Study On Grouting Blocking Mechanism Of Gushing Water In Karst Pipeline And Development Of Grouting Equipment

With the development of grouting in theory,process and materials,the application of grouting in construction has become more and more scientific.However,due to its high flow rate and quick flow rate,the karst pipeline type surge water is mostly turbulent flow field.The current grouting theory is based on laminar flow and Darcy’s law.The corresponding grouting block theory is not applicable.At the same time,in the engineering practice process,the choice of pulp and grouting parameters of the selection and the implementation of grouting engineering is often based on engineering analogy to determine,inevitably with a certain blindness.Therefore,this paper studies the law and mechanism of karst pipe gushing water injection by theoretical analysis and indoor model test.The concrete research results are as follows:(1)The article divides karst gushing water into five different types.Clearing karst pipeline gushing water with a large amount of water,fast flow,more difficult to control the characteristics.At the same time,it is the key to whether or not the accumulation velocity of cement slurry under certain conditions is effective.The theory of dynamic loading of single particles and the cumulative velocity of slurry is discussed.(2)The author has developed a visualized karst pipeline grouting simulation system.The system can realize the grouting pipeline grouting simulation test with different pipe diameter,moving water flow rate and grouting parameters.The system also can record the parameters such as diffusion pattern,pressure change and moving water flow during the process of moving water.(3)Grouting closure of the orthogonal test study under different diameter to test.The effects of flow rate change ratio,sedimentation height ratio and the reverse diffusion distance of slurry were analyzed.The main controlling factors of dynamic water blocking under different diameter are found.And the effects of moving water velocity,grouting flow rate and water-cement ratio on the effect of grouting plugging were studied.(4)The four typical dynamic water flow curves in the experiment were analyzed.The flow of water before grouting remained basically stable.During the grouting process due to the presence of grouting pressure,the flow of water flow decreased rapidly,and the flow of water during the grouting process changed drastically.After stopping the grouting,the flow of water gradually increased,but less than the initial flow of water.With the change of each factor,the three stages of moving water grouting will produce obvious difference.At the same time,the change of slurry movement state under the condition of moving water flow rate is studied.It is proposed to determine whether or not the blocking effect is achieved by the deposition rate of the slurry.The variation rule of slurry velocity in the two pipelines is analyzed.(5)Combined with karst pipeline type gushing water injection plugging mode and mechanism,the karst pipeline grouting pump was designed on the overall program.It has proposed a local pipeline optimization design,calculated the pipeline loss,and verified its superiority.The numerical analysis software Fluent was used to analyze the grouting pump.It has found the internal flow field of injection pump through the streamline,pressure and flow changes.And it provides a theoretical basis for further optimization of grouting pump.At the same time,the injection pump prototype debugging and testing to determine its operating conditions.