The Medeo mudflow-protection dam

Gerasimov, G. B.; Zinevich, Yu. N.; Shapovalov, G. I.

doi:10.1007/bf02307469

Cited by 4 publications

(3 citation statements)

References 3 publications

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“…This technology was mainly developed in the Soviet Union and in China; it was expected to be more cost-efficient than other dam construction methods, especially if applied in high (remote) mountain areas (Adushkin 2011). The most famous example is the Medeo dam that was constructed in the 1960s to protect the city of Alma Ata from debris flows: it actually did so in 1973 (Nedriga et al 1978;Gerashnov et al 1979). Other examples are the Baipaza HPP dam in Tajikistan (1968), the Ak-Su dam in Dagestan (1972), the Burlykia (1975) and Uch-Terek (1989) experimental dam in Kyrgyzstan and some others presented in Adushkin (2011).…”

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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“…one for the permanent service spillway, and the other for the emergency'-maintenance spillway [5]. Two tunnels were built for the first of the above-mentioned shafts and three for the second.…”

Section: Udc 62783mentioning

confidence: 99%

Multistage whirlpool shaft spillways

Slisskii¹,

Kuznetsov²,

Akhmedov³

1980

Hydrotechnical Construction

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In the construction of high-head hydraulic developments, the discharge of water to the downstream slde is effected from different reservoir levels through multistage spillways. If the hydraulic development has an earth dam, then the spillway for each level, with the intake below the normal pool level (NFL), uses a tunnel. The upper level spillway may also be a tunnel. All these spillways are either connected to a single tunnel (Chirkey hydraulic development) or carried separately to the downstream side (Fig. 1).The total length of the tunnels of a multistage spillway system may be reduced if the lower tunnel portions of the different levels are connected into a single tunnel by means of a shaft. In this case it is necessary to ensure hydraulically favorable (impactless) conditions of joining of the flows at their confluence in the shaft.A design ensuring impactless entry of flow from horizontal or inclined tunnels into a shaft (proposed by S. M. Slisskii) was investigated at the Hydraulic Structures Department of the V. V. KulbyshevMoscow Civil Engineering Institute (MISI) and at the '~aznii~nergeti-ka" Laboratory. One of the alternatives was used at the high avalanche protection Medeo dam, a schematic of the spillway of which is shown in Fig. ic.For impactless jolnln E of the flow from the tunnel with the flow in the shaft, the following solutions have been proposed: i. Each tunnel-shaft junction is constructed in the form of a spiral chamber, from which the water enters the shaft by rotating around the shaft axis. Under the action of the centrifugal forces, the water spreads over the shaft walls, forming an air core, and moves downward alon E a spiral having an increasing pitch.In comparison wlth the radius of the upper portion, the shaft radius below the spiral chamber is made larger by an amount equal to the thickness of the water layer spread over the shaft walls. Since the stream diameters in the shaft above the spiral chamber and the air core below the spiral chamber are equal, impactless joining of the flows is ensured.The inlet part of the shaft in this case may be constructed in the form of a circular welt or of a splral chamber [1][2][3][4]. In the first case, translational and rotational flows are joined, and, in the second, flows rotating in one or different sides are joined.2. The tu~el (free-flow or pressure) is connected to the shaft in such a way that the external tunnel wall is tangent to the shaft wall (Fig. 2). The flow within the limits of the shaft spreads over its walls and moves downward along the spiral. In the shaft center, an air core remains, whichmay be filled with the flow coming from above. A spillway of this type may be called a tangential spillway.For study of the hydraulics of tangential spillways, the flow was fed to the shaft through both an inclined conduit (MISI model) and a horizontal conduit ("Kaznii~nergetlka" model). Depending on the presence or absence, in the shaft, of flow coming from above, the nature of its motion (translational or rotational), the type of motion (fr...

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“…Then partial compression of the water containing the dissolved gas occurs [3,4]. The deformations corresponding to this process occur almost instantaneously --during the first several seconds after the load is applied to the soil.…”

Section: >'mentioning

confidence: 99%