Structural Selection Of Compound Foundation Based On Fuzzy Integral And Viscoelastic Analysis Of Composite Ground Settlement

Composite foundation has become a common method of soft ground treatment.The selection of composite foundation and the calculation of the settlement of composite foundation are important parts of the theoretical study of composite foundation.At present,there are many decision models and deformation calculation methods for composite foundation,however each model and method has its own scope of use.Reasonable selection and settlement calculation can save costs under the premise of ensuring normal use of functions.Because many factors can't give quantitative indicators and have fuzziness when dealing with foundation,based on its fuzzy characteristics,this paper applies the improved Sugeno fuzzy integral model to make decisions for various ground treatment schemes.The viscoelastic properties of soil were considered in the settlement calculation of substratum in composite foundation,and the viscoelastic solution of substratum was deduced.The main research content of this articleisas follows:(1)The Sugeno fuzzy integral is improved,and the improved fuzzy integral model is used as the optimal model of the composite foundation treatment scheme.And use this model to analyze the treatment scheme of a highway foundation.Two kinds of membership function models(half-normal distribution and half-? distribution)were used for calculation and comparison.The optimal decision-making scheme for foundation treatment was determined and the rationality of the model was verified.(2)Assuming that the foundation is a semi-infinite body line viscoelastic medium,the Kelvin model and the three-element model are selected as models to describe the viscoelastic relationship between rock mass.Under the space of Laplace,the Hankel transform is used to find the initial function solution for the displacement and stress of a single layer of viscoelastic foundation.The expressions of verticaldisplacement underthecondition oftheverticalforceacting on the surface of the semi-infinite body when Kelvin model is selected,and the vertical displacement expression under the condition of the uniform load acting on the surface of the semi-infinite body when the three-element model is selected are given.Through the solution of the degradation and example analysis,the correctness of the calculation method is verified.The research results lay a theoretical foundation for the study of the settlement of the composite foundation.(3)The viscoelastic characteristics of the soil were introduced into the settlement calculation of the substratum in the composite foundation.The three-element model was used to describe the viscoelasticity of the soil,and the viscoelastic solution for the settlement of the composite foundation under the uniform rectangular load was deduced.The results were applied to the settlement calculation of the cement mixing pile.In the analysis of the examples,through the comparison of various settlement calculation methods,the results show that the calculated results are closer to the measured values when the soil viscoelasticity is considered,which is morereasonable.