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.

Study on Crack Resistance of Hydraulic Roller Compacted Concrete Dam with Fly Ash Admixture

With the continuous improvement of the level of construction industry in modern industry, at the same time, the requirements of the construction industry for the crack resistance of concrete dams are also higher and higher. In the preparation stage of the experiment, the corresponding experimental materials and equipment are provided. In order to ensure that the concrete can meet the requirements of workability and strength grade, the proportion of materials is designed; During the experiment, the activity characteristics of fly ash admixture are extracted, the particle size distribution of admixture is tested, and the fracture data of hydraulic RCC dam is monitored; The experimental results show that when the ratio of cement and fly ash is 0.7:0.1, the number, width and area of concrete cracks are the minimum, which proves that the fly ash admixture under this ratio is more suitable for construction engineering.

Mesoscopic Simulation Method for Uniaxial Compression Test of RCC Dam Material Based on DEM

The roller compacted concrete (RCC) dam has become one of the most competitive dam types due to its fast construction speed, low cost, and strong adaptability. However, the macroscale compaction test can hardly reflect the mesoscopic structure on the RCC’s rolling characteristics. According to the characteristics of RCC dam materials, a numerical discrete element method (DEM) is proposed in this paper, which is used to simulate the irregular shape and proportion of RCC aggregates. Moreover, a mesoscopic parameter inversion method based on the adaptive differential evolution (ADE) algorithm is proposed to enhance the efficiency of model contact parameters determination and overcome the inconvenience and time-consumption of conventional methods. Compared with the physical test, the simulation compression curve has good consistency with the physical test curve, and the proposed method can adequately reflect the physical and mechanical properties of RCC dam materials, which provides a basis for the subsequent research on the properties of RCC dam materials under different filling times.