井壁约束内壁治理方法的力学分析

Mechanical Analysis of a Restricting Inside Lining Used in the Shaft-Curing Method

为了研究约束内壁法对特殊地层条件下井筒的治理效果,应用空间轴对称弹性理论建立了相应力学模型的受力分析方法.获得了井壁处于约束治理条件下的圣维南解,计算了某实际井筒在不同大小约束力作用下治理前后的相当应力变化.结果表明:井壁内侧的相当应力在治理前远大于外侧,治理后获得较大程度的减少,沿径向的相当应力曲线逐渐趋于水平;随着约束力增大,约束段内缘附近各点的相当应力减小.约束内壁方法通过提高井壁内缘这一薄弱环节的安全性,达到了增强井壁整体抗破坏能力的目的;约束段内缘附近的治理效果随约束力增大而越佳.

The effect of using a restricting inside lining during shaft curing in special strata was studied. A mechanical model stress analysis technique was developed based on three dimensional axisymmetric elastic theory. The Saint-Venant solution, and the equivalent stresses, in a real shaft before and after restriction were obtained. The results show that before restriction the equivalent stress of the inner shaft is far larger than the stress in the outer part. Inner shaft stress is greatly reduced by restriction. By improving the security of the inner shaft, which is the most fragile part of the structure, the security of the entire shaft is effectively enhanced. The curing effect near the restricted inner shaft is gradually improved as the restricting pressure increases.