One of the ways to increase the bearing capacity of the soil is the use of supported foundations to micropile. The requirement for designing this type of foundation is to know the behavior of the soil and micropile, especially in liquefable soils. One of the complex geotechnical issues is the investigation of soil-micropile interaction in liquefied soil. In this research, the bearing capacity of micropiles in liquefied soil has been investigated with the use of PLAXIS3D finite element software. The micropile must be designed and implemented according to the FHWA standard.
Validation of the modeling process and the results obtained from the software is done using a laboratory model such as a shaking table or a centrifuge. In this research, the centrifuge model in Wilson's studies was used to validate the modeling.
Mohr-Coulomb constitutive model has been used for static soil modeling. Then, using the Embedded Beam element, a micropile is also added to the soil. Damping is Rayleigh type and boundary conditions are free-field boundaries. Considering the increase in pore water pressure and decrease in effective stress during liquefaction, UBC3D-PLM constitutive model has been used.
After applying seismic force to saturated sandy soil with a relative density of 35% and 55%, the liquefaction and the influencing components in the settlement of micropile were investigated. In order to check the location of the liquefable layer in the micropile settlement, two types of layering have been considered for the soil. In the first case, the liquefable layer is located on the upper level of the model, this model is called TL. In the second case, the liquefable layer is placed between two dense layers, which is called the ML model. By changing different components including: peak ground acceleration(PGA), liquefaction layer thickness, soil elasticity modulus and micropile axial force, 72 different modes have been created. Each mode is calculated separately and its results are presen