Analytical Method And Its Applications For Additional Stress Of Foundation Considering Granular Characteristics

The additional stress is important basis for the settlement and stabilization analysis of foundation.The classical mechanics theory of continuous solid media has widely used to analyze the additional stress of foundation.But,the soils are not continuous solid media,they are granular porous media that composed of soil particles.The mechanism of force transmission in soils are obviously different from in the continuous solid media.Therefore,it has obvious irrationality that using the mechanics theory of continuous solid media to analyze the additional stress of foundation with granular characteristics.It is necessary to further discuss the additional stress analysis method of foundation considering the granular characteristics.Thus,this paper deeply research the additional stress analysis method of foundation under vertical load and its applications,by emphatically considering the granular porous characteristics of soils,under the support of the National Natural Science Foundation of China?NO.51378198?and the Specialized Research Fund for The Doctoral Program of Higher Education?NO.20130161110017?.The studies have important significance in theoretical and engineering.Firstly,considering the comprehensive influence of interaction between soil particles and the particle size and gradation,the laws of additional stress transmission in soils with the granular characteristics are researched by using the numerical analysis code(PFC^2D)with discrete element.The range?a frustum?and its controlling factors of force transmission in foundation under vertical uniform load have made clear.Based on the orthogonal test design and multivariate nonlinear fitting analysis method,the boundary analysis model of the range of force transmission in foundation under vertical uniform load?or the mathematic model of conic surface?was established.And the influence laws of the model parameters on the range of force transmission in foundation are analyzed.It lays a solid foundation for the study of the analysis model of the additional stress of the foundation with the granular characteristics.Secondly,based on the boundary analysis model of the force transmission of foundation,the solving problem of additional stress analysis of foundation is considered as the solving problem of the stress distribution of the frustum applied vertical uniform load at the top,the additional stress analysis model of foundation considering the granular characteristics is proposed.On the basis of this,the analytical solution of the stress distribution of the frustum under vertical load was established by introducing the Love displacement function and the principle of stress superposition.Thus,the additional stress analysis method of foundation under vertical load was proposed considering the granular characteristics.The additional stress analytical solution of soils under common foundations?rectangle,strip and circle?was developed further.The additional stresses of foundation under vertical uniform load were monitored by the indoor model tests and the numerical analysis code(PFC^3D)with discrete element.The rationality of this method was verified by comparing the monitoring results with the analytical results of additional stress es from this paper and the method based on the continuous solid mechanics.Finally,two applications of the additional stress analysis method of foundation considering the granular characteristics were researched.On the one hand,based on the theory of porous media,the deformation analysis model was proposed considering the change of deformation mechanics parameters.On the basis of this,combining the aforementioned additional stress analysis method of foundation considering the granular characteristics.The nonlinear settlement analysis methods of foundation were established.On the other hand,the compaction degree analysis model of foundation or subgrade with static penetration was established based on the aforementioned settlement analysis methods of foundation.The method for determining the compaction degree of foundation or subgrade was established considering the granular characteristics.And the rationality and feasibility of the methods was verified.The cases were calculated by these methods and the existing similar analysis methods.The rationality and feasibility of these methods of the deformation analysis and the determining compaction degree was verified by comparing the calculating results with the measured results.