Underground cavern group rock pillar stability estimation method

Abstract

The present invention provides an underground cavern group rock pillar stability estimation method. The method comprises the following steps of: (1) arranging an auxiliary cavern; (2) arranging expanded digging caverns; (3) arranging monitoring holes from the auxiliary cavern at the middle position of the two expanded digging caverns, and arranging stress detectors at the wall of the monitoring holes; and (4) performing expanding excavation of the expanded digging caverns at different time, checking read of monitoring instruments after the expanding excavation each time, wherein if the read has no obvious change, it shows that rock pillars between the expanded digging caverns are still in a safe state, the expanding excavation can be continuously performed, if the read of the monitoring instruments has obvious change, it shows that the initial stress states in the rock pillars have been changed, there is mutual interference between the two expanded digging caverns, and a spacing between the expanded digging caverns is a safe spacing of the caverns. The thickness of rock pillars is changed by manual operation to excite inherent strain change of the rock pillars so as to achieve reasonable assessment of the spacing of the cavern group, fully reflect actual geological conditions and crustal stress conditions, and therefore, the underground cavern group rock pillar stability estimation method has an important value for reasonable arrangement of the cavern group, the cavern diameter design, saving of engineering investment and the like.

Description

technical field [0001] The invention relates to a method for evaluating the stability of underground cavern group rock pillars, and is mainly aimed at deep underground projects with multiple caverns and multiple tunnels, such as underground powerhouse cavern groups, mountain-crossing tunnel groups, hydraulic tunnel groups and the like in hydropower projects. technical background [0002] In the construction process of underground caverns or tunnels in hydropower, subways, highways or railways, a parallel arrangement scheme is often adopted. The rock mass between the two caverns is called a rock pillar, and the thickness of the rock pillar is directly related to the cavern. layout. If the thickness of the rock pillars between the two caverns is too large, it will not only increase the project cost, but also affect the use function of the project; if the thickness of the rock pillars is too small, it will cause problems in the construction and operation between the two caverns...

AI Technical Summary

Problems solved by technology

The above achievements are basically based on engineering experience. Specific projects need to be analyzed in detail. However, at present, there is a lack of evaluation methods that are actually available on site. They mainly rely on engineering experience or numerical simulation. There is no clear understanding of the real mechanical state in rock pillars. Mutual disturbance often occurs between chamber groups

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