煤矿巷道湿式混凝土管道输送特性及喷射控尘机制研究

This project is put forward for how to improve transporting efficiency in long-distance pipeline and spraying quality of the moist dense concrete group, and reducing dust concentration and concrete repercussion effectively. Research deposition law of concrete with different proportion in long-distance pipeline, under discrete transporting condition by designing ground spraying test platform with 100m transport pipeline. Establishing large-grained transport features test to research pipeline plugging mechanism of large-grained material group including reducer positions. Using two temporary disturbance methods-graduated compression and countermotions of accumulation horizon to test movement restart function mechanism of static material group, so as to reduce accident probability effectively. Using relevant theories and technology such as hydromechanics, multiphase flow and numerical simulation to research and establish spray model of wet-spraying concrete, so as to analyze spray flow law and dust fog formation rule of concrete group. Using technological means such as rock mechanics test, chemical analysis to put forward improving method of mobility in pipeline. In order to optimize the best proportion scheme, adaptability research and combination technology among various additives are developed. Finally, completing the practical wet-spraying concrete underground.

项目针对煤矿巷道湿式喷射混凝土工艺中如何提高湿润稠密状混凝土料群长距离管道输送效率和喷射质量，有效降低粉尘和回弹产生而提出。通过设计100m长距离管道输送地面喷射试验平台，研究长输管道中不同配比混凝土在非连续输送条件下管道沉积规律；设置大颗粒管道中输送特性试验，探讨大颗粒料群在包括变径部位在内的管道堵塞机制，并试验"逐级加压"和"反向运转"两种堆积层瞬态扰动方法对静止料群的运动重启作用机制，降低管道堵塞事故概率；完善现有湿喷用混凝土工作性能评价指标体系，运用流体力学、多相流、数值模拟等有关理论和技术，建立湿式喷射混凝土的射流模型，分析混凝土料群的射流规律和尘雾形成规律；利用岩石力学、化学分析等技术和手段，提出管道流动性能改善措施，优化湿喷用最佳配比方案，对喷射质量保证体系的关键和变动因素进行试验，完善煤矿湿喷混凝土输送和喷射理论。

本项目完成了100m长距离管道输送地面喷射试验平台及模拟巷道的设计、建造，为系统开展矿用湿喷理论、材料、工艺和设备研究奠定了基础。试验得到了50次管道堵塞现象发生的时空规律，指出湿喷作业开始的10min为“堵管易发期”；试验证实，合理控制混凝土配比，完全可以在40min的停机间隔内保持混凝土的工作性能和再启动条件；分析了高水灰比湿喷混凝土中粗骨料颗粒形状的“楔效应”和“转动效应”形成管道流动阻滞性提高了湿喷混凝土长距离输送阻力；试验了不同“瞬态扰动”方法对大颗粒管路堆积层扰动效果，确定了“反泵+正泵启动”更有利于管路堆积层运动重启。润管剂50米管道润管试验表明，在15℃左右水温条件下搅拌2min以上充分溶解的润管剂能够预先润滑管路，提高混凝土管道中的流动性，有助于减少管路堵塞；试验了风压变化（0.1Mpa、0.2Mpa）、入射角变化（30°、60°、90°）、喷射距离（1m、1.5m、2m）等喷浆参数对回弹率影响规律，试验结果表明，1m左右喷射距离、0.2MPa风压、90°入射角喷射混凝土，可以实现巷帮回弹率降到10%以下，巷顶回弹率降到15%左右，湿喷过程基本无粉尘产生，各项指标明显优于干喷和潮喷工艺。