Two distinct three dimensional enalytical models are presented, envisaging the evaluation of stability conditions in te zone of tunnel face. One of the models is based on a composite block system, formed by an upper block above tunnel crown bearing over a lower wedge, which slides towards the tunnel face. Allowance is given for the inclusion of water pressures acting on the block and wedge faces. The second a published lower bound solution, modified by including radial body forces and percolation body forces to simulate gravity and flow net, both in spherical coordinates. The limitations of such analysis are outlined. Critical pressures determined for both models are compared with pubished analytical solutions and laboratory test results.
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Ruang Koleksi Umum
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