锚杆锚索在模拟矿井水中腐蚀速率试验研究

Experiment on corrosion rate of rockbolts and cables in simulated mine water

针对锚杆锚索在矿井水中易发生腐蚀并导致力学性能下降或失效问题,采用化学成分分析、显微结构观察、电化学试验等手段,测试了热轧335、热轧500、热处理600、热处理700四种锚杆以及1860MPa级锚索的基本特性,分析了其在模拟矿井水溶液中的电化学特性和腐蚀速率。研究表明:(1)测试的锚杆锚索材料极化特征相似,均为活性溶解状态;(2)在模拟矿井水溶液中热处理600锚杆腐蚀速率最低、热轧500锚杆最高,平均腐蚀速率约为0.2mm/a,热轧锚杆的平均腐蚀速率约为热处理锚杆的1.5倍;锚索的腐蚀速率约为锚杆的十分之一;(3)矿井水pH值对锚杆锚索腐蚀速率影响较为显著,在pH=2强酸性条件下腐蚀速率最大,在pH=5弱酸性条件下腐蚀速率降为强酸性下的20%左右,pH=5~11区间即弱酸、中性及碱性条件下腐蚀速率总体呈小幅度下降;(4)Cl^(-)浓度对锚杆锚索腐蚀速率也有影响,当Cl^(-)浓度由0.906mmol/L增大到90.6mmol/L过程中,四种锚杆腐蚀速率均逐渐降低;当Cl^(-)浓度增大到906mmol/L后,热轧锚杆腐蚀速率继续下降,而热处理锚杆腐蚀速率则开始增大。在100倍Cl^(-)浓度溶液中锚索腐蚀速率增加13.35%。

Rockbolts and cables are prone to corrosion affected by mine water,which usually leads to the degradation of mechanical properties and failure.The basic properties,electrochemical characteristics and corrosion rates of hot-rolled 335,hot-rolled 500,heat-treated 600,heat-treated 700 rockbolts and 1860 MPa cables in simulated highly-mineralized mine water were tested and analyzed by chemical composition analysis,microstructure observation and electrochemical tests.The main conclusions were as follows:The polarization characteristics of rockbolts and cables tested were active dissolved similarly.In the simulated corrosive solution,the corrosion rate of heat-treated 600 was the lowest and hot-rolled 500 the highest,with an average corrosion rate of 0.2 mm/a;the average corrosion rate of hot-rolled rockbolts was about 1.5 times that of heat-treated ones;the corrosion rate of cable was about one tenth of that of rockbolt.The pH of mine water had a significant effect on rockbolt corrosion rate,which reached the maximum in pH=2;when pH=5,the corrosion rate decreased to about 20%of that when pH=2;when pH=5~12,namely weak acid,neutral and alkaline solutions,the corrosion rate decreased slightly in general.Cl^(-)concentration had certain influence on the corrosion rate of rock bolt.The corrosion rates of the four rockbolts decreased gradually when Cl^(-)concentration increased from 0.906 mmol/L to 90.6 mmol/L.When increased to 906 mmol/L,the corrosion rate of hot-rolled rockbolt continued to decrease,while that of heat-treated rockbolts began to increase.The corrosion rate of cable increased by 13.35%in 100 times Cl^(-)concentration solution.