Open AccessThe Stability Analysis of a Cofferdam Using the Numerical Modelling
Author(s) -
Monika Súľovská,
Jakub Stacho,
M. Kopecký
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/960/2/022068
Subject(s) - cofferdam , excavation , geotechnical engineering , foundation (evidence) , pile cap , pile , engineering , geology , archaeology , history
The foundation of the bridge pillars required the construction of cofferdams in the Danube River. The cofferdams protected the area of the excavation pit mainly against the effects of flowing water. The paper includes analysis of the cofferdam for the foundation of the main central pillar of the asymmetrical bridge. The cofferdam has the ground plan dimensions of 44 x 20 m. It’s constructed of the double-row sheet pile walls. The stability of the cofferdam was analysed using numerical modelling based on the finite element method using Plaxis geotechnical software. The level of backfilling inside the cofferdam, required for construction of the foundations, was 6 m above the bottom of the river. The depth of the excavation pit of the cofferdam was about 4 m below the river bottom. The numerical model included 15 construction phases, which corresponded to the procedure of the construction. The analysis were focused mainly on construction phases, such as, e.g., the total backfill of the cofferdam, the loading from the piling rig, creating the excavation pit inside the cofferdam and installation of struts, and the load from the maximum level of the Danube River. The analysis showed that there are two critical phases. The first critical phase represents the situation when the piling rig works near the edge of the cofferdam, and the Danube River is at a minimal level. The second critical phase occurs when the full excavation pit created, and the Danube River is at a maximum level.