Study On The Engineering Property Of Silty Clay In Frozen Zone And The Stability Of Roadbed In Naquhe Region Of Qinghai-Tibet Railway

In this thesis, the engineering property of the frozen earth in the frozen railway roadbed in Anduo section (between DK1561+975-DK1562+530) of Naquhe region of Qinghai-Tibet railway was studied indoor. The change of engineering property of the earth samples with different water content , density and temperature were researched. The influence of concentration of the diffluent salt to the frozen strength was pilot studied. The thermal conductivity of the soil was experimented. With the result and data of the tests, the earth temperature field in Anduo section was demonstrated by numerical analysis, the structure parameter of the spall revetmentd and the rubble berm was given, the stability of the railway roadbed was evaluated.The study show that the frozen earth in this area is mainly silty clay. The content of the dissolvable solt is relative high,which is 12.01%, and the main salinity is NaCL and KCL. The research also revealed that frozen intensity would ascend jumpily when the water contend in the soil reached its optimization( 10.61%) and kept rising,and this phenomena got more obvious with the decrease of the temperature. Between 0C and 10C, the frozen intensity vared very obviously, when the temperature is under -10C, the variety of frozen intensity got gently, and the change is not obvious. The frozen strength was influenced by the solution thickness in the soil hole.when the thickness increased, the frozen intensity decreased.The structure parameter of the rubble berm and the spall revement in Naquhe region is that the sunlit side height of rubble berm of dia 20cm is 1.1m, the sunless side is 1m. The sunlit side width of it is 6m, the sunless side is 4m.The sunless side width of spall revement of dia 10cm is 1.0m, the sunlit side is 1.6m. In the condition of paved the roadbed, the roadbed is stable.