Research On Foundation Stability Of Masonry Pagodas In Collapsible Loess Regions

Ancient masonry pagodas have the characteristics of great gravity, poor ductility and sensitivity to ground deformation. Diseases like oblique induced by the failure of local foundation and unstable ground structures are more common in loess region. Limit analysis based on the theory of finite element strength reduction method can effectively predict and simulate the process of masonry pagoda unstable ground, thereby people can setting the threshold to assess the stability of existing masonry pagodas.Aiming at the characteristics and instability mechanism of masonry pagodas foundation carrying capacity in loess region, a collaborative space model of masonry pagodas, foundation and basis based on the finite element strength reduction method was established, to analysis the mechanism and factors of foundation stability. Taking a real masonry pagoda project for example, make inversion analysis of the process of masonry pagoda oblique and foundation failure. Moreover, the recommended value of structure stability coefficient was given under different conditions.The main work is as follows:(1) For loess region ancient masonry pagodas examples of diseases, raised ground stability problems caused partial failure and combined with the characteristics of masonry pagoda structure, the structure diseases and tower oblique mechanism of masonry pagoda foundations in loess regions were analyzed.(2) Based on the principle of finite element strength reduction method, the sensitivity of the key parameters like constitutive relation, strength and instability criterion was discussed. And the recommended values of these key parameters were given.(3) The spatial analysis model was established based on the collaborative work of masonry pagodas foundation and basis. Combined with engineering examples the stability problem induced by the local foundation failure was numerically simulated through the finite element strength reduction method and gave the stability safety factor of masonry pagoda foundation under different conditions, by the way of using displacement mutation as instability criterion.This paper confirms the mechanism of masonry pagodas tilt and ground failure, besides define the rationality of using the finite element strength reduction method to solve the problems of foundation stability. Measure the safety margin of pagoda ground in different conditions. Provide a new researching idea for dealing with the issue of foundation stability.