基于三参数强度准则的煤矿立井井壁 流固耦合理论分析

将煤矿立井混凝土井壁视为多孔介质,考虑地下水渗流作用的影响,应用三参数强度准则和弹塑性力学理论,推导出了立井混凝土井壁弹性区和塑性区应力的解析表达式,以及井壁承受的地下水压力P₀与塑性区半径r_p之间的解析表达式。计算结果表明当不考虑渗流作用时,井壁的极限承载力最大,井壁的环向压应力σ_θ是混凝土立方体单轴抗压强度的2.7倍左右;考虑渗流作用时,井壁所能承受的极限水压力P_c随混凝土孔隙率β增加而逐渐减小,当β=0.2时,井壁的环向压应力σ_θ是混凝土单轴抗压强度的2.4倍左右,故渗流作用对井壁应力分布影响很大;随着地下水压力的增大,处于弹性区的井壁混凝土径向压应力σ_r和环向压应力σ_θ逐渐增加,而当地下水压力增加,达到塑性半径所对应的极限荷载后,该位置的井壁混凝土径向和环向应力则保持不变。该成果为立井井壁结构设计提供了一定的理论参考。

Analysis of Coal Mine Shaft Lining with Fluid-solid Coupling Theory Based on Three-parameter Strength Criterion

As porous medium, concretes of the shaft lining of coal mine are affected by underground water seepage flow. The three-parameter strength criterion and elastic-plastic theory are used to obtain the stress distribution of shaft lining in the elastic zone and plastic zone, and the analytical expression between the groundwater pressure P₀ on shaft lining and the plastic zone radius r_p. The results show that the ultimate bearing capacity of the shaft lining is the largest when seepage flow is not considered, and the hoop stress σ_θ of the shaft lining is about 2.7 times of the uniaxial compressive strength of concrete cubes. However, when seepage flow is considered, the ultimate hydraulic pressure that the shaft lining can bear gradually decreases with the increases of porosity β, and when β equals 0.2, the hoop stress of the shaft lining is about 2.4 times of the uniaxial compressive strength of concrete cubes. Therefore, seepage flow has significant influence on the stress distribution of the shaft lining. Moreover, with the increase of hydraulic pressure, the radial stress σ_r and the hoop stress σ_θ of concrete in the elastic zone gradually increase, however, when the hydraulic pressure reaches or exceeds the limit pressure(corresponding to the plastic radius), the radial stress σ_r and the hoop stress σ_θ in this position remains unchanged. The results provide theoretical reference for the structure design of shaft lining.