| The seepage free surface is also called the lifeline of dam body.By calculating the position of it can the seepage domain range be determined.Applied to calculate the seepage free surface,such as initial flow method and abandoning element method,in which the real seepage free surface is usually approximated by multiple iterations based on the characteristics of boundary conditions,the methods may cause non-convergence of the results.A numerical method for calculating seepage free surface by considering kinetic energy correction(KEC)is presented based on the principle of real-domain total potential energy(RDTPE)and gradual splitting method(GSM).The main contents are as follows:(1)A numerical method of seepage free surface considering KEC is proposed.When the seepage spill point is calculated based on the principle of RDTPE that only uses two parts about the elevation head and the pressure head,while the influence of the seepage velocity head is neglected,which results in calculation errors.The calculation method of RDTPE is corrected by transforming the seepage velocity into kinetic energy.Whose accuracy is improved.(2)The similarity principle is used to determine the seepage free surface,which improves the calculation efficiency.After the seepage spill point is calculated by the principle of KEC,all the elements(i.e.transition elements)which are passed through by the seepage free surface are screened out under this state of spill point.Then the intersection points of all transition elements and free surface curves in the seepage domain are obtained by the principle of triangular similarity,then the whole seepage free surface can be directly obtained by connecting the intersection points and spill point.(3)The method of calculating seepage free surface based on the principle of minimum energy loss rate is improved,and the seepage free surface can be obtained directly under the condition of uncertain spill point.The GSM proposed by our research group needs to know the location of the spill point in advance.The method is re-edited by Fortran program and applied to the solution of earth-rock dams.And comparisons with analytical solutions or experimental solutions shows that the method has high accuracy. |
