| 蠕变条件下完整岩石的起裂和扩展准则 |
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| 引用本文： | 陈有亮,岳中琦,谭国焕,李启光.蠕变条件下完整岩石的起裂和扩展准则[J].上海大学学报(英文版),2002,6(1):24-35. |
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| 作者姓名： | 陈有亮 岳中琦 谭国焕 李启光 |
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| 作者单位： | [1]DeaprtmentofCivilEngineering,ShanghaiUniversity,Shanghai200072,China [2]DepartmentofcivilEngineering,TheunierisityofHongKong,PokulamROad,HongKong,China |
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| 基金项目： | ProjectsupportedbytheNationalNaturalScienceFoundationof
China( 5 980 90 0 5 )andtheHongKongJockeyClubCharities
Trust |
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| 摘 要： | The mechanism and criterion of crack initiation and propagation of rocks were investigated by many researchers,And the creep behaviour of rocks was also theoretically and experimentally studied by some scientists and engineers.The characteristics of crack initation and propagation of rocks under creep condition.however,are very improtant for rock engineering and still not paid enough attention by researchers,In this paper,the criterion and mechanism of crack initiation and propagation under creep condition were investigated using specimens collected from sandstone rock formations outcropping in the Emei Mountain,the Sichuan Province of China.Cuboid specimens under three point bending were used in this investigation.All specimens were classified into four sorts and used for Mode-I fracutre of creep frcture tests.The experimental result shows that due to creep deformation.rock crack will inevitably initialt and propagate under a load of KI,which is less than fracture toughness KIC but not less than a constant(marked as KIC2),KIC2 indicates the ability of rock to resist crack initiation and propagation under creep conditions and is less than fracture tough ness KIC.defined as creep fracture toughness in this paper,KIC2 should be considered as an importnat parameter on design and computation of rock engineering.The microstructureal mechanism for crack initiation and propagation of rock materials under creep condition was introduced based on competitive model between softening effect and hardening effect,and the validity of test result was explained.The test result was also verified in rheological theory.When KI is more than KIC2 but less than KIC,rock crack will initiate and propagate after a time interval of sustained loading under creep condition.In order to find the relation between duration of sustained lading.which can lead to crack initiation and propagation,and the initial stress intensity factor KI,an unequal0interval time sequence forecasting and predicting model was introduced,and the relation was obtained for homogeneous and isotropic fine-grained red sandstone.Finally a modified fracture toughness formula was given,in which the influence of fracture process zone(FPZ) was fully considered.
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| 关 键 词： | 岩石断裂力学 岩石断裂判据 坍方条件 |
| 收稿时间： | 8 October 2001 |
A criterion for crack initiation and propagation of intact rocks under creep condition |
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| You-Liang Chen Ph. D.,Z. Q. Yue,L. G. Tham,P. K. K. Lee.A criterion for crack initiation and propagation of intact rocks under creep condition[J].Journal of Shanghai University(English Edition),2002,6(1):24-35. |
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| Authors: | You-Liang Chen Ph D Z Q Yue L G Tham P K K Lee |
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| Institution: | 1. Department of Civil Engineering, Shanghai University, Shanghai 200072, China
2. Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China |
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| Abstract: | The mechanism and criterion of crack initiation and propagation of rocks were investigated by many researchers. And the creep behaviour of rocks was also theoretically and experimentally studied by some scientists and engineers. The characteristics of crack initiation and propagation of rocks under creep condition, however, are very important for rock engineering and still not paid enough attention by researchers. In this paper, the criterion and mechanism of crack initiation and propagation under creep condition were investigated using specimens collected from sandstone rock formations outcropping in the Emei Mountain, the Sichuan Province of China. Cuboid specimens under three point bending were used in this investigation. All specimens were classified into four sorts and used for Mode I fracture or creep fracture tests. The experimental result shows that due to creep deformation, rock crack will inevitably initiate and propagate under a load of K I , which is less than fracture toughness K IC but not less than a constant (marked as K IC2 ). K IC2 indicates the ability of rock to resist crack initiation and propagation under creep conditions and is less than fracture toughness K IC , defined as creep fracture toughness in this paper. K IC2 should be considered as an important parameter on design and computation of rock engineering. The microstructural mechanism for crack initiation and propagation of rock materials under creep condition was introduced based on competitive model between softening effect and hardening effect, and the validity of test result was explained. The test result was also verified in rheological theory. When K I is more than K IC2 but less than K IC , rock crack will initiate and propagate after a time interval of sustained loading under creep condition. In order to find the relation between duration of sustained loading, which can lead to crack initiation and propagation, and the initial stress intensity factor K I , an unequal interval time sequence forecasting and predicting model was introduced, and the relation was obtained for homogeneous and isotropic fine grained red sandstone. Finally a modified fracture toughness formula was given, in which the influence of fracture process zone(FPZ) was fully considered. |
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| Keywords: | crack initiation and propagation sandstone creep gray prediction |
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