Evaluation of the functions of a grid-type sabo dam and sediment routing management in a basin

近年来，许多格构式的沙波坝已经建成。这些水坝的功能是通过正常洪水期间运送的沉积物，并储存泥石流运送的危险大石块。本文首先研究了沙坝型泥石流的淤积过程，并采用平面沙坝型泥石流阻塞随机模型进行了水槽试验和数值模拟。将该模型扩展为三维模型，并用该模型表达了格网式沙堡坝泥石流的生成、发展和淤积过程。该模型对阐明格构式沙堡坝的作用是非常有用的。其次，利用该仿真模型，研究了沿着陡槽格构式沙坝最优坝位的确定方法。利用计算得到的泥石流固相浓度、流深、泥沙粒径组成、流速等水流特性和阻塞随机模型，可以评价建坝的适宜位置。由于我们仅在假想的河道中检验了该方法，因此我们希望将来将其应用于实际流域。

Recently, many grid-type sabo dams have been constructed. These dams have functions to pass through sediment transported during normal floods and to store hazardous big boulders transported by a debris flow. In this study, firstly, we pay attention to the sedimentation processes of debris flow by a grid-type sabo dam, and flume experiments and numerical simulations are carried out using stochastic model of blocking by a planer grid-type dam. The model is expanded into the three-dimensional model and processes of the debris flow generation, development and sedimentation by a grid-type sabo dam are expressed by the model. This model is found to be very useful to clarify the function of the grid-type sabo dam. Secondary, by using this simulation model, the method to find the optimal site of the grid-type sabo dam along the steep channel is investigated. By using both the calculated flow characteristics such as solid concentration of the debris flow, flow depth, composition of the sediment diameter in the flow, flow velocity, and etc. and stochastic model of blocking we can evaluate the suitable position of the dam construction. As we checked this method only in the imaginary channel, we want to apply it to the actual river basin in future.