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Öz

Investigation of Factors Affecting Discharge Capacity of Prefabricated Vertical Drains An important factor affecting the performance of PVDs is their discharge capacity. The effect of factors such as, the hydraulic gradient, lateral stresses on a PVD, the type of soil in which PVDs are placed, the structure of PVDs and their flexural stiffness were investigated. Four different types of PVDs were used to investigate the effects of PVD deformation during the consolidation of soil and clogging of the core area on the discharge capacity of PVDs. The discharge capacity of PVDs, which is large at low deformations, decreases significantly (up to 57%) within the range of hydraulic gradients applied in this study (0.10 to 1.00). At large deformations, PVDs have a lower discharge capacity although the change in hydraulic gradient has a negligible effect on them. On the other hand, experimental observations have shown that the deformations occurring during consolidation of soils have an important effect on the discharge capacity of PVDs. For the type of PVDs used, the discharge capacity decreases by 68% to 100% when PVDs deform by 41.5%. Furthermore, a 40% decrease in discharge capacity is observed when lateral stress is increased from 25 kPa to 200 kPa. Clogging of the core zone, shapes of deformation, structure of PVD, and resistance against buckling have varying effects on the discharge capacity of PVDs depending on the soil type

Anahtar Kelimeler

• Prefabricated vertical drain, model testing system for discharge capacity, discharge capacity of prefabricated vertical drains

Prefabrik Düşey Drenlerin (PDD) Boşaltma Kapasitesini Etkileyen Faktörlerin Belirlenmesi

Öz

PDD’lerin performansını etkileyen önemli faktörlerden biri boşaltma kapasitesidir. Bu nedenle dört farklı özellikteki PDD türü için, uygulanan hidrolik eğim, etkiyen yanal gerilme, uygulandığı zemin cinsi, PDD’nin yapısı ve bükülmeye karşı direnci gibi faktörler dikkate alınarak, zeminin konsolidasyonu sırasında oluşan PDD’nin deformasyonu ve çekirdek bölgesinin kirlenmesinin boşaltma kapasitesi üzerine etkileri araştırılmıştır. Sonuçlar değerlendirildiğinde, düşük deformasyon seviyelerinde yüksek olan PDD’lerin boşaltma kapasitesi, bu çalışmada uygulanan en düşük ve en yüksek hidrolik eğim seviyesi aralığında (0.10-1.00) hidrolik eğimin artmasıyla önemli bir miktarda (%57’ye kadar) azalırken, yüksek deformasyon seviyelerinde daha düşük olan boşaltma kapasitesi üzerinde hidrolik eğimin etkisinin ihmal edilebilir olduğu gözlenmiştir. Zeminin konsolidasyonu sırasında farklı PDD türlerinde meydana gelen deformasyonun boşaltma kapasitesi üzerindeki etkileri incelendiğinde, %41.5 civarında deformasyon meydana geldiğinde boşaltma kapasitesinin %68-%100 arasında azalabileceği, etkiyen yanal gerilmeye bağlı olarak ise, yanal gerilmenin 25 kPa değerinden 200 kPa’ya yükselmesi durumunda boşaltma kapasitesinde yaklaşık %40 azalma olduğu belirlenmiştir. PDD’nin çekirdek bölgesinin kirlenmesi, PDD’de meydana gelen deformasyon biçimleri, PDD’nin yapısı ve bükülmeye karşı direnci gibi faktörlerin de uygulandığı zemin cinsine göre boşaltma kapasitesi üzerinde değişik derecelerde etkileri olduğu gözlenmiştir

Anahtar Kelimeler

• Prefabrik düşey dren, boşaltma kapasitesi model deney sistemi, prefabrik düşey drenlerin boşaltma kapasitesi

Kaynakça

1. ASTM D4716, Standard test method for determining the (in-plane) flow rate per unit width and hydraulic transmissivity of a geosynthetic using a constant head, Annual Book of ASTM Standards, 1995.
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