初始损伤与硫酸盐耦合作用下混凝土的力学性能演化规律研究

Study on the evolution law of mechanical properties of concrete under the coupling of initial damage and sulfate

试验研究了初始损伤与硫酸盐腐蚀共同作用下混凝土的性能变化,建立了典型井壁混凝土硫酸盐腐蚀力学模型,分析了不同腐蚀时间井壁混凝土的承载力与裂缝的发展过程。结果表明:在初始损伤与硫酸盐腐蚀共同作用下,随着腐蚀龄期的延长,混凝土的抗压强度先增加后降低,弹性模量基本降低;混凝土的初始损伤越严重、腐蚀溶液浓度越高,混凝土的抗压强度增幅越小,降幅越大,弹性模量降低速率及降幅均越大;所建立的模型对井壁混凝土的腐蚀情况预测结果相对较好,受腐蚀井壁混凝土在受竖向压力破坏的过程中,裂缝朝着井壁外侧发展,破坏前内侧井壁混凝土并无征兆,危害性较大。

The performance changes of concrete under the combined action of initial damage and sulfate corrosion were studied,and a typical sulfate corrosion mechanical model of wellbore wall concrete was established.The bearing capacity and crack development process of wellbore wall concrete at different corrosion times were analyzed.The results show that under the joint action of initial damage and sulfate corrosion,as the corrosion age prolongs,the compressive strength of concrete first increases and then decreases,and the elastic modulus basically decreases.The more severe the initial damage of concrete and the higher the concentration of corrosive solution,the smaller the increase and greater the decrease in compressive strength of concrete,and the greater the rate and magnitude of decrease in elastic modulus.The established model has relatively good prediction results for the corrosion of wellbore wall concrete.During the process of vertical pressure damage to the corroded wellbore wall concrete,cracks develop towards the outer side of the wellbore wall,and there is no sign of damage to the inner wellbore wall concrete before damage,indicating greater harm.