clay, 22 % silt fraction

Specific gravity
ASTM D854 / IS 2720-3
Given

4-mass pycnometer

Result

G 2.67 at 27 °C

Particle shape (D4791)
ASTM D4791
Given

Flakiness + elongation gauges

Result

Flakiness 28 %, elongation 22 %

Shrinkage limit
ASTM D4943 / IS 2720-6
Given

Mercury displacement

Result

SL 14 %, shrinkage ratio 1.8

Linear Shrinkage
IS 2720-20 / BS 1377-2
Given

Result

Compaction & strength

10
Proctor compaction
IS 2720-7 / ASTM D698
Given

Compaction at 5 moisture points

Result

OMC 14 %, MDD 1.82 g/cc

California Bearing Ratio
ASTM D1883 / IS 2720-16
Given

Soaked 4-day, 2.5 / 5.0 mm

Result

CBR 8 % (governs at 2.5 mm)

Relative density
ASTM D4254 / IS 2720-14
Given

e_max / e_min, field e

Result

Dr 65 % → medium dense

Unconfined compression
ASTM D2166 / IS 2720-10
Given

Single specimen to failure

Result

qu 110 kPa → su 55 kPa, sensitivity 3

Triaxial UU
ASTM D2850 / IS 2720-11
Given

3 cells, undrained

Result

c_u 48 kPa, φ_u 0°

Triaxial CU
ASTM D4767 / IS 2720-12
Given

3 cells, CU + pore pressure

Result

c′ 8 kPa, φ′ 29°, A_f 0.6

Triaxial CD
ASTM D7181 / IS 2720-12
Given

3 cells, drained

Result

c′ 5 kPa, φ′ 32°

Direct shear
ASTM D3080 / IS 2720-13
Given

3 normal stresses

Result

c′ 6 kPa, φ′ 31°

Vane shear (lab)
ASTM D4648 / IS 2720-30
Given

Peak + remoulded torque

Result

su 52 → 17 kPa, sensitivity 3.1

Ring shear (residual)
ASTM D6467
Given

3 stages to large displacement

Result

φ′r 27.5°, c′r 0 (residual)

Consolidation & permeability

3
Oedometer / 1-D consolidation
ASTM D2435 / IS 2720-15
Given

e-log p loading

Result

Cc 0.32, Cv 2.4 m²/yr, pc′ 120 kPa

CRS consolidation
ASTM D4186
Given

Constant rate of strain

Result

Cv(σ′) curve + mv, continuous

Permeability
ASTM D2434 / IS 2720-17
Given

Falling-head

Result

k 3×10⁻⁷ m/s

Dynamic

2
Cyclic triaxial
ASTM D5311 / D3999
Given

CSR vs cycles to liquefaction

Result

Liquefies in 14 cycles at CSR 0.2

Resonant column
ASTM D4015
Given

Torsional resonance

Result

Gmax 95 MPa, damping 1.8 %

Rock laboratory

5
Rock UCS (uniaxial compression)
IS 9143 / ASTM D7012
Given

Result

Brazilian Tensile Strength
IS 10082 / ASTM D3967
Given

Result

Rock Density / Porosity / Absorption
IS 13030 / ISRM
Given

Result

Point load index
IS 8764 / ISRM
Given

Diametral on core

Result

Is(50) 3.2 MPa → UCS ≈ 77 MPa

Slake durability
IS 10050 / ISRM
Given

2-cycle wet-dry

Result

Id2 96 % → durable rock

Swell, chemical & special

5
Free swell index
ASTM D4546 / IS 2720-40
Given

Free-swell index

Result

FSI 80 % → high expansivity

Swell pressure
ASTM D4546 / IS 2720-41
Given

Constant-volume oedometer

Result

Swell pressure 220 kPa

Chemical aggressivity battery
IS 2720-21/22/26/27
Given

pH · sulphate · chloride · organic

Result

pH 7.8, SO₄ 1,200 ppm → moderate exposure

Organic content (LOI)
ASTM D2974 / BS 1377-3
Given

Loss on ignition at 440 °C

Result

OC 20 % → organic soil

Pinhole dispersion
ASTM D4647
Given

Flow at 50 mm head, dark effluent

Result

Class D1 → highly dispersive

Aggregates (IS 2386)

8
Aggregate Impact Value (AIV)
IS 2386-4 / BS 812-112
Given

Result

Aggregate Crushing Value (ACV)
IS 2386-4 / BS 812-110
Given

Result

Los Angeles Abrasion (LAA)
IS 2386-4 / ASTM C131
Given

Result

Ten Percent Fines Value (TFV)
IS 2386-4 / BS 812-111
Given

Result

Flakiness & Elongation Index
IS 2386-1 / BS 812-105
Given

Result

Aggregate Specific Gravity & Absorption
IS 2386-3 / ASTM C127
Given

Result

Aggregate Soundness (sulphate)
IS 2386-5 / ASTM C88
Given

Result

Stripping Value (bitumen adhesion)
IS 6241 · ASTM D3625
Given

Result

Bitumen & bituminous mix (IS 1201–1220)

6
Penetration of Bitumen
IS 1203:1978 / ASTM D5
Given

Result

Softening Point (Ring & Ball)
IS 1205:1978 / ASTM D36
Given

Result

Ductility of Bitumen
IS 1208:1978 / ASTM D113
Given

Result

Penetration Index (susceptibility)
Pfeiffer & Van Doormaal
Given

Result

Specific Gravity of Bitumen
IS 1202:1978 / ASTM D70
Given

Result

Marshall Stability & Volumetrics
ASTM D6927 / MS-2
Given

Result

One platform. From the rig to a signed report.

Code-checked to IS, Eurocode 7, NF P94-261, BS, AASHTO, ASTM and IRC — the same platform answers an Indian highway, a French foundation and a US bridge. 1-month free trial.