Based on the asymmetric characteristic of skeleton curve obtained from dynamic tests on soils,a function with double asymptotes is proposed for describing the dynamic constitutive relations of soils.The hysteresis loo...Based on the asymmetric characteristic of skeleton curve obtained from dynamic tests on soils,a function with double asymptotes is proposed for describing the dynamic constitutive relations of soils.The hysteresis loops observed during unloading and reloading show the same form as the skeleton curve and are constructed by taking the ultimate stress as the corresponding asymptote.The coeffcient of initial unloading modulus is used to ensure that the constructed hysteresis loop fts well with the experimental data.Then,a new dynamic constitutive model considering the asymmetry of skeleton curve is elaborated.The verifcation tests on saturated Nanjing fne sand are performed using a hollow cylinder apparatus to verify the applicability of the UD model.It is found that the predicted curves by the UD model agree well with the test data.展开更多
The time-dependent behaviors of coal and rocks were easily ignored. Besides, “three-stage” triaxial loading and unloading mechanics tests of sandstone were conducted based on the idea of the initial high in-situ str...The time-dependent behaviors of coal and rocks were easily ignored. Besides, “three-stage” triaxial loading and unloading mechanics tests of sandstone were conducted based on the idea of the initial high in-situ stress state recovery according to the full-life cycle evolution characteristics of surrounding rocks in deep mines(pre-excavation,excavation and post-excavation). The time-dependent stress-strain curves of sandstone were obtained. Meanwhile, the deformation and strength fitting relationships with time of sandstone were also built. Furthermore, the dilatancy and volumetric recovery mechanical mechanisms of sandstone were revealed. The results showed that: 1) There were significant time-dependent evolution characteristics on the deformation and strength of sandstone;2) There were significant correlations among the internal friction angle, cohesion and the simulated depths;3) Volumetric recovery phenomenon of sandstone was observed for the first time, which mainly occurred at the simulated depth of 2000 m. The above research conclusions could provide a certain theoretical basis for the stability control of surrounding rocks in deep mines.展开更多
基金the fnancial support by the Major Research Plan Integration Project of the National Natural Science Foundation of China under Grant No.91215301by the National Basic Research Program of China under Grant No.2011CB013601
文摘Based on the asymmetric characteristic of skeleton curve obtained from dynamic tests on soils,a function with double asymptotes is proposed for describing the dynamic constitutive relations of soils.The hysteresis loops observed during unloading and reloading show the same form as the skeleton curve and are constructed by taking the ultimate stress as the corresponding asymptote.The coeffcient of initial unloading modulus is used to ensure that the constructed hysteresis loop fts well with the experimental data.Then,a new dynamic constitutive model considering the asymmetry of skeleton curve is elaborated.The verifcation tests on saturated Nanjing fne sand are performed using a hollow cylinder apparatus to verify the applicability of the UD model.It is found that the predicted curves by the UD model agree well with the test data.
基金Projects(52034009, 51974319) supported by the National Natural Science Foundation of ChinaProject(2020JCB01) supported by the Yue Qi Distinguished Scholar Project of China。
文摘The time-dependent behaviors of coal and rocks were easily ignored. Besides, “three-stage” triaxial loading and unloading mechanics tests of sandstone were conducted based on the idea of the initial high in-situ stress state recovery according to the full-life cycle evolution characteristics of surrounding rocks in deep mines(pre-excavation,excavation and post-excavation). The time-dependent stress-strain curves of sandstone were obtained. Meanwhile, the deformation and strength fitting relationships with time of sandstone were also built. Furthermore, the dilatancy and volumetric recovery mechanical mechanisms of sandstone were revealed. The results showed that: 1) There were significant time-dependent evolution characteristics on the deformation and strength of sandstone;2) There were significant correlations among the internal friction angle, cohesion and the simulated depths;3) Volumetric recovery phenomenon of sandstone was observed for the first time, which mainly occurred at the simulated depth of 2000 m. The above research conclusions could provide a certain theoretical basis for the stability control of surrounding rocks in deep mines.
