Study On Periglaciation And The Countermeasures Of Highway Disaster In Middle Mount Tianshan

Environment engineering geological problems in permafrost regions varies differentlyduo to complex conditions. Roads in these regions may suffer different damages becauseof cold born geological effects and thus the performance will decrease. So detailedexploration in advance is necessary to analyze and illustrate the reason of cold borngeological effects. So this paper focuses on the research of permafrost regions of theTianshan mountains periglocial function landform.Firstly discussed are palsen, ice cone, and swamp distribution regularities and theircauseS, the main approach are field survey and image recognition to obtain field data. Thewetland in the permafrost seasonal frozen were scattered throughout the river terraces orthe foot of gentle slopes, permafrost regions wetland along the river terraces, both sides inthe gentle slope in valleys or the gentle slope on crest. Frost mound and wetland areassociated state; seasonal frozen high freezing expansion in the state degeneration,permafrost regions is in a stable state or development state.Secondly discussed is the geological types such as freeze-thaw slumps,gelifluction-brench and thermokarst lakes which are produced by ice-melt in slope zone.Freeze-thaw slump in survey area are small scale. It is a symbiotic relationship withgelifluction-brench. Gelifluction-brench only distribution in permafrost area are large scale.They are mainly distributed in the10~30°on the slope, and they form a symbioticrelationship with wetland.Later through the statistical data of field survey and aerial photograph, distributionregularities and causes of rock debris slope are discussed. Debris slope mainly distributed inthe ancient glacier function area, with the altitude over2500m. Debris slope in thesunny-slope are more than that in shady-slopes, the slop of debris slope is between30~40°.Lastly，various cold born geological process such as ice-accumulation, ice-melt androcky slope and their effects to road engineering were discussed, and preventive andtreatment measures were proposed due to their characteristics. Frost mound can cause highuneven frost heaving, forming ice crevasses, subgrade slide at local area, and bridge pilecaps crack. Freeze-thaw swamp and gelifluction-brench can bury roads, congestion bridge,accelerate the roadbed softening wet fall. Debris slope rock falling or rolling down canform the slope slump and roads damages. The main method to solve frost mound is to cutoff the water supply, strengthen its drainage capacity. The prevention and control of the damage which caused by freeze-thaw slumps and gelifluction-brench is to avoiddisturbance the thick ice layer and thaw settlement permafrost, the control principle is"primarily prevent, timely cure". The prevention and control of the granular slope must bein accordance with the local geological conditions and terrain conditions, reasonablearranging use three engineering measures which is clearing away the gravel，build theretaing wall or consolidate the solid.