干湿循环作用下红砂岩侧限膨胀应力时程模型

Time-history model of lateral constraint swelling stress of red sandstone under dry-wet cycles

采用湖南株洲地区的红砂岩样,进行了不同干湿循环次数和不同干燥温度影响下的侧限膨胀应力试验。结果表明:岩石侧限膨胀应力是时间的函数,可以用快速膨胀阶段、减速膨胀阶段和缓慢稳定阶段表征;干湿循环作用和干燥温度对红砂岩的膨胀产生显著影响,随循环次数的增大,最大侧限膨胀应力先增大后减小;干燥温度越高,不同循环次数下的侧限膨胀应力越大。建立了考虑循环次数与干燥温度影响的侧限膨胀应力时程模型,并验证了模型的正确性。所得结论可为保证膨胀岩地区工程建设的安全性和稳定性提供指导。

Test of the lateral constraint swelling stress is conducted at different numbers of dry-wet cycle and drying temperatures, and the samples are collected in the Zhuzhou of Hunan Province. Results show that, the lateral constraint swelling stress of rock is the function of time, and it can be uniformly characterized by the rapid swelling phase, the moderative swelling phase and the slow steady phase. Moreover, effect of dry-wet cycle and drying temperature have a significant effect on the swelling of red sandstone, and the maximum lateral constraint swelling stress increases firstly and then decreases with the increase of cycle numbers, and the higher the drying temperature is, the maximum lateral constraint swelling stress will be at the different cycle numbers. On this basis, a time-history model of lateral constraint swelling stress considering the influence of cycle number and drying temperature is established, and the correctness of the model is verified. In addition, the conclusions have guiding significance for the safety and stability of engineering construction in the area of swelling rock.