Our site uses cookies necessary for its proper functioning. To improve your experience, other cookies may be used: you can choose to disable them. This can be changed at any time via the Cookies link at the bottom of the page.


Numerical Analysis and Soil Box Study of the Influence of Trench

 

Additional Information - Posters

Plastic Pipes Conference Association # 1998 Gothenburg

Wijeyesekera, Warnakulasuriya

Gurnble (1983) and Molin (1981) used numerical analysis to demonstrate the significance of lateral earth loading on flexible pipe design. The restraint provided by the stiffness of the side fills on the pipe influences the shape of the deformed pipe. Low trench width to pipe diameter ratios can hinder the process of compaction and consequently the compactness of the surrounding soil. The influence from such effects can not be ignored and accordingly the trench width to pipe diameter ratio must therefore be a necessary parameter in the design of buried flexible pipes. This paper reports observations of pipe deformations, pipe strains, normal and shear stresses on the soil-pipe interface of a 2mm thick, 150mm-diameter GRP pipe buried, in dry sharp river sand contained in a soil box. The width of the 2m long 1.5m high soil box can be varied and accordingly results from tests for trench widths of 350,450, 600 and 800mm are given in the paper. Instrumentation provides direct measurements of the horizontal and vertical stresses at the trench boundary. Observation of pipe ovality and the strains on the pipe wall for different burial depths and trench widths are presented. These soil box test observations are complimented with numerical analysis results from a time marching 3D finite difference package. The effects of creep in changing the ovality of the 150mm pipe buried in a 800mm wide trench observed over a period of 4 months is also presented. This study concludes on the varying ways in which trench width effects the structural performance of buried flexible pipes and illustrates that single wave buckling at the top of the pipe as a most probable mode of failure.

Please note that the whole article content is available on PPCA website only :

Related papers

2001 Munich : Soil-Structure-Pipe Interaction with Particular Reference

Author(s) : Olliff, Rolfe, Wijeyesekera, Reginold

Soil-pipe interaction studies generally recognise the significance of deformations in the pipe due to soil loading, but not differential ground and structure movements, which can induce excessive stress concentrations in the pipeline. Plastics pipes can suffer failure due to such movements, though their flexibility...

Members of the Association

BOREALISBOROUGEFormosa Plastics CorporationHanwha TotalEnergiesINEOS O&PIRPCKorea Petrochemical IND. Co., LTD (KPIC)LyondellBasellORLEN UnipetrolPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE