Field Testing Research About The Mechanical Mechanism Of Tunnel's Single Shell Lining

The railway tunnel is the permanent building, for meeting the tunnel the long-term operation need, and the tunnel should make the lining work, moreover, we should consider its efficiency and the rationality in choosing the lining work form.Single shell lining is one new tunnel support system which has developed from 1970s, comparing with double shell lining, the most remarkable characteristic is that single shell lining cancels the waterproof board between the support layers, fully transmits the shearing force, and its mechanics tendency is a body. At present, there are many countries which have used single shell lining to make the tunnel permanent support system, like Norway, Germany, Finland, France, South Africa, Brazil, Japan, China, and so on. We may know that single shell lining is the widespread application in domestic and foreign. We need study further in structure stress mechanism, waterproof performance, lining surface smoothness and so on.This paper based on the field measurement work during construction of single shell lining in mountain tunnels , and research on measurement theory, measurement layout, and measurement information treating. Based on the diversified measurement information acquired from site, many kinds of experience methods and utmost strain rule, and synthesis feedback binding FEM are carried out. Among the information analyses, statistic analysis of the clearance restraining displacement information, the contacting pressure information, the concrete strain information is very important. In accordance with the distortion and stress change rule of mountain tunnel which adopting NATM of full pedestal sit, the supporting parameter and supporting time is determined appropriately, In addition, the stabilization of surrounding rock-supporting system is researched. Therefore, we achieve the economical efficiency while assuring the safety first.The research shows us: comparing with double shell lining under the same level degree load condition, single shell lining is smaller in the internal force. therefore we may suitably attenuate lining work thickness, simultaneously also reduce the excavating quantity and the lining masonry quantity, and save the investment; we cancel the waterproof board, and use the good water-resistance and good waterproofing concrete spurting layer in place of it. The construction operation is easy, and it can guarantee the waterproof quality, and reduces the time of the project. Therefore it has not only the very high theory value but also the huge economic efficiency in the project practice to study further on single shell lining.