The accelerated demand for engineering services has led to the extensive utilization of engineering blasting techniques.Blasting-induced changes in loess microstructure(e.g.particle breakage,pore structure change)dire...The accelerated demand for engineering services has led to the extensive utilization of engineering blasting techniques.Blasting-induced changes in loess microstructure(e.g.particle breakage,pore structure change)directly affect its macroscopic mechanical properties.However,there remains a notable lack of studies on the impact of explosions on loess microstructure and the quantificationof loess microstructure.This study employed micro-computed tomography(μ-CT)technology to examine loess samples extracted from the surrounding area of the explosion cavity,systematically investigating the volume,orientation,and morphological characteristics of particles and pores.The research findings indicated that the explosion caused a break for the particles with a diameter larger than 10μm,and the number of smaller particles increased.Blasting decreased the particle sphericity and orientation angle.The reduction in porosity was primarily attributed to a decrease in the volume of both macropores and mesopores,with a greater reduction in the volume of mesopores.Although the number of micropores increased,the volume change was insignificant.Furthermore,the explosion increased the pore fractal dimension and patch density,suggesting a more complex and fragmented pore structure.Moreover,the pore throat radius and channel length decreased with decreasing distance from the explosion cavity(D_(EC)),indicating that the pore's connectivity reduced.The radius of the blasting cavity was approximately 0.35 m.Additionally,the loess zone surrounding the blasting cavity was divided into failure,plastic,and elastic zones using the D_(EC)=0.2 m and 1.2 m as the boundaries.The impacts of the explosion on loess were mainly within the range of D_(EC)less than 1.20 m.The analysis of the traits,patterns,and mechanisms of explosions'impact on the loess's microstructure can provide microscopic insight into the macro-dynamic behavior,assess the impact of explosions on the surrounding loess,and identify the potential geological hazards triggered by blasting,which offers a theoretical foundation for the subsequent engineering design and security measures.展开更多
In this paper, quantitative study on the microstructure of loess is done based on the study of seismic subsidences of the Yongdeng M_S5.8 earthquake in 1995. Using SEM and image processing techniques, a comparison ana...In this paper, quantitative study on the microstructure of loess is done based on the study of seismic subsidences of the Yongdeng M_S5.8 earthquake in 1995. Using SEM and image processing techniques, a comparison analysis on the microstructure of loess is done and distribution curves of loess pores are obtained. Based on laser grain analyzer test and trellis structure changes under earthquake effect, the dynamic properties of loess are explained. At the same time, pore distribution of loess from seismic zone and non-seismic zone is compared. The result shows that the pore distribution features of different meizoseismal zones are different, and even that loess at the similar depths has substantial differences, too.展开更多
基金financiallysupported by the National Key&Program of China(Grant No.2022YFC3003403)the National Natural Science Foundation of China(Grant Nos.42472348 and 42220104005).
文摘The accelerated demand for engineering services has led to the extensive utilization of engineering blasting techniques.Blasting-induced changes in loess microstructure(e.g.particle breakage,pore structure change)directly affect its macroscopic mechanical properties.However,there remains a notable lack of studies on the impact of explosions on loess microstructure and the quantificationof loess microstructure.This study employed micro-computed tomography(μ-CT)technology to examine loess samples extracted from the surrounding area of the explosion cavity,systematically investigating the volume,orientation,and morphological characteristics of particles and pores.The research findings indicated that the explosion caused a break for the particles with a diameter larger than 10μm,and the number of smaller particles increased.Blasting decreased the particle sphericity and orientation angle.The reduction in porosity was primarily attributed to a decrease in the volume of both macropores and mesopores,with a greater reduction in the volume of mesopores.Although the number of micropores increased,the volume change was insignificant.Furthermore,the explosion increased the pore fractal dimension and patch density,suggesting a more complex and fragmented pore structure.Moreover,the pore throat radius and channel length decreased with decreasing distance from the explosion cavity(D_(EC)),indicating that the pore's connectivity reduced.The radius of the blasting cavity was approximately 0.35 m.Additionally,the loess zone surrounding the blasting cavity was divided into failure,plastic,and elastic zones using the D_(EC)=0.2 m and 1.2 m as the boundaries.The impacts of the explosion on loess were mainly within the range of D_(EC)less than 1.20 m.The analysis of the traits,patterns,and mechanisms of explosions'impact on the loess's microstructure can provide microscopic insight into the macro-dynamic behavior,assess the impact of explosions on the surrounding loess,and identify the potential geological hazards triggered by blasting,which offers a theoretical foundation for the subsequent engineering design and security measures.
文摘In this paper, quantitative study on the microstructure of loess is done based on the study of seismic subsidences of the Yongdeng M_S5.8 earthquake in 1995. Using SEM and image processing techniques, a comparison analysis on the microstructure of loess is done and distribution curves of loess pores are obtained. Based on laser grain analyzer test and trellis structure changes under earthquake effect, the dynamic properties of loess are explained. At the same time, pore distribution of loess from seismic zone and non-seismic zone is compared. The result shows that the pore distribution features of different meizoseismal zones are different, and even that loess at the similar depths has substantial differences, too.
