超高水材料充填胶结体工程特性试验研究

Experimental study on engineering characteristics of super-high water filling body

根据采空区内覆岩垮落与充填浆体的空间位置,将超高水材料采空区充填胶结体分为4种基本形态,即纯超高水材料胶结体(Ⅰ类)、下半部是超高水材料和矸石混合材料与上半部是纯超高水材料胶结体(Ⅱ类)、下半部是纯超高水材料与上半部是超高水材料和矸石混合材料(Ⅲ类)、超高水材料和矸石整体混合材料(Ⅳ类),在实验室进行了抗压、抗拉、抗剪等力学参数测试,并通过建立超高水材料充填开采"充填体-基本顶"力学模型,分析了材料属性变化对基本顶垮落步距的影响。研究结果表明,4种不同类型的超高水材料充填胶结体试件在加压过程中,应力-应变变化趋势基本相同;第Ⅳ类材料试件的抗压强度相对最高,比第Ⅰ类充填胶结体提高约20%;第Ⅱ,Ⅲ,Ⅳ类胶结体试件的抗拉和抗剪强度较第Ⅰ类也有明显提高,最大可提高40%和50%。充填胶结体属性变化对基本顶极限垮落步距影响的分析结果表明,超高水材料与矸石混合形成的第Ⅱ,Ⅲ,Ⅳ类胶结体增加了充填胶结体的强度,有利于基本顶的稳定。

According to the space position between the strata in the gob caving and filling slurry, super-high water material god filling cementing body is divided into four basic forms, namely pure super-high water material cementation body（class 1）, super-high water materials and waste rock mixed materials in lower half and pure super-high water material in upper half（class 2）, super-high water materials and waste rock mixed materials in upper half and pure super-high water materials in lower half（class 3）, and the super-high water materials and waste rock overall mixed materials（class 4）. The uniaxial compressive strength, tensile strength and shear strength mechanics parameters have been tested, and a mechanical model of ＂filling body-main roof＂ for backfilling mining has been established. Due to the mechanical model, the influence of the material parameters on limit span of the main roof has been analyzed. Study results show that, during the process of pressing, the features of stress-strain of the four types materials are nearly the same, and the class 4 material has the largest compressive strength, higher than class 1 by about 20%. The tensile strength and the shear strength of class 2, 3, 4 are commonly higher than class 1, and the maximum value can be increased by 40% and 50%. The analysis results of the influence of the material parameters on limit span of the main roof show that, the broken immediate roof mixed into the pure super-high water material and formed the materials of class 2, class 3 and class 4 can increase strength of the filling body, which are of benefit to the stability of the main roof for backfill mining.