Research On Grouting-Reinforcement Technology Of Geological Disaster In The Construction Of Water-Rich Section Of The Loess Tunnel

With the implementation of China’s The Belt and Road Initiatives, more and more tunnels are built in loess area. The low strength, deformation and self stability of the surrounding rock in the water-rich section of the Loess Tunnel cause the construction geological hazards in the loess tunnel. For water-rich section of loess tunnel construction geological disasters often use cement-water glass grouting reinforcement, and in the selection of grouting parameters and grouting and reinforcement of the strength of the composite soil often relies on the engineering experience, resulting in unreasonable design and waste of slurry, so research on grouting-reinforcement technology is very necessary.This article takes Changdao tunnel which comes form the highway from Shiyan to Tianshui for instance, combined with geological disasters in Changdao tunnel, through the indoor tests, grouting simulation test, numerical analysis and the monitoring and measuring method of cement-water glass Grouting parameters and grouting effect, the main research contents and results are as follows:(1) Test cement-water glass gelation time by inverted cup method, the gelation time of cement-water glass is between 29~134s in different water cement ratio, cement water glass concentration and cement water volume ratio. And it is concluded that conclusion that grouting-reinforcement in water-rich section of loess tunnel water cement ratio should be selected from 0.6 to 1.0, water glass density should be selected 30 to 35 Baume degrees, volume ratio of cement and water glass should be selected 1:1.(2) According to the slurry mixing ratio as the control index, to put to test of wet and soft loess by cement-water glass grouting, and the production test block, the maintenance of the unconfined compression strength, obtained the different grouting rate, mixing ratio and 7d curing age of the compressive strength of the test block which is between 40.8~247.5k Pa,and the value of elastic modulus is between 33.5~191.8MPa; 28 d curing age of the compressive strength of the test block is between 94.6~362.8k Pa,and the value of elastic modulus is between 55.7~316.3MPa.(3) To carry out the simulation test and plate load test, under the grouting pressure 0.4~1.0MPa, the size of the diffusion radius is 700 mm, the deformation modulus of the soil after grouting is 18.8MPa.(4)This paper adopts MIDAS / GTS to do finite element numerical analysis, the different thickness of grouting circle tunnel crown settlement and horizontal convergence displacement situation analysis, the thickness of grouting circle is 4m reasonable thickness. Finally, through monitoring measurement and analysis. It is proved that the scheme is feasible.Changdao tunnel example shows that for water-rich section of loess tunnel construction geological disasters grouting-reinforcement, the research methods and conclusions of this paper can be as a reference for similar engineering.