Traditional explosives have characteristics of high risk,large vibration,and poor directional fracturing.Consequently,an instantaneous expander with a single crack surface(IESCS),which is a novel nonexplosive directio...Traditional explosives have characteristics of high risk,large vibration,and poor directional fracturing.Consequently,an instantaneous expander with a single crack surface(IESCS),which is a novel nonexplosive directional rock-breaking technique,has been developed.The directional roof-cutting mechanism of the IESCS method,driven by high-pressure gas,was theoretically analyzed.Laboratory experiments and numerical simulations proved the directional slitting effect of the IESCS method to be excellent.Compared with shaped-charge blasting,the charge of IESCS was reduced by 8.9%,but the crack rate increased by 9%in field tests.After IESCS pre-splitting,the roof directionally collapsed along the cutting line,and the gangue filled the goaf.Moreover,the directional roof cutting by the IESCS could decrease roadway stress.The average pressure of hydraulic supports on the cutting side of the roof was 31%lower than that on the non-cutting side of the roof after pre-splitting.After the self-formed roadway constructed by the IESCS was stabilized,the final relative displacement of the roof and floor was 157.3 mm,meeting the required standard of the next working face.Thus,the IESCS was effectively applied to directional roof pre-splitting.The results demonstrate the promising potential of IESCS in the mining and geotechnical fields.展开更多
The burr is one of the common phenomena occurring i n metal cutting operations The mathematical mechanical model of two side dir ection burr formation and transformation is established with plane stress strain th...The burr is one of the common phenomena occurring i n metal cutting operations The mathematical mechanical model of two side dir ection burr formation and transformation is established with plane stress strain theory,based on the orthogonal cutting The main laws of formation and change of the burr are revealed,and it is confirmed by experiment result,which first realizes prediction of the forming and changing of the two side direction burr in metal cutting operation.展开更多
Based on experiments in lab, this paper analyzes the mechanism of directional broken controlled blasting and applies the technology to the cutting by utilizing its characteristic. The model cutting experiment and the ...Based on experiments in lab, this paper analyzes the mechanism of directional broken controlled blasting and applies the technology to the cutting by utilizing its characteristic. The model cutting experiment and the practical application result show that the cutting blasting technology is an effective way.展开更多
Severely deformed coal seams barely deliver satisfactory gas production. This research was undertaken to develop a new method to predict the positions of deformed coals for a horizontal CBM well. Firstly, the drilling...Severely deformed coal seams barely deliver satisfactory gas production. This research was undertaken to develop a new method to predict the positions of deformed coals for a horizontal CBM well. Firstly, the drilling cuttings of different structure coals were collected from a coal mine and compared. In light of the varying cuttings characteristics for different structure coals, the coal structure of the horizontally drilled coal seam was predicted. And the feasibility of this prediction method was discussed. The result shows that exogenetic fractures have an important influence on the deformation of coal seams. The hardness coefficient of coal decreases with the deformation degree in the order of primary structural, cataclastic and fragmented coal. And the expanding-ratio of gas drainage holes and the average particle size of cuttings increase with the increase of the deformation degree. The particle size distribution of coal cuttings for the three types of coals is distinctive from each other. Based on the particle size distribution of cuttings from X-2 well in a coal seam, six sections of fragmented coal which are unsuitable for perforating are predicted. This method may benefit the optimization of perforation and fracturing of a horizontal CBM well in the study area.展开更多
In this paper,the propagation of Spatholobus suberectus Dunn.was optimized based on the research results conducted in propagation for many years and the actual need for the planting materials.According to the requirem...In this paper,the propagation of Spatholobus suberectus Dunn.was optimized based on the research results conducted in propagation for many years and the actual need for the planting materials.According to the requirements of Good Agricultural Practices for Chinese Medicinal Drugs,cultural practices for propagation of S.suberectus were summed up and standardized,including the environmental requirements,land preparation,bed preparation,cutting of scions,cuttings treatment,cutting,management of cuttings at the nursery,bagged cuttings ready for transplanting,packing and handling,transportation,and preparation of records for archives.展开更多
基金This work was supported by the National Key Research and Development Program of China(No.2016YFC0600901)the National Natural Science Foundation of China(No.41941018)the Postgraduate Research&Practice Innovation Program of Jiangsu Province of China(No.KYCX21_2368).
文摘Traditional explosives have characteristics of high risk,large vibration,and poor directional fracturing.Consequently,an instantaneous expander with a single crack surface(IESCS),which is a novel nonexplosive directional rock-breaking technique,has been developed.The directional roof-cutting mechanism of the IESCS method,driven by high-pressure gas,was theoretically analyzed.Laboratory experiments and numerical simulations proved the directional slitting effect of the IESCS method to be excellent.Compared with shaped-charge blasting,the charge of IESCS was reduced by 8.9%,but the crack rate increased by 9%in field tests.After IESCS pre-splitting,the roof directionally collapsed along the cutting line,and the gangue filled the goaf.Moreover,the directional roof cutting by the IESCS could decrease roadway stress.The average pressure of hydraulic supports on the cutting side of the roof was 31%lower than that on the non-cutting side of the roof after pre-splitting.After the self-formed roadway constructed by the IESCS was stabilized,the final relative displacement of the roof and floor was 157.3 mm,meeting the required standard of the next working face.Thus,the IESCS was effectively applied to directional roof pre-splitting.The results demonstrate the promising potential of IESCS in the mining and geotechnical fields.
基金This project is supported by National Natural Science Foundation of China(No.59775071).
文摘The burr is one of the common phenomena occurring i n metal cutting operations The mathematical mechanical model of two side dir ection burr formation and transformation is established with plane stress strain theory,based on the orthogonal cutting The main laws of formation and change of the burr are revealed,and it is confirmed by experiment result,which first realizes prediction of the forming and changing of the two side direction burr in metal cutting operation.
文摘Based on experiments in lab, this paper analyzes the mechanism of directional broken controlled blasting and applies the technology to the cutting by utilizing its characteristic. The model cutting experiment and the practical application result show that the cutting blasting technology is an effective way.
基金funded by National Science and Technology Major Project of China (No. 2016ZX05067001-007)Shanxi Coalbased Scientific and Technological Key Project of China (No. MQ2014-04)+1 种基金Shanxi Provincial Basic Research Program-Coal Bed Methane Joint Research Foundation (No. 2015012014)Opening Foundation of Key Laboratory of Tectonics and Petroleum Resources (China University of Geosciences) Ministry of Education (No. TPR-2017-18)
文摘Severely deformed coal seams barely deliver satisfactory gas production. This research was undertaken to develop a new method to predict the positions of deformed coals for a horizontal CBM well. Firstly, the drilling cuttings of different structure coals were collected from a coal mine and compared. In light of the varying cuttings characteristics for different structure coals, the coal structure of the horizontally drilled coal seam was predicted. And the feasibility of this prediction method was discussed. The result shows that exogenetic fractures have an important influence on the deformation of coal seams. The hardness coefficient of coal decreases with the deformation degree in the order of primary structural, cataclastic and fragmented coal. And the expanding-ratio of gas drainage holes and the average particle size of cuttings increase with the increase of the deformation degree. The particle size distribution of coal cuttings for the three types of coals is distinctive from each other. Based on the particle size distribution of cuttings from X-2 well in a coal seam, six sections of fragmented coal which are unsuitable for perforating are predicted. This method may benefit the optimization of perforation and fracturing of a horizontal CBM well in the study area.
基金Scientific Research and Technology Development Project of Yulin City,Guangxi(Yushikegong 201833050)Guangxi Science and Technology Plan Project(Guike AA18126004)Science and Technology Innovation Platform Establishment Plan Project of Yulin City,Guangxi(2019CXPT00A5).
文摘In this paper,the propagation of Spatholobus suberectus Dunn.was optimized based on the research results conducted in propagation for many years and the actual need for the planting materials.According to the requirements of Good Agricultural Practices for Chinese Medicinal Drugs,cultural practices for propagation of S.suberectus were summed up and standardized,including the environmental requirements,land preparation,bed preparation,cutting of scions,cuttings treatment,cutting,management of cuttings at the nursery,bagged cuttings ready for transplanting,packing and handling,transportation,and preparation of records for archives.
