Stress distribution of rock around a horizontal tunnel

摘要

Study of stress distribution during creep of the rock surrounding a circular horizontal tunnel is a very important problem, mainly for mining engineering. At big depths, an opening excavated in rock can close completely after time intervals which are of the order of several tens of years. For the design of underground cavities one must be able to predict quite accurately not only the stress and strain distribution around them, but also the apperance and possibly slow spreading in time of a, micro-craked domain produced just by the excavation. Since the microcraking is related to dilatancy, the irreversible volumetric changes, either dilatancy or compressibility have started to be studied too. If the stress is in the dilatancy domain damage by mi-crocraking can develop steadily in time, ultimately leading to a major underground failure. That is why it is important to study the stress variation during creep when microcraks are also developing.