Dam construction by blasting

Petrov, G. N.; Reifman, L. S.; Khusankhodzhaev, F. Z.

doi:10.1007/bf02378065

Cited by 5 publications

(2 citation statements)

References 1 publication

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“…Figure 4a). Petrov et al (1975) and Adushkin (2000Adushkin ( , 2011 highlight the advantages of blast-fill dams compared to traditional rock-fill dams: blast-fill dams are generally less susceptible to inner erosion due to the presence of both fine-and very coarse-grained material created by the blast and they are considered to be more stable, especially in seismic conditions. Korchevsky et al (2011) explain the latter characteristic through analogy with natural rockslide dams that proved to be very stable (using examples mainly from the Tien Shan) -probably also due to the mixture of fine-and coarse-grained material contributing to a larger resistance to friction when experiencing high amplitude shaking.…”

Section: Blast-fill Damsmentioning

confidence: 99%

The Kambarata 2 blast-fill dam, Kyrgyz Republic:blast event, geophysical monitoring and dam structure modelling

Havenith

Torgoev²,

Torgoev

et al. 2015

GEOENVIRON DISASTERS

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Background: The blast-and earth-fill dam of the Kambarata 2 hydropower station is situated in the seismically active Central Tien Shan region of the Kyrgyz Republic. More than 70% of the dam volume was produced during a blast event on December 22, 2009. In 2010-2011, dam construction was completed after earth filling on top of the blasted material and installing concrete and clay screens together with bentonite grouts. A geophysical survey had been completed in 2012-2013, mainly to monitor the resistivities inside the dam. Results: The geophysical survey completed on the Kambarata 2 dam site showed lower resistivity zones in the earth fill and relatively higher resistivities in the blast-fill material. Topographic, geophysical and piezometric inputs had been compiled within a 3D geomodel constructed with GOCAD software. This model was compared with the design structure of the dam in order to define the upper limits of the underlying alluvium, the deposited blast fill, earth fill and top gravel materials (represented by the dam surface). The central cross-section of this model was extrapolated over the full length of the main dam profile. Conclusions: On the basis of a calibrated hydrogeological model and known geomechanical properties of the materials, dam stability calculations were completed for different scenarios considering different reservoir levels and varying seismic conditions. Some of these scenarios indicated a critical vulnerability of the dam, e.g., if impacted by a horizontal seismic acceleration of Ah = 0.3 g and a vertical seismic acceleration Av = 0.15 g, with an estimated return period of 475 years. As a general conclusion, it was noted that this case study can be used as an example for surveys on much larger natural -landslide or moraine -dams. A series of geophysical methods (e.g., electrical and electro-magnetic techniques, seismic and microseismic measurements) can be applied to investigate even very deep dam structures. These methods have the advantage over classical direct prospecting techniques, such as drilling, of using equipment that is much lighter and thus more easily transportable and applicable in difficult terrain. Furthermore, they can provide continuous information over wider areas. This specific application to a blast-fill dam allows us to better outline the strengths and weaknesses of the exploration types and geomodels as a series of investigated parameters can be verified more easily than for natural dams.

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Section: Blast-fill Damsmentioning

confidence: 99%

The Kambarata 2 blast-fill dam, Kyrgyz Republic:blast event, geophysical monitoring and dam structure modelling

Havenith

Torgoev²,

Torgoev

et al. 2015

GEOENVIRON DISASTERS

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“…This concept is verified by the service experience of the above-menNoned existing avalanche dams and the results of experimental blasts, which testify to the stability of the basic geotectmical characteristics of blasted avalanches, viz., high density and piping stability. These properties are increased with the magnitude of the blast, the drop of the rock into place, and the dimensions of the resillting fill, insofar as they depend mainly on the compression of the roekfiU upon falling [2].…”

mentioning

confidence: 99%

Blast-placed membraneless rockfill dams for hydropower schemes

Bakhtiyarov¹,

Kornakov²,

Korchevskii³

1976

Hydrotechnical Construction

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One of the most widespread typesofdam adopted in the construction of hydropower schemes in mountain regions is the rockfill dam built from local natural materials. For dam heights of the order of 250-350 m, the fill volumes become very large (50-120 million m s) and the construction of such hydropower schemes requires very high capital and labo~ inputs. For these dams the problems of reducing the cost and time of construction have not been wholly solved. Therefore, the development and application of fundamentally new and progressive design and construction technologies for high earth and earth-and-rockfill dams must become the principal trend in dam construction in mountain regions. In the construction of dams from local materials the following two stages stand out [1]:Stage I. Foundation preparation, which is accompanied by the driving of diversion tunnels and construction of cofferdams, dewatering of the river bed, cleaning the excavation on the area of contact between the foundsdon and the water-retaining elements of the dam (core or membrane), and blanket and curtain grouting.Stage 1I. Construction of the dam prism, including work on the winning of materials from quarries, the mechanical processing of material suitable for placement in the water-retaiuing elements of the dmaa; transport of the excavated and processed materials from quarries and plant to the dam; and the dumping, spreading, and compaction of the various materials in the dam prism.The execution of the above-mentioned interrelated works, where the dam dimensions are increased and the construction operations are shifted deep into mountainous regions, is rendered substantially more complex owing to the difficult access conditions in narrow gorges. The steepness of the slopes complicates the development of quarries for the dam rockfill, and the substantial distance of the loam, gravel and sand borrow pits from thedamsite gorge, located in the main rock massif, give rise to high haulage costs. The difficulties are aggravated immeasurably by the low capacity of modern transport equipment in comparison withthe growing volumes of dams. Furthermore, the construction of a high rockfill dam of traditional type necessitates the driving of a large number of special transportation and auxiliary tunnels and various types of shafts, whose total length together with the hydraulic tunnels can amount to 35-40 km (e.g., at the Nurek and Rogun hydropower schemes). The combination of these factors causes a marked increase in the length and complexity of the communication services, the fleetsofmechanical and service plants, the number of personnel, the volume of design work for items in the work areas and the township.The unfavorable effect of the above-mentioned factors is markedly reduced where dams are constructed by directional blasts. This method, which is the most expedient under poorly accessible, mountainous conditions, enables large economies to be effected by a single heave of the whole voktme of construction material into the dam prism by means of explosiv...

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