“Geotechnical Analysis, Design and Construction Seminar” has been organized for Ritta engineers. Assoc. Prof. Wanchai Teparak is invited to lecture geotechnical analysis and design which focused on the theory including bored pile, soil protection system in excavation, and groundwater level related to construction. For practical issue, Mr. Visanu Vivatanaprasert, our managing director presented experience in excavation. Various configurations i.e., excavation in soft Bangkok clay, excavation in sand, and excavation after existing structure demolition are shown. There is a discussion among the presenters and attendees after the lecture which fulfills engineering expertise.