Kamiloglu, Hakan Alper

This study was aimed to (1) investigate the failure surface mechanism occurring behind the wall supporting narrow backfill with experimental and numerical approaches; (2) determine the effect of internal friction angle (phi), friction (delta), heel length (beta), foundation thickness (alpha), backfill inclination (psi), and backfill width (theta) parameters on lateral earth thrust coefficients; and (3) derive finite-element analysis (FEM)-response surface method (RSM)-based lateral earth thrust coefficient equations for inverted T-type retaining walls supporting narrow backfill. The study was performed for granular backfill. A small-scale test was performed to investigate the failure surface mechanism in the narrow granular backfill. The particle image velocimetry method was employed to determine failure surface patterns for various heel lengths and backfill widths. Finite-element (FE) analyses were also performed to verify the experimental results. From the analyses, it was seen that two characteristic soil blocks formed behind the horizontally translated wall. Due to these soil blocks, the wall was divided into three characteristic regions. Lateral active earth thrust coefficients were derived for the regions. RSM was employed to derive FE-based lateral earth thrust coefficient estimation equations for each region. In this context, three design matrices were created, comprising 76 runs. In the design, parameters phi, delta, beta, alpha, psi, and theta were used as independent variables. A total of 76 FE analyses were performed for various parameter combinations. The results of the FE analyses were used as a response. From the statistical analyses, lateral active earth thrust estimation equations for narrow backfill were derived. The suggested equations were compared with the results of experimental, numerical, and analytical studies, and it was seen that the method gives reliable results. The effects of independent variables and their interactions on lateral earth pressure coefficients were examined.

AtıfWoS3·OpenAlex3

İncele

Kamiloglu, Hakan Alper; Turan, Huseyin

The shallow spread foundations are one of the widely used foundation types for low-rise, low-cost or commercial buildings. However, it is not possible to use this type of foundation for soils with low bearing capacity or capable of excessive settlements. In these cases, stabilized soil layers overlying insufficient soil may be alternative to the high-cost foundation systems. As the temperature of the soils depends mostly on air temperature for shallow depths, curing conditions of the stabilized soil layers are affected by the air temperature. The effect of curing temperature on the pressure-settlement relation of the layered soil is a gap in the literature. This study investigates the effect of Bayburt tuff on pressure-settlement characteristics of layered soil for various curing temperatures. The specific objectives of this paper are to (1) examine the effect of using the waste tuffs as a stabilization agent in layered soils, (2) evaluate the usability of response surface methodology (RSM) to estimate shear strength parameters (c, ϕ), unconfined compression strength, and secant modulus of the stabilized soil with less experiment, (3) investigate the effect of dimensions of the stabilized soil block (length, with and thickness) on pressure-settlement relations under various curing temperature (T = 3 °C, 13 °C, 23 °C, 33 °C, 43 °C). This study comprises experimental and numerical parts. In the experimental part, strength parameters (c, ϕ) and secant modulus of stabilized soil samples were estimated with response surface methodology for various curing temperatures (3 °C, 23 °C, 43 °C). The effects of curing temperature on shear strength and Bulk’s modulus parameters were determined with the derived RSM model. In the numerical part of the study plate load test was simulated with the derived 2D axisymmetric FE model. The parameters required for the FE analyses were determined with the derived RSM model. As a result of the study, it was seen that it is possible to estimate experimental parameters accurately using the RSM approach with fewer tests. Bayburt tuff and lime mixtures increase the stiffness of the layered soil. The curing temperature has considerable effects on the pressure-settlement relationship up to a certain value. After a certain value increasing curing temperature has no considerable effects on the stiffness of the layered soil.

AtıfScopus3·WoS1

İncele

Kamiloglu, Hakan Alper; Turan, Huseyin

Response Surface Methodology (RSM) is useful to find the optimum value of the response, to examine the relationship between independent variables and responses, or to shorten very complicated and timeconsuming numerical analyses. Although the RSM is a commonly used method in many branches of engineering, the use of this method is limited in geotechnical studies. In this study, the effect of curing temperature on shear strength and unconfined compressive strength parameters of lime stabilized clayey soil was examined. Within the scope of the study, it was aimed to evaluate the Response Surface Method to estimate these parameters with less experimental effort. In the study effect of the temperature was controlled with five different curing temperature level (3 degrees C, 13 degrees C, 23 degrees C, 33 degrees C, 43 degrees C). Three axial (UU) and unconfined compression tests were performed on 40 pieces of stabilized soil samples cured along 28 days at various temperatures. The experimental design was performed with Response Surface Methodology to reduce the test number. Within this scope, an equation was derived statistically to estimate the deviator strength of the samples. Statistical analyses were performed considering deviator strengths of the 18 pieces of samples. As a result of the study, it was seen that it is possible to estimate shear strength and unconfined compression strengths of the samples accurately by using fewer test numbers with Response Surface Methodology.

AtıfWoS2·OpenAlex2

İncele

Kamiloglu, Hakan Alper; Sadoglu, Erol

Failure surfaces are very effective in active lateral earth thrusts acting on cantilever retaining walls. The intersection of failure surface and cantilever retaining wall should be taken into account for determination of active earth thrust. Calculations of lateral earth thrusts vary for two different cases, short heel or long heel, based on the intersection of cantilever wall and failure surface. However, the common methods are devoted to a particular case (long heel or short heel). This study intended to suggest a new lateral earth thrust method that is applicable to cantilever walls with a short heel or long heel using the limit-equilibrium approach. For this purpose, an earth thrust-maximization algorithm was prepared and coded by using Matlab Environment to determine active earth thrust coefficients and failure surface inclination angles occurring behind a cantilever wall in an active case. Also, the failure surfaces occurring behind model cantilever walls and the failure cases were examined experimentally by using particle image velocimetry (PIV) analysis. Consequently, long-heel and short-heel cases and the effective parameters on the cases were investigated analytically and experimentally. (C) 2019 American Society of Civil Engineers.

AtıfWoS23·OpenAlex24

İncele

Kamiloglu, Hakan Alper; Sadoglu, Erol

Cantilever retaining walls are earth-retaining structures commonly used in construction. Conventional methods used to determine the active earth thrust acting on a wall often neglect friction between the soil and wall. This study presents an analytical solution for determining the active earth thrusts acting on a cantilever retaining wall with a short heel and a shear key that supports granular backfill. Three different earth thrusts were considered to be acting on three different parts of the rear face of the wall; the thrusts were derived using the limit equilibrium method. The active earth thrust formulas were also simplified in terms of earth thrust coefficients, unit weight, and wall height. An algorithm was developed to obtain earth thrust coefficients depending on various wall dimensions and internal friction angles and to prepare graphs representing earth thrust coefficients and failure surface angles. The effects of wall dimensions and internal friction angles on the earth thrusts and failure surface angles were determined. Finally, the proposed method of determining earth thrust coefficients was compared with other approaches.

AtıfWoS21·OpenAlex20

İncele

Kamiloglu, Hakan Alper; Yurdagül, Erman; Tekin, Ilker; Cokorilo, O

Subgrade is one of the most important factor which affects the operating time of highways. Subgrade of highways which are a part of freight transportation network exposes to more pressure. Therefore, stabilization of subgrades becomes more important for these highways. Usage of sustainable and eco friendly resources produce economic and effective solutions for stabilization of highways. BS can be a good example of the solution which are mined in Bayburt city, the north-east of Turkey. Bayburt Stone (BS) is Eocene age and consist of zeolite minerals. Because of containing high value of amorphous silica, tuffic Bayburt stones have pozzolanic activity. Therefore, the stones have binding characteristics when they mix in lime. In this study, It is intended to show that BS waste which obtained from the stone quarries during the stone processing, can be used as a stabilizing material in subbase layers of highways. Within the scope of the study lime and lime - BS mixtures were used to improve clayey subbase layers. In the experimental studies, different amount of 0.2-80 mu m diameter BS and lime mixtures were used and improvement results of lime, lime - BS mixtures were compared. The obtained stabilization materials were tested for clayey soils. In this context nonconfined compression test, shear box, XRD, XRF and Particle Sizer tests, standard compaction and soil classification tests (Liquid-Plastic Limit Test, Sieve Analysis, Hydrometer Analysis) were performed. As a result of study it was observe that the strength of samples which obtained from lime-BS increased remarkably and it's possible to make compaction with lower compaction energies.

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