Two-dimensional unconfined seepage flow toward a highway cut slope

Abstract

The unconfined gravity-flow system near a free-outflow boundary such as a highway cut slope was investigated by using a higher-order numerical model. Unlike the Dupuit–Forchheimer equation, which is applicable mainly to a hydraulic flow problem, the proposed model accounts for the effects of the vertical component of the flow for a full treatment of the problem of plane phreatic flow. The model equations were numerically solved by means of a finite-difference scheme. Their accuracy was then verified using the solutions of the full two-dimensional potential-flow method and rigorous mathematical approaches, revealing that for a face slope flatter than 70º, the differences between the solutions of the model and the earlier approaches for the relative seepage-face height were nearly negligible. The comparison results also demonstrated the substantial effects of the slope of the downstream face on this height and the seepage discharge. Furthermore, the accuracies of the model predictions for the phreatic-surface profile and the distributions of the piezometric head at different vertical sections are much better than the earlier method, which approximates the trapezoidal-shaped aquifer by its equivalent rectangular one. Such a satisfactory performance may be attributed to the model’s higher-order correction factor for the effects of the phreaticsurface curvature and steep slope.

Keywords

unconfined seepage flow;phreatic surface;artificial cut;seepage discharge;non-hydrostatic groundwater flow;seepage-face height;

Data

Language:	English
Year of publishing:	2023
Typology:	1.01 - Original Scientific Article
Organization:	UL FGG - Faculty of Civil and Geodetic Engineering
UDC:	556.51
COBISS:	209981187
ISSN:	0352-3551
Views:	43
Downloads:	7
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary title:	Dvodimenzionalni tok podzemne vode s prosto gladino proti avtocestnemu vkopu
Secondary abstract:	Z numeričnim modelom višjega reda je bil raziskan gravitacijski tok pri prosti gladini v bližini meje prostega odtoka, kot je na primer vkop avtoceste. Za razliko od Dupuit–Forchheimerjeve enačbe, ki se uporablja predvsem za hidravlični tok, predlagani model upošteva vplive vertikalne komponente toka za celovito obravnavo problema ravninskega toka vode pri prosti gladini. Enačbe modela toka so bile numerično rešene s pomočjo diferenčne sheme. Natančnost rešitve je bila preverjena ob upoštevanju dvodimenzionalnega toka in s strogimi matematičnimi pristopi. Za naklone vkopa, ki je položnejši od 70º, so razlike v višini vode na precejnem robu med rešitvami tega modela in prejšnjimi pristopi skoraj zanemarljive. Primerjava rezultatov je prav tako pokazala na znatne vplive naklona vkopa na višino vode na precejnem robu in odtok. Poleg tega je natančnost modelne napovedi za potek gladine podzemne vode in porazdelitev hidravličnih višin na različnih navpičnih odsekih veliko boljša od prejšnje metode, ki vodonosnik trapezne oblike upošteva kot ekvivalentni pravokotni vodonosnik. Zadovoljivo rešitev je možno pripisati modelnemu korekcijskemu faktorju višjega reda za učinke ukrivljenosti gladine podzemne vode in strmega pobočja.
Secondary keywords:	precejanje pri prosti gladini;gladina podzemne vode;vkop;odtok;nehidrostatsko precejanje;višina vode na precejnem robu;
Type (COBISS):	Article
Pages:	str. 95-109
Volume:	ǂVol. ǂ36
Issue:	ǂno. ǂ65
Chronology:	Dec. 2023
DOI:	10.15292/acta.hydro.2023.06
ID:	25202088