Sprayed Bentonite Technology for Sealing of Pond Dams

In this paper, the research focused on the evaluation of efficiency of sprayed bentonite as a sealing layer of pond dams is presented. The technology of sprayed bentonite was tested on the real scale model of the earth filled dam which was built as a section with the width of 3 m. The model of the dam was built as homogeneous of relatively permeable earth material and is equipped with the drain to monitor seepage water. Seepage water is collected in the shaft instrumented by the ultrasonic sensor to measure the water level. The facility is also equipped by the measurement of water level in the storage upstream of the dam. First, the seepage was measured through a dam without the sprayed bentonite sealing layer. Then, the bentonite layer was sprayed on the upstream face of the dam. The spraying technology was developed based on the similar technology for dry process of sprayed concrete. The technology including the special nozzle was developed at Czech Technical University in Prague within the recent research. After the application of the sealing layer, the seepage through a dam was measured once again and compared to the seepage without the sealing layer. The results indicate about four times lower seepage after the application of the sealing bentonite layer. Hence, the technology can be considered as efficient for given purpose and will be further investigated.