Geotechnical assessment and remediation of differential settlement in grain bins using unreinforced bored piles

This paper aims to perform a stability analysis of an existing grain bin project based on the 2018 Turkish Building Earthquake Code (TBEC), and to achieve soil improvement and reinforcement solutions using unreinforced bored piles. In the study area, after the construction of the grain bins, static loading was applied, and soil problems were observed in certain sections. As a result, some grain bins were partially taken out of use. To diagnose the problem and understand the soil stratigraphy, eight (8) boreholes were drilled in the study area. The results indicated that the soil was exposed to surface water, which caused settlement problems. To solve this problem, the soil was improved by supporting it with unreinforced piles. The grain bins with capacities of 28000 kN for wheat and 24000 kN for barley, consisting of 18 storage cells with a diameter of 14 m each, located in Sarioğlan district, Kayseri city, Turkey, were investigated in this paper. The observations of differential settlement and heave as geotechnical problems started after two of these grain bins were loaded twice with approximately 15000 kN. The extensive laboratory and field tests revealed that the soil consisted of vegetative soil, alluvial soil of various thicknesses and sandstone, in addition to the fact that the study area is close to an active fault. Bearing capacity and horizontal slip were checked according to TBEC (2018), and settlement analyses were carried out using PLAXIS 2D and 3D to identify the mechanical characteristics of the grain bins that have differential settlement problems in the field. The amount of settlement occurring in the existing condition was determined to be approximately s0=47 mm. In the case of ground improvement and reinforcement, the maximum total settlement was found to be s1=23 mm, the maximum differential settlement s=0.21 mm, and the angular distortion =0.0015%. As a result of the investigations, it was understood that there was no bearing capacity and horizontal slip failure, and the numerical analyses indicated that the use of unreinforced bored piles with controlled embankment brought the settlement and angular distortion to permissible limits.