Shotcrete Support of a Ventilation Shaft in Hard Rock

2013 ◽  
Vol 438-439 ◽  
pp. 1133-1136
Author(s):  
Shi Liang Xu
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Stability Analysis ◽  
Hard Rock ◽  
Ventilation Shaft ◽  
Highway Tunnel ◽  
High Geostress ◽  
Q System

Ventilation shaft is important for the operation of 18 km long Qinling highway tunnel. The main geological problems encountered in the shaft excavation are high geostress and rockburst. Shotcrete can provide effective support in the rockburst conditions during the excavation of shaft in hard rock. According to the classification of rock mass Q system and engineering experience, the parameters of shotcrete support with bolt and mesh are determined, and the numerical simulation is carried out for stability analysis. Finally the dry mix shotcrete technology is applied for the support.

Research on the Surrounding Rock Damage of Deep Hard Rock Tunnels Caused by Bottom Excavation

2012 ◽  
Vol 170-173 ◽  
pp. 1700-1703
Author(s):  
Zhen Wang ◽  
Chu Nan Tang ◽  
Tian Hui Ma ◽  
Lian Chong Li ◽  
Yue Feng Yang
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Hard Rock ◽  
Surrounding Rock ◽  
Rock Damage ◽  
Simulation Approach ◽  
High Geostress ◽  
Intact Rock Mass ◽  
Rock Tunnels ◽  
Rock Tunnel

The damage features of surrounding rock in the process of bottom excavation in deep hard rock tunnel were investigated, combining with the actual tunnel data of JinpingⅡHydropower Station and using numerical simulation approach. The evolution mechanism of microfractures initiation, growth and expansion in deep intact rock mass was performed. It’s shown that the fractures caused by bottom excavation develop to deeper surrounding rock due to stress adjustment, and the zone that have been supported also has some damage. The research results provide important references to understand the damage features of surrounding rock in deep hard rock under high geostress.

scholarly journals Substantiating a technique to process hard rock involving extraction of valuable components and use of wastes to form mesorelief

2019 ◽  
Vol 109 ◽  
pp. 00003
Author(s):  
Kateryna Babii ◽  
Oleksandr Ikol ◽  
Yevhenii Malieiev
Keyword(s):  
Rock Mass ◽  
Hard Rock ◽  
Industrial Product ◽  
Power Dependence ◽  
Landscape Restoration ◽  
Hard Rocks ◽  
Mineral Losses ◽  
Scientific Value ◽  
Practical Implications

A technique to process rock mass from hard-rock technogenic media has been developed; it is aimed at recovery of mineral losses, restoration of the environment at the territory of mining enterprises by means of rock mass extraction, its processing and redistribution for the purposes of land recultivation and landscape restoration. Classification of dry ore-containing hard rocks of dumps has been developed; that has made it possible to improve technological scheme of the processing of rock mass from technogenic media, emphasize its variants of use, and specify the required facilities and their productivity. Scientific value of the paper is in determining the effect of changes in the losses in pre-processing dry wastes upon the yield of industrial product and wastes; the effect has demonstrated that the yield of industrial product is in polynomial dependence upon the pre-processing losses while yield of tailings is in the power dependence. Practical implications of the paper are in the fact that the proposed method helps form mesorelief with the properties close to the natural one. The method involves restoration of the initial landscape with the help of opening hard rocks followed, completed by laying water-bearing and potentially fertile layers.

scholarly journals Empirical and finite element based stability analysis of highway cut slopes in Uttarakhand Himalayan terrain, India

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hari Om Singh ◽  
Tariq Anwar Ansari ◽  
T. N. Singh ◽  
K. H. Singh
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Rock Mass ◽  
Stability Analysis ◽  
Slope Stability ◽  
Kinematic Analysis ◽  
Empirical Methods ◽  
Geotechnical Data ◽  
Cut Slopes

AbstractThe present paper deals with different empirical methods and finite element method of slope stability analysis along National Highway (NH)-7, in Uttarakhand, India. The highway is only path in the hilly terrain of Lesser Himalayan for the public transport and have strategic importance due to militaries possession routes. This route is also significant due to having many holistic places, connecting to this. There was numerous landslides happened along the Highway in past due to various natural and anthropogenic activities. Hence, keeping an eye to the socio-economic development of the distant area, slope stability analysis is very crucial along the road cut sections. To identify the vulnerable locations and to collect the geotechnical data, the field investigation was carried out between Shivpuri to Byasi along NH-7 in Garhwal, Uttarakhand. Then geotechnical data was intended followed by rock mass characteristic, kinematic analysis and Qslope stability. Additionally, to review the stability results, numerical simulation (finite element method) was employed and slope mass behavior and failure mechanism of cut slopes were also evaluated. The rock mass characteristic and kinematic analysis illustrate normal and good variety of rock mass mainly wedge mode with flexural toppling of failure. The slope mass rating, continuous slope mass rating and also Qslope stability analysis showed, road cut slopes are critically stable and unstable. The results of different empirical methods shows a decent correlation between them. Further the numerical simulation analysis also evaluates that two cut slopes are unstable and other one is critically stable. This substantial empirical and numerical analysis of cut slopes provides a collective approach to stable and develop the holistic road corridor in Himalayan terrain.

scholarly journals Analysis of engineering geology conditions based on the quality of rock mass in the Tiga Dihaji Dam’s diversion tunnel, South Sumatera, Indonesia

2021 ◽  
Vol 325 ◽  
pp. 05001
Author(s):  
Zekrinaldi ◽  
Ferian Anggara ◽  
Hendy Setiawan
Keyword(s):  
Rock Mass ◽  
Geological Strength Index ◽  
Strength Index ◽  
Diversion Tunnel ◽  
Rock Mass Quality ◽  
Geological Conditions ◽  
Q System

This research has examined the rock mass quality case study in the Tiga Dihaji Dam’s diversion tunnel. Observations of geological conditions were carried out on the surface and subsurface of the study site and show that the study area consists of tuffaceous sandstone and carbonate interbeds. The method of this study is based on the classification of the Geological Strength Index (GSI), Rock Mass Rating (RMR), and the Q-system. The results indicate that tuffaceous sandstone has a GSI value of 15 - 87.5 (very poor - very good), RMR 48 - 82 (fair - very good), and Q-system 0.01 – 60.0 (exceptionally poor - very good). Meanwhile, carbonate interbeds have a low value, with a GSI value of 10.5 - 77.5 (very poor to very good), RMR 17.0 – 56.0 (very - poor fair), and Q-system 0 - 35.2 (exceptionally poor - good). Moreover, a correlation was made between rock mass quality for conditions in the study area. The correlation between GSI and RMR was obtained by the equation GSI = 2.2885RMR 82.567 (R2 = 0.6653), RMR and Q-system RMR = 2.0175ln(Q) + 63.061 (R2 = 0.4987), and GSI and Q-system GSI = 7.2119ln(Q) 54.578 (R2 = 0.8095).

Seepage Numerical Simulation Methods of Hard Fractured Rock Mass

2013 ◽  
Vol 423-426 ◽  
pp. 1330-1333
Author(s):  
Gang Lei
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Permeability Coefficient ◽  
Hard Rock ◽  
Fractured Rock ◽  
Triaxial Compression ◽  
Equivalent Plastic Strain ◽  
Simulation Method ◽  
Numerical Simulation Methods ◽  
Fissure Water

According to the seepage action of hard rock fissure water, a numerical simulation method is proposed in this paper. The basic mechanical properties for rock mass changed significantly during the process of secondary stress adjustments, and the rock deterioration constitutive model (RDM) can accurately reflect both the abruptness of the rock yield failure and the changes of mechanical parameters after yield. On the basis of RDM, the permeability coefficient with equivalent plastic strain function was introduced in this method which can update the permeability coefficient, and carried out numerical simulation on hard rock fissure water seepage action by FLAC3D. The results of the seepage triaxial compression experiment proved the rationality of the method.

Research on Optimization of Excavating Seguence for Dawangou Tunnel

2013 ◽  
Vol 353-356 ◽  
pp. 3703-3706
Author(s):  
Chang Yu Jin ◽  
Pan Pan Zhao ◽  
Chun Fu Xiang ◽  
Zi Feng Xia ◽  
Long Bin Dong ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Numerical Analysis ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Brittle Failure ◽  
Hard Rock ◽  
Local Energy ◽  
Change Trend

In response to the limitation of conventional index for stability and optimal design of underground rock mass engineering. The new evaluating indicator, local energy release rate, which can analysis the energy release intensity in the process of the brittle failure of hard rock is used in numerical analysis. Numerical simulation of construction sequence was studied for Dawangou tunnel using energy release rate index and a new constitutive model reflecting the brittle failure of hard rock. Based on the change trend of energy release rate, rock displacement and plastic zone, an optimization excavation is suggested. The optimal excavating sequence could serve as reference in the design and construction.

scholarly journals Numerical Simulation on Zonal Disintegration in Deep Surrounding Rock Mass

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Xuguang Chen ◽  
Yuan Wang ◽  
Yu Mei ◽  
Xin Zhang
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Model Test ◽  
Surrounding Rock ◽  
Geometric Progression ◽  
Zonal Disintegration ◽  
Forming Process ◽  
Fractured Zones ◽  
High Geostress ◽  
Zonal Disintegration Phenomenon

Zonal disintegration have been discovered in many underground tunnels with the increasing of embedded depth. The formation mechanism of such phenomenon is difficult to explain under the framework of traditional rock mechanics, and the fractured shape and forming conditions are unclear. The numerical simulation was carried out to research the generating condition and forming process of zonal disintegration. Via comparing the results with the geomechanical model test, the zonal disintegration phenomenon was confirmed and its mechanism is revealed. It is found to be the result of circular fracture which develops within surrounding rock mass under the high geostress. The fractured shape of zonal disintegration was determined, and the radii of the fractured zones were found to fulfill the relationship of geometric progression. The numerical results were in accordance with the model test findings. The mechanism of the zonal disintegration was revealed by theoretical analysis based on fracture mechanics. The fractured zones are reportedly circular and concentric to the cavern. Each fracture zone ruptured at the elastic-plastic boundary of the surrounding rocks and then coalesced into the circular form. The geometric progression ratio was found to be related to the mechanical parameters and the ground stress of the surrounding rocks.

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