Innovation structures of very lean roller compacted concrete dams

Over the past 20 years, rolled compacted concrete (RCC) dams have continued to be built in many countries because of their technical and economic advantages over conventional dams of vibrating concrete and embankment dams. The aim of this study is the development of new structural and technological solutions in RCC dams in order to reduce the consumption of cement and expand their use on non-rock foundations, which will allow them to successfully compete with concrete face rockfill dams. The numerical analyses of static and seismic stress-strain state (SST) of gravitational dams in roller compacted very lean concrete dams have been made, as well as their stability, strength and cost have been assessed. For rock and dense sandy-gravel foundations the most economical is the concrete face rockfill dam and symmetrical RCC dam of very lean concrete with bases (0.5-0.7) of both slopes and outer zones of conventional concrete and central zone of rockfill strengthened by cement-ash mortar. Taking into account that the cost of diversion and spillway tunnels for very lean RCC dam will be less and the construction period - shorter than for the concrete face rockfill dam, it can be concluded that variant of symmetrical RCC dam of very lean concrete is the technically and economically effective. Symmetrical RCC dams of very lean concrete with 1V/(0.5-0.7)H slopes have more seismic resistance and technical and economic efficiency as compared with conventional gravitational RCC dams and other types of dams. These dams up to 200 m high can be built on rock foundations and up to 100 m high - on dense sandy gravel foundations.

Experimental Centrifuge Study of the Effects of Valley Topography on the Behavior of a Concrete Face Rockfill Dam

The recent focus on water conservancy projects globally has resulted in the construction of increased numbers of concrete face rockfill dams in narrow valleys. However, valley topography impacts the deformation of a dam and further influences the distribution of stress and position of cracks on the face slab. This study conducted two centrifuge experiments to study the influence of the valley topography on the behavior of a concrete face rockfill dam from construction to impoundment. Experimental models of concrete face slab sand-gravel dams with “U”-type and “V”-type valley topographies were established. The settlement of the dam crest, the displacement of the upstream slope of the dam, and the stress on both sides of the face slab were observed. The experiment also represented the cracking of the face slab during impoundment. The results showed that the “V”-type valley topography effectively reduced the progression of dam crest settlement and influenced stress on the slab resulting from impounded water pressure. Furthermore, the flexural form of the face slab in the “U”-type valley topography took on a “D” shape and cracks progressively developed on the face slab with increased water load. The flexural form of the face slab in the “V”-type valley topography showed a “B” shape, and cracks occurred under a particular water impoundment pressure.

Subsurface Topographic Modeling Using Geospatial and Data Driven Algorithm

Infrastructures play an important role in urbanization and economic activities but are vulnerable. Due to unavailability of accurate subsurface infrastructure maps, ensuring the sustainability and resilience often are poorly recognized. In the current paper a 3D topographical predictive model using distributed geospatial data incorporated with evolutionary gene expression programming (GEP) was developed and applied on a concrete-face rockfill dam (CFRD) in Guilan province- northern to generate spatial variation of the subsurface bedrock topography. The compared proficiency of the GEP model with geostatistical ordinary kriging (OK) using different analytical indexes showed 82.53% accuracy performance and 9.61% improvement in precisely labeled data. The achievements imply that the retrieved GEP model efficiently can provide accurate enough prediction and consequently meliorate the visualization insights linking the natural and engineering concerns. Accordingly, the generated subsurface bedrock model dedicates great information on stability of structures and hydrogeological properties, thus adopting appropriate foundations.