Utilisation of Data Derived from Large-Scale Experiments and Study of Natural Blockages for Blast-Fill Dam Design

Recent technological and methodological advances for the investigation of landslide dams

“…Several studies report consistent changes in geotechnical properties with depth within the dam. Compressed rock density in a blast-fill dam increases from ~1.7 tons/m 3 near the surface to just over 2.0 tons/m 3 at depth (Korchevskiy et al, 2011). The Val Pola rockslide in Italy shows progressive decrease of hydraulic conductivity from 10 -3 m/s near the top to 10 -6 m/s at 70 m depth, though the data scatter at similar depths is around two orders of magnitude (Crosta et al, 2010).…”

“…Post-emplacement modifications, such as self-compaction under overburden, precipitation of minerals, inflow of fine sands and clays, or debris fans forming at the downstream face can alter dam permeability, erodibility, and overall material strength. Korchevskiy et al (2011), for example, observed a decrease in seepage through the Burlykiya blast-fill dam during the first month after dam formation at constant lake level, and attributed this to the natural formation of reverse filters due to transfer of fine particles within the dam.…”

“…Over time, weathering, mineralization and cementation influence the performance of dams. Korchevskiy et al (2011;p. 625) summarize that "siltstone, mudstone, sandstone and conglomerate with clayey and carbonate-clayey cement and some varieties of shale and gneiss undergo rapid and intense weathering", which can lead to density heterogeneities and a high infiltration gradient, and may increase the potential for piping and internal erosion.…”

“…Much can be learned from the study of artificial dams or from the construction and analysis of blast-fill dams. In blast-fill dam design, the dams are essentially treated as deposits with two zones of contrasting permeability: the upper carapace and the body (Adushkin, 2006;Adushkin, 2011;Korchevskiy et al, 2011). Reservoir levels are recommended to be kept below the facies transition because "the abrupt difference between the permeability of the upper and lower parts may lead to internal erosion if high discharge through the void spaces in the carapace directly affects the underlying comminuted debris" (Korchevskiy et al, 2011;p.…”

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

“…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.…”