Research On Preparation And Hydration Heat Regulation Technology Of High-strength Lining Concrete For Tunnels

The preparation and pouring construction of tunnel high-strength lined concrete is the key construction link of the tunnel project.Especially during the pouring construction of largevolume high-strength lined concrete,hydration heat is generated inside the lined concrete,and the temperature difference between the interior and the outside of the lined concrete structure leads to temperature cracks in the lining concrete,thus threatening the safety of the tunnel project.Therefore,based on a tunnel project in Liaoning Province,China(the tunnel design requires a tunnel lining concrete thickness of 3m and a strength grade of C80),this article aims to translate the information.The C80 tunnel is prepared by using the activity of agricultural waste rice husk ash after combustion and grinding,as well as the mineral admixtures such as fly ash High-strength lined concrete.It not only realizes the comprehensive benefits of agricultural waste,but also achieves the purpose of reducing costs.The variation law of hydration temperature rise in highstrength concrete of different sizes was studied using experimental and finite element methods,and the hydration heat generated after the pouring of the high-strength lining coagulant in the tunnel was numerically simulated.Therefore,the temperature control measures and suggestions for the high-strength lining coagulation of the tunnel are put forward.The main research contents are as follows:(1)C80 high-strength concrete was prepared by using mineral admixture rice husk ash,and tests were carried out on concrete slumble,expandability,cube compressive strength,split tensile strength etc.,and obtained the mechanical and working performance of high-strength concrete.Through the method of extreme variance,the influence of the dosage changes of the three mineral admixtures of rice ash,fly ash and silica ash on the performance of high-strength concrete was analyzed,so as to determine the optimal matching ratio of tunnel high-strength lining concrete.(2)The hydration heat of high-strength concrete under different size effects was experimentally studied,and the influence of the size effect on the hydration heat of high-strength concrete was obtained.Using Midas finite element software,the change of hydration temperature rise of concrete in the test and numerical simulation was compared and analyzed,the accuracy and feasibility of numerical simulation was verified,and the hydration temperature rise of largevolume concrete was predicted.(3)Numerical simulations were conducted to investigate the issue of concrete hydration heat generated during the casting construction of a tunnel project in Liaoning Province.The study obtained the variation pattern of hydration temperature rise for high-strength tunnel lining concrete.By employing the method of extreme variance analysis,the impact of cold water pipe flow rate,inflow temperature,and diameter on the hydration heat of high-strength tunnel lining concrete was analyzed.The results showed that the order of the three factors’ influence on the hydration heat of high-strength tunnel lining concrete was as follows: inflow temperature >diameter > cold water pipe flow rate.Based on the actual project conditions,recommendations for optimal temperature control measures were provided,offering technical references for addressing the issue of hydration heat in high-strength tunnel lining concrete.