scholarly journals Analysis of rock mass behavior with Empirical and Numerical method for the construction of diversion tunnel, Laos

2022 ◽  
Vol 1212 (1) ◽  
pp. 012028
Author(s):  
D J W Mboussa ◽  
S Sun
Keyword(s):  
Numerical Modeling ◽  
Rock Mass ◽  
Field Investigation ◽  
Geological Strength Index ◽  
Rock Masses ◽  
Mountain Area ◽  
Diversion Tunnel ◽  
The Stability ◽  
The Cost ◽  
The Impact

Abstract Tunneling construction in the mountain area is a challenge for engineers and geotechnicians because of instability due to the presence of discontinuities. The objective of this paper is the modeling of surrounding rock masses for the stability of the diversion tunnel to predict the behavior of rock masses during the excavation process for the Nam Phoun hydropower station project in Laos. Field investigation and laboratories test was realized; Empirical methods as Rock mass designation and Geological Strength Index were performed, rock masses were classified in three categories (RM-1, RM-2, and RM-3); in situ stresses were obtained from existing equations, numerical modeling was performed by the 2D plane strain finite element code Phase2 developed by Rocscience, using Generalized Hoek-Brown criterion for each type of rock masses. The results of numerical modeling show the strength zones of stresses and deformations around the tunnel and predict the instabilities around the tunnel during excavations processes. Thus, for all rock’s masses, it will be necessary to consider an analysis for the supports design before the excavation’s process. The findings of this study allow a clearer understanding of the importance to assess a predictive analysis of slope stability during the feasibility phase of a project by engineers to have an idea of instabilities and its significant in preventing the impact on the cost of the project.

The Stability Analysis of Over-Dip Stratoid Structure Rock Slope

2012 ◽  
Vol 446-449 ◽  
pp. 1963-1966
Author(s):  
Shu Qiang Lu ◽  
Mo Xu
Keyword(s):  
Rock Mass ◽  
Slope Stability ◽  
Rock Slope ◽  
Simulation Analysis ◽  
Limit Equilibrium ◽  
Field Investigation ◽  
Left Bank ◽  
Diversion Tunnel ◽  
Rock Mass Structure ◽  
The Stability

The rock mass structure of granite is massive, so the stability of granite slope is good. Massive rock become stratoid structure when the rock mass contain discontinuities such as joints and faults. The deformation and destruction of the slope rock mass is controlled by the behaviour and orientation of the discontinuities. Especially, the over-dip discontinuities controlled the slope stability. In this paper, based on the abundant field investigation on the slope in left bank diversion tunnel inlets of Nuozadu power station in Lancang River, the types of rock mass structures and the combination between structural planes and slope surface are studied in detail so as to analyze the slope deformation mechanism. Finally, the slope stability is researched systematically by limit equilibrium method and FLAC numerical simulation analysis. A set of technical and methodological system on stability research of over-dip stratoid structure rock slope will hoped to be established.

Liberalization at Any Cost? Implications of IMF Policy for Sovereignty and Stability in East Asia

2000 ◽  
Vol 15 (1) ◽  
pp. 43-56
Author(s):  
Michael Spaulding
Keyword(s):  
East Asia ◽  
International Political Economy ◽  
Free Market ◽  
East Asian ◽  
Financial Governance ◽  
State Governance ◽  
The Stability ◽  
Cost Implications ◽  
The Cost ◽  
The Impact

Globalization pits pressures for liberalization against state claims to political and economic sovereignty. Less powerful states in particular face strong pressure from the international trade regime to liberalize their economies irrespective of the impact on domestic stability and national goals. East Asia has been a hold-out against the global trend toward liberalization. This paper shows that the bail-out package demanded by the IMF in 1997 during the East Asian financial crisis imposed unprecedented restrictions on state governance without regard for long-term implications. The paper argues that the IMF's motivation was to harmonize financial governance of the affected economies with Western practices. However, the cost of this initiative to the stability of the region has been overlooked. The East Asian region has carved out for itself a unique niche in the international political economy by resisting penetration of Western finance capital. Already governments have fallen and deep resentments have been sewn over the reversal. More seriously for the future, assumptions that free-market liberalism can be imposed top-down ignore the extent to which economic institutions and preferences are embedded in culture.

Fear Induced Stabilization in an Intraguild Predation Model

2020 ◽  
Vol 30 (04) ◽  
pp. 2050053
Author(s):  
Mainul Hossain ◽  
Nikhil Pal ◽  
Sudip Samanta ◽  
Joydev Chattopadhyay
Keyword(s):  
Growth Rate ◽  
Hopf Bifurcation ◽  
Intraguild Predation ◽  
Equilibrium Points ◽  
Stable Limit ◽  
Interior Equilibrium ◽  
The Rich ◽  
The Stability ◽  
The Cost ◽  
The Impact

In the present paper, we investigate the impact of fear in an intraguild predation model. We consider that the growth rate of intraguild prey (IG prey) is reduced due to the cost of fear of intraguild predator (IG predator), and the growth rate of basal prey is suppressed due to the cost of fear of both the IG prey and the IG predator. The basic mathematical results such as positively invariant space, boundedness of the solutions, persistence of the system have been investigated. We further analyze the existence and local stability of the biologically feasible equilibrium points, and also study the Hopf-bifurcation analysis of the system with respect to the fear parameter. The direction of Hopf-bifurcation and the stability properties of the periodic solutions have also been investigated. We observe that in the absence of fear, omnivory produces chaos in a three-species food chain system. However, fear can stabilize the chaos thus obtained. We also observe that the system shows bistability behavior between IG prey free equilibrium and IG predator free equilibrium, and bistability between IG prey free equilibrium and interior equilibrium. Furthermore, we observe that for a suitable set of parameter values, the system may exhibit multiple stable limit cycles. We perform extensive numerical simulations to explore the rich dynamics of a simple intraguild predation model with fear effect.

scholarly journals A natural experiment reveals the impact of hydroelectric dams on the estuaries of tropical rivers

2019 ◽  
Vol 5 (3) ◽  
pp. eaau9875 ◽  
Author(s):  
E. Ezcurra ◽  
E. Barrios ◽  
P. Ezcurra ◽  
A. Ezcurra ◽  
S. Vanderplank ◽  
...  
Keyword(s):  
Pacific Coast ◽  
Economic Consequences ◽  
Coastal Sediments ◽  
Coastal Protection ◽  
Hydroelectric Dams ◽  
Sediment Trapping ◽  
Tropical Estuaries ◽  
The Stability ◽  
The Cost ◽  
The Impact

We tested how sediment trapping by hydroelectric dams affects tropical estuaries by comparing two dammed and two undammed rivers on Mexico’s Pacific coast. We found that dams demonstrably affected the stability and productivity of the estuaries. The two rivers dammed for hydroelectricity had a rapid coastal recession (between 7.9 and 21.5 ha year−1) in what should otherwise be an accretional coastline. The economic consequences of this dam-induced coastal erosion include loss of habitat for fisheries, loss of coastal protection, release of carbon sequestered in coastal sediments, loss of biodiversity, and the decline of estuarine livelihoods. We estimate that the cost of the environmental damages a dam can cause in the lower part of basin almost doubles the purported benefits of emission reductions from hydroelectric generation.

Stability Analysis about the Impact of Soft Rock to the Underground Cavern Group

2013 ◽  
Vol 706-708 ◽  
pp. 560-564
Author(s):  
Yi Huan Zhu ◽  
Guo Jian Shao ◽  
Zhi Gao Dong
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Stability Analysis ◽  
Soft Rock ◽  
Element Model ◽  
Underground Excavation ◽  
Power Station ◽  
Excavation Process ◽  
The Stability ◽  
The Impact

Soft rock is frequently encountered in underground excavation process. It is difficult to excavate and support in soft rock mass which has low strength, large deformation and needs much time to be out of shape but little time to be self-stabilized. Based on a large underground power station, finite element model analysis was carried out to simulate the excavation process and the results of displacement, stress and plasticity area were compared between supported and unsupported conditions to evaluate the stability of the rock mass.

scholarly journals Engineering Gology Model of Bener Dam Diversion Tunnels in Geological Risk Disaster Mitigation

2020 ◽  
Vol 6 (3) ◽  
pp. 205-215
Author(s):  
Daru Jaka Sasangka ◽  
Dian Insani ◽  
I Gde Budi Indrawan
Keyword(s):  
Rock Mass ◽  
Laboratory Data ◽  
Poor Quality ◽  
Disaster Mitigation ◽  
Primary Data ◽  
Diversion Tunnel ◽  
Rock Mass Quality ◽  
The Difference ◽  
The Stability ◽  
Quality Type

The Bener Dam Diversion Tunnel Plan is located in Bener District, Purworejo Regency. Engineering geology mapping data, drillimg data and laboratory data used as primary data. Surface and subsurface analysis show that each rock unit has different index and mechanical properties. Generally, the rock mass quality conditions in the dam belonged to good Rock (80%) in the Rock Mass Rating (RMR) system (Bieniawski, 1989).  The other rock mass quality type also found among them fair rock (5%), poor rock (5%), and very poor rock (10%). Poor rock mass quality conditions were controlled by geological structures, especially faults that partially cut through the tunnel geometry. The very poor quality of rock mass was in the volcanic lens (loose sand material) did not cut through the tunnel path. The difference stand-up time of the rock on the tunnel requires proper mitigation (Nguyen Nguyen, 2015). The stand-up time belonged to the dangerous condition was in the fault zone with poor rock mass quality, while the lens with very bad rock mass quality did not affect the stability of the excavation of the tunnel.

scholarly journals A modeled radiological dispersive device release and the impact to decision-making in an urban environment

2020 ◽  
Vol 35 (4) ◽  
pp. 316-322
Author(s):  
Paulo Oliveira ◽  
Ubiratan Oliveira ◽  
Ricardo Stenders ◽  
Ademir Silva ◽  
Helio Vital ◽  
...  
Keyword(s):  
Decision Making ◽  
Early Stage ◽  
Radioactive Material ◽  
Sensitive Information ◽  
Training Environment ◽  
Stability Class ◽  
Radiological Dispersion Device ◽  
The Stability ◽  
The Cost ◽  
The Impact

A radiological dispersion device is a weapon that combines radioactive material with conventional explosives for spreading radioactive material across an inhabited area. This study is focused on evaluating key parameters in an radiological dispersion device scenario. The calculations were performed to include two different situations: by using explosives and by simple mechanical release. Simulations were conducted with the use of the HotSpot Health Physics Codes. The results suggest the existence of significant correlations between stability classes in scenarios where they evolve with time, producing alternations between them. As long as the stability class remains constant, this latter finding offers the possibility of creating a suitable response, based on temporal evolutions. Therefore, the purpose of this study is to: estimate the size of the potentially affected population, estimate absorbed doses, and estimate the cost-effectiveness in order to help initial responses by providing time-sensitive information about the event. A methodology capable of providing useful information allows prompt decisions and initial assessments of future risks to be made efficiently. This approach can also provide a training environment for the personnel responsible for the decision-making at an early stage of the response.

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).

scholarly journals Constraint Embankment Construction to Prevent the Collapse of Underground Caves

2019 ◽  
Vol 2019 ◽  
pp. 1-18
Author(s):  
Zhen Zhang ◽  
Zhongda Chen
Keyword(s):  
Tensile Strength ◽  
Rock Mass ◽  
Numerical Solutions ◽  
Geological Strength Index ◽  
Concrete Slabs ◽  
Construction Specifications ◽  
Reinforced Concrete Slabs ◽  
Local Construction ◽  
Embankment Height ◽  
The Stability

Dozens of underground karst caves were found before constructing the Changli highway. The thickness-to-span ratio of nearly half of the caves is less than 0.05, and the greatest ratio is only 0.35, far less than the value demanded by local construction specifications (0.8). The caves located at K50 + 700 and K178 + 800 are by far the only two caves that have become unstable. Only one passive measure was taken when constructing the highway, i.e., building 0.5 m thick continuous reinforced concrete slabs above the embankment; this measure did not contribute to the improvement of the stability of the underground caves. Numerical solutions based on strength reduction and analytical solutions based on the beam hypothesis are used to assess the stability of underground caves. The capacity of an underground cave to bear embankment construction is observed to be proportional to the tensile strength of the rock mass and the square of the thickness-to-span ratio of the cave roof. The tensile strength of the rock mass is ψ times lower than that of the intact rock. The value of ψ is mainly determined by the geological strength index (GSI). To prevent instability of underground caves, the embankment height should be reasonably controlled. However, local construction specifications requiring that the thickness-to-span ratio of underground cave be greater than 0.8 are conservative.

scholarly journals Rock Mass Rating and Geological Strength Index of rock masses of Thopal-Malekhu River areas, Central Nepal Lesser Himalaya

2013 ◽  
Vol 16 ◽  
pp. 29-42 ◽  
Author(s):  
Jaya Laxmi Singh ◽  
Naresh Kazi Tamrakar
Keyword(s):  
Rock Mass ◽  
Surface Condition ◽  
Geological Strength Index ◽  
Rock Mass Rating ◽  
Rock Slopes ◽  
Lesser Himalaya ◽  
Rock Masses ◽  
Strength Index ◽  
Rock Mass Structure ◽  
Exposed Rock

The rock slopes of the Thopal-Malekhu River areas, Lesser Himalaya, were characterized applying various systems of rock mass classification, such as Rock mass Rating (RMR) and Geological Strength Index (GSI), because the study area comprises well exposed rock formations of the Nawakot and Kathmandu Complexes, across the Thopal-Malekhu River areas. In RMR system, mainly five parameters viz. Uniaxial Compressive Strength (UCS) of rock, Rock Quality Designation (RQD), spacing of discontinuity, condition of discontinuity, and groundwater condition were considered. The new GSI charts, which were suitable for schistose and much disintegrated rock masses, were used to characterize rock slopes based on quantitative analysis of the rock mass structure and surface condition of discontinuities. RMR ranged from 36 to 82 (poor to very good rock mass) and GSI from 13.5±3 to 58±3 (poor to good rock mass). Slates (of the Benighat Slate) are poor rock masses with low strength, very poor RQD, and close to very close spacing of discontinuity, and dolomites (Dhading Dolomite) are fair rocks with disintegrated, poorly interlocked, and heavily broken rock masses yielding very low RMR and GSI values. Phyllites (Dandagaun Phyllite), schist (Robang Formation) and quartzite (Fagfog Quartzite, Robang Formation and Chisapani Quartzite), dolomite (Malekhu Limestone), and metasandstone (Tistung Formation) are fair rock masses with moderate GSI and RMR values, whereas quartzose schist and gneiss (Kulekhani Formation) are very good rock masses having comparatively higher RMR and GSI. The relationship between GSI and RMR shows positive and good degree of correlation. DOI: http://dx.doi.org/10.3126/bdg.v16i0.8882   Bulletin of the Department of Geology Vol. 16, 2013, pp. 29-42

Sign in / Sign up

Export Citation Format

Share Document