内水外渗作用下有压管道衬砌渗透损伤耦合分析

为研究内水外渗作用下有压管道混凝土衬砌渗透损伤规律,基于弹塑性损伤有限元理论,建立了损伤度与渗透率的匹配关系,采用增量变塑性损伤刚度迭代方法,模拟了水工隧洞充水运行过程中,混凝土衬砌在渗流-损伤-应力耦合作用下的损伤过程,并对衬砌与围岩的承载比例及受力变形特征进行了分析。工程应用结果表明,混凝土衬砌损伤系数沿衬砌厚度由内而外线性减小,损伤开裂减小了衬砌的水力梯度,改善了衬砌的受力条件;洞周锚杆系统发挥自身刚度作用加固围岩,且承担内水外渗的体积荷载,提高了衬砌和围岩联合承载能力;固结灌浆对提高围岩承担内水荷载及防渗能力起主要作用。

Coupling Analysis of Pressure Pipe Lining Damage under Internal Water Exosmosis

On the basis of the elastoplastic damage finite element theory, matching relationship of damage ratio and permeability is established in order to research the damage law of concrete lining of pressure tunnel subjected to inner water exosmosis. The damage process of concrete lining under the action of seepage damage stress coupling is simulated by using incrementally variable plastic damage stiffness iterative method during the operation process of hydraulic tunnel fully filled with water. The bearing ratio and characteristics of stress and deformation of the lining and the surrounding rock are also analyzed. The engineering calculation results show that the damage degree of concrete lining decreases linearly along the lining thickness from inside to outside. Because of the crack damage, the hydraulic gradient of the lining is reduced and the stress condition of the lining is improved. In addition, the anchor system around the cavity gives full play to the role of its stiffness to reinforce the surrounding rock and undertake the body force of seepage from inner to outer. Besides, the combined bearing capacity of lining and surrounding rock is enhanced by the anchor system. The major role of consolidation grouting is to improve the underground rock to bear the internal water load and reduce the seepage discharge as an anti seepage measure.