To investigate the mechanical behavior of segmental lining, a three-dimensional numerical analysis and test using three actual segments were used to analyze the effects of axial force and reinforcement ratio on the fa...To investigate the mechanical behavior of segmental lining, a three-dimensional numerical analysis and test using three actual segments were used to analyze the effects of axial force and reinforcement ratio on the failure mechanism and ultimate bearing capacity of segmental lining. Both numerical and test results confirmed that the cracking load, yield and ultimate load were strongly influenced by axial force, and it was also proved that the yield and ultimate load would increase with the increase of reinforcement ratio, but the cracking load was almost not affected. The cracking load, yield and ultimate load are about 28.7%, 500% and 460% larger due to the effect of axial force respectively. The comparison between numerical calculation and test results showed that the finite element analysis resuits were in good agreement with the test results.展开更多
According to the test results of the physical and mechanical properties of similar materials in various quality mixture, a type of material with obvious tendency of rockburst was selected to produce a large-size model...According to the test results of the physical and mechanical properties of similar materials in various quality mixture, a type of material with obvious tendency of rockburst was selected to produce a large-size model to simulate rockburst phenomena in tunnels. The prototype model comes from a typical section of diversion tunnels in Jinping Hydropower Station in China. The simulation of excavating tunnels is carried out by opening a hole in the model after loading. The modeling results indicated that under the condition of normal stresses in the model boundaries the arch top, spandrel and side walls of the tunnel produced an obvious jump reaction of stress and strain and the acoustic emission counts of the surrounding rock also increased rapidly in a different time period after the "tunnel" excavation, showing the clear features of rockburst. The spalling, buckling and breaking occurred in the surrounding rock of model in conditions of over loading. It is concluded that the modeling tunnel segment in Jinping Hydropower Station is expected to form the tensile rockburst with the pattern of spalling, buckling and breaking.展开更多
Based on the first unde rwater railway shield tunnel, the Shiziyang shield tunnel of Guangzhou Zhu- jiang River, the prototype test was carried out against its segmental lining structure by using ＂multi-function shie...Based on the first unde rwater railway shield tunnel, the Shiziyang shield tunnel of Guangzhou Zhu- jiang River, the prototype test was carried out against its segmental lining structure by using ＂multi-function shield tunnel structure test system＂. And the mechanical characteristics of segmental lining structure using straight assembling and staggered assembling were studied deeply. The results showed that, the mechanical characteristics of segmental lining structure varied with the water pressures; especially after cracking, the high water pressure played a significant role in slowing down the growing inner force and deformation. It also testi- fied that the failure characteristics varied with straight assembling structure and staggered assembling structure. Shear thilurc often occurred near longitudinal seam when using straight assembling.展开更多
基金Supported by National Natural Science Foundation of China (No. 10902073)
文摘To investigate the mechanical behavior of segmental lining, a three-dimensional numerical analysis and test using three actual segments were used to analyze the effects of axial force and reinforcement ratio on the failure mechanism and ultimate bearing capacity of segmental lining. Both numerical and test results confirmed that the cracking load, yield and ultimate load were strongly influenced by axial force, and it was also proved that the yield and ultimate load would increase with the increase of reinforcement ratio, but the cracking load was almost not affected. The cracking load, yield and ultimate load are about 28.7%, 500% and 460% larger due to the effect of axial force respectively. The comparison between numerical calculation and test results showed that the finite element analysis resuits were in good agreement with the test results.
基金supported by National Natural Science Fundation of China (Grant No. 40772176)Key Program for Research Group of SKLGP (Grant No. SKLGP2009Z002)Research Fund for the Doctoral Program of Higher Education of China(Grant No. 20105122110008)
文摘According to the test results of the physical and mechanical properties of similar materials in various quality mixture, a type of material with obvious tendency of rockburst was selected to produce a large-size model to simulate rockburst phenomena in tunnels. The prototype model comes from a typical section of diversion tunnels in Jinping Hydropower Station in China. The simulation of excavating tunnels is carried out by opening a hole in the model after loading. The modeling results indicated that under the condition of normal stresses in the model boundaries the arch top, spandrel and side walls of the tunnel produced an obvious jump reaction of stress and strain and the acoustic emission counts of the surrounding rock also increased rapidly in a different time period after the "tunnel" excavation, showing the clear features of rockburst. The spalling, buckling and breaking occurred in the surrounding rock of model in conditions of over loading. It is concluded that the modeling tunnel segment in Jinping Hydropower Station is expected to form the tensile rockburst with the pattern of spalling, buckling and breaking.
基金Joint Funds of National Natural Science Foundation of China(No.U1134208)National Key Basic Research Program of China(No.2010CB732105)National Natural Science Foundation of China(No.50925830,No.51208432)
文摘Based on the first unde rwater railway shield tunnel, the Shiziyang shield tunnel of Guangzhou Zhu- jiang River, the prototype test was carried out against its segmental lining structure by using ＂multi-function shield tunnel structure test system＂. And the mechanical characteristics of segmental lining structure using straight assembling and staggered assembling were studied deeply. The results showed that, the mechanical characteristics of segmental lining structure varied with the water pressures; especially after cracking, the high water pressure played a significant role in slowing down the growing inner force and deformation. It also testi- fied that the failure characteristics varied with straight assembling structure and staggered assembling structure. Shear thilurc often occurred near longitudinal seam when using straight assembling.
