含土洞、溶洞的机场滑行道路基稳定性评估

STABILITY EVALUATION OF AIRFIELD RUNWAY SUBGRADE CONTAINING EARTH CAVES AND KARST

某新建机场滑行道路基中存在土洞和溶洞,且路基上部土层承载力低。为了评估该滑行道路基稳定性,采用地层结构模型,按弹塑性有限元理论分析未加固和加固路基在飞机重力荷载作用下的力学响应,计算结果显示:(1) 在飞机动载作用下,未加固路基表层土和上部土洞、溶洞产生较大的塑性变形,洞周岩土体出现塑性屈服,整个路基处于不稳定状态;(2) 对路基表层土进行注浆加固,或同时对路基表层土、土洞、溶洞注浆加固,路基面和土洞、溶洞周边位移减少,路基中产生的塑性屈服区也大大减小,但路基表层土中仍存在塑性屈服区,路基面竖向变形仍较大,建议对滑行道路基采用其他加固措施。

There are some earth caves and karst in the airfield runway subgrade of some newly constructed airport, and the bearing capacity of the overburden soil in the subgrade is low. In order to access the stability of the airfield runway subgrade, the mechanical response of the subgrade with and without strengthening after the action of airplane gravity load is analyzed by using the layer-structure model and the elastoplastic finite element method. Under the action of the dynamic airplane load, the large plastic deformation takes place in the overburden soil of earth caves and karst of the subgrade without strengthening. The plastic zone appears around the caves, and the whole subgrade is in the unstable state. After the overburden soil of the subgrade is grouted, or the overburden soil of the subgrade, earth caves and karst are grouted, the displacements and the plastic zone there are greatly reduced, but there is still the plastic zone in the overburden soil of the subgrade, and the vertical deformation of the roadbed is quite large. Thus, other strengthening measures are proposed for the runway subgrade.