关键词: 硬石膏岩, 湿度应力场, 膨胀试验, 初始湿度, 吸水率

Abstract: The traditional humidity stress field theory cannot perfectly describe the time-dependent relationship between the swelling state and humidity state when simulating the swelling process of anhydrite rock mass. Based on this theory, the swelling tests on anhydrite rock mass were designed to investigate the swelling with different initial humidities and soaking time. In addition, tensile strength tests were carried out after swelling. The testing results showed that with the increase of initial humidity, the duration time of swelling, the maximal axial swelling strain, and the maximal lateral swelling stress increased. The water absorption rate and crystallisation water rate of anhydrite increased at the end of the test, while the free water rate was close to zero. Under the same initial humidity, with the increase of soaking time, the water absorption rate exhibited a rapid increase first and then slowly grew. The crystallisation water rate gradually increased to the water absorption rate, while the free water rate decreased to close to zero. With the increase of water absorption rate, the maximum axial swelling strain, the maximum lateral swelling stress and the tensile strength increased. Therefore, this study proposed the time-dependent humidity state equations and the time-dependent swelling constitutive model according to the testing results.

Key words: anhydrite rock, humidity stress field, swelling test, initial humidity, water absorption