🏗️ Ukwakha — ukubheka ukumba okujulile Imodeli ephilayo

Isisekelo — imodeli engemuva kwezinombolo

Wonke ubudlelwano isilingisi esibusebenzisayo, nomthombo wabo. Izinto ezihlala zingashintshi ezimakwe njengokuthathelwa yizilinganiso zesibonelo.

Ukuqina kwesistimu kukaClough no-O'Rourke: ukuqina kokugoba kodonga kwahlukaniswa nesine samandla ebanga elingaxhaswanga.

S = EI / (γw · h⁴), h = depth − lowest strut level (unsupported height)[3][5]

Imitha ngayinye ebiwe ingeza ukugobeka ngesivinini esikhuphuka njengoba ukuqina kwesistimu kwehla; ukwengeza umthwalo kusengaphambili kuyakunciphisa, ubuso obuvulekile obujule kunephoyinti lokumisa buyakhasa kancane.

Δδh = ΔH · ρ(S) · (1 − 0.8·preload); ρ(%) = clip(2.3 − 0.7·log10 S, 0.12, 1.6); creep 2.5 mm/d per m of h above 3.5 m (berm −2 m)[3][5][10]Amanani esibonelo okufundisa, hhayi amanani esiza sangempela.

Ukuntywila komhlaba ngemuva kodonga: cishe u-0.75 × ukugobeka kodonga, kuthe tyaba kuze kufike ku-0.75 H, kunciphe kuze kufike ku-zero ku-2 H (isikhumulo sobumba obuthambile kuya kokumaphakathi).

δv,max = 0.75·δh,max; δv(d) = δv,max for d ≤ 0.75H, × (2 − d/H)/1.25 to 0 at d = 2H[3][4]

Inhlabathi esele ngaphansi kwesisekelo kufanele ibe nzima kuneningi lengcindezi yamanzi avaliweyo aphusha phezulu esuka ku-aquifer.

FS = γt·(z_aq − H) / (γw·(z_aq − z_wt − s_in)); required ≥ 1.2[10]

Ukugeleza okuzinzile kukaThiem: ukwehla kwehla ngelogarithimu yebanga elisuka emithonjeni; imithombo yokubuyisela yengeza umphumela ophambene.

s(r) = Q/(2πT)·ln(R/r) − Q_r/(2πT)·ln(R/r_r) (steady radial flow, superposition; heads lag the steady state with τ = 1.5 d); Q_r ≤ 0.55·Q[9]Amanani esibonelo okufundisa, hhayi amanani esiza sangempela.

Ukuminyana kobubanzi obu-1 bukaTerzaghi: ingcindezi yamanzi ehlisiwe isakazeka ebumbeni ngezinsuku, futhi ubumba buyaminyana njengoba ingcindezi esebenzayo ikhuphuka.

∂u/∂t = c_v ∂²u/∂z²; Δσ' = −Δu; settlement = Σ m_v·Δσ'·Δz (unloading: 0.1·m_v)[8]

Ukuphambuka kwekhoneni: umehluko wokuntywila ngaphesheya kwesakhiwo owahlukaniswe nobude baso, uma kuqhathaniswa nemikhawulo kaBjerrum.

β = (s_near − s_far) / L; 1/500 = 2 ‰ (limit where cracking is not acceptable), 1/300 = 3.3 ‰ (first cracking)[6][7]

Ingcindezi yomhlaba ebonakalayo kaPeck ku-strut engaphansi kakhulu ngobude bayo obuthwala: lapho ubuso obuvulekile bujule kakhulu, kuthwala okwengeziwe.

P = 0.3·γ·H · (half span above + h) · 5 m ≥ preload; shown as % of design load 2400 kN[2]Amanani esibonelo okufundisa, hhayi amanani esiza sangempela.

Ukufundwa kwamathuluzi kunephutha lokulinganisa — funda izindlela zokuthambekela, hhayi amanani ngamanye.

reading = true value + N(0, σ); σ = 0.5 mm (settlement points), 1.0 mm (inclinometer)[1]Amanani esibonelo okufundisa, hhayi amanani esiza sangempela.

Izinto ezingaguquki ezisetshenziswa yimodeli

final depth 15 m · struts at 1, 4, 7, 10, 13 m, 5 m apart along the wall, crew starts 0.5 m below a level and needs 2 days · over-excavation allowance 4 m unsupported · wall 0.8 m concrete (EI = 1.28 GN·m²/m per m) · γ = 19 kN/m³ · building 12 m long, near edge 6 m behind the wall · water table 1 m · aquifer T = 300 m²/d, R = 400 m, excavation radius 12 m, recharge line 4 m behind the wall (effective radius 3 m) · clay 5 m above the aquifer, m_v = 0.2 /MPa, c_v = 0.15 m²/d · ground factors lognormal (σ 0.10 wall, 0.15 m_v, 0.20 c_v) · base unworkable below FS 1.05 · recharge capped at 55 % of the water pumped (supply from the discharge, well clogging)Amanani esibonelo okufundisa, hhayi amanani esiza sangempela.

Ukungahleliwe: i-generator ye-mulberry32 enembewu; ukusabalalisa okusetshenzisiwe — uniform, exponential (inverse CDF), normal (Box–Muller), Poisson (Knuth). Imbewu iyabonisa futhi ingabelwana.

Imithombo

1. R. B. Peck — Advantages and limitations of the observational method in applied soil mechanics (Ninth Rankine Lecture) — Géotechnique 19(2), 171–187, 1969
2. R. B. Peck — Deep excavations and tunneling in soft ground (apparent earth-pressure diagrams for braced cuts) — Proc. 7th ICSMFE, Mexico City, State-of-the-Art Volume, 225–290, 1969
3. G. W. Clough, T. D. O'Rourke — Construction induced movements of in-situ walls (system stiffness EI/(γw·h⁴), settlement envelopes) — ASCE Geotechnical Special Publication 25, Design and Performance of Earth Retaining Structures, 439–470, 1990
4. A. I. Mana, G. W. Clough — Prediction of movements for braced cuts in clay — Journal of the Geotechnical Engineering Division 107(GT6), ASCE, 1981
5. A. Gens — Deep excavations: empirical methods for movements; procedures to reduce movements (early bracing, preloading, avoiding over-excavation) — NZ Geotechnical Society lecture notes, 2010
6. L. Bjerrum — Allowable settlement of structures (angular distortion 1/500, 1/300, 1/150); summarised in NGI report "Skadegrenser" — Proc. European Conf. SMFE Wiesbaden, Vol. II, 135; NGI, 1963
7. M. D. Boscardin, E. J. Cording — Building response to excavation-induced settlement — Journal of Geotechnical Engineering 115(1), 1–21, 1989
8. Evolution of primary consolidation settlement with time — Terzaghi 1-D consolidation, Tv = c_v·t/H_dr², U–Tv relation (Fundamentals of Foundation Engineering, §4.8) — University of Newcastle (open textbook)
9. Steady-state pumping: the Thiem equation s = Q/(2πT)·ln(R/r); superposition of wells — University at Buffalo, Aquifer hydraulics notes
10. C.-Y. Ou — Deep Excavation: Theory and Practice (upheaval / uplift check against a confined aquifer, dewatering, strut preload) — Taylor & Francis, 2006