Purpose–This study aims to investigate the service performances of a new full-section asphalt concrete waterproof sealing structure(FSACWSS)for the high-speed railway subgrade through on-site tracking,monitoring and ...Purpose–This study aims to investigate the service performances of a new full-section asphalt concrete waterproof sealing structure(FSACWSS)for the high-speed railway subgrade through on-site tracking,monitoring and post-construction investigation.Design/methodology/approach–Based on the working state of the waterproof sealing structure,the main functional characteristics were analyzed,and a kind of roller-compacted high elastic modulus asphalt concrete(HEMAC)was designed and evaluated by several groups of laboratory tests.It is applied to an engineering test section,and the long-term performance monitoring and subgrade dynamic performance testing system were installed to track and monitor working performances of the test section and the adjacent contrast section with fiber-reinforced concrete.Findings–Results show that both the dynamic performance of the track structure and the subgrade in the test section meet the requirements of the specification limits.The water content in the subgrade of the test section is maintained at 8–18%,which is less affected by the weather.However,the water content in the subgrade bed of the contrast section is 10–35%,which fluctuates significantly with the weather.The heat absorption effect of asphalt concrete in the test section makes the temperature of the subgrade at the shoulder larger than that in the contrastive section.The monitoring value of the subgrade vertical deformation in the test section is slightly larger than that in the contrastive section,but all of them meet the limit requirements.The asphalt concrete in the test section is in good contact with the base,and there are no diseases such as looseness or spalling.Only a number of cracks are found at the joints of the base plates.However,there are more longitudinal and lateral cracks in the contrastive section,which seriously affects the waterproof and sealing effects.Besides,the asphalt concrete is easier to repair,featuring good maintainability.Originality/value–This research can provide a basis for popularization and application of the asphalt concrete waterproof sealing structure in high-speed railways.展开更多
As a kind of transportation mode for crossing channels, undersea tunnel has incomparable advantages for its directness, convenience, fastness, insusceptibility to weather conditions, and smaller influences on environm...As a kind of transportation mode for crossing channels, undersea tunnel has incomparable advantages for its directness, convenience, fastness, insusceptibility to weather conditions, and smaller influences on environments. In recent years, with the development of undersea tunnel construction, the design and construction technologies have been greatly enhanced. The first undersea tunnel in China has just been built. Waterproofing is the key technique of undersea tunneling. A new concept of waterproofing scheme of grouting, sealing, draining and divided sections was adopted in the construction of the tunnel based on the researches, the in-situ geological features, the astuteness of the current technology and the cost of construction. The structural details of the sealing and draining system are introduced to illustrate the salient features of the new waterproofing technique. It is hoped that experiences described in the paper can offer guidance for the construction of the extensive undersea tunnels in the coming years.展开更多
基金funded by the National Natural Science Foundation of China[51778136 and 41972299].
文摘Purpose–This study aims to investigate the service performances of a new full-section asphalt concrete waterproof sealing structure(FSACWSS)for the high-speed railway subgrade through on-site tracking,monitoring and post-construction investigation.Design/methodology/approach–Based on the working state of the waterproof sealing structure,the main functional characteristics were analyzed,and a kind of roller-compacted high elastic modulus asphalt concrete(HEMAC)was designed and evaluated by several groups of laboratory tests.It is applied to an engineering test section,and the long-term performance monitoring and subgrade dynamic performance testing system were installed to track and monitor working performances of the test section and the adjacent contrast section with fiber-reinforced concrete.Findings–Results show that both the dynamic performance of the track structure and the subgrade in the test section meet the requirements of the specification limits.The water content in the subgrade of the test section is maintained at 8–18%,which is less affected by the weather.However,the water content in the subgrade bed of the contrast section is 10–35%,which fluctuates significantly with the weather.The heat absorption effect of asphalt concrete in the test section makes the temperature of the subgrade at the shoulder larger than that in the contrastive section.The monitoring value of the subgrade vertical deformation in the test section is slightly larger than that in the contrastive section,but all of them meet the limit requirements.The asphalt concrete in the test section is in good contact with the base,and there are no diseases such as looseness or spalling.Only a number of cracks are found at the joints of the base plates.However,there are more longitudinal and lateral cracks in the contrastive section,which seriously affects the waterproof and sealing effects.Besides,the asphalt concrete is easier to repair,featuring good maintainability.Originality/value–This research can provide a basis for popularization and application of the asphalt concrete waterproof sealing structure in high-speed railways.
基金supported by the National Basic Research Program of China (973 Program,Grant No. 2010CB732104)the Fundamental Research Funds for the Central Universities (Grant No. 2011JBM133)
文摘As a kind of transportation mode for crossing channels, undersea tunnel has incomparable advantages for its directness, convenience, fastness, insusceptibility to weather conditions, and smaller influences on environments. In recent years, with the development of undersea tunnel construction, the design and construction technologies have been greatly enhanced. The first undersea tunnel in China has just been built. Waterproofing is the key technique of undersea tunneling. A new concept of waterproofing scheme of grouting, sealing, draining and divided sections was adopted in the construction of the tunnel based on the researches, the in-situ geological features, the astuteness of the current technology and the cost of construction. The structural details of the sealing and draining system are introduced to illustrate the salient features of the new waterproofing technique. It is hoped that experiences described in the paper can offer guidance for the construction of the extensive undersea tunnels in the coming years.
