The rectangular pipe has a higher utilization space comparing with the circular pipe, therefore, the rectangular pipe jacking has more potential applications for underground space excavation. However, ground response, jacking force, and pipe bearing state during rectangular pipe jacking are necessary to be analyzed before construction. In this presentation, four different rectangular pipe aspect ratios with the same utilization cross-section were investigated by using the 3D finite element method. In addition, till now, there is no generally accepted prediction equation for rectangular pipe jacking. It is suggested that the prediction equations of circular jacking will overestimate the jacking force for rectangular pipe jacking. Therefore, the modified prediction equation is established by considering the mechanism and behavior of the surrounding soil. In order to implement the specific phenomenon of friction force, the pipe-soil contact ratio λ is defined to evaluate the contact state, before being introduced to the modified friction force prediction equation. This modified friction force equation was verified and is applicable for the jacking force of rectangular pipe lacking.

◆About Prof.Hideki Shimada

Hideki Shimada, Professor of Department of Earth Resources Engineering, Kyushu University. He has published over 100 papers, and based on the citations report of 47 papers collected by Web of Science, the average H-index is 10 with 292 citations. He also published two books, and more than 20 scientific publications were in major international journals and top world conferences. He has achieved Academic Category Winner by International Society Trenchless Technology, No-Dig Award 2007 and 2013. He is now Vice-Chair of JSTT.