杂散电流对地下结构耐久性影响试验研究

地下结构改扩建工程会破坏原有杂散电流防护体系,对地下结构耐久性不利,影响地铁的安全运营。本文采用不同钢筋接头形式的钢筋笼模拟地下结构改扩建工程中杂散电流防护体系的改变, 提出杂散电流存在下的地下结构耐久性预测模型,研究改扩建工程中杂散电流对地下结构耐久性的影响。根据试验结果分别计算改扩建工程前后地下结构耐久性,焊接钢筋混凝土结构的耐久性约为绑扎钢筋混凝土结构的两倍,能够满足地下结构耐久性100年的要求。地下结构工程维修非常困难,因此地下结构改扩建工程施工要保持钢筋网络良好的电气连接性能,确保地下结构耐久性满足要求。

Study on Durability of Sub Structure Affected by Stray Current

The original protection system for stray current can be destroyed by the expansion project of the sub structures. It exerts negative effects on the durability and normal using of subway. Different joint style of reinforcement cages are used to simulate the change of the protection system during the expansion project and the durability prediction model of sub structure is put forward, then the durability affected by stray current is analyzed. The durability before and after the expansion project are calculated according to the test results, the durability of welding reinforced concrete is two times as that of binding reinforced concrete. Sub structure is hard for maintenance, therefore it's critical to make sure the reinforced network has well electrical connection and the durability of sub structure is guaranteed.