study on rock mass boreability by tbm penetration test under different in situ stress conditions

by:Gewinn     2019-09-05
Rock drilling is a comprehensive parameter reflecting the interaction between rock mass and tunnel boring machine (TBM).
There are many factors that affect rock mechanical properties, including rock conditions, rock specifications and operating parameters.
As one of the important properties of rock conditions, in-situ stress is not specifically studied for rock drilling.
In this study, three sets of shield penetration tests under different in situ stress conditions were carried out in three Shield Tunnels of Jinping secondary hydropower station.
By analyzing the correlation between the rock tunnel tunneling operation parameters collected during the test and the rock mass drillability index, the influence of the original ground stress on the rock mass drillability and The Rock Tunnel tunneling process is revealed.
The muck generated by each test step is collected and analyzed through the slag screen test.
The results show that under the action of the shield cutter, the ground stress not only affects the drillability of the rock, but also affects the crushing process of the rock.
If the stress in situ is high enough, the stress is caused-
The induced damage on the tunnel Palm surface is conducive to the crushing of the Rock and the corresponding rock drilling index is reduced.
In addition, in the process of rock crushing, due to the stress of the rock, the drillability index of the rock increases.
Through the comparison of the optional index of the predicted rock mass features (RMC)
According to the prediction model of drillability index calculated by penetration test results, the degree of influence of different in-situ stress on rock drillability is obtained.
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