Interlaid rock is an important component in the construction of neighborhood tunnels that supports and reinforces the area between two tunnels.However,the blasting load during excavation can sometimes damage the inter...Interlaid rock is an important component in the construction of neighborhood tunnels that supports and reinforces the area between two tunnels.However,the blasting load during excavation can sometimes damage the interlaid rock and threaten the stability of a tunnel’s structure.This paper presents a case study of the small clearance section of the Liantang highway tunnel project in Shenzhen,China,where the minimum distance between the two tunnels involved is only 0.5 m.To reduce the damage to the interlaid rock caused by blasting loads,we proposed a four-part excavation method with a vibrationcushioning rock layer in the following tunnel of neighborhood tunnels.Numerical simulation was used to model the damage prevention mechanism of the vibration-cushioning rock layer and to better understand the propagation of cracks in the interlaid rock.Furthermore,based on the simulation results,combined microseismic controlled-blasting technology was implemented,using innovative blasting patterns combined with different charge structures and blasting equipment designed according to the varying thickness of the interlaid rock.Finally,this implementation succeeded in protecting interlaid rock during blasting operations.展开更多
To solve the uneven burden of same-type holes reducing the blasting efficiency due to the limitation of drilling equipment,we need a double-face program-controlled planning method for hole position parameters used on ...To solve the uneven burden of same-type holes reducing the blasting efficiency due to the limitation of drilling equipment,we need a double-face program-controlled planning method for hole position parameters used on a computer-controlled drilling jumbo.The cross-section splits into even and uneven areas.It also considers the uneven burden at the hole’s entrance and bottom.In the uneven area,various qualifying factors are made to optimize the hole spacing and maximize the burden uniformity,combined with the features of the area edges and gridbased segmentation methods.The hole position coordinates and angles in the even area are derived using recursion and iteration algorithms.As a case,this method presents all holes in a 4.8 m wide and 3.6 m high cross-section.Compared with the design produced by the drawing method,our planning in the uneven area improved the standard deviation of the hole burden by 40%.The improved hole layout facilitates the evolution of precise,efficient,and intelligent blasting in underground mines.展开更多
In the recent decades, effects of blast loads on natural and man-made structures have gained considerable attention due to increase in threat from various man-made activities. Site-specific empirical relationships for...In the recent decades, effects of blast loads on natural and man-made structures have gained considerable attention due to increase in threat from various man-made activities. Site-specific empirical relationships for calculation of blast-induced vibration parameters like peak particle velocity （PPV） and peak particle displacement （PPD） are commonly used for estimation of blast loads in design. However, these relation- ships are not able to consider the variation in rock parameters and uncertainty of in situ conditions. In this paper, a total of 1089 published blast data of various researchers in different rock sites have been collected and used to propose generalized empirical model for PPV by considering the effects of rock parameters like unit weight, rock quality designation （ROD）, geological strength index （GSI）, and uniaxial compressive strength （UCS）. The proposed PPV model has a good correlation coefficient and hence it can be directly used in prediction of blast-induced vibrations in rocks. Standard errors and coefficient of correlations of the predicted blast-induced vibration parameters are obtained with respect to the observed field data. The proposed empirical model for PPV has also been compared with the empirical models available for blast vibrations predictions given by other researchers and found to be in good agreement with specific cases.展开更多
基金the National Natural Science Foundation of China(No.51934001).
文摘Interlaid rock is an important component in the construction of neighborhood tunnels that supports and reinforces the area between two tunnels.However,the blasting load during excavation can sometimes damage the interlaid rock and threaten the stability of a tunnel’s structure.This paper presents a case study of the small clearance section of the Liantang highway tunnel project in Shenzhen,China,where the minimum distance between the two tunnels involved is only 0.5 m.To reduce the damage to the interlaid rock caused by blasting loads,we proposed a four-part excavation method with a vibrationcushioning rock layer in the following tunnel of neighborhood tunnels.Numerical simulation was used to model the damage prevention mechanism of the vibration-cushioning rock layer and to better understand the propagation of cracks in the interlaid rock.Furthermore,based on the simulation results,combined microseismic controlled-blasting technology was implemented,using innovative blasting patterns combined with different charge structures and blasting equipment designed according to the varying thickness of the interlaid rock.Finally,this implementation succeeded in protecting interlaid rock during blasting operations.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.FRF-AT-19-005)the National Natural Science Foundation of China(No.51934001).
文摘To solve the uneven burden of same-type holes reducing the blasting efficiency due to the limitation of drilling equipment,we need a double-face program-controlled planning method for hole position parameters used on a computer-controlled drilling jumbo.The cross-section splits into even and uneven areas.It also considers the uneven burden at the hole’s entrance and bottom.In the uneven area,various qualifying factors are made to optimize the hole spacing and maximize the burden uniformity,combined with the features of the area edges and gridbased segmentation methods.The hole position coordinates and angles in the even area are derived using recursion and iteration algorithms.As a case,this method presents all holes in a 4.8 m wide and 3.6 m high cross-section.Compared with the design produced by the drawing method,our planning in the uneven area improved the standard deviation of the hole burden by 40%.The improved hole layout facilitates the evolution of precise,efficient,and intelligent blasting in underground mines.
文摘In the recent decades, effects of blast loads on natural and man-made structures have gained considerable attention due to increase in threat from various man-made activities. Site-specific empirical relationships for calculation of blast-induced vibration parameters like peak particle velocity （PPV） and peak particle displacement （PPD） are commonly used for estimation of blast loads in design. However, these relation- ships are not able to consider the variation in rock parameters and uncertainty of in situ conditions. In this paper, a total of 1089 published blast data of various researchers in different rock sites have been collected and used to propose generalized empirical model for PPV by considering the effects of rock parameters like unit weight, rock quality designation （ROD）, geological strength index （GSI）, and uniaxial compressive strength （UCS）. The proposed PPV model has a good correlation coefficient and hence it can be directly used in prediction of blast-induced vibrations in rocks. Standard errors and coefficient of correlations of the predicted blast-induced vibration parameters are obtained with respect to the observed field data. The proposed empirical model for PPV has also been compared with the empirical models available for blast vibrations predictions given by other researchers and found to be in good agreement with specific cases.
