Based on the manufacturing method now used in our country,caused low bear- ing capacity in the bolt-end,which is a potential danger in the bolt supporting tunnel and a waste of money,and presented the new type strong ...Based on the manufacturing method now used in our country,caused low bear- ing capacity in the bolt-end,which is a potential danger in the bolt supporting tunnel and a waste of money,and presented the new type strong steel big-end bolt can solve this problem.Analyzed the active state of the end of bolt by ANSYS,we can know that it is very disadvantage when bolt bore eccentric load.Contrasted with the different that com- mon bolt and big-end bolt when they bore the same loading.The common bolt is bigger than the big-end bolt in stress value.Study on the processing technic of the new type of the strong steel big-end bolt,the new metal big-end bolt was produced by heat processing over big-end bolt and upset.From the microscopic examination on bolt metal,it is con- cluded that heat processing on the bolt-end refines the crystal grain of the metal material, which not only increase its extension but improve its property.Moreover the strength ability of the bolt material can be exerted completely.展开更多
Estimating the cracking capacity of the face slab and recommending effective crack-control measures are important for the anti-seismic safety of concrete-faced rockfill dams(CFRDs). In this paper, two-dimensional anal...Estimating the cracking capacity of the face slab and recommending effective crack-control measures are important for the anti-seismic safety of concrete-faced rockfill dams(CFRDs). In this paper, two-dimensional analyses of CFRDs are performed to simulate the seismic cracking behavior of conventional reinforced concrete(RC) face slab and a type of composite face slab. The composite face slab is composed of a ductile fiber-reinforced cement-based composite(DFRCC) layer and an RC substrate. For this purpose, a co-axial rotating smeared crack model for concrete and DFRCC is coupled with the generalized plasticity model for the rockfill material, and then implemented in a finite element program. The results show that during strong earthquakes,an RC slab is more likely to develop a penetrating macro-crack in its thickness dimension. In contrast, the crack-controlling composite slab demonstrates excellent resistance to seismic cracking, and no penetrating macro-cracks are observed. Major harmful cracks that form in the concrete substrate are stopped by the DFRCC layer in composite slabs.展开更多
文摘Based on the manufacturing method now used in our country,caused low bear- ing capacity in the bolt-end,which is a potential danger in the bolt supporting tunnel and a waste of money,and presented the new type strong steel big-end bolt can solve this problem.Analyzed the active state of the end of bolt by ANSYS,we can know that it is very disadvantage when bolt bore eccentric load.Contrasted with the different that com- mon bolt and big-end bolt when they bore the same loading.The common bolt is bigger than the big-end bolt in stress value.Study on the processing technic of the new type of the strong steel big-end bolt,the new metal big-end bolt was produced by heat processing over big-end bolt and upset.From the microscopic examination on bolt metal,it is con- cluded that heat processing on the bolt-end refines the crystal grain of the metal material, which not only increase its extension but improve its property.Moreover the strength ability of the bolt material can be exerted completely.
基金supported by the National Natural Science Foundation of China(Grant Nos.51379028,51421064&51279025)
文摘Estimating the cracking capacity of the face slab and recommending effective crack-control measures are important for the anti-seismic safety of concrete-faced rockfill dams(CFRDs). In this paper, two-dimensional analyses of CFRDs are performed to simulate the seismic cracking behavior of conventional reinforced concrete(RC) face slab and a type of composite face slab. The composite face slab is composed of a ductile fiber-reinforced cement-based composite(DFRCC) layer and an RC substrate. For this purpose, a co-axial rotating smeared crack model for concrete and DFRCC is coupled with the generalized plasticity model for the rockfill material, and then implemented in a finite element program. The results show that during strong earthquakes,an RC slab is more likely to develop a penetrating macro-crack in its thickness dimension. In contrast, the crack-controlling composite slab demonstrates excellent resistance to seismic cracking, and no penetrating macro-cracks are observed. Major harmful cracks that form in the concrete substrate are stopped by the DFRCC layer in composite slabs.
