Analysis Of Damage Tests And Water-Heat Transfer For Adjoining Rock Around The Tunnels In The Cold Region

With the economic development in Western China and old industrial base in Northeast China, many infrastructures, such as railway, highway and tunnel, are being constructed. But the frozen hazards are being faced with because the Western China and the Northeast China are mostly located in the cold region. Supported by National Natural Science Foundation of China (40372119), the author has studied tunnel located at cold region, and the followings are done.(1) CT technology is used to study the meso-damage structure change of the adjoining rock for tunnel under the freezing action. The main investigations are as following. 1) The paper presents the analytical method based on the statistical section frequency in light of CT technology. 2) The meso-damage structure change of Tongchuan greywacke and Yao County sandstone undergoing different times of freeze-thaw cycles are studied. The test results show that for the Yao County sandstone with high porosity rate, high water rate and low strength, the damage change is remarkable with increasing of times of freeze-thaw cycles, and CT mean value reduces. And for Tongchuan greywacke with low porosity rate, low water rate and high strength, the freeze-thawing cycles do little damage at initial stage, but the cycles do a great damage at latter stage. 3) In order to study the meso-damage structure changes of three kinds of adjoining rock for tunnel, Tongchuan marble, Tongchuan greywacke and Tongchuan soft sandstone are respectively frozen under different temperatures. The results indicate that the meso-damage structure changes are codetermined by the property of heat-expansion and cold-contraction for rock material and the expansion property of phase change from water to ice. 4) In order to study the meso-damage structure changes of three kinds of rock, Tongchuan marble, Tongchuan greywacke and Tongchuan soft sandstone are respectively frozen at different lowing temperature rates. The results show that low temperature rate has little influence on the hard rock with low porosity, and has some influence on the soft rock with high porosity.