Lateral soil resistance of cyclic loading heating pipes

Supervisor: Prof. Dr.-Ing. Martin Achmus
Researcher: Dipl.-Ing. M. Narten
Duration: 2012 - 2015
Funded by: Federal Ministry for Economic Affairs and Energy (BMWi)

The soil resistance as a result of the static (constant) displacement of the pipe is well understood today. Addtionally the  effective cyclic displacement depending on the alternating fluid temperature affects also the soil resistance. Therefor the cyclic displacement influences the friction resistance in axial direction and the soil resistance in lateral direction. At the IGtH experimental investigations were conducted investigating the development of the axial friction resistance dependent on load cycles. But the influence of the cyclic loading on the lateral bedding behavior on heating pipes is not known up to now.

The research project “Lateral soil resistance of cyclic loading heating pipes” is realized at the IGtH in cooperation with the FFI Hannover and the research center of the AGFW and is funded by the BMWi. Though this basic knowledge gaps concerning the soil resistance and  bedding behavior depending on the cyclic loading of destinct heating pipes is to be closed. Hence, experimental tests scaled 1:1 were executed at the FFI Hannover (Figure 1). These tests generally serve to investigate different influencing parameters and were the basis for the numerical model which were calibrated with the experimental results (Figure 2). With the calibrated FE model  a parametric study was carried out to analyse the influences of different parameters.

The intention of this project is to implicate the cyclic influence in the existing methods for the calculation of pipes. This should include information for the boundary conditions for which this influence is very important and have to be considered.