Slurry Pressure Research Articles

CFD–DEM modelling of the infiltration of non-spherical slurry particles in granular soils

The slurry filtration process at an excavation surface plays an important role in supporting pressure transmission, which is crucial to the stability of a tunnel face during slurry shield tunnelling. In this paper, a series of coupled computational fluid dynamics (CFD)–discrete element method (DEM) numerical simulations were carried out to model the slurry filtration column test. Oblate spheroids of varying aspect ratios were adopted to represent slurry particles. A simplified pitching torque model was implemented to better simulate the motion of slurry particles. The pressure distribution, void fraction, permeability and orientations of the particles were analysed as the aspect ratio was systematically changed. The pressure distribution, void fraction and the permeability within a stratum are highly dependent on the aspect ratio of the particles. Particles with larger aspect ratios tend to effectively seal infiltration channels and transfer slurry pressure to effective pressure, thereby helping to maintain stability at the tunnel face. This research study explores how particle shape impacts the slurry infiltration procedure and the microstructure of the filter cake.

Slurry pressure at the cutting zone in multi-wire sawing: An experimental study

Multi-wire sawing has been widely used in the processing of semiconductor material wafers employed in integrated circuits, solar cells, etc. Recently, free abrasive multi-wire sawing has been gradually replaced by solid abrasive multi-wire sawing technology in the domain of solar wafers. However, free abrasive sawing still plays an important role in the processing of electronic-grade monocrystalline silicon wafers, where the requirements on the wafer quality are continuously increasing. Because the free abrasive multi-wire sawing process is very complex, its material removal mechanisms are not fully understood. In this study, experiments were designed to measure the slurry pressure at the cutting zone during a free abrasive multi-wire sawing process to fabricate monocrystalline silicon wafers, and the pressure distribution condition throughout the cutting zone was obtained. Two sets of micropores of 0.17 mm diameter were processed on the experimental workpiece to transmit the cutting zone fluid pressure to the sensor. Each group of micropores consisted of 17 small pores, divided into three rows, with the row spacing consistent with the pitch width of the wire guide. During installation, the center line of each row of micropores was aligned with the center line of the steel wire. The pressure at the cutting zone was measured using the micropores to transfer the slurry pressure to the sensor. Calibration experiments were conducted by considering the capillary effects of the micropores, and the actual pressure at the cutting zone was obtained. Experimental results show that the slurry pressure was 0.16 bar at 40 mm near the slurry inlet. As the distance from the slurry inlet increased, the pressure fluctuated around 0.14 bar. Furthermore, at a distance of 160 mm from the slurry inlet, the sensor was not able to detect the pressure at the cutting zone. The experimental results from the free abrasive multi-wire sawing pressure measurement showed that material removal involves a three-body action comprising the metal wire, abrasive grains, and workpiece. At the cutting zone far from the location of the slurry inlet, forming a stable and continuous film with the slurry is difficult. The experimental results confirm that the force of material removal during the sawing process mainly comes from the wire tension of the steel wire. The film thickness of the slurry in the cutting zone is determined by the diameter of the abrasive between the wire and ingot. The experimental conclusion is of great significance for understanding the complex material removal process in the cutting zone for multi-wire sawing.

CFD simulations for flashing pressurized slurry in metallurgical processing

A compressible multiphase CFD model has been developed to simulate the flashing process of the three-phase slurry at high temperatures and pressures. The model is validated with the gas-water flash process in the literature. A comparison of simulation results for gas-liquid and gas-liquid-solid systems indicates that the presence of solids changes important physical characteristics of these systems, including velocity, pressure, and shock location. The simulations indicate that changing the deflection angle, length, and diameter of the blast tube will significantly influence the flashing process. Increased blast tube length can reduce the velocity of the outlet significantly. The performance of the blast tube will be impaired if the deflection angle is too large. Increased tube diameter boosts mass flow rate while decreasing shock strength and increasing velocity at the outlet. These simulation results would be beneficial for the design and operation of flashtubes.

Behavioral Investigations of Three Parallel Large Reinforced Concrete Circular Pipes with the Construction of Pipe Jacking

The pipe jacking method is gradually attracting increasing levels of attention and is becoming an important method for constructing underground engineering. However, jacking large-size concrete pipes in urban core areas subjected to complicated geological conditions is still a big problem preventing the employment of the pipe jacking method, and further studies related to pipe jacking are required. This paper presents a case study on the construction of three parallel large-size reinforced concrete circular pipes in the upper-soft and lower-hard composite formations, in which the construction work was implemented using the slurry balance pipe jacking method with the sequence of jacking the 1# and 3# pipes prior to the 2# pipe being implemented in field construction. This case study was implemented by employing numerical simulations with the aforementioned pipe jacking sequence, which focused on the stress and deformation variations of the reinforced concrete circular pipes, as well as the vertical settlement of the ground surface during the jacking processes, and considering the influences from the excavation pressure and grouting pressure of the drag-reducing thixotropic slurry. The simulation results revealed that a higher excavation pressure from the pipe jacking machine can easily induce an excessive pushing and squeezing effect of the excavated soil with the uplift phenomenon, while the increasing grouting pressure can be used to reduce the overall vertical settlement of the ground surface, whereas an excessive grouting pressure may have no effectiveness on protecting the reinforced concrete circular pipes. This work provides the numerical foundations for investigating the behavior of jacked parallel large-size reinforced concrete circular pipes.

‘Smart’ transonic atomization and heating of a pulsating non-Newtonian liquid sheet

We introduce proportional integral derivative (PID) controls into transonic pulsatile steam-assisted non-Newtonian slurry heating and disintegration. The purpose is to ensure consistent, reliable atomization during generic process upset scenarios, while this implementation involves a sudden pronounced slurry property shift. The uniquely interrelated physical responses of phase interfacial atomizer instabilities require continuously coupled PID controllers, the first of which automates slurry flow based on slurry pressure drop. The second compensates for the variable phase momentum ratio and sets a new heating steam flow based on the targeted droplet size. Three tests with increasing rigor were conducted to demonstrate successful coupled controller adaptability. During controller compensations, slurry and steam flows were significantly altered and drastically changed atomization characteristics. For a 100-fold increase in slurry viscosity, however, the controllers successfully maintained consistent droplet size and slurry flow resistance. The control methodology was shown to be mesh-independent and to operate across multiple atomization regimes.

Influence of nozzle structure and process parameters for 3D printing HTPB-based propellant

This paper studies the influence of nozzle structure and process parameters on the solid propellant 3D printing process, so as to better guide nozzle structure optimization and process improvement, and realize continuous extrusion and molding of solid propellant. Four characteristic parameters such as nozzle diameter, nozzle shrinkage angle, process temperature, and wall slip coefficient are selected, and the influence of these four parameters on the extrusion speed and pressure of solid propellant slurry in the nozzle is discussed by using the orthogonal test principle and ANSYS/POLYFLOW. The results show that the most significant factor affecting the outlet velocity uniformity index and outlet pressure is the wall slip coefficient, followed by the nozzle diameter, and the influence of temperature and contraction angle is small.

Tunnel Face Stability Considering the Influence of Excess Slurry Pressure

With excess slurry pressures exerted on the tunnel face, slurry particles tend to infiltrate into the soil in front of the tunnel. There will be excess pore pressure ahead of the tunnel in the case of infiltration, leading to an impairment in the supporting effect contributed by the excess slurry pressure. Corresponding to three slurry infiltration scenarios distinguished by the forms of the filter cake, different pressure transfer models are employed to describe the pore pressure distribution. Using the kinematic approach of limit analysis and the numerically simulated seepage field, the study of tunnel face stability under different slurry infiltration cases is extended by employing a 3D discretization-based failure mechanism. In addition, two simple empirical formulas describing the pore pressure distributions above the tunnel and in advance of the tunnel are established and verified. Combined with the dichotomy method and strength reduction method, the safety factors yielding rigorous upper-bound solutions are obtained by optimization. The proposed method is validated by a comparative analysis. The developed framework allows considering the influence of excess pore pressure on the whole failure mechanism and the three-dimensional characteristics of seepage. A parameter analysis is performed to study the effect of the excess slurry pressure, hydraulic conditions, soil strength properties, and pressure drop coefficient. The results show that the steady-state flow model leads to much more conservative results than the full-membrane model. The safety factor increases with the increasing excess slurry pressure and the decreasing pressure drop coefficient. The present work provides an effective framework to quickly assess the face stability of tunnels under excess slurry pressure considering different filter cake scenarios.

Investigations of filter-clog mechanism and prediction model of slurry penetration during slurry pressure transfer

Investigations of filter-clog mechanism and prediction model of slurry penetration during slurry pressure transfer

Shield Attitude Adjustment Induced by Slurry Pressure Balance (SPB) Shield Tunneling Considering the Effects of Overbreak Cutter: A Numerical Simulation by DEM and Engineering Application

Based on a cross-river tunnel of Wuhan Metro Line 8, we present a two-dimensional discrete element model for shield attitude adjustment considering the effect of overbreak cutters. The shield shell mechanics under the influence of over-excavation rate, over-excavation orientations, and overburden load are simulated, and the tunneling mechanics law and the ultimate range during the adjustment of the shield attitude are investigated. The simulation results indicate the following: (1) The greater the over-excavation rate, the smaller the force exerted by the soil layer in the negative direction of the shield movement; therefore, increasing the over-excavation rate is helpful in expanding the range of shield attitude adjustment. (2) The shield is stressed symmetrically while conducting positive and negative horizontal adjustments in the soil layer, which has a symmetrical distribution, but vertical upward adjustment is more difficult than vertical downward adjustment. (3) With the increase in overburden load, the space of the shield attitude adjustment is gradually reduced at the same over-excavation rate. A good engineering application was achieved in this project using the simulation model. It is recommended to use the attitude adjustment method by controlling the tunneling parameters. In difficult situations such as high overlying loads, the over-excavation cutter can be used to assist in adjusting the shield attitude.

Effect of Pressure, Concentration and Sludge Volume on Two-phase Filtrate Volumes Using Bentonite Clay Sludge

The effect of pressure, solids concentration and volume of slurry on total and two-phase filtrate volumes was investigated to establish optimum conditions for routine laboratory filtration. Full factorial design with three levels was utilized to obtain 27 unique experiments. The slurry used was prepared by mixing crushed and sieved bentonite clay of 75 microns with distilled water at different concentrations as obtained from the design of experiment. A filter press was utilized and the results were used to calibrate a two-phase exponential equation for sludge filtration to extract the first and second stage filtrate volumes. The total filtrate volume improved with increasing applied pressure and decreasing solids concentration. A slurry volume of 0.22 litres was found to be ideal. Similar effects were noticed on the first and second stage filtrate volume except that an optimum was discovered at 0.18 litres of slurry. The second stage filtration produced an upward curve with a point of inflection at a range of 0.18 to 0.22 litres of slurry. The second stage filtrate volume is also discovered to be directly proportional to the total filtrate volume. This connection may be considered for use to assess the filterability of other slurries.

A novel hydro‐mechanical coupled multiphysics model for slurry penetration in sand with application to face stability analysis of shield tunnel

AbstractThe slurry penetration in tunnels driven by the slurry TBM in the highly permeable water‐bearing ground is a complicated multiphysics process, which significantly affects the stability of the excavation face but has not been fully modelled. This study establishes a novel hydro‐mechanical coupled multiphysics modelling approach for face stability analysis. Different from existing methods, the proposed one is able to quantify simultaneously the spatial and temporal variation of slurry concentration, viscosity, stagnation gradient, soil porosity and pore pressure, as well as the soil skeleton deformation induced by the transferred slurry pressure in two or three‐dimension. The spatial and temporal pressure transfer from slurry suspension to soil skeleton during slurry penetration can be obtained. The coupled formulations are implemented into a finite element package for initial and boundary value problems at the engineering scale and enhanced by the Petrov‐Galerkin weighted residual stabilisation technique. After being validated through the experimental slurry infiltration tests, it is applied to a field case analysis to predict the excess pore pressure in front of the tunnel face, which shows good agreement with the field measurement. The efficiency of the applied slurry pressure and the pressure transfer mechanism are thus verified. Comparative calculations about the influence of the pressure transfer model are presented to further improve the understanding of the pressure transfer mechanism. The proposed approach is also verified applicable to estimate the optimum slurry pressure.

A new pressure gradient model of slurry shield pipeline system coupling with rheological properties and wall slip behaviour under sandy stratum

Pipeline transport is of uttermost importance during slurry shield tunneling, and the precise calculation of the pressure gradient of the pipeline system is the premise for the optimal design of industrial slurry pipeline system. This paper proposed a new muck slurry pressure gradient model of slurry shield pipeline system coupling with the wall slip behaviour based on the Herschel-Bulkley rheological model (H-B model) to estimate the pressure gradient of the muck slurry under sandy stratum. Effects of the sands volume fraction and average particle size on the rheological properties of the muck slurry in pipeline system were investigated to construct the H-B rheological parameters prediction models, which were coupled into the proposed pressure gradient model. Besides, the accuracy and dependability of the proposed model were validated through the engineering field tests and model tests, and the prediction results of the proposed pressure gradient model has an average error of 10.6% and 8.2% with engineering field test data and model test data respectively. The results indicated that the muck slurry is a typical thixotropic fluid. The sand volume fraction and particle size both significantly affect the rheological properties of the muck slurry, the yield stress and plastic viscosity of H-B rheological parameters increase exponentially with the sand volume fraction increasing and increase linearly with the average particle size increasing, the power law index of H-B rheological parameters increases linearly as average particle size and sands volume fraction increase. Ultimately, the research results can provide reasonable suggestions and references for the designing of pipeline system and efficient tunneling of slurry shield.

Experimental investigation on the reinforcement of a high-pressure jet grouting pile for an ultra-shallow tunnel in a strongly weathered stratum

In this paper, the performance of a high-pressure grouting material and consolidation body, the key parameters of tunnel surrounding rock reinforcement, and the field reinforcement effect are compared and studied. The results show that 1) the compressive strength, elastic modulus, and seepage resistance of the consolidation body are related to the water–cement ratio. The permeability of the consolidation body increases with increasing water–cement ratio under the constant head; under the condition of a certain water–cement ratio, the strength increases with an increase in cement content. To meet the construction requirements and the slurry stability, a small water–cement ratio is appropriate. 2) Slurry pressure, rotary spray speed, and lifting speed on the single pile static load bearing capacity have a significant impact. Under the same static load conditions, the greater the slurry pressure, the lower the cumulative settlement value of the single pile, the cumulative settlement value increases less, and the amount of change in rebound is the same; with the increase in the rotational speed of the rotary spray, the lower the cumulative settlement value of the single pile, and the rate of change of the cumulative settlement value of the single pile decreases; and with the increase in the lifting speed, the cumulative settlement value of the single pile increases and the rate of change of the cumulative settlement value decreases. 3) The pile body cement soil is more uniform, has high strength, and is brittle, and the stratum where the slurry part is located is a loose powder clay layer and sandy layer. 4) After high-pressure jet grouting pile reinforcement, the top surrounding rock is more stable after the excavation of an ultra-shallow buried tunnel, the fissures between the surrounding rocks are filled with cement soil consolidation, and the integrity is improved. Certain piles also play a certain role in stopping water; high-pressure jet grouting pile reinforcement to improve the integrity of the surrounding rock played a role in consolidating the weak soil layer above the tunnel vault, creating conditions for the safe excavation of the shallow buried section of the tunnel.

Experimental method and application of the slurry “diffusion-bleeding-seepage” of isolated overburden grout injection

Isolated overburden grout injection (IOGI) is a green mining method to control surface subsidence. Slurry water significantly influences grouting effectiveness and mining safety. This study establishes a three-dimensional visualization experimental system for slurry “diffusion-bleeding-seepage” to investigate the seepage law of slurry water. The system is composed primarily of a transparent box (1.2 m × 0.5 m × 0.25 m) and support, with the solid–liquid coupling seepage similar material and modules for mining, grouting injection, slurry pressure and displacement monitoring, overburden saturation monitoring, and water leakage monitoring of the working face. A similar material with good permeability and non-disintegration is obtained by hydrophilic, water absorption, and permeability tests. Grouting and mining are simulated by pulling acrylic sheets and pumping slurry. With the fly ash slurry entering the injection layer, the slurry undergoes water–cement separation, and the water bleeding is formed to seep into the similar material. The volumetric water content of the similar material is obtained by arranging multiple groups of volumetric water content sensors into the similar material. The corresponding saturation is obtained by theoretical calculation. The experimental system is used to simulate the seepage of slurry water in a high initial saturation overburden, and the characteristics of injection slurry diffusion and water bleeding are obtained. The profile distribution of seepage of slurry water is found to possess a semi-elliptical shape. Under the condition of high initial saturation, slurry water appears in the working face. The system provides a convenient method for further research of IOGI slurry water seepage.

Establishing the Influence of CaCl2 on the Vulnerability of Cement Slurries to Gas Migration Using the Modified Wellbore Simulation Chamber Apparatus

Summary A modified wellbore simulation chamber (MWSC) apparatus was used to perform a series of gas migration tests to identify the vulnerability period of cement slurries containing three different percentages of CaCl2. In addition, the Virtual Cement and Concrete Testing Laboratory (VCCTL) software was used to establish a correlation between the vulnerability period and the fundamental properties of the hydrating slurry, such as the degree of hydration (DoH) and the volume fraction of hydration products. MWSC test results confirmed that as long as the slurry pressure is higher than the formation gas pressure, gas migration does not take place. However, once the slurry pressure drops below the formation gas pressure, gas migration can occur. The incorporation of CaCl2 affects the vulnerability period in two ways. First, CaCl2 increases the strength gain rate of the slurry, thus shortening the time for the slurry pressure to drop below the formation gas pressure. In addition, the incorporation of CaCl2 shortens the time needed for the slurry to develop sufficient rigidity to withstand gas migration. However, the effect of CaCl2 on the latter is significantly higher. The test results show that for the studied cement slurry, the incorporation of 2% CaCl2 reduces the vulnerability period by approximately 40%. It was also shown that regardless of the percentage of CaCl2, all three mixtures developed sufficient rigidity to withstand gas migration when they reached the DoH of approximately 25%. At this hydration stage, the sum of volume fraction of hydration products for all the mixtures was approximately 24%.

Analytical study and field investigation on the effects of clogging in slurry shield tunneling

The pressurized slurry is the essential part of the slurry pressure balanced shield (SPBS) for stabilizing the working face and transporting the excavated soil. If clogging occurs in case of adverse ground conditions or equipment failure, a series of consequences will happen, such as sudden changes in slurry pressure, massive ground loss, and deformation or even collapse at tunnel workface. The present study reviewed and summarized the clogging mechanism of the slurry shield under different ground conditions. Then, based on the law of conservation of mass and Bernoulli’s Equation, an analytical approach was developed to investigate the effects of clogging on the slurry velocity and pressure along with the deformation of tunnel workface. Furthermore, a case study and field measurements were conducted to validate the analytical method. The significant findings drawn from the study can be summarized as follows: (1) The clogging of a slurry shield imposes severe effects on the slurry pressure balancing mechanism of shield tunneling. It can occur in both cohesive and non-cohesive ground with different formation mechanisms. (2) During the initial clogging, the slurry pressure above the spring line increases, and that below the spring line decreases. With the clogging deteriorating, the slurry velocity drops considerably at the top of the deposit area and escalates near the discharging port. The presence and increase of deposit lead to a sharp rise of slurry pressure in the slurry chamber, especially in the clogging region. (3) The reverse circulation of the slurry system (RCSS) is useful to clear the clogging. Still, the slurry deposits at the bottom will obstruct the slurry reverse flow, resulting in inward deformation of the tunnel face and a drastic increase in overcutting volume. (4) The ultimate volume deviation ratio of the slurry was proposed as a useful index to alarm the potential risk of collapse induced by the RCSS. (5) The timely adoption of RCSS is strongly suggested when any abnormal changes in the slurry pressure or the ultimate volume deviation ratio are observed for the first time.

A Comprehensive Method for the Optimization of Cement Slurry and to Avoid Air Channeling in High Temperature and High-Pressure Conditions

Air channeling in the annulus between the casing and the cement sheath and/or between the cement sheath and formation is the main factor affecting the safe operation of natural gas wells at high temperatures and pressures. Prevention of this problem requires, in general, excellent anti-channeling performances of the cement sheath. Three methods to predict such anti-channeling performances are proposed here, which use the weightless pressure of cement slurry, the permeability of cement stone and the volume expansion rate of cement sheath as input parameters. Guided by this approach, the anti-channeling performances of the cement slurry are evaluated by means of indoor experiments, and the cement slurry is optimized accordingly. The results show that the dangerous transition time of the cement slurry with optimized dosage of admixture is only 76 min, the permeability of cement stone is 0.005 md, the volume shrinkage at final setting is only 0.72%, and the anti-channeling performances are therefore maximized. The effective utilization of the optimized cement slurry in some representative wells (LD10–1-A1 and LD10–1-A2 in LD10–1 gas field) is also discussed.

Surface integrity and material removal mechanism in fluid jet polishing of optical glass

Fluid jet polishing (FJP) is a promising technology that has been increasingly used in the superfinishing of complex optical lenses, mirrors, and molds on several materials. The influence mechanism of polishing parameters on the damage characteristics, element composition, and surface quality of optical glass was studied through a series of FJP experiments to achieve the high-efficiency and low-damage ultra-precision polishing requirements of optical components. A numerical model for FJP was developed based on computational fluid dynamics (CFD), and the effects of slurry pressure and particle size on the flow field and particle motion characteristics were studied combined with statistical theory. The brittle-ductile transition model and erosion model when abrasive particles eroded optical glass were established to obtain a better understanding of the material removal mechanism during FJP. The damage control strategy can be clarified according to the coupling relationship between the impact velocity and particle size of abrasive particles when radial and transverse cracks are generated in the optical glass. The experimental results verify that the established model can predict the material removal characteristics well. The simulation results also indicate that the erosion removal of the optical glass by abrasive particles is a completely ductile mode under the polishing experimental conditions in this study. The results can provide solid theoretical support for equipment upgrade and process optimization of FJP.

Slurry flow characteristics through a horizontal pipeline at different Prandtl number

The settling behavior of solid particles in the slurry pipeline leads to bed formation and sedimentation at the bottom of the pipeline. This in turn causes the blockage of the pipeline resulting in more energy consumption and a pressure drop in the slurry pipeline. The present work investigates the effect of the different Prandtl numbers on the slurry flow characteristics through a horizontal pipe. Since the flow is a liquid-solid mixture, therefore, a steady-state three-dimensional Eulerian two-phase model in combination with the RNG k-ε turbulence model is implemented for the current simulation in the commercial software ANSYS FLUENT. Numerical predictions and procedures for the mixture of solid concentrations are generally in good agreement with the past experimental data available in the literature. Slurry flow features are examined at four different Prandtl numbers i.e., 2.88, 3.42, 4.62 and 5.83 for different-sized glass beads (125, 200, 275, 350 and 440 μm) slurry for the concentration ranging from 40 to 60% (by weight) at a mean flow-velocity of 5 m/s. The findings show that the pressure drop rises with the escalation in particle sizes and Prandtl number for chosen efflux concentration range. Furthermore, low Prandtl fluid demonstrates relatively higher granular pressure, temperature and wall shear stress, which further increases with raise in solid concentration and particle size. In addition, higher Prandtl number fluid demonstrates maximum specific energy consumption (SEC) for every particle and efflux concentration range. • 3D CFD modeling of slurry flow via horizontal straight pipe is investigated. • Effect of different Prandtl number on slurry flow characteristics is studied. • Effect of particle size and concentration on slurry pressure drop is presented. • At lower Prandtl number, maximum granular pressure and temperature is established. • Transportation of slurry with higher Prandtl fluid is more energy efficient.

Prediction of maximum ground surface settlement induced by shield tunneling using XGBoost algorithm with golden-sine seagull optimization

In order to avoid damage during shield tunnel construction to adjacent buildings on the ground, it is of paramount importance to precisely predict the Maximum Surface Settlement (MSS) deformation induced by shield tunneling under the surface. In this paper, a hybrid algorithm model incorporating the Extreme Gradient Boosting (XGBoost) with the Golden-sine Seagull Optimization Algorithm (GSOA) is proposed, namely the GSOA-XGBoost model. A total of 323 datasets including torque, penetration rate, thrust, cutterhead rotation speed, slurry pressure, grouting pressure, cover depth, and distance between cutting face and monitored section are taken as input parameters, and the corresponding measured MSS deformation is adopted as the output parameter. This dataset is employed to train the MSS prediction algorithm model. The analysis results indicate that the proposed GSOA-XGBoost hybrid algorithm model is much superior to other models in terms of accuracy, stability and computation time, and strong correlations are discovered between the predicted and measured settlements. Our model can predict the MSS deformation caused by shield tunnel construction with higher reliability, strong robustness and fault-tolerant capacity, and greatly reduces the engineering risk. Simultaneously, the consistency of the slurry pressure and grouting pressure values is calculated by the SOA-XGBoost and the grid search method, which demonstrates the feasibility and rationality of proposed hybrid algorithm model.