Development and Application of Slurry Flow Model for Slurry Shield Tunnelling Based on BP Modified Rheological Model
In order to improve the formation quality of filter cake in slurry shield tunnelling and maintain the stability of the excavation face,accurate prediction of the rheological characteristics of bentonite slurry is often required in the design of slurry parameters.Addressing the issues of numerical divergence and heavy reliance on empirical values in the solution process of slurry flow models for shield tunnelling,indoor rheological tests of slurry with different bentonite contents were conducted.Based on the experimental results,the Bingham-Papanastasiou(BP)modified rheological model was incorporated into the computational fluid dynamics(CFD)framework to develop an optimized numerical method for simulating slurry flow.The effectiveness and accuracy of this numerical method were validated by conducting numerical simulations of Poiseuille flow between parallel plates with Bingham fluids.Subsequently,a three-dimensional numerical model of slurry pipe flow was established to investigate the pipe flow characteristics of slurry under different rheological parameters.The results show that with the increase of bentonite content,the yield stress and consistency coefficient of the slurry exhibit an increasing trend.Moreover,an increase in rheological parameters leads to more energy loss of slurry during infiltration into the formation.As the consistency coefficient k increases from 0.1 Pa·s to 0.75 Pa·s,the pressure drop increases by 6.21 kPa,which can better maintain the effec-tive transformation of slurry pressure and improve the formation quality of filter cake.
Slurry shield tunnellingIndoor rheological testsCFDSlurry fluid dynamic characteristicsDevelop-ment of flow modelPressure drop
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