Numerical simulation of formation mechanism of unloading joints in granitic pluton  

作　　者：JIA Zhenyang LI Gang FENG Fan 

机构地区：[1]College of Earth Sciences,Jilin University,Changchun 130061,China [2]Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Ministry of Natural Resources,Changchun 130061,China

出　　处：《Global Geology》2024年第1期35-42,共8页世界地质（英文版）

摘　　要：The Beishan pluton in Gansu of China was selected as the simulated model.The simulation results indicate that the formation of unloading joints in granite is mainly influenced by the unloading rate of confin-ing pressure.Among the rates tested,the slowest unloading rate 0.025 MPa/s is found to be most conducive to the development of unloading joints.Therefore,a slower unloading rate is favourable for the occurrence of unloading joints.A series of simulations with varying initial depths of uplift ranging from 900 m to 200 m were conducted.The results confirm that when the specimen rises to a depth of 550-500 m,the unloading joints begin to form.The uplift from a depth of 700-500 m,with variations in both vertical and lateral un-loading rates,was simulated.The generation of unloading joints exhibits a negative correlation with vertical unloading and no correlation with lateral unloading,indicating that the unloading joints are mainly controlled by the unloading of vertical pressure.Throughout the simulation process,the vertical joints exhibit irregular and unrealistic regularity,suggesting a more complex formation mechanism than that of the unloading joints.

关 键 词：GRANITES ROCKBURST underloading joints numerical modeling 

分 类 号：TU45[建筑科学—岩土工程]