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徐平. 基于Tresca屈服准则的瓦斯抽采孔的弹塑性解答[J]. 岩土工程学报, 2013, 35(zk2): 16-20.
引用本文: 徐平. 基于Tresca屈服准则的瓦斯抽采孔的弹塑性解答[J]. 岩土工程学报, 2013, 35(zk2): 16-20.
XU Ping. Elastoplastic analysis of gas drainage hole based on Tresca yield criterion[J]. Chinese Journal of Geotechnical Engineering, 2013, 35(zk2): 16-20.
Citation: XU Ping. Elastoplastic analysis of gas drainage hole based on Tresca yield criterion[J]. Chinese Journal of Geotechnical Engineering, 2013, 35(zk2): 16-20.

基于Tresca屈服准则的瓦斯抽采孔的弹塑性解答

Elastoplastic analysis of gas drainage hole based on Tresca yield criterion

  • 摘要: 瓦斯抽放是降低煤与瓦斯突出事故的有效措施之一,但对于“三软”不稳定煤层,在高地应力作用下,瓦斯抽放孔在钻孔过程中或运营一段时间后会出现塌孔。考虑到瓦斯抽放孔的长度远大于直径,因此可将地应力作用下瓦斯抽放孔的弹塑性变形问题简化为平面应变问题。假定塌孔区域范围内的煤岩体介质符合Tresca屈服准则,采用复变函数的保角映射方法,根据瓦斯抽放孔边界与瓦斯抽放压力相等和弹塑性边界处应力连续的边界条件,得到了非均匀高地应力作用下,塌孔区域(即塑性流动区域)、弹塑性边界处位移和应力的解答公式。最后,选取实测的地应力数据和煤岩体物理力学参数,分析了在地应力作用下,瓦斯抽采孔的塑性区域(即可能发生塌孔的区域)的形状、以及弹塑性边界径向应力和径向位移沿周边的分布特点,为今后类似的工程和研究提供了参考。

     

    Abstract: Gas drainage is one of the effective methods to reduce coal and gas outburst accidents. However, for three types of soft and unstable coal seams, the gas drainage hole will collapse easily in some degree during the hole drilling process or after gas drainage for some of time under high geo-stresses. The length of gas drainage hole is much larger than the diameter, so the elastoplastic analysis of gas drainage hole under non-uniform geo-stresses can be simplified to be a plane strain problem. The rock and coal of the collapsed area are supposed to obey the Tresca yield criterion, the conformal mapping method of complex variable functions is adopted, the inner side of the gas drainage hole is equal to the gas pressure and the stresses at the elastoplastic interface are continuous, and the equations for collapsed area, stress and displacements at the elastoplastic interface are derived. In the end, the geo-stresses and physical and mechanical parameters of coal and rock are selected. The collapsed area near the vertical drainage hole and radial stress and radial displacement distribution characteristics at elastoplastic interface are analyzed. The results may provide reference for the similar projects and studies.

     

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