Abstract
Water flow and hydromechanical coupling process in fractured rocks is more different from that in general porous media because of heterogeneous spatial fractures and possible fracture-dominated flow; a saturated-unsaturated hydromechanical coupling model using a discontinuous deformation analysis (DDA) similar to FEM and DEM was employed to analyze water movement in saturated-unsaturated deformed rocks, in which the Van-Genuchten model differently treated the rock and fractures permeable properties to describe the constitutive relationships. The calibrating results for the dam foundation indicated the validation and feasibility of the proposed model and are also in good agreement with the calculations based on DEM still demonstrating its superiority. And then, the rainfall infiltration in a reservoir rock slope was detailedly investigated to describe the water pressure on the fault surface and inside the rocks, displacement, and stress distribution under hydromechanical coupling conditions and uncoupling conditions. It was observed that greater rainfall intensity and longer rainfall time resulted in lower stability of the rock slope, and larger difference was very obvious between the hydromechanical coupling condition and uncoupling condition, demonstrating that rainfall intensity, rainfall time, and hydromechanical coupling effect had great influence on the saturated-unsaturated water flow behavior and mechanical response of the fractured rock slopes.
Highlights
Fractured rock masses including numerous discontinuities with various attitudes and different scales are complicated geological media that have undergone a long period of geological evolution
The results indicate that the safety coefficients under hydromechanical coupling conditions are smaller than that under uncoupling conditions, which is in agreement with the water pressure, stress, and displacement variation
An unsaturated coupled model based on discontinuous deformation analysis (DDA) has been proposed for the analysis of saturated-unsaturated water flow behavior and mechanical response of the fractured rocks such as dam foundation and rainfall infiltration in rock slopes, and a systematic numerical code was developed to analyze the hydromechanical process, indicating the feasibility and
Summary
Fractured rock masses including numerous discontinuities with various attitudes and different scales are complicated geological media that have undergone a long period of geological evolution. It is desirable to evaluate spatial and random distribution of the fractured rock flow [12], and a sound numerical method of intact rock and fractures should be proposed to model water movements in the deformed rocks for performance assessments and design optimization in a lot of rock engineering such as rock slopes and dam foundation. A fractured rock slope considering rainfall infiltration as a case study and the water pressure distribution on the fault surface and inside the rocks was demonstrated with rainfall time increasing, and the displacement, principle stress distribution, and slope stability were described considering the hydromechanical coupling and uncoupling process, indicating that rainfall intensity, rainfall time, and hydromechanical coupling effect under unsaturated conditions have great influence on the movement of seepage flow through fractured rock slopes and corresponding stability
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