Kil zeminler üzerine inşa edilen dairesel batardolarda hidrolik taban göçmesi davranışının sayısal analizi

Öz

Yeraltı suyu ile nehir, göl ve deniz gibi yüzey sularının bulunduğu ortamlarda temel ve kazı imalatlarının geçici olarak kuru koşullarda gerçekleştirilmesi amacıyla inşa edilen batardolarda, su seviyesinin batardo tabanı kotunun üzerinde kalması durumunda taban altında oluşan potansiyel fark, hidrolik taban göçmesi mekanizmasını tetikleyebilmekte; bu da efektif gerilmelerin azalmasına ve zemin mukavemetinde önemli kayıplara yol açabilmektedir. Bu çalışmada, su seviyesinin yüksek olduğu durumlarda, kil zeminlerde inşa edilen dairesel batardolarda hidrolik taban göçmesi davranışı, eksenel simetri varsayımı altında gerçekleştirilen sonlu eleman analizleri ile incelenmiştir. Analizlerde, zemin kohezyonundaki değişimlerin ve batardo geometrisinin yeraltı suyu hidrolik yükü, boşluk suyu basıncı ve hidrolik eğim dağılımları üzerindeki etkileri değerlendirilmiştir. Elde edilen bulgular, hidrolik taban göçmesi davranışının zemin kohezyonu ile batardo geometrisinin birlikte etkisi altında şekillendiğini ve batardo yarıçapının hidrolik stabiliteyi belirleyen baskın bir parametre olduğunu göstermektedir. Ayrıca, batardonun iki tarafı arasındaki göçmeye neden olan kritik su seviyesi farkının zemin kohezyonundaki artışla birlikte yükseldiği, ancak bu etkinin özellikle daha büyük batardo yarıçaplarında belirginleştiği belirlenmiştir.

Anahtar Kelimeler

• Batardo
• hidrolik taban göçmesi
• killi zeminler
• sonlu elemanlar analizi
• yeraltı suyu akımı

Numerical analysis of hydraulic heave failure in circular cofferdams constructed on clay soils

Öz

In environments where groundwater and surface waters such as rivers, lakes, or seas are present, cofferdams are constructed to temporarily provide dry conditions for foundation and excavation works. When the water level remains above the cofferdam base elevation, the hydraulic head difference developing beneath the base may trigger hydraulic heave failure mechanisms, leading to a reduction in effective stresses and a significant loss of soil strength. In this study, the hydraulic heave failure behavior of circular cofferdams constructed on clay soils under high groundwater conditions is investigated using finite element analyses performed under the assumption of axial symmetry. The analyses evaluate the influence of variations in soil cohesion and cofferdam geometry on the distribution of groundwater hydraulic head, pore water pressure, and hydraulic gradient. The results indicate that hydraulic heave failure behavior is governed by the combined effects of soil cohesion and cofferdam geometry, with cofferdam radius identified as a dominant parameter controlling hydraulic stability. Furthermore, it is shown that the critical water level difference causing hydraulic heave failure between the two sides of the cofferdam increases with increasing soil cohesion, while this effect becomes more pronounced for larger cofferdam radii.

Anahtar Kelimeler

• Cofferdam
• hydraulic heave
• clayey soils
• finite element analysis
• groundwater seepage

Kaynakça

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