恒阻吸能材料及锚固体力学特性研究与应用

锚固支护作为地下工程围岩控制的主体,与围岩联合承载形成锚固体,共同抵抗动力灾害释放的能量。传统锚杆(索)支护强度、延伸率不足,在抵抗动力灾害时易破断失效。恒阻吸能材料是一种具有高强、高延伸的新型支护材料。为明确恒阻吸能新材料及其锚固体的力学特性,本文开展了恒阻吸能支护材料与现场常用支护材料MG335、MG500的静力拉伸与动力冲击试验。在此基础上,对MG335、MG500与恒阻吸能支护材料锚固下的岩体开展了霍普金森冲击对比试验,研究了高速冲击下锚固体的变形破坏特征。相比于MG335、MG500锚固体,通过霍普金森冲击试验得到恒阻汲能锚固体的峰值应力提高了42.2%与63.9%,所能吸收的动力冲击能量提高了42.0%与63.2%。恒阻吸能支护技术能够增强锚固体的抗冲承载能力与吸能能力。结合上述试验成果,提出了强扰动下围岩恒阻吸能支护的工程建议,并在千米冲击地压矿井中应用。

Bearing mechanism of roof and rib support structure in automatically formed roadway and its support design method

Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway excavation.The stability control of automatically formed roadway is the key to the successful application of the new method.In order to realize the stability control of the roadway surrounding rock,the mechanical model of the roof and rib support structure is established,and the influence mechanism of the automatically formed roadway parameters on the compound force is revealed.On this basis,the roof and rib support structure technology of confined lightweight concrete is proposed,and its mechanical tests under different eccentricity are carried out.The results show that the bearing capacity of confined lightweight concrete specimens is basically the same as that of ordinary confined concrete specimens.The bearing capacity of confined lightweight concrete specimens under different eccentricities is 1.95 times higher than those of U-shaped steel specimens.By comparing the test results with the theoretical calculated results of the confined concrete,the calculation method of the bearing capacity for the confined lightweight concrete structure is selected.The design method of confined lightweight concrete support structure is established,and is successfully applied in the extra-large mine,Ningtiaota Coal Mine,China.

交通隧道高强约束混凝土拱架性能研究与应用

在交通隧道,尤其是大断面交通隧道建设过程中常面临开挖扰动剧烈,围岩控制困难,传统支护强度不足,易出现支护构件破断、拱架屈曲失稳、拱顶冒落掉块等问题。约束混凝土拱架是一种高强、高刚、稳定性好的新型支护形式,能够满足此类隧道的围岩控制要求。目前针对交通隧道约束混凝土拱架的研究均为单榀小比尺试验,无法模拟现场拱架之间的协同承载,试验结果与现场拱架真实受力和变形情况存在较大差别。基于此,研发了交通隧道支护结构大型力学试验系统,开展了组合工字钢拱架、组合约束混凝土拱架与单榀约束混凝土拱架的大比尺力学性能对比试验,研究了拱架的变形破坏机制与整体承载性能。试验结果表明:(1)工字钢拱架整体呈现"拱顶弯曲,拱腰弯扭,拱架变扁平"的变形形态,变形破坏严重。2类约束混凝土拱架的节点位置在加载后期出现大变形或破坏,单榀拱架拱顶出现平面内弯曲,整体变形较为明显,组合拱架除节点处焊缝撕裂外,加载结束时整体未出现较大变形。(2)组合约束混凝土拱架的刚度和承载能力分别是组合工字钢拱架的2.51倍和2.63倍,是单榀约束混凝土拱架的4.18倍和2.78倍,组合约束混凝土拱架稳定性能和承载能力较高。(3)试验拱架均呈现出拱顶、拱底外侧受压,拱腰外侧受拉的受力特性,拱顶位置应力的增长速率较快,拱腰位置由于向外变形受限,易发生平面外失稳,拱顶和拱腰是拱架的关键受力位置。在上述研究的基础上,提出了约束混凝土支护体系在交通隧道中应用的工程建议,研究成果可为该类支护体系的设计和后期研究提供依据。