Influence of tunneling methods on the strainburst characteristics during the excavation of deep rock masses

Energy accumulation and dissipation play an important role during the entire process of rock failure. Some flaws, such as preexisting holes, will influence energy accumulation and dissipation. In order to investigate the energy evolution of coal specimen with preexisting holes under uniaxial compression through numerical approaches, the particle simulation method was used in numerical simulations. In this paper, the energy evolution of coal specimen was theoretically analyzed, and the influence of different hole arrangement, such as diameter, spacing, angle, and number, on the evolution characteristics of energy was also discussed. At the same time, the arrangement of the artificial boreholes for preventing the rockburst was explored. The results show that, compared with the intact coal specimen, the change of diameter, spacing, angle, and the number of holes weakened the coal specimen’s capacity to store energy and release strain energy. When the diameter, the vertical distance, and relative angle of preexisting holes were 15 mm, 10∼15 mm, and 60°, respectively, the energy storage limit reached optimal value. For arrangement of the artificial boreholes, the diameter, spacing, and angle can be designed on the basis of those optimal values. This study has a guiding significance in designing the arrangement of the artificial boreholes for mitigation of rockburst.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Energy Accumulation and Dissipation of Coal with Preopening under Uniaxial Loading

Wei

Li³

2021

“…Zhu et al [131] revealed transient unloading could cause tensile stress near the free excavation surface, which might result in tensile failure of the surrounding rockmass. Fan et al [132] discussed the influence of unloading rates on the strain-burst characteristics during the excavation of deep-rockmasses. Li et al [133] studied the influence of unloading disturbance on the adjacent tunnel.…”

Section: Rock Damage and Failure Induced By Blastingmentioning

confidence: 99%

Numerical Simulation on Damage and Failure Mechanism of Rock under Combined Multiple Strain Rates

Zhu

Wei

Niu

et al. 2018

During underground hard-rock mining, the drilling and blasting method currently remains the most economical excavation method, and the rock may experience a multistrain-rate spectrum under quasi-static, dynamic, and rheological loading conditions and their combination as well. The study on the damage mechanism of rock under multistrain-rate condition that induced by mining excavation is the fundamental issue for predicting the mining-induced hazards such as rockburst. In this study, the state of the art of rock damage and failure under different strain rates is reviewed first. Then, the numerical model for rock failure under multiple strain rates is formulated when the rock damage is taken as the main thread. Meanwhile, we summarize our work in this area over the past ten years, and the constitutive law for the damage and failure of rock under multistrain rates is presented. Finally, several numerical examples, i.e., rock damage and failure under combined static and dynamic load, rock damage and failure triggered by dynamic stress redistribution due to excavation, rock damage and failure induced by blasting, and rock damage and failure due to the combination of dynamic disturbance and rheological load, are presented. Based on these numerical simulations, the associated rock damage mechanism and failure behaviors under differently combined multiple strain rates are clarified, which may provide a theoretical basis for clarifying the rock failure mechanism during rockbursts and rock blasting. Also, further studies on the damage and failure of rock under multiple strain rates are suggested.

“…Also, some scholars have noticed the relationship between rockburst intensity and rock blasting. Fan et al studied the influence of tunneling methods on the strainburst characteristics during the excavation of deep rock mass [24]. Liu et al put forward a method for dynamic risk assessment and management of rockbursts in drill and blast tunnels [25].…”

Section: Introductionmentioning

confidence: 99%

Rockburst Prediction on the Superimposed Effect of Excavation Accumulation Energy and Blasting Vibration Energy in Deep Roadway

Xiang

2021

In deep mining, much elastic energy is stored in rock mass due to the high geostress. Rockburst will be induced by accumulated energy during excavation. Meanwhile, because of blasting vibration energy in the host rock, there will be an obvious superimposed effect on the probability and intensity of rockburst. To explore the most reasonable and effective method for understanding rockburst problem under blasting, a deep roadway of Sanshandao gold mine was studied. On the basis of in situ geostress data, the accumulated energy of three-centered arch roadway after quasi-static excavation was derived. Then, a series of in situ blasting vibration were monitored, and the blasting vibration energy was calculated by employing the equivalent theory of elastic vibration boundary. Finally, the tendentiousness of rockburst was evaluated qualitatively with the superimposed energy. The results indicated that the disaster-driven energy was increased by 45.1% and 28.2% on different places of roadway. Also, the probability and intensity of rockburst would be raised.