The deep mining faces in No.12 coal mine in Pingdingshan have an engineering background of a large amount of waste,transportation difficulties,mine environmental pollution and conventional filling surface production capacity.An innovation of fully mechanized mixed mining of backfilling and caving (MMBC) is developed and the characteristics of technology are introduced.By means of theoretical analysis,physical similarity simulation and field measurement,the spatial structure characteristics of the fully mechanized mixed mining coal face are studied systematically.The influence of backfill ratio on the strata spatial structure was theoretically analyzed.The physical simulation results show that in the backfilling section of the mixed mining face,the basic roof only bends and sinks,immediate roof caves,and some basic roof fractures occur in the caving section.The basic roof subsidence in the caving section is 4.2 times the average of that in the backfilling section which shows the obvious characteristics of asymmetry.In-situ measurements show that the stope pressure in backfilling section is not obvious,while it is significant in the caving section.The first weighting step is about 30 m,and the periodic weighting step distance is about 22 m,also the dynamic load coefficient is about 1.7.The rock borehole results show that roof is intact and strata spatial structure shows "two belts"development characteristics in backfilling section;the immediate roof caves,and basic roof breaks in the caving section,overlying structure has the "three zone" development characteristics,which shows the obvious characteristics of asymmetry.%基于平煤十二矿深部开采面临的排矸量大、辅助运输困难、矿区环境污染以及常规充填面产能不足工程背景,创新了矸石充填与垮落法混合综采技术并阐述了其技术内涵.采用理论分析、物理相似模拟和现场实测方法系统地研究了混合综采工作面覆岩运移规律和空间结构特征.通过理论分析得到了不同充实率状态下混合综采工作面覆岩空间结构特征;物理相似模拟结果表明,混合综采工作面充填段基本顶仅发生弯曲下沉,而垮落段直接顶垮落、基本顶断裂,垮落段基本顶平均下沉量是充填段的4.2倍,覆岩空间结构表现出明显的非对称特征.矿压实测数据显示,充填段采场无明显的来压现象,垮落段来压现象显著,初次来压步距约30 m,周期来压步距约22 m,动载系数达1.7左右;岩层钻孔窥视结果观察到充填段顶板完整,覆岩空间结构呈现“两带”发育特征;垮落段覆岩结构呈“三带”发育特征,混合综采工作面覆岩非对称性空间结构特征显著.
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