Tunneling Parameters Research Articles

Analysis of the Mechanical Characteristics of Tunnels Under the Coupling Effect of Submarine Active Faults and Ground Vibrations

With the rapid development of modern transportation construction, the construction of cross-harbor tunnels has solved the problem of traffic connection between cross-straits, bays and islands. The construction of sub-sea tunnels has technical difficulties such as high difficulty of marine geological survey, close hydraulic connection between strata and seawater, and more developed adverse geology. Based on this, this paper studies the mechanical characteristics of the submarine tunnel under seismic action at the active fault. Firstly, the mechanical model of the universal fault interface is established, and the calculation model of the fault interface is theoretically derived by the method of vibration mechanics, and the influence of the change of the strength of the contact surface and the stiffness of the surrounding rock on both sides of the fault on the transfer coefficient is obtained. Secondly, based on the ground motion input method of two-dimensional homogeneous half-space field, the relevant program of viscoelastic artificial boundary ground motion input is written by MATLAB program, which lays the foundation and premise of load input for mechanical response calculation. Finally, the outcomes of the tunnel parameters and the interplay between the tunnel and the surrounding rock on the cracking of the tunnel lining shape and the mechanical response of the cross-fault sub-sea tunnel underneath seismic motion are mentioned, and it is concluded that the increase in seismic intensity for different seismic intensities under the sea floor has an essentially constant proportion to the increase in acceleration of the seismic response; the seepage effect under the sea floor for the tunnel lining structure reduces the seismic response displacement, velocity and The seabed seepage for the tunnel lining structure reduces the peak seismic response displacement, velocity and acceleration by about 20–35%.

Flat bands and high Chern numbers in twisted multilayer graphene

Motivated by recent Physical Review Letters of Wang and Liu [Phys. Rev. Lett. 128(17), 176403 (2022)] and Ledwith, Vishwanath, and Khalaf [Phys. Rev. Lett. 128(17), 176404 (2022)], we study [G. Tarnopolsky, A. Kruchkov, and A. Vishwanath, Phys. Rev. Lett. 122(10), 106405 (2019)] chiral model of two sheets of n-layer Bernal stacked graphene twisted by a small angle using the framework developed by Becker et al. [Probab. Math. Phys. 3(1), 69 (2022)]. We show that magic angles of this model are exactly the same as magic angles of chiral twisted bilayer graphene with multiplicity. For small inter-layer tunneling potentials, we compute the band separation at Dirac points as we turning on the tunneling parameter. Flat band eigenfunctions are also constructed using a new theta function argument and this yields a complex line bundle with the Chern number −n.

Study on dynamic control system of tunnel variable air volume ventilation based on first-order delay and predictive compensation control model

Using a variable air volume ventilation system is an efficient way to save energy in the tunnel. To address the issues of low control parameter accuracy and high operating energy consumption, the transient flow field and ventilation resistance characteristics were analyzed using conservation equations, and the first-order delay mathematical model of tunnel ventilation control was established by taking tunnel and jet fan parameters into account. The airflow dynamic control model's related parameters and transfer function were also solved. The overshoot, steady value, and adjustment time of the control system were evaluated using simulation and experiment. In full-scale experiments, the required wind speed was converted into the frequency of the jet fans to achieve variable air volume ventilation control. The results show that the variable air volume ventilation control system has the characteristics of nonlinear, and the first-order delay time transfer function is related to the 1/2-th power of ventilation resistance and pressure. The control system performs well, and the response parameters are all within the error range. Moreover, the discussion results of the comparative tests also illustrated that the purpose of dynamic wind speed adjustment could be achieved through frequency conversion control.

Development of shield model test system for studying the bias load of shield in soil-rock compound strata

The deviation mechanism and control of shield attitude are crucial, especially in soil-rock compound strata. To address this issue, a model test apparatus was established to conduct shield bias-load testing during tunneling. A model test was performed on shield tunneling in upper-soft lower-hard strata to verify the functionality of the developed test system. Subsequently, numerical simulations were conducted to investigate the shield bias moment in such strata and its influencing factors. The results demonstrated that the developed shield bias-load model test apparatus effectively controlled tunneling parameters and monitored the shield's bias moment in real-time. In the upper-soft lower-hard strata, the shield's bias moment increased as the proportion of rock layers in the tunnel face increased in the head-up direction, with the highest increase occurring when the soil and rock ratio in the tunnel face was 1:1. Interaction decoupling analysis in the numerical models revealed that the interaction between the shield shell and the strata was the primary cause of the shield's attitude change in soil-rock compound strata. Additionally, the shield's bias moment increased as the soil-rock modulus ratio decreased, with the bias moment range of the soil modulus being 4.66 times that of the rock modulus. This study provides valuable insights for shield operation in soil-rock compound strata.

Identifying Effective Rock-Breaking Ratio Based on Rock Chip Information for Rock-Breaking Efficiency Evaluation of TBM

The rock chip information (shape, size, and particle size distribution) could comprehensively reflect the characteristics of rock mass and rock-breaking efficiency of TBM. This study is aimed at defining a novel index (effective rock-breaking ratio, P r ) to identify the rock-breaking efficiency of TBM based on the rock chip information. To evaluate this approach, a series of field sieving and measuring tests of rock chips was conducted at the water conveyance tunnel construction projects of China. The rock-breaking efficiency evaluation and tunneling parameter improvement of TBM were researched based on P r index. The results showed as follows: (1) from the perspective of energy conversion, the rock chip surface area was calculated through the rock chip cumulative volume distribution model. P r is used to evaluate the rock-breaking efficiency of TBM based on the proportion of surface area of rock chips with particle size larger than 5 mm; (2) P r has a good linear correlation with coarseness index (CI) and specific energy (SE), the higher the TBM tunneling efficiency, the larger P r and CI values, the less SE values; (3) P r increases at first and then decreases with the rise of thrust force of TBM. The optimal thrust force intervals for grade II and III surrounding rocks can be determined to improve the rock-breaking efficiency of TBM. Findings from this study are insightful in terms of accurately evaluating the excavation efficiency and improving the tunneling parameters of TBM.

Vote-Based Feature Selection Method for Stratigraphic Recognition in Tunnelling Process of Shield Machine

Shield machines are currently the main tool for underground tunnel construction. Due to the complexity and variability of the underground construction environment, it is necessary to accurately identify the ground in real-time during the tunnel construction process to match and adjust the tunnel parameters according to the geological conditions to ensure construction safety. Compared with the traditional method of stratum identification based on staged drilling sampling, the real-time stratum identification method based on construction data has the advantages of low cost and high precision. Due to the huge amount of sensor data of the ultra-large diameter mud-water balance shield machine, in order to balance the identification time and recognition accuracy of the formation, it is necessary to screen the multivariate data features collected by hundreds of sensors. In response to this problem, this paper proposes a voting-based feature extraction method (VFS), which integrates multiple feature extraction algorithms FSM, and the frequency of each feature in all feature extraction algorithms is the basis for voting. At the same time, in order to verify the wide applicability of the method, several commonly used classification models are used to train and test the obtained effective feature data, and the model accuracy and recognition time are used as evaluation indicators, and the classification with the best combination with VFS is obtained. The experimental results of shield machine data of 6 different geological structures show that the average accuracy of 13 features obtained by VFS combined with different classification algorithms is 91%; among them, the random forest model takes less time and has the highest recognition accuracy, reaching 93%, showing best compatibility with VFS. Therefore, the VFS algorithm proposed in this paper has high reliability and wide applicability for stratum identification in the process of tunnel construction, and can be matched with a variety of classifier algorithms. By combining 13 features selected from shield machine data features with random forest, the identification of the construction stratum environment of shield tunnels can be well realized, and further theoretical guidance for underground engineering construction can be provided.

Analysis of machine learning-based applications for intelligent construction of shield tunnels

With the quick advancement of the level of information science in shield tunnel construction, the monitoring methods of shield equipment during tunnel boring work are increasingly improved and the recorded construction data includes not only information on the internal workings of the shield equipment, but also on its interaction with the external strata. Machine learning data analysis is powerful and has a wider range of applications and scope than traditional data analysis methods in the civil construction industry. Through the use of machine learning methods, the data and information collected can be mined and analysed in depth to find the intrinsic connections and linkages that can help improve the safety and efficiency ragarding shield tunnel construction. This work presents a literature analysis of current situations of machine learning for shield tunnel construction at home and abroad, briefly describes the basic principles of machine learning methods, summarises and analyses the research situation in shield tunnel construction, reviews the progress of machine learning-based shield equipment condition analysis, intelligent prediction and control methods for shield tunneling parameters and shield tunneling surface deformation prediction, and summarises the current research The study also summarises the shortcomings of current research. Finally, an outlook on the development of shield tunneling towards intelligence is presented.

Analytical solution for seepage pressure of multilayered sand seabed considering interaction between wave-current action and shield tunnel

Existing theoretical studies of the seepage field around subsea shield tunnels under wave action take less account of the tunnel lining permeability, especially the effect of wave and current action on tunnel. Moreover, the solutions generally treat the sand as homogeneous and isotropic, ignoring the influence of multilayered seabed. In this paper, the analytical solutions are presented for the seepage pressure and liquefaction evaluation of sand around tunnel in multilayered seabed under wave and current action. The pore pressure response of pure seabed is obtained by the transmission and reflection matrix method. The mirror image method is introduced to establish governing equation of excess pore pressure reflected by tunnel, and the analytical solution of equation is obtained by Fourier series expansion under the condition of continuous seepage between sand and lining. Based on the superposition principle, the seepage pressure and liquefaction evaluation of sand around tunnel in multilayered seabed are obtained. Then the analytical solutions are compared with numerical and experimental results, and good agreement is obtained. In addition, the influencing factors of wave parameters (wavelength, period, current), seabed parameters (permeability, shear modulus, saturation) and tunnel parameters (lining thickness, lining permeability) are analyzed.

Nonuniform STM Contrast of Self-Assembled Tri-n-octyl-triazatriangulenium Tetrafluoroborate on HOPG.

We have assembled 4,8,12-tri-n-octyl-4,8,12-triazatrianguleniumtetrafluoroborate (TATA-BF4) on highly oriented pyrolytic graphite (HOPG) and have studied the structure and tunneling properties of this self-assembled monolayer (SAM) using scanning tunneling microscopy (STM) under ambient conditions. We show that the triazatriangulenium cations TATA+ form hexagonally packed structures driven by the interaction between the aromatic core and the HOPG lattice, as evidenced by density functional theory (DFT) modeling. According to the DFT results, the three alkyl chains of the platform tend to follow the main crystallographic directions of HOPG, leading to a different STM appearance. The STM contrast of the SAM shows that the monolayer is formed by two types of species, namely, TATA+ with BF4- counterions on top and without them. The cationic TATA+ platform gives rise to a seemingly higher appearance than neutral TATA-BF4, in contrast to observations made on metallic substrates. The variation of the STM tunneling parameters does not change the relative difference of contrast, revealing the stability of both species on HOPG. DFT calculations show that TATA-BF4 on HOPG has sufficient binding energy to resist dissociation into TATA+ and BF4-, which might occur under the action of the electric field in the tunneling gap during STM scanning.

Analysis of the Disc Cutter Cutting Load and Performance during TBM Tunneling in Soft-Hard Varied Strata through Laboratory Cutting Test

Abstract Tunnel boring machine (TBM) disc cutters are specially designed for breaking hard rocks and always exhibit unsatisfactory performance during the soft-hard varied stratum tunneling process. To figure out the load and cutting performance of the disc cutter and avoid unsatisfying excavation face crushing effects, a soft-hard varied strata excavation face model was made and rotary cutting tests with full-scale disc cutters were conducted. The load and cutting performance of the disc cutter under different TBM operating conditions were monitored and analyzed based on the test. It was found that the variation of the disc cutter load did not meet the CSM model completely, and the tangential force of the disc cutters in the heterogeneous areas was only about 30–40 % of that in the uniform areas of the excavation face model. An ideal criterion for the excavation face to be crushed successfully was established and the unknown parameters in it were obtained by fitting the test data. The gradation information and fractal dimension of crushing debris were obtained by the sieved-and-weighed method, which can provide indicators for the crushing effect of the disc cutters. Three different disc cutter poor performance modes in the heterogeneous strata cutting process were analyzed: (1) rotating starting failure of the disc cutters caused by tangential load insufficiency, (2) excavation face crushing failure caused by low crack extending capacities of the materials being cut and improper operating parameters (too small cutting depths or too large disc cutter spacing), and (3) adverse excavation face crushing forms (large or powdery debris). These analyses can help with the performance evaluation of disc cutters and the tunneling parameter adoption of the TBM in soft-hard varied strata tunneling engineering.

Energy storage potential analysis of phase change material (PCM) energy storage units based on tunnel lining ground heat exchangers

Low geo-temperature geothermal energy in the surrounding rock can be extracted by tunnel lining ground heat exchangers (GHEs) and stored in phase change material (PCM) plates to realize the cold energy utilization. However, the research of the coupling heat transfer of tunnel lining GHEs and PCM plates has been rarely reported. In this study, a 3D coupling heat transfer model of tunnel lining GHEs and PCM plates was developed to investigate the cold energy storage performances of PCM plates under different PCM and tunnel parameters. The circulative iteration calculation is used to solve the coupling model. The results show that the cold energy storage of PCM plates utilizing tunnel lining GHEs for energy storage is feasible. The PCM melt fraction and solid phase PCM proportion within the PCM plates decrease and increase respectively with an increase in the PCM thermal conductivity and melting temperature and a reduction in the surrounding rock temperature. The cold energy storage efficiencies of PCM plates improve by 77.8% and 34.1% as the PCM thermal conductivity and melting temperature increase by 1 W/(m K) and 4 ℃. Moreover, the cold energy storage efficiency of PCM plate enhances by 68.5% as the surrounding rock temperature reduces from 10 to 1 ℃. A larger difference between the surrounding rock temperature and PCM melting temperature is efficient for the cold energy storage of PCM plates, and the cold energy storage time and temperature difference show a power function relationship. Finally, increasing the tunnel lining GHEs length is conducive to enhancing the cold energy storage efficiency of PCM plates, whereas this enhancement is limited. In actual applications, selecting a reasonable tunnel lining GHEs length is necessary.

Pipe Curtain Deformation and Surface Subsidence Caused via Excavation of Transverse Pilot Tunnel under Pipe Curtain Support

Relying on the Shenyang Metro Line 4 Shifu Road station, the impact of the construction parameters of the transverse pilot tunnel on the surface subsidence and the pipe curtain deformation was first studied through numerical simulation, followed by the analysis of the impact of the excavation of the transverse pilot tunnel on the deformation characteristics of the pipe curtain through on-site monitoring. The results show the following: the excavation of the middle pilot tunnel is the key stage of the construction. The excavation sequence of H2 and H4 and H6 → H1 and H3 → H5 and H7 caused the least surface subsidence. Increasing the grouting width and improving the strength of the initial support can control the pipe curtain deformation very well, and it is reasonable to choose 1.5 m as the grouting width.

Application of Cross-hole Seismic Tomography to Inferred Cavities Condition.

The construction of the Rajamandala hydroelectric power plant civil works has experienced critical problems that arise in the implementation process, with the occurrence of cracks cavities conditions in the headrace tunnel locations. We applied the cross-hole seismic tomography to detect important heterogeneities and mechanical proprieties of the formations between two boreholes in this case inferred cracks cavities condition. The seismic source is inside the borehole “a sparker” and the receivers “hydrophones” are in an adjacent one, the sparker is lowered into the borehole one step at the time. Seismic waves, propagating in the tunnel wall rock, spread widely, and are reflected and refracted when encountering interfaces between rocks with different acoustic impedances. Reflected waves returning to the receivers are recorded. After the processing of the first arrivals of the P waves we obtain a cross section of the seismic velocities in between the two wellbores. With the cross-hole seismic tomography, the basis could be provided to the tunnel construction and parameter adjustments to guarantee the construction safety. Our result shown that there is a weak zone above the tunnel with low Vp zone (~1.2 km/s) may be related to weak zone (may be fracture, unconsolidated rock, and fluid-filled rock or landslide caving). Checker-board resolution test is also conducted to determine the tomogram areas that are reliable to be interpreted. Our challenges are we have poor resolution due to not enough raypath. The Cross-hole seismic tomography can effectively and safely guide the excavation of the tunnel section working surface in combination with reconstructed images and excavation technology.

Statistical and numerical analysis on characteristics and influence factors of construction cracks of large-diameter underwater shield tunnel: a case study

Tunnel excavation is prone to segment cracks, which may lead to serious safety accidents. This work aims to investigate the type, location and occurrence time of cracks in a large-diameter underwater shield tunnel and also ascertain the causes of the cracks. The correlations between crack characteristics and shield tunneling parameters were analyzed. The effect of jack deflection and poor assembly on cracks were investigated using a refined finite element model of two consecutive rings with consideration of the assembly clearance and the constraint effect of the shield machine. The results confirmed that 93% of the cracks were formed between the current ring and the last ring jacking stage. Positive cracks induced by jack deflection occurred during the current ring jacking stage, while the lengths of the cracks, proportional to the constraint of the boring machine on the segments, remained constant during the subsequent construction process. The cracks caused by poor assembly quality arose during the current and next ring jacking stages. Furthermore, the cracks generated in the current ring jacking stage would propagate during the subsequent construction process. The type, length, and number of cracks were influenced by the assembly clearance. The inverted V-shape longitudinal joints caused more cracks than any other assembly defects. The finding of this study results and conclusions are expected to contribute to the reduction of cracks at the jacking stage of the large-diameter underwater shield tunnels with eccentricity force transfer platforms.

Autonomous intelligent control of earth pressure balance shield machine based on deep reinforcement learning

In order to reduce the construction risk caused by human operation error and improve the geological adaptive ability of the shield machine, an autonomous intelligent control method is proposed for shield machine within the framework of interaction–judgment–decision based on Deep Deterministic Policy Gradient (DDPG) deep reinforcement learning in this study. Due to the strong nonlinear relationship between the shield machine's tunneling parameters, this research builds a deep reinforcement learning environment using mechanism model of sealed cabin pressure. DDPG agent model of the shield machine is established to replace the shield machine to interact and train with the geological environment. By minimizing the difference between the target pressure setting value and the sealed cabin pressure value, the dynamic balance between the sealed cabin pressure and the pressure on the excavation surface is realized, and the best strategy is obtained. Through real-time interaction with the geological environment, the method in this paper can dynamically adjust the tunneling parameters, accurately control the sealed cabin pressure, and has a strong geological adaptive ability. By realizing the intelligent decision-making of the tunneling parameters, it greatly improves the independent decision-making ability of the shield machine system, reduces the inaccuracy of human operation, and provides an effective guarantee for the efficient and safe operation of the shield machine. This study applies deep reinforcement learning technology to the control field of earth pressure balance shield machine, promotes AI technology, and provides a new idea for the development of AI construction technology in engineering field.

Intelligent real-time prediction of multi-region thrust of EPB shield machine based on SSA-LSTM

During the tunneling process of shield machine, the accurate determination of tunneling parameters is the guarantee of safe operation of shield machine. Through the real-time construction data analysis and mining of shield machine, the tunneling parameters at the next moment are obtained in real-time. Based on this, this paper proposes an intelligent real-time prediction method for multi-region thrust of EPB shield machine based on Sparrow Search algorithm-Long and Short-term Memory (SSA-LSTM). By correlation analysis of the construction big data, the data features with a great correlation of shield machine thrust are obtained. And it is used as the input of LSTM prediction model to explore the nonlinear relationship between inputs and output. SSA is used to optimize LSTM prediction model to establish a more accurate nonlinear relationship, and then the multi-region thrust of shield machine at the next moment is accurately obtained. The simulation results show that SSA-LSTM model can accurately predict the thrust of each region of shield machine at the next moment, and the prediction performance is better than other models. The method provides a reference basis for shield machine to implement accurate thrust regulation and provides a guarantee for effective control of Earth pressure balance (EPB) in sealed cabin to ensure construction safety, which has engineering application value.

Development of a Test Rig for the Measurement of Small Wind Turbines in a Wind Tunnel

Abstract This paper describes the development, design and function of a test rig for the measurement of small wind turbines in a wind tunnel and presents the first exemplary measurements of the performance characteristics of various horizontal and vertical rotors. A central part of this test rig is the developed control system with an electronic load, which enables an automated recording of the measured values for the evaluation of the power coefficients (cp) and tip-speed ratio (λ) values. Another challenge emerges owing to the known differences in the power spectrum, because the power coefficients of drag rotors (<20%) are different from those of buoyancy rotors (<40%). The system was adapted to the different ranges by means of a stepless switching using various resistors. The entire control and regulation unit was compactly implemented using a programmable logic controller (PLC) and dynamically linked to the operating parameters of the wind tunnel. This enables an automated operation of the wind tunnel during the determination of the performance parameters of the investigated wind turbines.

Analysis of rock cuttability based on excavation parameters of TBM

Rock cuttability has great influence on the rock excavation efficiency of TBM (tunnel boring machine). In order to evaluate rock cuttability in real time, quickly, accurately and efficiently during TBM excavating, the relevant excavation parameters of Zagros, Kerman and Bazideraz tunnels were first collected. Then, the regression analyses between excavation parameters and rock cuttability were carried out. The two-dimensional regression analyses studied the relationship between operating parameters (thrust F and rotation speed RPM) and the characterization parameters (torque T and penetration rate PR). The three-dimensional regression analyses were utilized to create the PR and specific energy SE models based on operating parameters. The result shows that the established three-dimensional regression models have good prediction performance, and its performance is superior to two-dimensional models. Moreover, the prediction model of uniaxial compressive strength UCS and the classification model of rock cuttability were founded based on SE. The rock cuttability is divided into three levels, namely, easy (level 1), medium (level 2), and poor (level 3), in which the corresponding SE ranges are 0 to 6, 6 to 10 and exceeds 10 kWh·m−3, respectively. Finally, the intelligent algorithms, combined with excavation parameters, were introduced to establish UCS prediction model and rock cuttability classification model, and the good prediction performance was achieved. The above studies can provide necessary references and ideas for real-time, rapid, accurate and effective evaluation of rock cuttability based on TBM excavation parameters, and has certain guiding significance for engineering application.

Evaluation of Longitudinal Equivalent Bending Stiffness of Shield Tunnel with Residual Jacking Force

Existing tunnels are often subject to longitudinal bending when undercrossing tunnelling. It is of significance to more accurately evaluate the longitudinal equivalent bending stiffness (LEBS) of the existing tunnel within the influential zone. A new analytical method is proposed for the LEBS of tunnel segmental lining joints with consideration of incorporating combined action of residual jacking force and bending moment. The solution can degenerate into a special case with no residual jacking force, which agrees well with other classical solutions and validates the model and solutions. Sensitivity analyses are carried out for the bending moment, tunnel geometry, tensile stiffness of bolts and concrete grade on the LEBS, and effective ratio of the LEBS considering residual jacking force. The LEBS and the effective ratio of LEBS increase nonlinearly as an S-curve with the residual jacking force and decrease with an increasing bending moment. The results show that the LEBS of the shield tunnel is variable stiffness, which exhibits a significant nonlinearity. The maximum increment of the LEBS reaches 80.3% as the ring width increases from 1 m to 2 m, and the LEBS of the shield tunnel increases by approximately 1.3 × 107 kN·m2 for every 4-bolt added. The influential order on the LEBS of shield tunnels is the tunnel diameter > lining thickness > bolts diameter > ring width > the number of bolts > elastic modulus of bolts. When the effective ratio of LEBS is more than 0.85, it does not change with the ring width, lining thickness, tensile stiffness of bolts, and concrete grade. The response characteristics of the tunnel parameters on the LEBS, considering the residual jacking force, could provide a theoretical basis for the design and deformation control of shield tunnels when undercrossing tunnelling.

Study on the Classification and Identification Methods of Surrounding Rock Excavatability Based on the Rock-Breaking Performance of Tunnel Boring Machines

Rock mass conditions are extremely sensitive to tunnel boring machine (TBM) tunneling. Therefore, establishing a surrounding rock excavatability (SRE) classification system applicable to TBM tunnels. Accurately and intelligently identifying excavatability grades can also facilitate efficient TBM tunneling and intelligent construction. Specific excavation and penetration rates were used to evaluate SRE. Their correlations with geological and tunneling parameters were explored using the field data from two water conveyance tunnels in China with different lithologies. A high-precision empirical SRE classification system was constructed using TOPSIS for multi-objective decision-making, and it was verified using engineering cases. An intelligent identification model for SRE grades in the stable phase of a TBM excavation cycle was established using 12,382 TBM rock-breaking datasets and deep forest models. Ten characteristic parameters, e.g., total thrust, were selected as model input features. Hyperparameter optimization was achieved using the grid search method. Deep forest was compared with decision tree, random forest, support vector classifier, and deep neural network. The contribution of the model’s features was measured using random forest. The main conclusions are as follows: the proposed SRE classification method is feasible and matches well with the actual excavation. In the intelligent identification of SRE classification, the accuracy and F1 scores when using deep forest were 96.33% and 0.9581, respectively. Deep forest exhibited better grade identification performance than the four models. Among the ten input features, penetration is the most important feature for the model’s input, while the top shield cylinder rod’s chamber pressure is the least important. The findings can provide some references for SRE classification and prediction and intelligent TBM control.