Grouting sealing method of flow-control speed-down in karst pipelines and its engineering application

Abstract

For the large-flow and high-speed dynamic water sealing problem in karst pipelines, the dynamic water sealing mechanism under flow-control speed-down conditions is researched systematically by numerical calculation, model test and engineering application. Firstly, numerical simulation for the dynamic water turbulent flow in the pipeline is conducted under different water heads and flow rates. The change laws of flow velocity and pressure are analyzed during the flow-control speed-down. Secondly, the flow-control speed-down test for dynamic water in the pipeline is carried out using the self-developed karst pipeline model test system. The functional relation between the value opening and the flow velocity after flow-control in the pipeline is deduced, and the numerical results are supplemented and verified. Finally, the proposed dynamic water sealing method of flow-control speed-down is successfully applied to the water gushing treatment project of the China Resources Cement (Pingnan) Riverview Limestone Mine. The results show that: (i) As the degree of flow-control speed-down increases, the flow velocity in the pipeline decreases gradually and the pressure increases gradually. (ii) The flow-control speed-down test effectively reduces the flow velocity and increases the slurry retention rate in the pipeline. (iii) The large-flow and high-speed water inrush at the construction site is effectively treated, and the validity and applicability of the proposed method are verified, which have important guiding significance for the disaster treatment of large-scale water inrush in karst areas.