scholarly journals Design Methodology for Grout Curtains Under Dams Founded on Rock

2021 ◽  
Author(s):  
Suihan Zhang ◽  
Fredrik Johansson ◽  
Håkan Stille
Keyword(s):  
Rock Mass ◽  
Design Methodology ◽  
Grout Curtain ◽  
Internal Erosion ◽  
Rock Foundation ◽  
Empirical Methods ◽  
Dam Foundation ◽  
Time Estimates ◽  
Grout Spread ◽  
Hydraulic Jacking

AbstractGrout curtains are commonly constructed under dams to reduce the seepage through the rock foundation. In the design of grout curtains, empirical methods have mainly been used since the introduction of dam foundation grouting. Although empirical methods have been used with success in several projects, they have their limitations, such as poor control of the grout spread, only an indirect consideration of the threat of internal erosion of fracture infillings in the grouted zones, and the risk of hydraulic jacking. This paper presents a theory-based design methodology for grout curtains under dams founded on rock. In the design methodology, the grout curtain is designed as a structural component of the dam. The risk of erosion of fracture infilling material is explicitly accounted for along with the reduction of the hydraulic conductivity of the rock mass, and an optimization of the total uplift force. By applying the proposed design methodology, engineers can create a design better adapted to the prevailing geological and hydrogeological conditions in the rock mass, resulting in more durable grout curtains. The proposed methodology also enables cost and time estimates to be calculated for the grout curtain’s construction. Applying the principles of the observational method during the grouting execution also allows the design to be modified via predefined measures if the initial design is found to be unsuitable.

scholarly journals Engineering geological behaviour of recent conglomerate deposits in dam foundation. The case of Agiokampos dam in Thessaly, Cen- tral Greece.

2013 ◽  
Vol 47 (4) ◽  
pp. 1759
Author(s):  
V. Marinos ◽  
S. Lazaridou ◽  
V. Perleros ◽  
K. Sotiropoulou
Keyword(s):  
Rock Mass ◽  
Bearing Capacity ◽  
Grout Curtain ◽  
Back Analysis ◽  
Internal Erosion ◽  
Diaphragm Wall ◽  
Strength Parameters ◽  
Dam Foundation ◽  
Surficial Zone ◽  
Cementing Material

A typical example of dam foundation on Neogenic conglomerate deposits is presented in this paper. The case of Agiokampos dam in east Thessaly in central Greece. The level of natural compactness and the nature of the cementing material are crucial elements for the strength, the bearing capacity and the permeability of these formations. These conglomerates of medium consistency, do not allow relying on traditional sampling and tests in the boreholes. Lugeon tests are meaningless and falling head tests are recommended. Back analysis on slopes is certainly a useful tool for approaching the strength parameters of the global rock mass. Thus it is understood that the engineering geological assessment before any testing and analysis is of prime importance.Due to the fine nature of the cement, permeability is generally low and no leakages are expected. However, an impermeable grout curtain must be created due to some higher values. Conglomerates are not easily groutable and a combination of a diaphragm wall is suggested. Finally, a carpet grouting is designed since the surficial zone is susceptible to internal erosion.

Comparison of Permeability and Groutability of Ostur Dam Site Rock Mass for Grout Curtain Design

2012 ◽  
Vol 46 (2) ◽  
pp. 341-357 ◽  
Author(s):  
S. M. Sadeghiyeh ◽  
M. Hashemi ◽  
R. Ajalloeian
Keyword(s):  
Rock Mass ◽  
Grout Curtain ◽  
Dam Site

3-D fracture network dynamic simulation based on error analysis in rock mass of dam foundation

2018 ◽  
Vol 25 (4) ◽  
pp. 919-935 ◽  
Author(s):  
Deng-hua Zhong ◽  
Han Wu ◽  
Bin-ping Wu ◽  
Yi-chi Zhang ◽  
Pan Yue
Keyword(s):  
Rock Mass ◽  
Error Analysis ◽  
Dynamic Simulation ◽  
Fracture Network ◽  
Network Dynamic ◽  
Dam Foundation ◽  
Simulation Based

scholarly journals Geophysical Evaluation of the Inner Structure of a Historical Earth-Filled Dam

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 664 ◽  
Author(s):  
David Zumr ◽  
Václav David ◽  
Josef Krása ◽  
Jiří Nedvěd
Keyword(s):  
Electrical Resistivity ◽  
Geophysical Methods ◽  
Seepage Flow ◽  
The Body ◽  
Internal Erosion ◽  
Dam Foundation ◽  
High Resolution Data ◽  
15Th Century ◽  
Ground Penetrating ◽  
Non Destructive

Small earth dams usually lack the detailed seepage monitoring system that would provide high resolution data on changes in seepage flow. Alternative solution is monitoring of the temperature and electrical resistivity in the body of the dams. Geophysical methods are useful techniques for a non-destructive exploration of the subsurface. We have utilized the combination of electrical resistivity tomography (ERT), ground penetrating radar (GPR) and multi-depth electromagnetical conductivity meter (CMD) techniques to observe the inner structure, especially internal failures, of the historical earth-filled dams. Longitudinal and transversal profiles of four typical fishpond dams in the Czech Republic were measured within this research. The dams were constructed as early as in the 15th century, some of them went through minor reconstruction. The aim of the application of geophysical methods for investigation of old fishpond dams was to detect and localize the boundary of the dam foundation, new earth material from the reconstruction works, cone of water depression, technical objects location, potential internal erosion, cavities, inhomogeneity in the water content pattern and any other anomalies. The primary results show that the ERT is suitable to observe the dam stratification, dam foundation, bedrock below the dam and large anomalies. GPR is suitable for small objects and anomalies detection in the shallow depths.

A Study on Three-Dimensional Seepage of Dam on the Deep Pervious Fracture Rock Foundation

2012 ◽  
Vol 542-543 ◽  
pp. 1061-1064
Author(s):  
Hai Tao Mao ◽  
Xiao Ju Wang
Keyword(s):  
Finite Element ◽  
Fractured Rocks ◽  
Three Dimensional ◽  
Rock Foundation ◽  
Range Limit ◽  
Fracture Rock ◽  
Seepage Field ◽  
Dam Foundation ◽  
Flow Through ◽  
Hydro Project

The theme of this paper concentrates on hydro- projects’ seepage field in rocks, including the properties of the seepage which flow through both hole qualitative like rocks and fractured rocks. Present the finite element analyzing program which can solve the problem of three dimensional seepage field in hole qualitative rock medium. Apply the program some hydro-project, computed the seepage field in the dam foundation and dam abutments. Besides, further research is done on the decision of the model range limit. And the influence of the pariah shape.

Design Methodology to Evaluate Hydraulic Jacking in Pressure Tunnels

IFCEE 2018 ◽  
2018 ◽  
Author(s):  
Mohammad Moridzadeh ◽  
Peter Dickson
Keyword(s):  
Design Methodology ◽  
Hydraulic Jacking

Seepage Regime in Canyon Mass With Influence of Water-Storage Reservoir Impoundment Speed

2008 ◽  
Author(s):  
M. Kalabegishvili
Keyword(s):  
Rock Mass ◽  
Water Level ◽  
Peak Load ◽  
Water Storage ◽  
Energy System ◽  
Arch Dam ◽  
Dam Foundation ◽  
Storage Reservoir ◽  
Functional Relations ◽  
Nonstationary Field

Generally, most waterpower plants have to function under energy system peak load operation. Thus, there is a relatively quick water level variation observed in water-storage reservoirs, which contributes to the problems, especially in case of high-pressure waterworks facilities. Swift reservoir draw-down enhances seepage volumetric forces acting from the rock mass, which may lead to rock mass cracking and eventually to the development of landslide processes. A rapid impoundment of the water-storage reservoir is no less damaging. In this case, seepage in the rock mass is progressing in non-steady conditions, there occurring, in the inception stage: - high magnitude seepage hydrodynamic forces at the rock mass surface, creating additional loads on the rock mass, causing deflection of its surface, which may promote dam-foundation contact opening; - with increased pore pressures and seepage gradients, there may occur suffusion and other undesirable processes in the rock mass. In the work is given a numerical analysis of some parameters of seepage mode given based on right-bank investigation admitting presence of break in the dam filling-up mode. Options of time-intervals for the two basic versions – in case of sudden rising of water level in the upstream and in case of slow filling-up and setting up steady-state seepage mode in the massive – are being discussed. Determination of seepage flow parameters (including gradients) requires nonstationary field task to be solved. Finite-elements approximation for time analysis of the task is solved by finite-difference scheme. Seepage calculations are carried out by cyclic-iteration scheme – where volumetric water content, hydraulic conductivity and elasticity module determined numerically by functional relations. The subject of research is Enguri waterpower plant arch dam, at present the highest in the world (Georgia, height 271.5m, fig. 1.1). Consideration is being given to a variety of cases: - canyon slope in the zone of major geological fracture; - foundation in the central part of the dam.

scholarly journals Stability of a rock mass using the key block theory: a case study

2020 ◽  
Vol 150 ◽  
pp. 03024
Author(s):  
Y. Zerradi ◽  
A. Lahmili ◽  
M. Souissi
Keyword(s):  
Rock Mass ◽  
Underground Mines ◽  
The Finite Element Method ◽  
Empirical Methods ◽  
Mining Operations ◽  
Initial Equilibrium State ◽  
Eastern Zone ◽  
Geometrical Data ◽  
Key Block

In underground mines, excavating disturb the initial equilibrium state of the rock mass, and therefore require selection of a support in order to control the movement of rocks, avoid landslide and work safely. Thus, the progress of mining operations in the ST2 mineralization, in the eastern zone of the Bouazzer mine, is disrupted because of stability problems. On the basis of field observations and analyzes of core drill, the geological and structural study, carried out in this area, has shown the existence of three types of facies: altered and cracked diorite, cobaltiferous mineralization which is in contact with serpentinites. In fact, the empirical methods such as Barton, Bieniawski and the recommendations of the AFTES have qualified the rock mass as poor, furthermore they proposed as kind of supports: steel arches, shotcrete and rock-bolts. Numerical simulation by the finite element method proved to be very complex due to existence of several types of discontinuities (faults, shistosities and joints).These discontinuities are natural fractures that delimit various shapes and sizes of wedges, which can become detached from the roof or siding of the excavation and collapse under their own weight. Although the empirical methods cited above provide supports for each facies, however, this support is expensive and difficult to implement in practice because it must cover the entire surface of the excavation and thus not allowing to detect stable blocks that do not require a support. For this it was essential to carry out an analysis of wedges to better locate unstable blocks. The treatment of fracturing data has highlighted the presence of five sets of discontinuities of which three sets are principals and the other two are minor joints. Then, while taking into account the geometrical, mechanical data of the discontinuities as well as the geometrical data of the excavation, we were able to detect the shape and the size of the unstable blocks and the sets of discontinuities delimiting them and which favor their sliding and tilting. Thus, we calculated the number of anchor bolts needed to stabilize these blocks in order to ensure an acceptable safety factor. This study shows clearly how a wedge analysis of the rock mass can guide and optimize the support work.

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