膨胀泥化软岩巷道围岩损伤与新型棚式支护机理研究

Problem of roadway supporting in expansive soft rock is one of the most complex topics in rock mechanics area. Aiming at the problem of damaged mechanism of surrounding rock and supporting mechanism of shed in expansive mudding soft rock roadway, relying on methods of basic experiments, similar simulation tests, numerical analysis and theoretical analysis, we will study the expansion characteristics, damaged mechanism of surrounding rock, strength evolution of new sheds and its supporting mechanism systematically. In study of this project, based on soft rock rheological experiments, viscoelasto-plastic model was modified. Nonlinear viscoelastic-plastic constitutive model, which contains parameters of loading stress, humidity and time, for expansive mudding soft rock will be established. Based on FLAC3D, this model will be used in numerical simulation. Based on soft rock expansion experiments, combination yield criterion of granular material sliding, damaged model on expansive mudding soft rock will be established. Evolution relation between plastic zone of surrounding rock and supporting strength will be revealed from this model. Shed’s structure is changed by adding internal beams and braces. Based on bending moment analyzing and similarity simulation testing on carrying capacity, strength evolution of different sheds’ will be illustrated. Relying on stress and displacement analysis in shed and surrounding rock, controlling mechanism of new sheds on surrounding rock will be illustrated. This project possesses a broad application prospects, for mines with expansive mudding soft rock are widely distributed in western region.

膨胀软岩巷道稳定问题是目前岩石力学领域最复杂的课题之一。本项目以膨胀泥化软岩巷道围岩损伤与棚式支护作用机理为研究对象，综合采用基础实验、相似模拟试验、数值模拟、理论分析等方法，系统研究泥化软岩膨胀变形特征、围岩损伤演化机理、新型棚式支架强度演化规律及其支护机理。在该项目研究中，基于软岩流变实验修正西原模型，建立包含加载应力、湿度和时间参数的膨胀泥化软岩非线性黏弹塑性本构模型，并基于FLAC3D软件实现该模型的数值应用。基于软岩试块膨胀变形实验，结合粒状材料滑移屈服准则，建立膨胀泥化软岩滑移损伤力学模型，揭示围岩塑性区与支护强度演化关系。通过增加内部横梁和斜撑改变支架结构形式，基于支架弯矩解析及承载能力相似模拟试验，揭示不同结构棚式支架强度演化规律。基于支架—围岩应力、位移耦合分析，揭示新型棚式支架围岩控制机理。鉴于西部地区膨胀软岩矿井分布范围的广泛性，本项目研究具有广阔的应用前景。

巷道支护问题一直是困扰我国煤矿安全高效开采的关键问题之一。随着煤炭开采程度加剧，资源开发加速向西部转移。内蒙古自治区是西部主要产煤省份之一，其蒙东褐煤主产区遭遇膨胀泥化软岩巷道支护难题。膨胀泥化软岩中含有较高比例的膨胀性粘土矿物，在该膨胀岩层中，强烈的膨胀变形极易导致锚杆预应力丧失，棚式支护成为该特殊地质条件的必然选择。由于传统的棚式支护强度较低，寻找新的高强度棚式支护成为突破该瓶颈的必由之路。.本课题以揭示膨胀泥化软岩巷道围岩损伤与新型棚式支护机理为目标，围绕泥化软岩膨胀演化模型、围岩损伤演化机理、新型棚式支架强度演化规律，以及新型棚式支架耦合作用机理开展研究，试验获得泥化软岩随时间的膨胀演化本构模型，建立了考虑粒状材料静态和动态力学行为的巷道围岩塑性区扩展力学模型，获得了集中荷载下支架弯矩力学计算公式。基于支架弯矩解析结果，为有效提高支架顶拱、底拱强度，设计出高强度的底板横梁支架、顶板横梁支架、顶底板横梁支架、顶底板横梁+斜撑四类支架。通过相似模拟试验和数值模拟对四种支架的强度和应力演化进行了分析。通过原始支架和新型支架强度和成本比较，得出在底板横梁模型中，底角相对强度达到2.964，相对成本达到1.294；在顶板横梁模型中，顶拱相对强度达到2.345，相对成本达到1.274；在顶梁+底梁模型中，顶拱相对强度达到2.345，底角相对强度达到2.964，相对成本达到1.568；在顶梁+底梁+斜撑支架中，顶拱相对强度达到2.635，底角相对强度达到5.905，但相对成本达到1.930。底梁模型和顶梁+底梁模型显示出比原始支架更高的强度和不太高的成本。虽然顶梁+底梁+斜撑支架显示出更高的强度，但它们也显示出比原始支架高得多的成本。.在内蒙古自治区上海庙矿区，以及陕西、甘肃、宁夏、新疆等境内亦存在严重的膨胀泥化软岩巷道支护难题，鉴于膨胀泥化软岩巷道在我国西部地区分布范围的广泛性，该课题研究具有广阔应用前景。