矸石-粉煤灰充填采煤覆岩结构与变形规律

矸石-粉煤灰充填采煤可解决“三下”压煤和固体废弃物排放造成的环境污染问题。根据充填采煤工作面覆岩移动规律,提出矸石-粉煤灰充填采煤覆岩存在3类结构;在弹性地基薄板理论基础上,建立了基本顶力学模型,推导出了基本顶弯曲下沉的理论公式,给出了基本顶破断的临界条件;据此,分析了基本顶变形影响因素,并进行了工程实践。结果表明,基本顶最大下沉量理论计算值与实测值基本一致,各因素对基本顶弯曲下沉影响大小依次为:基本顶弹性模量、覆岩载荷、直接顶弹性模量、充填体弹性模量。邢台矿7606工作面采空区基本顶的最大下沉量为234 mm,沿专用铁路线地表最大下沉量为16 mm,仅直接顶产生了局部裂隙和离层,基本顶完整性较好,覆岩属于第II类结构,地表变形得到了有效控制。

Structure and Deformation Law of Overlying Strata for Waste Rock-fly Ash Backfilling Mining

Waste rock-fly ash backfilling mining can solve problems of “three unders” mining and environmental pollution caused by solid waste emissions. According to overlying strata movement law, three kinds of structure of overlying strata in waste rock-fly ash backfilling mining face were put forward, and which were verified by a physical simulation experiment. Mechanical model of basic roof was built on the basis of thin plate with elastic foundation theory. Then subsidence formula and breakage critical condition of basic roof were given out. Then the factors of basic roof subsidence were analyzed. Results show that the largest basic roof subsidence theoretical calculation formula is in keeping with measured values in field. According to the influence level, factors of basic roof subsidence as follows: the basic roof elastic modulus, overlying strata load, immediate roof elastic modulus and backfilling body elastic modulus. As an artificial controllable factor, backfilling body elastic modulus plays an important role on strata structure and ground surface deformation. Practice shows that the maximum basic roof subsidence of 7606 working face in Xingtai mine is 234 mm and ground subsidence is 16 mm. The immediate roof appears crack and delimitation and basic roof is integral. So, the overlying strata structure belongs to the class II. Ground surface deformation has been effectively controlled.