Mechanical behavior of Tien-Liao mudstone in hollow cylinder tests

A series of hollow cylinder tests were conducted to study the stress–strain characteristics and the yield surface of Tein-Liao mudstone, a soft rock widely distributed in southwestern Taiwan. These tests were carried out under different stress paths designed to utilize the versatility of the hollow cylinder testing system. The test results were used to establish the yield surface of the mudstone in the principal stress space. The experimental results were used to examine the accuracy of existing yield criteria, such as the Coulomb criterion, the extended Hoek-Brown model, and the Kim-Lade model. Among the three yield criteria examined, the Kim-Lade model provided the best agreement with the experimental results, although both the extended Hoek-Brown model and the Kim-Lade model are adequate for modeling the yield surface of the mudstone.