Determination of the relationship between direct tensile test and Brazilian splitting test of cemented tailings backfill

Abstract

Cemented tailings backfill (CTB) is an artificial structure that provides ground support for the mining structure in the cut-and-fill mining method. The stability of CTB has a bearing on safe and economical production in mines. Tensile strength is an important design parameter that affects the quality of CTB. The Brazilian splitting test (BT) operation is more convenient but the accuracy of results is insufficient. The direct tensile test (DTT), the results of which are accurate though the test threshold is high, can be used to determine the tensile strength of CTB. Therefore, by determining the differences between the results of the two test methods, the tensile strength of CTB can be obtained more precisely using BT. In this study, DTT and BT were performed on CTB with various solid mass contents, binder contents and curing times. The findings demonstrated that, with only numerical differences, the tensile strength of CTB obtained from DTT and BT follows the same pattern of variation with binder content, solid mass content and curing period. The results of BT were lower than those of DTT because the Poisson effect reduces the tensile strength of the BT specimens. A linear fit between the DTT and BT results showed a strong linear correlation with a scale factor of 2.435. This study obtained the scale relationship between the DTT and BT results for the CTB at the test level. The study's findings can serve as a guide for improving the quality assessments and strength designs of CTB in mines.