# A Coupled CFD–DEM Simulation of Slurry Infiltration and Filter Cake Formation during Slurry Shield Tunneling

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## Abstract

**:**

## 1. Introduction

## 2. Theory and Methodology

#### 2.1. Governing Equations of DEM

#### 2.2. Governing Equations of CFD and Fluid–Particle Intercation

## 3. Model Implementation

#### 3.1. Valiadation

#### 3.2. CFD Meshing

#### 3.3. DEM Initialization

#### 3.4. CFD–DEM Coupling Settings

## 4. Discussion

#### 4.1. Filter Cake Formation

#### 4.2. Porosity Distribution Inside the Filtration Column

## 5. Conclusions

- (1)
- The interaction between sand and slurry particles could be classified into three types by the sedimentation behavior of slurry particles on the sand particles: Type I, Type II, and Type III. For Type I, a dense and thick filter cake forms on the sand column surface. For Type II, a relatively loose filter cake and an “infiltration zone” are observed. For Type III, no obvious filter cake forms since the slurry particles are too small to clog the pores inside the sand column. These results are in accordance with Min et al.’s experimental results.
- (2)
- Three types of distribution of porosity along the column are obtained. Based on the porosity distribution, the ranges of zones of pure water, filter cake, infiltration, and sand column could be identified.
- (3)
- The coupled CFD–DEM method is capable of simulating slurry filtration and filter cake formation during a filtration column test. With the development of computing technology, this method has the potential to simulate more complex problems such as full-scale modelling of an in situ slurry shield project.

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 1.**Schematic diagram of the conventional slurry infiltration process (adapted from [2]).

**Figure 2.**Schematic diagram of a slurry infiltration column test (adapted from [7]).

**Figure 3.**Coupling process of computational fluid dynamics (CFD)–discrete element method (DEM) (adapted from [10]).

**Figure 6.**Three types of filter cake on the sand column surface: (

**a**) Type I; (

**b**) Type II; (

**c**) Type III.

**Figure 8.**Porosity distribution along the infiltration column of initial state and after infiltration: (

**a**) Type I; (

**b**) Type II; (

**c**) Type III.

Settings | Value |
---|---|

DEM time step | 1 × 10^{−6} |

Coupling interval | 100 |

Model Type | B |

VoidFractionModel | divided |

AverageingModel | dense |

ForceModels | DeFeliceDrag Archimedes |

Fluid Viscosity | 1 × 10^{−6} m^{2}/s |

Fluid Type | Newtonian |

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## Share and Cite

**MDPI and ACS Style**

Zhang, Z.; Yin, T.
A Coupled CFD–DEM Simulation of Slurry Infiltration and Filter Cake Formation during Slurry Shield Tunneling. *Infrastructures* **2018**, *3*, 15.
https://doi.org/10.3390/infrastructures3020015

**AMA Style**

Zhang Z, Yin T.
A Coupled CFD–DEM Simulation of Slurry Infiltration and Filter Cake Formation during Slurry Shield Tunneling. *Infrastructures*. 2018; 3(2):15.
https://doi.org/10.3390/infrastructures3020015

**Chicago/Turabian Style**

Zhang, Zixin, and Tong Yin.
2018. "A Coupled CFD–DEM Simulation of Slurry Infiltration and Filter Cake Formation during Slurry Shield Tunneling" *Infrastructures* 3, no. 2: 15.
https://doi.org/10.3390/infrastructures3020015