The water inflow into a karst pipeline is characterized by great flow rate and fast flow speed, which makes it difficult to block. Phosphate cement has the characteristics of rapid setting, fast hardening, and good interface bonding, which have inherent advantages for plugging pipelines. However, under the condition of high water ratio, whether the performance of phosphate cement can still maintain the characteristics of rapid setting and fast hardening needs to be studied. In this paper, based on the characteristics of phosphate cement, the feasibility of using high activity phosphate slurry to block the water gushing in karst pipeline was studied. The basic properties of the slurry with different the molar ratio of the MgO to the KH₂PO₄, such as setting time, strength and viscosity were studied with the condition of high water-binder ratio. The hardened slurry was tested by X-ray diffraction, thermogravimetric Analysis and scanning electron microscopy analysis, and its microscopic mechanism was analyzed. The results show that under the condition of water-cement ratio 1.0, using light burned magnesia as raw material, the slurry can achieve quick setting and hardening, and it is found that the molar ratio of the MgO to the KH₂PO₄ has a great influence on setting time, strength and micro properties. The research showed that potassium magnesium phosphate cement is feasible to prepare dynamic water plugging material that use light burned MgO as raw material under high water-cement ratio.

流入岩溶管道的水流量大，流速快，难以堵水。磷酸盐水泥具有快速凝固，快速硬化和良好的界面粘合的特点，这对于堵塞管道具有固有的优势。但是，在高水比的条件下，需要研究磷酸盐水泥的性能是否仍能保持快速凝固和快速硬化的特性。本文根据磷酸盐水泥的特点，研究了用高活性磷酸盐浆液堵住岩溶管道中涌水的可行性。MgO与KH ₂ PO ₄摩尔比不同的浆料的基本性能在高水合比的条件下研究了固化时间，强度和粘度等。通过X射线衍射，热重分析和扫描电子显微镜分析测试硬化的浆料，并分析其微观机理。结果表明，在水灰比为1.0的条件下，以轻烧氧化镁为原料，浆料可以快速凝固和硬化，发现MgO与KH ₂ PO ₄的摩尔比为1。对凝固时间，强度和微观性能的影响很大。研究表明，在高水灰比的条件下，磷酸钾镁水泥可以制备轻质氧化镁为原料的动态堵水材料。