Experimental Study On P-y Curves Of Laterally Loaded Pile Which Is Embedded In Karst Foundation

With the overall planning of "One Belt and One Road" in our country, the development of railways, highways, airports and other constructions have a wider space. Inevitably, a large number of infrastructure construction have to passed through the karst area. The difficulty arises in complex karst regions where bridge pile foundation be built, especially in earthquake-prone areas. Therefore, it is the great importance to study socketed piles under lateral loads in karst areas. Nowadays there are many articles talking about stability of karst cave and the influence of karst in pile foundation. The scholars from the perspective of structural mechanics, simulate kars roof to the cantilever beam, the simply supported, the fixed beam and other mechanical model and then study the rock-socketed pile’s lateral load bearing properties in karst. The current specification also failed to provide an effective method for design calculation. Therefore, the study on the rock-socketed pile’s laterally load bearing properties in karst is a valuable research issue.On the basis of looking up domestic literatures about Level load pile model test research. In this thesis, we simulate soil karst by different combinations ratio of gypsum, cement, sand, soil and to her materials. We design model test combined with similar theoretical. Through use of special process dealing with karst cave, simulate of pile foundation working under the condition of through the karst cave or not, and used the handing basket loading way of rocket-socketed piles for levels unidirectional loading. Based on pile body strain values deduced to pile bending moment diagram, Pile soil resistance diagram, pile Horizontal displacement diagram, and the p-y curve of rock-socketed pile’s, in karst cave or not, can be obtained. Compared the curve with specification about stiff clay p-y curve, the results showed that the curve of stiff clay should not be used in the design of pile foundations in karst region, according to its graphics development trend can be seen under the condition of through karst cave that the pile foundations of p-y curve corresponds to the distribution of the hyperbolic function, without through karst cave that the pile foundations of p-y curve corresponds to the distribution of the power function, used the empirical formulas matched the actual measured p-y curve under the two kinds of working conditions, obtains its correction coefficient and two kinds of working conditions of p-y curve correction formulas. Researches show that, under the conditions of through karst cave that the ultimate bearing capacity of pile foundation level will be markedly reduced, With no through the cave of the pile foundation p-y curve instead of through the cave pile foundation design is unsafely, so its need to combine the actual situation for analysis. The research of this paper will provide important theoretical basis with the calculate and analysis of laterally load pile in karst foundations, also for other special soil conditions or under other working environment of pile foundation study provides important reference value.