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Stability considerations : |
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There are various methods by which a braced cut can be expected to attain failure. Before carrying out a braced excavation the stability criteria are first judged and adequate steps are taken up to ensure the stability. Building of struts or walls nor wales cannot prevent these phenomenon. These aspects are described in the subsequent sections. |
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Bottom heave |
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Consider a excavation pit as shown in the figure and the rectangular soil mass adjacent to it. If this soil mass is considered as a foundation with the failure surfaces as shown the heaving of soil will occur at the bottom of the pit due to release of overburden pressure at that point. The pit has to be safeguarded against this heaving. |
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Fig.6.35 Bottom heave |
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