Liquefaction analysis in existing building soil and modeling with finite element method

In this thesis work, soil of an existing structure was examined in terms of geological and geotechnical aspects. Soil studies were carried out to determine the physical and mechanical properties of the soil. Obtained parameters from the soil studies were used. Using these parameters, the local soil class was determined as ZD, considering Türkiye Building and Earthquake Regulation 2018. In addition to, bearing capacity, settlement and liquefaction calculations of soil were made. According to TBDY 2018, safe bearing capacity of the soil is calculated as 337 kPa, total settlement is was calculated as 4,576 cm, as a result of the liquefaction calculations made, the building soil is insecure against liquefaction. Due to risk of liquefaction, soil improvement was required and jet grout was applied. 13 meters long inclined and vertical columns were produced around the foundation and 18 meters columns were produced to from an impermeable curtain around the building soil. Design calculations pf the produced columns were made. The bearing capacity of the 13 meters columns is calculated as 61,3 tons. The bearing capacity of the 18 meters columns is calculated as 88,9 tons. After the jet grout application liquefaction calculation was made and it was seen that the risk was eliminated. Idealized soil profile is modeled as three-dimensional and two-dimensional using the finite element program. In the three-dimensional model, displacement in the soil and behavior of jet grout columns were examined. In two-dimensional model, behavior of the project building soil of in case of earthquake was examined. For the liquefaction situation, the result of the dynamic analysis made in the finite element program and numerical calculations reveal the existence of the liquefaction risk in the soil. Disappearance of the risk in numerical calculations after improvement and the decrease in the pore water pressure of the finite element software indicate that the liquefaction state of the soil has improved.