Uplift resistance of two pipelines buried wall-to-wall (not bundled)

[917947]

Hello everyone

I am working in an offshore pipeline project where we are planning to install two 10 inch pipelines wall-to-wall directly on the seabed. The pipelines will then be covered by rock dumping. Designing the rock cover height for uplift resistance for a single pipeline is rather straight forward. The uplift interaction when you have two pipelines in a single cover could be different. Please share your insights on how to design an optimum rock cover that will satisfy the uplift resistance requirements for the two pipelines.

Thanks

 

[oldestguy]

Not in that business, but I would look at all possible options, such as : failure of any strapping, allowing each to act independently or to separate; side by side presentation with one full and one empty; possible uneven bedding presenting a tilted orientation or one above the other.

 

[917947]

Thanks for the reply 'oldestguy'
It is true that all possible failure scenarios should be considered. I imagine that the worst case scenario would be when the two pipelines mobilize the uplift resistance at the same time. In such a case, we might end up with a limited shear surface. The uplift resistance, we know, is a contribution from both weight and shear.
Please keep any ideas coming in!