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深部巷道顶板围岩分级及支护参数优化研究

Study on Surrounding Rock Classification and Support Parameter Optimization for Deep Roadway Roof

  • 摘要: 安徽刘塘坊铁矿围岩呈缓倾角层状分布,开采过程中极易发生岩层剥离、坍塌等灾害,随着采深逐渐加大,巷道顶板支护模式及参数亟需优化升级。首先,开展矿岩节理裂隙参数统计,对矿山深部围岩质量进行分级;基于围岩质量分级、断面尺寸及服务年限与功能三大主要因素,采用分项定量加权取值方法,对该矿顶板支护等级进行评分。其次,通过不同支护方法和参数条件下巷道围岩稳定性的数值模拟,揭示了不同支护方式对巷道松动圈范围、应力集中区及塑性区的影响机制,并定量分析了混凝土、锚杆及锚网联合支护对巷道最大沉降和顶板控制率的影响。结果表明:在支护成本允许的条件下,对巷道顶板支护效果影响程度依次为混凝土厚度>锚杆排距>锚网>锚杆长度;当支护效果低于30%时,属欠支护状态,增加支护成本可显著提升支护效果;当支护效果高于45%时,则处于过支护状态,继续增加支护成本所带来的效果增益有限。最后,根据支护效果与成本对比优选,提出了一套巷道分级支护形式及参数优化方案,相关成果可为类似地下矿山工程的顶板分级与支护设计提供参考。

     

    Abstract: The surrounding rock of the Liutangfang Iron Mine in Anhui Province exhibits a gently inclined layered structure,making it inherently prone to rock delamination and collapse during extraction;as mining depth increases,the roadway roof support system and its parameters urgently require optimization and upgrading. To address this,joint and fracture parameters of the ore rock were first statistically analyzed to classify the quality of the deep surrounding rock,and then a subitem quantitative weighted scoring method was adopted to rate the roof support grade based on three primary factors:surrounding rock quality classification,crosssectional dimensions,and service life and function. Subsequently,numerical simulations of roadway stability were conducted under various support methods and parameters,which revealed the influence mechanisms of different support techniques on the extent of the loosening zone,stress concentration zones,and plastic zones,while also quantitatively assessing the effects of concrete,rock bolts,and boltmesh combined support on maximum roadway settlement and roof control ratio. The results show that,within the constraints of support cost,the order of influence on support effectiveness is concrete thickness>bolt spacing>mesh reinforcement>bolt length;When the support effectiveness falls below 30%,the system is undersupported and increased expenditure can significantly improve performance,whereas when it exceeds 45%,the system becomes oversupported and further cost increases yield only marginal gains. Finally,based on a comparative optimization of support effectiveness and cost,a set of graded support schemes and parameter optimization proposals is put forward,and the findings are expected to provide a useful reference for roof classification and support design in similar underground mining projects.

     

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