Coal bump is a dynamic process,thus it is necessary to reveal the process validly.2D-ball code is an efficient approach developed by the authors based on the basicDEM rationale proposed by Cundall.Numerical simulation...Coal bump is a dynamic process,thus it is necessary to reveal the process validly.2D-ball code is an efficient approach developed by the authors based on the basicDEM rationale proposed by Cundall.Numerical simulations show that the coal bump experiencesa process of energy accumulation,sudden release of energy and energy decrease.The stiffness of coal particles has a great influence on the coal bump morphosisand particle velocity.Generally,the larger the stiffness of particles,the longer the shootingoff period and the larger the bump velocity.This is in agreement with the results of laboratoryexperiment and in-situ studies.However,the stiffness of particles has an influence onthe quantity value energy and no influence on the releasing energy pattern of the coalbump.展开更多
A 3D numerical model considering the soil-structure interaction is presented in this paper to examine the ground movement and internal force during the construction of Qingdao North Metro Station, China with a special...A 3D numerical model considering the soil-structure interaction is presented in this paper to examine the ground movement and internal force during the construction of Qingdao North Metro Station, China with a special focus on the convex effect of the crossing excavation. The influence of intersection angles and soil resilience characteristics on deformation behavior is discussed, and the suitability of two alternative constitutive models applied in excavation simulation is also considered. The analysis results show that a notable convex effect appears to be associated with the crossing excavation, and the intersection is the key area requiring special attention. The displacements at the comer decrease with increasing crossing angles. The axial loads of struts along the retaining pile wall are unequal, and the values near the cross section are generally larger than the average loads of the left-sided ones. The modified Cam-Clay （MCC） model, which is capable of describing the loading-unloading criterion and identifying the stiffness difference of strain hardening between loading and unloading, can yield a relatively high accuracy of estimation for the behavior of excavations in comparison to the Mohr-Coulomb （MC） model. Furthermore, slight soil deformation resilience after unloading can reduce the ground surface settlement and enhance the ground stability.展开更多
基金Supported by the National Natural Science Fundation of China(50534080,50674063)Taishan Scholar Engineering Construction Fund of Shandong Province of China(J06N04)
文摘Coal bump is a dynamic process,thus it is necessary to reveal the process validly.2D-ball code is an efficient approach developed by the authors based on the basicDEM rationale proposed by Cundall.Numerical simulations show that the coal bump experiencesa process of energy accumulation,sudden release of energy and energy decrease.The stiffness of coal particles has a great influence on the coal bump morphosisand particle velocity.Generally,the larger the stiffness of particles,the longer the shootingoff period and the larger the bump velocity.This is in agreement with the results of laboratoryexperiment and in-situ studies.However,the stiffness of particles has an influence onthe quantity value energy and no influence on the releasing energy pattern of the coalbump.
基金Project (No. 2007AA11Z134) supported by the National High-Tech R&D Program (863) of China
文摘A 3D numerical model considering the soil-structure interaction is presented in this paper to examine the ground movement and internal force during the construction of Qingdao North Metro Station, China with a special focus on the convex effect of the crossing excavation. The influence of intersection angles and soil resilience characteristics on deformation behavior is discussed, and the suitability of two alternative constitutive models applied in excavation simulation is also considered. The analysis results show that a notable convex effect appears to be associated with the crossing excavation, and the intersection is the key area requiring special attention. The displacements at the comer decrease with increasing crossing angles. The axial loads of struts along the retaining pile wall are unequal, and the values near the cross section are generally larger than the average loads of the left-sided ones. The modified Cam-Clay （MCC） model, which is capable of describing the loading-unloading criterion and identifying the stiffness difference of strain hardening between loading and unloading, can yield a relatively high accuracy of estimation for the behavior of excavations in comparison to the Mohr-Coulomb （MC） model. Furthermore, slight soil deformation resilience after unloading can reduce the ground surface settlement and enhance the ground stability.
