A Study on Rupture Occurrence and Progression due to Seepage Forces

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Laboratory tests are carried out for investigating the rupture occurrence and its progression of the hydraulic fracturing within an one-dimensionally horizontal flow domain.These tests give the conclusions ; (1) The initial rupture occurs at the hydraulic gradient of 0.1-0.3 times as small as critical one in vertically flow, (2) The shape, size and density of soil particle take an effect of the occurrence of seepage failure. According to the simple two-dimensional tests, namely, two types of seepage flow, the following are recognized (3) The direction and speed of the rupture progression varies in spite of homogeneous sample, and depends on the local heterogeneity in soil mass, (4) Bearing capacity at the ground surface falls down at the early stage of rupture progression.From another two-dimensional experiment with bending flow zone, it is found out that : (5) The progression pattern is (1) heave at the down-stream ground surface -> (2)break-down at bending point-> (3) vertically progression reached to the surface. (6) Summation of the effective weights above bending elevation can be one of indices when we predict the failure occurrence over and near the bending zone.The computer simulations are also developed by the aids of (a) steady state seepage flow model, (b) unsteady seepage flow through deformable material model, (c) probabilistic model.