Theory And Application Of Seepage And Stress Fields Coupling Of The Channel Project Overlying Goaves

Inter-basin water transfer projects are systematic engineering with wide range,long distance and multiple influential factors, some channels inevitably have to passthrough the ancient goaves. Seepage and goaves are dangerous to the normaloperation of the channel as well as the maintenance and repair. Present analysis ofchannel seepage and stability mostly dissevers the seepage field with stress field, thusthe interaction between the two fields could not be well reflected, and furthermore, thegeological model is simplified to different extent, so it is difficult to have an overallreflection on the geotechnical body comprehensively and factually. Moreover, themathematical model of seepage analysis is mostly the empirical formula-Darcy’s law,or analyzes the seepage according to equivalence principle between the temperatureand seepage fields, meanwhile finite element fixed mesh method is widely used inpositioning of seepage saturated surface, Computational Fluid Dynamics (CFD) havebeen gradually applied to the simulation of seepage field because of its relativelymature method for convection term until recent years. Thus, the research of the theoryand application of seepage and stress fields coupling of the channel project overlyinggoaves is of important theoretical significance and practical value. On the foundationof summarizing previous studying achievements, the achievements obtained in thispaper are listed as follows.(1) The three-dimensional Navier-Stokes equations coupled with VOF method ofthe channel seepage were established. The equations were discreted by finite volumemethod, and an actual channel project was taken as a case. The research illustratedshown that the VOF method is feasible in channel seepage analysis. Application of themethod to channel seepage simulation and solving the saturated surface was of highprecision and small computing workload, which provided a basis for the applicationof the method to seepage calculation of practical engineering.(2) The three-dimensional seepage and stress fields coupling analysis theory ofthe channel was proposed. Based on the three-dimensional geo-engineering integratedmodel, including faults and stratigraphic etc., the seepage and stress fields couplinganalysis model of the channel was performed. Scripts were developed for the two setsof non-matching grids to solve the data transfer problem, and considering thenonlinear characteristics of rock mass at the same time, the finite element method wasapplied to analyze the effect of the seepage, underground goaves on the deformation and stability of the channel. This research provided important theoretical significanceand practical value for the safe and stable operation of the inter-basin water transferprojects.(3) The global sensitivity analysis method, Expanded Fourier AmplitudeSensitivity Test was applied. Under the reasonable definition of the parameters’probability distributions, the global sensitivity analysis of the parameters of channelseepage and stress fields coupling model was carried out. Combined with thefirst-order and overall global sensitivity coefficient of each parameter, the researchillustrated provided guidance to the design of similar projects.