An Investigation of the Effect of Curing Temperature on the Deformation Characteristics of the Stabilized Soil Layers Treated with Lime and Tuff Wastes with Response Surface Method

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.