The Adhesion Factor in Soft Bangkok Clay from the Data Analysis of Precast Concrete Manhole Installation

Abstract

This research presents a correlation equation for analyzing the actual weight used in the installation of precast concrete manholes and the adhesion factor. The study investigates the relationship between undrained shear strength (S_u), perimeter length (L), and adhesion factor (Adhesion Factor; AF) of precast concrete manholes constructed in soft Bangkok clay. Data from the installation of 32 precast concrete manholes in Bangkok were utilized, with a perimeter length of 22.5 meters and an average undrained shear strength ranging from 1.03 to 2.70 tons per square meter. Validation of the correlation equation using field measurement data revealed that the calculated weight for manhole installation had a deviation of only -3.54% to +2.67% compared to the actual weight used in the field. Therefore, the correlation equation can be applied for analyzing frictional force (F_friction) and bearing capacity at the base (W_bearing). This helps optimize the design of precast concrete manholes in soft Bangkok clay, reduces errors in calculating the actual weight for installation, and contributes to cost and time savings in construction.