scholarly journals Predicting the excavation damaged zone within brittle surrounding rock masses of deep underground caverns using a comprehensive approach integrating in situ measurements and numerical analysis

2021 ◽  
pp. 101273
Author(s):  
Ding-Ping Xu ◽  
Xiang Huang ◽  
Shao-Jun Li ◽  
Huai-Sheng Xu ◽  
Shi-Li Qiu ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Surrounding Rock ◽  
In Situ Measurements ◽  
Comprehensive Approach ◽  
Rock Masses ◽  
Excavation Damaged Zone ◽  
Underground Caverns ◽  
Damaged Zone ◽  
Deep Underground

3-D FLAC Numerical Analysis of Rheological Character and Stability of Underground Caverns Surrounding Rock Mass of Xiao Langdi Key Water Control Project

2006 ◽  
Vol 306-308 ◽  
pp. 1473-1478
Author(s):  
Wei Shen Zhu ◽  
Jian Hua Liu ◽  
Shu Cai Li
Keyword(s):  
Numerical Analysis ◽  
Back Analysis ◽  
Surrounding Rock ◽  
Construction Process ◽  
Water Control ◽  
Long Period ◽  
Underground Caverns ◽  
Rheological Character ◽  
Measured Displacement

A brief description is given to the visco-plastic constitutive model of 3-D FLAC software and some treating methods for the numerical analysis. The excavation steps and the exerting time of excavation loads are determined in the light of the real construction process. The rockmass mechanical parameters are determined according to back analysis of in-situ measured displacement data. The analysis results of displacement and stability of the opening complex surrounding rocks in the construction process and in a long period of time after excavation completion are given.

Numerical Modelling and Assessment of Excavation Damaged Zone around the Underground Excavations: A Case Study

2006 ◽  
Vol 324-325 ◽  
pp. 77-80 ◽  
Author(s):  
Deng Pan Qiao ◽  
Zong Sheng Zhang ◽  
Shu Hong Wang ◽  
Ya Bin Zhang
Keyword(s):  
Rock Mass ◽  
Stress Field ◽  
Numerical Modelling ◽  
Underground Mining ◽  
Rock Masses ◽  
Stress Concentrations ◽  
Anisotropic Rock ◽  
Excavation Damaged Zone ◽  
Damaged Zone

This paper presents a study on the quantification of the degree of damage from the microseismic event data, for assessment of excavation damaged zone of anisotropic rock in Jinchuan mine and presents numerical simulation and prediction on the deformation and failure of the rock masses surrounding laneway under rock mass properties and excavating conditions. Following an introduction to the engineering geology and mechanical properties of the rock mass in the Jinchuan mine areas, this paper reveals the features of the measured in situ stresses and puts emphasis on an analysis of the mechanism of underground opening and damage induced by the underground mining. Stress and AE redistribution induced by excavation of underground engineering results in the unloading zone in parts of surrounding rock masses. A micromechanics-based model has been proposed for brittle rock material undergoing irreversible changes of their microscopic structures due to microcrack growth. A systematical numerical modeling analysis method was completed. Based on numerical modelling, a series of predicting curves for rock mass response and deformation are obtained, which provides the basis of guiding the design and construction of anisotropic rock cave in Jinchuan mine. The use of the in situ stress field results in enhanced modeling of the stress concentrations and potential failures at the mines has also been reviewed. Knowledge of the prevailing rock stress field at the mines is a critical component for such modeling which has led to improved rock mechanics understanding and operations at Jinchuan mines.

Study on Deformation and Damage of Rock Mass Subject to High In Situ Stress by Using a Elastoplastic Damage Model and Considering the Impact of Weak Planes

2013 ◽  
Vol 838-841 ◽  
pp. 705-709
Author(s):  
Yun Hao Yang ◽  
Ren Kun Wang
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Damage Model ◽  
Back Analysis ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
High In Situ Stress ◽  
Underground Caverns ◽  
The Impact

Large scale underground caverns are under construction in high in-situ stress field at Houziyan hydropower station. To investigate deformation and damage of surrounding rock mass, a elastoplastic orthotropic damage model capable of describing induced orthotropic damage and post-peak behavior of hard rock is used, together with a effective approach accounting for the presence of weak planes. Then a displacement based back analysis was conducted by using the measured deformation data from extensometers. The computed displacements are in good agreement with the measured ones at most of measurement points, which confirm the validities of constitutive model and numerical simulation model. The result of simulation shows that damage of surrounding rock mass is mainly dominated by the high in-situ stress rather than the weak planes and heavy damage occur at the cavern shoulders and side walls.

scholarly journals The Method of Determining Excavation Damaged Zone by Acoustic Test and the Application in Engineering Cases

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Qian-Cheng Sun ◽  
Hao-Sen Guo ◽  
Zhi-Hua Xu ◽  
Yue Liu ◽  
Xiao Xu
Keyword(s):  
Rock Mass ◽  
Damage Evolution ◽  
Hard Rock ◽  
Damage Zone ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Surrounding Rock ◽  
Excavation Damaged Zone ◽  
Damaged Zone ◽  
Columnar Jointed Rock Mass

It is very important to accurately determine the depth of excavation damaged zone for underground engineering excavation and surrounding rock stability evaluation, and it can be measured by acoustic test, but there is no quantitative method for analysis of the results, and it relies heavily on the experience of engineers, which leads to the low reliability of the results and also limits the application of the acoustic method. According to substantial field test data and the feedback of surrounding rock support parameters, the boundary method is proposed to determine the depth of excavation damaged zone in surrounding rock based on the relation between the ultrasonic velocity of measured point and the background wave velocity of rock mass. When the method is applied to the columnar jointed rock mass of Baihetan and the deep-buried hard rock of Jinping, the excavation damaged zone was well judged. The results in the Baihetan project show that the proposed method of determining excavation damage zone by the acoustic test can well demonstrate the anisotropy characteristics of the columnar jointed rock mass, and the damage evolution characteristics of jointed rock mass at the same position can also be obtained accurately. Moreover, the method also can accurately reveal the damage evolution process of the deep-buried hard rock under the condition of high ground stress, which proved the applicability of this method in jointed or nonjointed rock masses.

Development of new models for the estimation of deformation moduli in rock masses based on in situ measurements

2017 ◽  
Vol 77 (3) ◽  
pp. 1191-1202 ◽  
Author(s):  
Slobodan Radovanović ◽  
Vesna Ranković ◽  
Vladimir Anđelković ◽  
Dejan Divac ◽  
Nikola Milivojević
Keyword(s):  
In Situ Measurements ◽  
Rock Masses ◽  
New Models

scholarly journals Comparative Study of the Excavation Damage and Rockburst of the Deeply Buried Jinping II Diversion Tunnels Using a TBM and the Drilling-Blasting Method

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Jing Yang ◽  
Xing-Guo Yang ◽  
Jia-Wen Zhou ◽  
Yong Liu ◽  
Bao-Shun Dong ◽  
...  
Keyword(s):  
Rock Mass ◽  
Stress Concentration ◽  
High Stress ◽  
Tunnel Boring Machine ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
High In Situ Stress ◽  
Damaged Zone ◽  
Blasting Method

The rock mass failure induced by high in-situ stresses during the excavation of deep diversion tunnels is one of the key problems in the construction of the Jinping II Hydropower Station. Based on the results of acoustic wave tests and rockburst statistical analysis conducted, this study focuses on the excavation damaged zone (EDZ) and rockburst events in the Jinping II diversion tunnels excavated using the tunnel boring machine (TBM) method and the drilling-blasting method. The unloading failure mechanism and the rockburst induced by the two different excavation methods were compared and analyzed. The results indicate that, due to the different stress adjustment processes, the degree of damage to the surrounding rock mass excavated using the drilling-blasting method was more serious than that using the TBM method. The EDZ induced by the TBM was usually distributed evenly along the edge of the excavation surface. While, the drilling-blasting method was more likely to cause stress concentration, resulting in a deeper EDZ in local areas. However, the TBM excavation method can cause other problems in high in-situ stress areas, such as strong rockbursts. The drilling-blasting method is more prone to structural controlled failure of the surrounding rock mass, while the TBM method would induce high stress concentration near the edge of excavation and more widely distributed of stress adjustment induced failure. As a result, the scale and frequency of the rockburst events generated by the TBM were significantly greater than those caused by the drilling-blasting method during the excavation of Jinping II diversion tunnels. The TBM method should be used carefully for tunnel excavation in high in-situ stress areas with burial depths of greater than 2000 m. If it is necessary to use the TBM method after a comprehensive selection, it is suggested that equipment adaptability improvement, advanced prediction, and prediction technology be used.

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