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我国煤矿深部软岩巷道大地压、强流变、大变形等问题突出,此类巷道稳定需要较大的支护力,因此提出全圆钢桁架支架支护技术。桁架采用8段双层12#工字钢构件组成,每段构件之间连接采用端头焊接390 mm×800 mm×30 mm钢板和螺栓连接,在实验室借助分步多次逐级加载、测试系统测试了全圆钢桁架支架在垂向和水平向荷载按不同比例组合作用下的极限荷载和极限变形量。试验结果表明:在均压荷载作用下,钢桁架的极限承载力为1 500 t,弹性极限压缩变形为12.18 mm;非均压荷载组合比值为0.2时,支架极限承载力为900 t,弹性极限变形为26.3 mm;极限荷载破坏方式为连接块处的错动和支架直径收缩变形破坏。与传统U型钢支架相比,钢桁架支护反力提高10倍以上。针对极软岩巷道变形规律,提出恒阻大变形锚杆索+预留变形量的一次支护,在高预紧力支护下通过恒阻装置释放变形能并形成锚网索-围岩耦合支护圈,然后采用全圆钢桁架强力二次支护,在均压下发挥钢桁架的最佳支护力学性能,其支护方式在深部大地压、强流变软岩巷道中有着广泛的应用前景。
The problems such as the earth pressure, strong rheology and big deformation of the soft rock roadway in the deep coal mine in China are outstanding. Such roadway needs a large supporting force for stability, so the support technology of the full-round steel truss support is proposed. The truss consists of 8 sections of double 12 # I-beam members, the connection between each member is made by the end welding of 390 mm × 800 mm × 30 mm steel plates and bolts, step by step loading in the laboratory step by step, the test The ultimate load and ultimate deformation of the full-round steel truss support under different combinations of vertical and horizontal loads were systematically tested. The experimental results show that the ultimate load carrying capacity of steel truss is 1 500 t and the elastic limit compression load is 12.18 mm under load equalizing load. The ultimate load carrying capacity of steel truss is 900 t and the elastic limit The deformation is 26.3 mm. The ultimate load failure mode is the dislocation of the connection block and the shrinkage deformation of the stent. Compared with the traditional U-shaped steel bracket, steel truss support reaction force increased more than 10 times. Aimed at the deformation of extremely soft rock roadway, the paper proposed a primary support with large deformation and constant deformation of anchor cable and pre-deformation, and released the deformation energy through the high resistance device and formed the anchor net-surrounding rock coupling Support ring, and then the use of full-round steel truss strong secondary support, under equal pressure to play the best supporting mechanical properties of steel truss, the support in deep deep pressure, strong rheological soft rock roadway has a wide range of Application prospects.