Deep Rock Tunnelling Support for Radial Stress Compensation
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Solution Overview
Problem
The New Austrian Tunneling Method is inadequate for deep rock engineering due to the loss of radial stress and stress concentration leading to surrounding rock instability and destruction.
Innovation Solution
An excavation compensation method involving engineering geological information acquisition, hazard type determination, and application of high pre-stressing anchor net and truss-type arch strategies to manage radial and tangential stress, along with energy gathering directional blasting and gradation grouting to stabilize the surrounding rock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the New Austrian Tunneling Method is used for deep rock engineering, then the surrounding rock self-support capacity is utilized, but the radial stress loss and stress concentration cause surrounding rock instability
Solution Approach 1:
The patent applies preliminary anti-action by implementing pre-stressing support before the surrounding rock can undergo significant stress loss. The pre-stressing force is applied in advance to counteract the upcoming radial stress reduction, preventing the rock from entering an unstable stress state. This proactive approach addresses the contradiction by anticipating and preventing the radial stress loss problem inherent in traditional methods.
Solution Approach 2:
The patent implements preliminary action through timely support installation and pre-stressing application immediately after excavation. By acting before the second excavation effect causes tangential stress concentration and rock destruction, the support system establishes a stable stress state early in the process, preventing the progression to instability while maintaining the self-support capacity utilization of the New Austrian Tunneling Method.
2Productivity
If excavation is performed in deep rock, then tunnelling construction is enabled, but the first excavation effect causes radial stress to drop to zero and load-bearing capacity to reduce
Solution Approach 1:
The patent applies preliminary action by installing support structures and applying pre-stressing forces immediately after excavation before the surrounding rock loses its load-bearing capacity. This timely intervention prevents the complete drop of radial stress to zero by establishing a compensating stress state, thereby maintaining rock strength while enabling continuous tunnelling construction progress.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the pre-stressing force magnitude and support timing based on the depth, rock properties, and excavation progress. This allows optimization of the compensation effect to match the actual stress state changes during excavation, maintaining load-bearing capacity while enabling efficient construction across different geological conditions.
3Ease of manufacture
If traditional support methods are used, then construction simplicity is maintained, but stress concentration in tangential stress leads to surrounding rock destruction
Solution Approach 1:
The patent applies preliminary anti-action by implementing pre-stressing support that counteracts the upcoming tangential stress concentration before it causes rock destruction. The pre-stressing force is calibrated to offset the stress concentration effect, preventing rock failure while maintaining relatively simple support implementation procedures similar to traditional methods.
Data Source
AI summary
The present disclosure relates to the technical field of stability control of surrounding rock of tunnelling, and provides an excavation compensation method for tunnelling in deep rock engineering, including: acquiring an engineering geological information of the tunnelling in deep rock engineering; determining an engineering hazard type based on the engineering geological information; determining an excavation compensation support strategy for the surrounding rock of the tunnelling in deep rock engineering based on the engineering hazard type; and performing a supplementary support control on the surrounding rock of the tunnelling in deep rock engineering based on the excavation compensation support strategy. Through the supplementary support strategy, the difference value between a radial stress of the surrounding rock of the tunnelling in deep rock engineering and an initial crustal stress can be reduced to within a preset approximate value range, further effectively preventing a stress concentration phenomenon occurred in a tangential stress.