NONPLASTİK SİLT KUM KARIŞIMLARINDA BOOTSTRAP YÖNTEMİ İLE BOŞLUK SUYU BASINCI OLUŞUMUNUN DEĞERLENDİRİLMESİ

Year 2018, Volume: 7 Issue: 1, 197 - 205, 31.01.2018

Eyyüb Karakan Selim Altun

https://doi.org/10.28948/ngumuh.386530

Abstract

   Bu
çalışmanın temel amacı, tekrarlı yükler altında nonplastik silt kum
karışımlarının boşluk suyu basıncı üretimini literatürdeki üç farklı modeli
kullanarak incelemektir. Boşluk suyu basıncı oluşumunda, kumlu zeminlerde silt
içeriğinin etkisini araştırmak amacıyla dinamik üç eksenli deneyler
yapılmıştır. Deneylerde sıvılaşma kriteri olarak, 200 çevrimdeki değer ya da
birincil sıvılaşma başlangıcından hangisi daha önce gerçekleşir ise, o durum
göz önüne alınmıştır. Altı farklı silt içeriğinde (FC=%0-100) hazırlanan
örneklerden, farklı tekrarlı gerilme genliği oranlarında aşırı boşluk suyu
basıncı üretiminin ölçülmesi için gerilme kontrollü dinamik üç eksenli deneyler
gerçekleştirilmiştir. Deneyler D_r=%25-50 rölatif sıkılıkta ve 100
kPa efektif çevre gerilmesi altında yapılmıştır. Deney sonuçları siltli
kumların drenajsız dinamik koşullar altında ne denli etkilendiğini bulmak için
kullanılmıştır. Seed ve ark. [3], Booker ve ark. [2] ve Polito ve ark. [8]
boşluk suyu basıncı üretimi model sonuçları çalışma kapsamında sunulmuştur.
Boşluk suyu basınçları model katsayısı a,
silt içeriği, rölatif sıkılık ve tekrarlı gerilme genliği oranına bağlı olarak
tahmin edilmeye çalışılmıştır.

Keywords

Boşluk suyu basıncı, nonplastik silt–kum karışımı, dinamik üç eksenli deney, bootstrap yöntemi

CYCLIC PORE WATER PRESSURE GENERATION IN NON-PLASTIC SILT-SAND MIXTURES

Abstract

   The aim of
this paper is to evaluate the applicability of the available three different
models to predict excess pore water pressure generation in non-plastic silty
sand mixtures during cyclic loading. Cyclic triaxial tests were performed to
investigate the effect of silt content on the pore pressure generation in sand.
These tests were carried to 200 cycles or to onset of initial liquefaction,
whichever occurred first. Several stress-controlled cyclic triaxial tests were
performed to measure excess pore water pressure generation at different levels
of cyclic stress ratios for the specimens prepared at six different silt
contents (FC=0% to 100%). The specimens were tested under 100 kPa confining
pressures at two relative densities of 25% and 50%. Results of these tests were
used to investigate the behavior of silty sands under undrained cyclic triaxial
testing conditions. Seed et al. [3], Booker et al. [2] and Polito et al. [8]
pore water pressure generation models based on test results are also presented in
this paper. An attempt to estimate the pore pressure model coefficient a as a function of silt content, relative density, cyclic stress ratio
was made.

Keywords

Pore water pressure, non-plastic silt-sand mixtures, cyclic triaxial tests, bootstrap method

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