Abstract
Zonal disintegration refers to the special phenomenon whereby fractured zones and intact zones appear alternately in deep-buried surrounding rocks under high stress conditions, which are different from that of the shallow rock mass. Because the divisional rupture law in engineering practice is closely related to the force characteristics of the bolt body, this paper analyzed stress distribution rules of the same bolt body at different times and that of different bolt bodies at the same time in the case of zonal disintegration based on coordination deformation between the bolt body and surrounding rock. The nonlinear rheological mechanics model of rock mass on the elastic-plastic interface under the maximum support pressure was established. It puts forward the theoretical calculation formula about the mechanics criterion and breakdown moment of the zonal disintegration. Using the mechanics model of interaction between a bolt and the surrounding rock, the distribution locations along the bolt body of the anchor neutral points and its maximum axial forces were discussed with the multiple theoretical neutral points. Furthermore, the location and width of each fracture zone were back analyzed. The results show that the rock mass on the elastic-plastic interface of the surrounding rock has a significant creep effect after the excavation of the deep underground cave. While maximum deviator stress of the rock mass is more than its long-term strength, the rock mass will fracture along a radial direction and come into the fractured zone. The multiple redistribution of the surrounding rock stress will generate alternate distribution phenomena of the fractured zone and intact zone. Meanwhile, the distribution regularity of the peaks and troughs interval of the displacement of surrounding rock leads to multiple neutral points along the anchor length direction. The computed results of zonal disintegration through the back analysis can reflect the actual space-time evolution laws of zonal disintegration in deep underground caves.
Highlights
Since the twenty-first century, the development and utilization of deep rock mass engineering has been the most active research direction in the field of civil engineering
The zonal disintegration of surrounding rock is typical of deep rock mass engineering and has attracted great attention from experts and scholars in the field of rock mechanics engineering, both in China and abroad
Due to the continuity of the bolt body, the l0 section of the bolt body tends to displace towards the exterior of the cave which is prevented by the surrounding rock around the l0 section of the bolt body and some negative frictional resistance is distributed on the surface of that bolt body, which is in a tensile status
Summary
Since the twenty-first century, the development and utilization of deep rock mass engineering has been the most active research direction in the field of civil engineering. E surrounding rock shows a significant time effect and leads to many engineering disasters such as zonal disintegration, rock burst, and extruding deformation [1, 2] Among these disasters, the zonal disintegration of surrounding rock is typical of deep rock mass engineering and has attracted great attention from experts and scholars in the field of rock mechanics engineering, both in China and abroad. Mechanics and instability criterion [12,13,14,15] of the zonal disintegration of surrounding rock in deep roadways have been studied and numerical simulation tests of the zonal disintegration under different working conditions have been carried out [16,17,18]. One engineering case study is presented to demonstrate the effectiveness, accuracy, and applicability of the proposed method for the zonal disintegration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
