沿空留巷堆喷工艺巷旁支护体稳定性分析

    Stability analysis of roadside support body for gob-side entry retaining by heap spraying technology

    • 摘要: 为研究堆喷工艺对沿空留巷的适应性,基于11212-2工作面沿空留巷的工程实际,运用数值模拟、物理试验、理论分析的方法,对堆喷工艺巷旁支护体进行了研究。结果表明:切顶条件下,支护体顶板围岩破断特征呈倒梯形,力学模型计算得到的支护体支护阻力为4.16 MPa;数值模拟说明切顶条件下,顶板围岩垮落充分,支护体上部围岩破断边缘类似倒梯形,验证了前面分析的合理性;堆喷工艺混凝土材料具有早强性,1 d强度达到12 MPa,增阻速度快,28 d达到40.6 MPa,最终强度高并且没有强度损失;前期支护体容易发生横向变形,内置钢筋网片结构后,计算减少78%横向变形;后期支护体存在拉压应力区和剪应力区,容易发生破坏,设计内置对拉钢筋,底部施加锚杆。

       

      Abstract: In order to study the adaptability of heap spraying technology to gob-side entry retaining, based on the engineering practice of gob-side entry retaining in 11212-2 working face, the support body beside the gob-side entry of the heap spraying technology was studied by means of numerical simulation, physical test and theoretical analysis. The results are as follows: under the condition of roof cutting, the fracture characteristic of the surrounding rock on the roof of the support body is an inverted trapezoid. The support resistance of the support body calcucated by a mechaincal model is 4.16 MPa. The numerical simulation shows that under the condition of roof cutting, the surrounding rock of the roof collapses sufficiently, and the broken edge of the surrounding rock on the upper part of the support body is similar to an inverted trapezoid, which verifies the rationality of the previous analysis. The sprayed concrete material has early strength, the 1 d strength reaches 12 MPa, the resistance increase speed is fast, and the 28 d strength reaches 40.6 MPa, the final strength is high and there is no strength loss. In the early stage, the support body is prone to lateral deformation. After the steel mesh structure is built in, the lateral deformation is reduced by 78%. In the later stage, there are tension-compression stress areas and shear stress areas in the support body, which are prone to damage. The design has built-in tension steel bars and bolts are applied at the bottom.

       

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