| According to the problem of operational karst tunnel drainage system which was blocked by the precipitation crystal produced in the tunnel drainage pipe, the sand, the surrounding rock fragments and the surrounding rock particles, this paper has further research on this issue. Based on summarizing the achievement of the predecessor and combined with the model test, the paper has studied and analyzed the factors that affect the tunnel drainage system. The main research works are as follows:1. Through the real field investigation of the tunnel, the paper has not only studied the chemical composition of the blockage of the tunnel drainage pipe, but also analyzed the ionic species and the ionic concentration of the water sample. It illustrated the factors that would cause blockage of tunnel pipes, and stated the effects that would cause the generation crystal precipitation in the tunnel pipe.2. Based on empirical formula and DBL theoretical equation, this paper calculates the speed rate of precipitation crystal in the tunnel pipe, and Reach to a conclusion that DBL theoretical equation is fit for calculating the speed rate of crystal precipitation crystal.3. Taking model test to observe the regularity of the production of precipitation crystal which was influenced by different longitudinal tunnel pipe and different water flow. And through the comparison of 15 days for a period, the mass variation of the tunnel pipe and the turning parts indicate the specific influence of longitudinal slope and water flow on the generation of crystalline precipitation.4. On the basis of analyzing the reasons that cause the blockage of tunnel pipe, this paper Raises the proposals of using ripple longitudinal tunnel pipe in the drainage system, putting Carbonic Anhydrase and antiscalant into the tunnel pipe. These measures can effectively restrain the production of precipitation crystal,and then delay the process of blockage of the tunnel pipe. |
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