Hi

I am modelling a DN900 undergriund HDPE pipeline.

When calculating Virtual Anchor Lengths I am getting La value less than 3xLb. Is it possible?

I am guessing it's because the E is low for HDPE compared to Steel.

If that's the case how should I assign the spacings in Zone 2?

Some numbers:

Pipe: DN900 HDPE 81.4mm thick
Pressure = 800 kPa

Temperature= 5 to 25 deg C

Soil - Stiff Sandy Clay
Ultimate longitudinal soil resistance, P1= 105,000 N/m
Transversr stiffness, K = 184 

Lb = 1300 mm
La = 3000 mm