Analytical Solution Of Vertical Drain Foundation Consolidation Considering The Effect Of Temperature

In practical engineering,how to accelerate the consolidation of vertical drain foundation and improve the stability and safety of foundation is always one of the hot issues in soil mechanics research.The traditional analytical solution of the foundation consolidation theory of vertical drain is based on the theory of elasticity and the assumption of drainage conditions,which can well describe the process and law of foundation consolidation of vertical drain.However,these analytical solutions do not take into account the effect of temperature on foundation consolidation,which cannot be ignored.Therefore,the traditional analytic solution can not accurately describe the actual situation.In order to solve the problem of vertical drain foundation consolidation better,it is necessary to consider the influence of temperature and establish a more accurate theoretical and mathematical model.Therefore,this paper establishes a mathematical model,deduces the consolidation equation by analytical method,and gives a vertical drain foundation consolidation model under the influence of factors such as vacuum prepressure,well resistance and uneven distribution of initial pore pressure when considering temperature.The theoretical deduction is completed and verification analysis is carried out.The main work and contents are as follows:(1)The temperature effect is considered in the vacuum preloaded vertical drain foundation,the corresponding consolidation calculation model is established,and the analytical solution of consolidation is given.The obtained solutions are degraded and compared with the existing ones to verify the correctness of the solutions in this chapter.According to this solution,a calculation program is prepared for example calculation,and the consolidation curve is drawn.The results show that when the vacuum degree is a certain value,the consolidation rate of the vertical drain foundation increases with the increase of temperature,and the time required for the completion of consolidation decreases.The higher the temperature,the less obvious the increase of the consolidation rate.The change of n value will affect the rate of consolidation.The larger n value is,the slower the rate of consolidation will be.When the vacuum degree is a certain value,the excess pore pressure dissipation rate will slow down with the increase of temperature.When the temperature is a certain value,the excess pore pressure dissipation rate decreases with the increase of vacuum degree.(2)A calculation model of consolidation of vertical drains foundation considering temperature effect and well resistance change is established.The general solution of consolidation of vertical drains foundation considering temperature effect and well resistance change is obtained by analytical method.The correctness and rationality of this solution are verified by degradation study and comparison with existing solutions.The consolidation curve of vertical drains foundation considering temperature effect and well resistance change is drawn by an example.The results show that both temperature effect and well resistance change have great influence on consolidation of vertical drains foundation.The higher the temperature is,the faster the consolidation rate is,but the influence of temperature on the consolidation is gradually weakened.Well resistance has a more significant effect on consolidation rate than temperature.When the drain spacing ratio and temperature remain unchanged,the well resistance reaches a certain value,the consolidation rate tends to zero,and the consolidation degree tends to a certain value.With the increase of well resistance,the dissipation rate of excess pore pressure slows down obviously.The higher the temperature is,the faster the excess pore pressure dissipates.(3)In view of shortcomings the current theory of vertical drains foundation thermal consolidation,a calculation model of vertical drains foundation consolidation based on axial symmetry is established,and the general solution of vertical drains foundation consolidation considering temperature and on-uniform distribution of initial excess pore water pressure is derived by analytical method.The calculation expressions of excess pore pressure and consolidation degree under trapezoidal distribution,rectangular distribution,triangle distribution and inverted triangle distribution of initial pore pressure are given.According to the analytical solution obtained,the calculation program is compiled to study the consolidation characteristics of vertical drains foundation through parameter sensitivity analysis.The consequences show that the distribution of original pore pressure has great impact on the consolidation characteristics at constant temperature.When the initial pore pressure distribution is rectangular or triangle,the dissipation rate of excess pore pressure is faster with the increase of temperature,and the pore pressure value at the bottom of the vertical drains foundation is always the largest in the consolidation process.When the initial pore pressure distribution is inverted triangle or trapezoidal,the pore pressure at the bottom of the foundation becomes larger with the increase of temperature.(4)Due to the current theory and deficiency of thermal consolidation,the consolidation model of vertical drain foundation group well based on axisymmetric is established,and the governing equation of group well consolidation of vertical drain foundation considering the influence of temperature is derived by analytical solution method,and its analytical solution is given.The solution obtained in this paper is degraded and compared with the existing analytical solutions to verify the reliability and rationality of the solution.Finally,according to the analytical solution,the calculation program is developed,and the consolidation characteristics of vertical drain foundation group wells are studied by parameter sensitivity analysis.And compared with the existing experimental consolidation data The results show that with the increase of temperature,the consolidation rate of vertical drain foundation group well is faster,but when the temperature is higher,the effect on consolidation is no longer significant.Compared with single-well,the division of group well unit has little influence on group well consolidation.When the time factor is the same,the increase of temperature can accelerate the dissipation of excess pore pressure in the group well of vertical drain foundation.The dissipation rate of excess pore pressure will slow down in the depth of foundation soil.