Study On The Roadbed Settlement Change Rule After Constructed In Permafrost Regions Of The High Altitude

Mastering the roadbed settlement change rule after constructed is the basis of solving the problem of roadbed long-term stability in permafrost regions. This study based on the project of the china-russia crude oil pipeline great line, select the typical embankment section along the highway in permafrost regions, using DS18B20 temperature sensor and layered settlement instrument observe the temperature change and settlement change rule of roadbed after constructed in permafrost region, combined with laboratory test, permafrost geothermal and the permafrost changed study the roadbed settlement deformation. Analysis results show that after highway finishes construction and begins to operate, because of the ground temperature rise, permafrost degradation and the permafrost moving down that brought by the roadbed soil, which bring on the natural seasonal melted layer compression and permafrost melted compression that are the main cause of roadbed settlement deformation, settlement caused by permafrost melted compression is the largest, about 50%; especially on August-November 4 months, because melting permafrost layer compressed, the roadbed settlement deformation is obvious, In December as seasonal freezing and the permafrost move up stably, embankment settlement began to slow; Under the influence of the slope of shade and sunny, roadbed thawing settlement development has a certain slope tropism, in a freezing and thawing cycle period, permafrost melting time under roadbed of shade slope is about 30d less than permafrost melting time under roadbed of sunny slope, embankment settlement of the shade slope is less than embankment settlement of the sunny slope; In the same conditions, the high ice content permafrost thaw compression deformation is greater than the lower, permafrost melted compression deformation of embankments whose filling height is above 3 meters will increase with the increase of the filling height. Based on the field measured data, combined with laboratory test data apply ABAQUS finite element software to establish the temperature field and settlement deformation model, to predict roads within the period in the design of the sedimentation of roadbed deformation. The research results can provide theoretical reference of building roads and analysising roadbed settlement deformation for the permafrost regions of Greater Khingan Mountains.