Research and application of heap spraying technology based on safe and high-efficiency supporting structure
REN Xingyun;HAO Bingyuan;LI Xianjun;WANG Hongwei;FENG Xuchao;ZHANG Ji
针对煤矿井下作业环境的特殊性和现有支护技术的不足,提出了堆喷技术,确定了工艺参数,研发了堆喷外加剂(S2),揭示了S2强化堆喷料性能的作用机理,形成了一套完整的堆喷构筑矿用支护结构体的工艺方法,并应用于沿空留巷等工程实践。结果表明:①堆喷技术可以根据需要构筑支护结构体,不受空间断面限制,操作工远离危险区,安全高效控制围岩;②堆喷料潮拌及输料管路分段加水工艺,提前湿润物料,可以促进堆喷料水化作用、增强粘附性及和易性、降低粉尘和回弹率;③S2的促凝组分包括NaAlO2、Al2(SO4)3、NaF、Al(OH)3和快硬硫铝酸盐水泥(SAC-42.5),增粘抗裂组分为硅灰(GS)、聚丙烯纤维(JB),提高了支护结构材料的凝结速度和抗压强度,且具有微膨胀特性;④现场堆喷标准试件的单轴抗压强度测试结果为1天12.0 MPa,3天18.1 MPa,7天27.5 MPa,28天42.1 MPa,90天42.3 MPa,具有高强承载能力,且后期强度不倒缩,强度增长过程分为三个阶段:初期快速增长阶段(龄期0~14 d)、中期持续增长阶段(龄期14~28 d)、后期稳定阶段(龄期>28 d);⑤堆喷技术构筑巷旁隔离墙实现沿空留巷,拓展了矿用支护结构体的高效施工方法。
Aiming at the special characteristics of underground coal mine operation environment and the deficiency of existing support technology, heap spraying technology was proposed, technological parameters were determined, heap spraying admixture (S2) was developed, the mechanism of S2 was revealed, and a complete set of heap spraying construction technology was formed and applied to gob-side entry retaining. The results show that: ① Heap spraying technology can be used to construct the supporting structure according to need, which is not restricted by operating space and the operator is far away from the danger zone, so that the surrounding rock can be controlled safely and efficiently. ② Heap spraying material tide mixing and conveying pipeline segmentation with water process, wetting materials in advance, can promote material hydration, enhance adhesion and workability, reduce dust and rebound rate. ③ The accelerating components of S2 include NaAlO2, Al2(SO4)3, NaF, Al(OH)3 and fast-hardening sulfoaluminate cement (SAC-42.5), and the viscosifying and anti-cracking components are silica fume (GS), polymer propylene fiber (JB), S2 improves the compressive strength of the supportintg structure material and has micro-expansion properties. ④ Uniaxial compressive strength of the standard specimens molded by heap spraying is 12.0 MPa at 1 d, 18.0 MPa at 3 d, 27.5 MPa at 7 d, 42.1 MPa at 28 d and 42.3 MPa at 90 d, with high strength supporting capacity, and late strength does not shrink, the strength growth process is divided into three stages: the initial rapid growth stage (age 0−14 d), the medium sustained growth stage (age 14−28 d), and the later stable stage (age>28 d). ⑤Heap spraying technology can build the isolation wall along roadway to realize gob-side entry retaining, having a positive effect on expanding the construction method of supporting structure.
supporting structure;heap spraying technology;heap spraying process;heap spraying admixture;gob-side roadway retaining
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会