Stability of shallow-buried Qanat foundation under cyclic load
Qanat is an underground water engineering structure widely distributed in western and central Asia,and Xinjiang region of China.With the proposal of the'Belt and Road Initiative',the newly construction of high-speed railway will inevitably encounter the problem of intersection with qanat in the above areas.The hidden shallow qanat culverts under low embankments may collapse under the load of high-speed trains,affecting the stability of the upper foundation and subgrade.A large-scale model test was utilized to study the stability of shallow qanat foundation under cyclic load.The earth pressure and the compression deformation characteristics affect by qanat depth was discussed,while the potential failure surface of soil mass was analyzed combined with PIV technology.The results aredrawnas follows.The earth pressure above the culvert changes from'first increasing and then decreasing'to'continuously decreasing'along the surface depth with the increase of cyclic load,and are eventually all smaller than both sides of the horizontal.Meanwhile,increasing the qanat depth can also reduce the surface settlement rate and increase the ultimate cyclic load which foundation structure can bear.However,the accumulated settlement will increase when the qanat structure completely collapsed.The critical cyclic load frequency for the surface begin to appear large deformation are all 5～10 Hz for each foundation,and the high deformation area of foundation changes from'inverted cone type'to'funnel type'with the increase of qanat depth.When the buried depth reaches 7.5D(D is the diameter of the qanat),the potential sliding failure surface only extends above the qanat,indicating the effect of cyclic load has a critical turning point between 5.5D and 7.5D.The results provide a reference for the stability analysis and reinforcement treatment of high-speed railway foundation in the qanat region.
万方数据
维普
