Numerical Analysis of Plate-Load Test Results on Fractured Rocks Using an Equivalent-Continuum Model: Case Study of the Bakhtiary Dam Site

Abstract

The plate-load test (PLT) is widely performed at large dam sites to determine the rock mass deformability. Analytical relations based on the theory of elasticity, as suggested by the International Society for Rock Mechanics and the American Society for Testing and Materials test standards, are commonly used to interpret the test results and calculate the rock mass deformation modulus. However, because of inconsistency of the test gallery geometry with the half-space medium assumption embedded in the analytical relations, a systematic error occurs in the calculation of the deformation modulus. Furthermore, when the tests are conducted on jointed rock masses, the test results show a considerable scatter, mainly due to the anisotropy of the deformability of jointed rock masses. In this paper, numerical modeling is used to interpret the results of a series of PLTs conducted at the Bakhtiary dam site in southwest Iran. An equivalent continuum model, called