A Research Of The Deformation And The Settlement Forecasting Of High Embankment On The Middle Of Kangding Airport, Sichuan China

With the great development of West China, the airport construction is becoming in our country, especially in mountainous southwest of China. Airport construction in these areas is characterized by complicated terrain, geomorphic and geological condition, deep cut and fill, large amounts of earthwork, high level, short time and small planned investment.Kangding airport is located on the southwest foot of Zheduo mountain stretching from south-east to north-west on eastern Tibean Plateau. It will be the second highest airport in the world after Bangda airport (4,400m) located on Tibet. The maximum height of the embankment is 46.6 m and the maximum height between the bottom and the top of the slope is 85.8 m. The total quantity of the excavated and filled earth-rock material is above 28,000,000 m³. The whole engineering sites are located on the moraine soil during the ice age of cuttlebone canal (Q₃^agl) and Nanguanmen (Q₃^lgl). Besides boulders, gravels and sands, special boulders exist in the debris, which is characterized by inhomogeneous grain size, out-of-order intermixture, difficult size classification and unstratified feature.Based on the research for the basic geological conditions in the preliminary and detailed investigation, and the field tests of the engineering, ground treatment detection tests,in-situ monitoring,numerical simulations for the settlement and deformation of the high embankment and the prediction of the settlement that occurs after the embankment attained its scheduled level of Kangding airport are carried out. Some work and creative conclusions are put out as follow.(1) Moraine soil is typical non-homogeneous foundation,which is characterized by block and crushed stone soil, distributing non-unniformly and anfractuous layers. However, as a whole,it can be recognized as fine natural foundation because of its engineering properties such as big dry density, high compactness, hyposmosis, strong bearing capacity and small deformation etc. (2) Based on large field test, general requirements and filling methods are determined, superiority of filling body with packed block and moraine soil is analyzed.The result will be very useful for optimum design and construction.(3) Researched on the monitoring items such as monitoring methods, monitoring programme and analyzed the deformation regularity of high embankment after Batas handling by formula calculations and three-dimention numerical simulation.(4) The settlement that occurs after the embankment attained its scheduled level is predicted by the regressive parameters models and the artificial neural net work. The predicted results are probably equal to the in-situ monitoring results, which show that models have preferable precision. Among these models, the forecasted results by BP model are most reasonable.