Abstract: Some inconveniences arise in determining the thickness of geomembrane in plain reservoir basins using the curve intersection method. Such inconveniences include the difficulty in obtaining material's characteristic curves, the need for multiple readings of figures and curves, repeated tension tests, and limited selectivity. To address these challenges, we present a simplified curve intersection method (comprising a simplified linear elastic method and a simplified hyperbolic method) for determining the thickness of HDPE geomembrane based on the fundamental principle of the curve intersection method and the linear elastic and hyperbolic stress-strain constitutive relationships observed during the elastic stage of materials. As a case study, we calculated the thickness of HDPE geomembrane in a plain reservoir in Xinjiang using the proposed method. The results indicated the following: 1) compared to the curve intersection method, the proposed simplified curve intersection method demonstrated a slight calculation error. The average error of the safety factor of tensile stress was approximately 2.22%, while that of strain safety factor was around -4.24%. These findings suggest that the proposed method is reasonably accurate. 2) In identical conditions, square pores exhibited the lowest safety factor of tensile stress, which can be taken as the criterion for determining the safe operation of projects. 3) Under the same pore conditions, the safety factor increased approximately linearly with the thickness of geomembrane. 4) The calculated thickness range of HDPE geomembrane satisfying the safety factor requirements was not less than 0.5 mm. The simplified curve intersection method enables convenient calculation of geomembrane thickness, meeting the demands of determining HDPE geomembrane thickness during the engineering design phase.

Key words: geomembrane thickness, curve intersection method, simplified linear elastic method, simplified hyperbolic method, safety factor, reservoir in plain region