山区机场高填方地基变形分析

At present, a large number of high-fill projects are used in mountainous airports, and the settlement and deformation of high-fill subgrades is an important issue to be solved. In this paper, based on the Unified Hardening (UH) model, by studying relationships between the stone content and the internal friction angle and cohesion, and based on the extended SMP criterion and transforming stress, the stone content is introduced into the UH model, and the UH model considering stone content is established. The change law of the intersection of the current yield surface and the mean principal stress axis is used as the judgment criterion for loading and unloading of the UH model considering stone content, which makes the unified consideration of hardening and softening be realized. And the semi-implicit back reflection stress update algorithm is adopted. The loading and unloading criterion is applied to the stress update algorithm. And the finite element application of the UH model considering stone content is realized. Then the finite element analysis of the large-scale triaxial test of the soil-stone mixture is carried out by the finite element program of the UH model considering stone content, and the validity of the finite element program is verified by comparing the calculated results of the finite element with the actual test results. Finally, using the finite element program of the UH model considering stone content, the three-dimensional finite element analysis is carried out for the high-fill subgrade of airport in the mountain area, and the vertical displacement curve of the ground settlement monitoring point is obtained. The calculated curves are compared with the curves by the UH model without considering stone content, the Modified Cambridge (MCC) model and the measured data. And the vertical displacement contour, the lateral displacement contour, the pore water pressure contour and the change curve of pore water pressure with time of high-fill subgrade are obtained, and thereby the displacement and pore water pressure change laws of the airport's high-fill subgrade are obtained. The rationality of the UH model considering the stone content in analyzing the deformation of the high-fill subgrade of the mountainous airport is explained.