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A project end to end ​

This page uses all eight members of the Lythos family, one after another, on an imaginary port expansion site. Every step was actually run with the program's own starter project (or a small change to it), and the output is quoted as it came.

About the numbers

Each step uses its own program's starter example; the soil profiles are not identical from step to step. The aim is not to finish one design but to show how the right tool answers the right question.

Office building footings — Lythos Bearing ​

A 2.5 × 4.0 m pad footing on layered ground (fill / stiff clay / dense sand); V = 1700 kN, H = 150 kN, M = 300 kNm.

bash
lythos-bearing example -o office.bearing
lythos-bearing run office.bearing
text
Checks
  Bearing: FS = 2.96 ≥ 3.00 — NOT OK
  Sliding: FS = 5.33 ≥ 1.50 — OK
  Eccentricity: e/B = 0.071 ≤ 0.167 — OK

  The bearing check is satisfied from B = 2.51 m

Vesić gives qult = 533.5 kPa; Meyerhof is the most conservative (466.0 kPa). Decision: B = 2.60 m. → Bearing examples

Preload fill for the warehouse yard — Lythos Settle ​

A 4 m high preload fill with a 12 m crest on soft clay:

python
values = forms.defaults()
values.update(shape="embankment", emb_crest=12.0, emb_height=4.0, emb_gamma=20.0)
r = Session(lang="en").analyse(values)
text
s = 228.0 mm · t90 = 5.1 years · Settlement check: NOT OK
center   total =  228.0 mm
shoulder total =  190.6 mm
midslope total =  108.5 mm
toe      total =   17.0 mm

90 % of the settlement takes 5.1 years — too long for a preload. Vertical drains will clearly be needed. → Settle examples

Stability of the fill — Lythos LE ​

A 6 m fill on the same kind of soft clay (su = 12 + 1.8·z kPa), raised in one lift:

text
one lift, 6 m, su0 = 12 kPa : FS = 0.896
stage 1,  3 m, su0 = 12 kPa : FS = 1.362
stage 2,  6 m, su0 = 24 kPa : FS = 1.366

In one lift the fill fails (Bishop 0.896). Built in two stages, once consolidation under the first has raised su0 to 24 kPa, the second is safe at 1.37. Settle's t90 is the measure of that wait. → LE examples

Warehouse piled foundation — Lythos Pile ​

A 3 × 3 group of bored piles, D = 0.80 m, L = 20 m, Q = 10 000 kN:

text
CHECKS
  Single pile: FS = 4.31 (required 2.50) — OK
  Group: FS = 3.10 (required 2.50) — OK
  Settlement: 32.8 mm (allowed 40.0 mm) — OK

  Required length: L = 18.50 m (tip at 20.00 m)

A length sweep shows an interesting detail: at L = 18 m the FS is only 1.84; as soon as the tip enters the dense sand (L = 20 m) it jumps to 4.31. Founding the piles in the dense sand is what matters. → Pile examples

Quay wall — Lythos SPWA ​

An 8 m retained height, an NZ 26 sheet pile quay with two rows of anchors; kh = 0.1:

text
Theoretical Required Embedment (D_req): 4.64 m
Design Embedment Depth (D_design):     6.00 m
...
Max. Absolute Moment: 564.58 kNm/m   (LE: 559.61)
Max. Deflection: 73.3 mm   (LE: 51.5)
STATUS: NOT OK - DEFLECTION EXCEEDED!

Limit equilibrium says the wall is adequate; the staged beam-spring analysis shows the deflection exceeding the H/120 = 66.7 mm limit. That is exactly the value of putting the two side by side: a stiffer section or prestressed anchors are needed. → SPWA examples

Pumping station deep excavation — LythosFEA ​

An 8 m excavation behind a bored pile wall (D1000 @ 1.2 m) with two rows of prestressed anchors; six stages:

text
stage 5/6: 5 - stress anchor row 2, excavate to 22.0 m
stage 6/6: 6 - factor of safety
lowest factor of safety: 2.034
Factor of safety (SSR)2.03
Wall max. moment219 kNm/m
Wall max. deflection20.8 mm
Anchor loads306 / 450 kN

→ FEA examples

Access ramp — Lythos MSEW ​

A 6 m MSE wall with 50×4 steel strips:

text
External stability (FS)       value   required
  Sliding                      2.99      1.50   OK
  Overturning                  6.02      2.00   OK
  Bearing capacity             7.51      2.50   OK
Internal stability
  Pullout                      1.62      1.50   OK   (z = 5.625 m)
  Required uniform length: L = 5.13 m (FHWA minimum 4.20 m)

Pullout of the top layer governs — that is where the overburden is smallest. → MSEW examples

Fill quarry — Lythos Kinematic ​

Six joint sets are screened against a 20 m rock face in the quarry:

text
Planar Sliding: 1 / 6
  E3               CRITICAL

The critical set goes to limit equilibrium: planar sliding with a tension crack, FS = 0.891. For FS = 1.5 the support required, at Hoek & Bray's optimum angle, is 697 kN/m. → Kinematic examples

Summary ​

StructureToolResultDecision
Office footingBearingFS = 2.96 < 3.00B = 2.60 m
Preload fillSettle228 mm, t90 = 5.1 yearsVertical drains
Fill stabilityLE0.90 → 1.36 / 1.37Two-stage construction
Warehouse pilesPileFS 4.31 / group 3.10L ≥ 18.5 m
Quay wallSPWAδ = 73 mm > 67 mmStiffer section
Deep excavationFEASSR = 2.03Adequate
Access rampMSEWEvery check OKL ≥ 5.13 m
Quarry faceKinematicFS = 0.89697 kN/m of bolting

Each step's project file comes from the example command and re-runs with run; every number on this page can be reproduced on your own machine.

Released under the AGPL-3.0 licence.