Document Type : Original Article

Authors

• Maryam Ghiasi ¹
• Vahid Rostami ²

¹ Master's degree Department of Civil Engineering, Faculty of Engineering and Technology, Islamic Azad University, Hamedan Branch, Hamedan, Iran

² Assistant Professor, Department of Civil Engineering, Faculty of Engineering, Ha.C., Islamic Azad University, Hamedan, Iran

Abstract

One of the crucial parameters in the design of foundations is the subgrade reaction coefficient, and accurately estimating this parameter is always a priority for engineers. Various methods have been proposed to determine this parameter, among which the Winkler method is one of the most well-known. The fundamental issue in this method is estimating the numerical value of the subgrade reaction coefficient (ks), which is influenced by multiple factors such as the properties of the soil beneath the foundation, the groundwater level, and the presence of additional parameters like micropiles, nails, etc. In this research, the impact of micropiles on reducing settlement and determining the subgrade reaction coefficient, both in the presence and absence of groundwater, has been investigated using the finite element method with the software (PLAXIS3DFOUNDATION). A foundation with dimensions of 10 meters in width and 20 meters in length was utilized for this purpose. The studies in this research were conducted using a sensitivity analysis method. In other words, the subgrade reaction coefficient was examined with variations in micropile diameter, micropile length, and different spacing of micropiles across four types of soil with varying elastic moduli.
The results of the research indicate that increasing the micropile diameter from 0.2 meters to 0.3 meters will increase the subgrade reaction coefficient by 47 to 55 percent. Additionally, increasing the spacing of micropiles from 2 meters to 4 meters results in a reduction of the subgrade reaction coefficient by 20 to 33 percent. Furthermore, increasing the length of micropiles leads to an increase in the subgrade reaction coefficient. The findings of this study demonstrate that raising the groundwater level to the foundation level significantly reduces the subgrade reaction coefficient.

Keywords

• Micropile
• Subgrade Reaction Coefficient
• Static Loading
• Sandy Soil

Main Subjects

• Geotechnics