Sensitivity Analysis Of Frost-heave For Tunnels In Frozen Zoneand Study On The Technique Of Preventing Frost Damage With Insulationt

With the development of China’s economy, the implementation of the WesternDevelopment Policy, the demand for transportation infrastructure is constantlygrowing, especially in the technical issue of construction of China’s Tibetan plateaurailway and road,as a result,the engineering concern and attention for high-altitudepermafrost tunnel in cold regions are kept increasingly. Highway tunnel-theconstruction of important structures, is followed by an unprecedented building boom.Tunnels in rock fissures and pore water freezes rock volume expansion occurs when thevolume expansion to be bound by permafrost tunnel lining and the surrounding rock isnot frozen, freeze rock permafrost tunnel lining produce force, permafrost surroundingrock tunnel lining freeze resistance, constrain its volume expansion, which formedrock heaving force.Tunnel lining heaving force and joint action by other forces may cause the end ofthe tunnel to take water, ice, frost heave, and trigger the tunnel lining cracks,crumbles, peels, which leads to the tunnel leaks, forms ice, or a series of hangingfreezing, threatening the normal operation of the tunnel. Consequently,Permafrost ZoneTunnel Project is listed in the research as an important research topic. Becausepermafrost zone tunnel project has its own peculiarities, on the one hand, it reflects thecharacteristics and problems those are absent in non-permafrost regions. On the otherhand, permafrost zone and non-permafrost zone share some common problems that arereflected more clear and thorough in the permafrost zone. Thus, the engineering issuefor permafrost zone tunnel project has drawn widespread attention in early stage andcauses the study boom among researchers and scholars nationally. The main challengesfaced by the Permafrost Zone Tunnel Project are:①Tunnel lining layer suffers fromthe effects of frost heave force.②Permafrost zone tunnel surrounding rock and liningsuffer repeated freeze-thaw action that causes a variety of frost damage. Since therewere a lot of frost damage occurred permafrost tunnel problems, it has been treated asa highlighted engineering issue. With the in-depth study into the tunnel heave force, Ifind that lining heave force is the most important research point,including the impact ofthe factors determining heave force,the calculation of heave force, the heave force, thesensitivity analysis of frost heave,the mechanism of the heave of rock, the formation ofheave force and the prevention of heave force damage, and antifreeze measures andengineering in the process of tunnel construction.The main purposes of this paper are as follows:①To explore the mechanism of frost damage and study the phenomenon of frostheave in permafrost permafrost tunnel②Define the range that thaws circle tunnel surrounding rock through measuringand analyzing the rock temperature of tunnel construction project.③To study the factors affecting heave heave force and stress and the frost heavestress distribution in the tunnel lining, based on of freezing and thawing of thelithosphere as theoretical foundation, the measurement of heaving freeze-thaw circles asreference，and base on elasticity and elastic-plastic finite element as numerical method.④To study and summarize the application of frost insulation technology.