水-温作用下水工隧洞钢筋混凝土衬砌开裂特性

Study on cracks of reinforced concrete lining of hydraulic tunnel under the combined action of water pressure and temperature load

考虑水工隧洞初次充水加压过程和温度场演化的时差性,采用塑性-损伤-接触特征的多裂缝混凝土本构模型,结合某发电引水隧洞实例,研究水工隧洞钢筋混凝土衬砌结构在内水压与温度场联合作用下的开裂特征;同时针对内水水温与外围围岩的温度传导过程,对水工隧洞初次充水加压过程中不同加压和温降的叠加作用下衬砌开裂特征进行对比分析.数值分析结果表明:水工隧洞初次充水运行时,温降的同步作用导致衬砌结构开裂时机提前,致使裂缝宽度的普遍增大和裂缝条数的减少;水-温联合作用下,提高隧洞充水加压速度将增加集中裂缝的最大宽度,并对衬砌结构裂缝分布有较大影响;衬砌-围岩之间的热传递并不改变衬砌最大裂缝产生的位置,而会降低衬砌裂缝的最大宽度.

The plastic-damage-contact constitutive model for concrete was applied to study the cracking characteristics of the concrete lining of hydraulic tunnel,under the combined action of water pressure and temperature load,and the time difference between the first water-filling process and temperature field change was especially considered.And the combined effect of water-filling speed and temperature load for concrete lining was discussed by taking temperature conduction and mechanics characteristic of concrete lining into account.The result shows that the synchronous effect of temperature drop leads to crack earlier and generally increases the crack width and decreases the amount of cracks when the hydraulic tunnel operates with water for the first time.Under the combined action,increasing the velocity of filling tunnel increases the maximum width of concentrated crack and has a great influence on the crack distribution of lining structure.The thermal transmission between lining and surrounding rock has little effect on the crack position,but decreases the maximum crack width.