Study On Preparation And Stratum Adaptation Of Green Anti-salt Slurry For Submarine Tunnel

With the increase of nuclear power projects,submarine tunnels are gradually increasing as the main way of water intake and drainage.Slurry shield is widely applied into crossing river and submarine tunnel because of its fine stratum adaptability.It's the good slurry performance and the suitable slurry ratio that determine the tunneling efficiency and the economic cost of slurry shield.It is inevitable to encounter the pollution of sea water to slurry in the tunnel excavation on the seabed,and the great pollution to the soil and water environment can be probably caused by the traditional polymer pulping materials with the discharge of the abandoned slurry.Therefore,it is extremely necessary to study the green salt-resisting slurry in the strong permeability stratum of subsea tunnel.In order to solve the aforementioned problems,the Lufeng nuclear submarine drainage tunnel project was taken as the engineering background and the suitable slurry materials was selected,we made the permeability test device to solve the problems of the water pollution in seabed slurry shield and the traditional polymer slurry materials are difficult to degrade through the indoor experiment.Moreover,we also develop a new green salt resisting slurry.The main research results and work in this paper are as follows:(1)The slurry ratio of good performance,good stratum adaptability and high economic profits was studied.Taking the main properties of slurry such as specific gravity,viscosity and water loss as indexes,the bentonite pulping performance of various manufactures was compared,and various pulping agents were added to modulate the bentonite slurry into good performance and economic benefits.The influence of various additives on the properties of slurry was quantitatively analyzed,and the preparation of slurry for actual shield construction was prepared.(2)Developing slurry permeability test device.A large number of relevant information at home and abroad is consulted,designing and improving the device that can simulate the slurry permeability test.(3)The constituents of underground water and seawater was found similar through the analysis of water quality,so we used the salt additive xanthan gum to resist pollution of seawater,and used the pregelatinized starch to replace the traditional tackifying agent CMC,proposing a new type of green salt-resisting slurry.The mechanism of salt resistance of xanthan gum was also explained.(4)Through laboratory test,the adaptability of slurry ratio to the characteristics of the engineering stratum was verified,and the slurry design was optimized.Aiming at the characteristics of high permeability of fully weathered granite and medium coarse sand in engineering stratum,the pore water pressure and final filtration loss in stratum are monitored by seepage test.The slurry proportioning scheme for these two kinds of strong permeability stratum was mainly studied.It can also provide a reference for slurry shield construction of similar subsea tunnel.