Abstract: An elastic-damage-mechanics model of jont rock masses is presented based on the damage-mechanics and deforming of rock.The equivalent elastic-damage flexibility tensor and calculation of true stresses of joint rock masses are also derived from the deforming energy. By combining the geometry property of rock with their mechanics properties, the mud density is predicted to keep the stability of wellbore, the damage parameters and strength parameters of an integrated rock are known.The mud density of preventing wellbore collapes is evaluated.

Key words: damage, mechanics analysis, joint, rock, wellbore collapas, wellbore pressure, drilling mud, density

摘要： 含节理裂隙的硬脆性泥页岩井壁坍塌是钻井工程中的难题。本文应用损伤力学理论,从岩体的变形能出发,建立了节理裂隙岩体的弹性损伤--断裂力学模型。由裂纹变形能推导出含节理裂隙的硬脆性泥页岩等效弹性损伤柔度张量,并推导出含节理裂隙岩体的真实应力求法。此力学模型将节理面几何特性与宏观力学特性联系起来。在预测此类岩石保持井壁稳定的泥浆密度时,只需知道损伤参数和完整岩石的强度参数,即可求出防止井壁坍塌的泥浆密度。

关键词: 损坏, 受力分析, 节理, 岩石, 井塌, 井压力, 钻井液, 密度