【摘要】 钻井井筒的地层经历两次应力重分布,第一次是在钻进过程中;第二次是在构筑井壁后。本文在一定的假设下,研究了钻井井筒围岩弹性与弹塑性区的应力、位移,以及由弹性转变为弹塑性变形的临界深度和塑性区半径问题,得到一系列计算公式,并提出了井壁压力的简化计算式。根据泥浆比重对井壁压力和围岩塑性区半径的影响,建议了泥浆比重的选用值。更多还原

【Abstract】 The ground surrounding a bored shaft experiences two stages of stress redistribution, i. e. one during shaft boring and the other after the lining is built. Study has been made, with some assumptions, on the stress in surrounding ground of the zones with elastic and elasto-plastic deformation and on the displacement of the surrounding ground. Formulae have been derived for calculating the radius of plastic zone and the critical depth, where the elastic deformation is changed into plastic deformation.A simplified formula for calculating the pressure on the shaft lining has been put forward. The values of specific gravity of the mud used in shaft boring are determined according to its effect on the radius of the plastic zone and on the pressure exerted on the shaft lining.更多还原