Study on long-term uniaxial compression creep mechanical behavior of rocksalt-mudstone combined body

Abstract

Rocksalt and mudstone are usually under common stress in salt storage caverns, resulting in different mechanical properties from pure rocksalt and mudstone. To accurately obtain the creep mechanical characteristics of rocksalt-mudstone combined body, we have made three different combinations. The long-term creep experiment of bedded rocks can more closely reflect the long-term mechanical behavior of surrounding rock of salt storage caverns. The experimental results indicated that the long-term creep curve of the combined body includes initial and steady creep stages, and even includes accelerated creep stage. The strain of mudstone layer in the combined body was lower than that of rocksalt because of the higher strength. With the increase of the height ratio of mudstone, the creep strain of the combined body and each rock layer decreased, but the creep rate increased. A new nonlinear creep-damage constitutive model was proposed, which can well describe the creep evolution characteristics of the experiment. Compared with the fitting curves of classical Burgers and Nishihara creep constitutive models, it is revealed that the proposed model is most consistent with the experimental data. The duration of the long-term creep experiment under lower stress has a highly significant effect on the accuracy of predicting rock creep results. This research will contribute to a deeper understanding of the long-term creep characteristics of bedded rocks in salt storage caverns.

Development of a shear creep damage model of jointed rock masses considering the influence of freeze-thaw and chemical corrosion

“…In addition, rock engineering failure often doesn't occur immediately after construction, but evolves gradually over time. The creep characteristics of jointed rock masses is closely related to the long-term stability of rock mass engineering (Wang et al, 2021;Lyu et al, 2021). In engineering projects such as slope remediation, tunnel construction, and mining operations, the movement and sliding of joint surfaces due to prolonged shear loading are among the primary forms of damage.…”

A thermodynamic damage model for 3D stress-induced mechanical characteristics and brittle–ductile transition of rock

“…There have been many research results on the mechanical properties and brittle–ductile characteristics of rocks based on uniaxial and conventional triaxial stress states (Abioye, 2017; Baud et al., 2021; Cai et al., 2007; Hajiabdolmajid et al., 2002; Heard, 1960; Hudson et al., 1972; Lyu et al., 2021, 2022; Wang et al., 2021, 2022; Wong and Baud, 2012). Many existing researches have shown that the strength, deformation, failure, and brittle–ductile behaviours of rocks have relationships with stress states (Alejano et al., 2021; Barla et al., 2010; Labuz and Dai, 2000; Li et al., 2018; Liu et al., 2019; Mogi, 1966; Shi et al., 2017; Wawersik and Brace, 1971; Zheng et al., 2022a).…”

A new fractional-order model for time-dependent damage of rock under true triaxial stresses

“…Creep characteristics are the key mechanical properties of rock. Many previous scholars have established creep models based on the test results of rock time-dependent characteristics under uniaxial and conventional triaxial conditions, which play an important role in the excavation and support design of shallow rock engineering (Akagi et al., 1984; Barla et al., 2012; Bieniawski, 1970; Liu et al., 2019; Lyu et al., 2022; Malan, 1999; Mirza, 1978; Sterpi and Gioda, 2009; Wang et al., 2015). With the continuous development of rock engineering to the deep earth, some deep projects have been built, such as the China Jinping Deep Underground Laboratory (Feng et al., 2017) and the large underground powerhouse of Baihetan Hydropower Station (Pei et al., 2018; Zhao et al., 2022).…”