Calculation and test of the effects of geosynthetic clay liner on pipeline cathodic protection

Laying geosynthetic clay liner around buried pipeline that passes through environmental sensitive area can reduce the risk of contamination of the surrounding environment caused by pipeline leakage, but it may generate shielding effect on the pipeline cathodic protection current flow. In order to identify the severity of such shielding effect, a calculation model of pipeline potential under the anisotropic soil structure is established. With the boundary element method, the pipeline potential distribution under different cathodic protection current is calculated before and after laying geosynthetic clay liner, and the change of cathodic protection scope with soil resistivity is analyzed at a given natural potential. A 1 500 m pipeline section where geosynthetic clay liner has been laid is selected for modeling and field test, and the potential changes at flow injection point that is 200 m from pipe head end are calculated and measured. It is found that the calculation results and the measurement results coincide well, verifying the accuracy of the algorithm.