Data-driven real-time prediction for attitude and position of super-large diameter shield using a hybrid deep learning approach

The presented research introduces a novel hybrid deep learning approach for the dynamic prediction of the attitude and position of super-large diameter shields-a critical consideration for construction safety and tunnel lining quality.This study proposes a hybrid deep learning approach for predicting dynamic attitude and position prediction of super-large diameter shield.The approach consists of principal component analysis(PCA)and temporal convolutional network(TCN).The former is used for employing feature level fusion based on features of the shield data to reduce uncertainty,improve accuracy and the data effect,and 9 sets of required principal component characteristic data are obtained.The latter is adopted to process sequence data in predicting the dynamic attitude and position for the advantages and potential of convolution network.The approach’s effectiveness is exemplified using data from a tunnel construction project in China.The obtained results show remarkable accuracy in predicting the global attitude and position,with an average error ratio of less than 2 mm on four shield outputs in 97.30%of cases.Moreover,the approach displays strong performance in accurately predicting sudden fluctuations in shield attitude and position,with an average prediction accuracy of 89.68%.The proposed hybrid model demonstrates superiority over TCN,long short-term memory(LSTM),and recurrent neural network(RNN)in multiple indexes.Shapley additive exPlanations(SHAP)analysis is also performed to investigate the significance of different data features in the prediction process.This study provides a real-time warning for the shield driver to adjust the attitude and position of super-large diameter shields.

Experimental and numerical investigation of the flexural performance of channel steel-bolt joint for prefabricated subway stations

Flexural performance of joints is critical for prefabricated structures.This study presents a novel channel steel-bolt(CB)joint for prefabricated subway stations.Full-scale tests are carried out to investigate the flexural behavior of the CB joint under the design loads of the test-case station.In addition,a three dimensional(3D)finite element(FE)model of the CB joint is established,incorporating viscous contact to simulate the bonding and detachment behaviors of the interface between channel steel and concrete.Based on the 3D FE model,the study examines the flexural bearing mechanism and influencing factors for the flexural performance of the CB joint.The results indicate that the flexural behavior of the CB joint exhibits significant nonlinear characteristics,which can be divided into four stages.To illustrate the piecewise linearity of the bending moment-rotational angle curve,a four-stage simplified model is proposed,which is easily applicable in engineering practice.The study reveals that axial force can enhance the flexural capacity of the CB joint,while the preload of the bolt has a negligible effect.The flexural capacity of the CB joint is approximate twice the value of the designed bending moment,demonstrating that the joint is suitable for the test-case station.

Numerical study on transverse deformation characteristics of shield tunnel subject to local soil loosening

In this study,a refined numerical model for segmental lining of a shield tunnel,which contains detailed models of reinforcement and connecting bolts,is established using finite element software.The model is first validated by the results from a full-scale model test.Then,based on the load-structure method,this numerical model is adopted to investigate the internal force distribution and the transverse deformation characteristics of the shield tunnel when it is subject to local soil loosening.The influence of loosening position,loosening range,and loosening extent on the mechanical response is extensively studied through comprehensive numerical analyses.The results show that the main influence of local soil loosening on the ring is to disturb the force balance and change the constraint conditions,thus changing the deformation pattern and force state.After the loosening occurs,the bending moment of the ring in the loosening range increases and the axial force decreases.The vertical convergence of the ring is the largest and the equivalent stiffness of the ring is the smallest when the local soil loosened at the haunch and the loosening range a is 90°.The vertical convergence of the ring increases with increasing of the loosening extent,and the equivalent stiffness decreases linearly with increasing of the loosening extent.The results can enhance our understanding of mechanical behaviors of segmental lining associated soil loosening,and will show a possible way for detecting soil loosening based on the measured deformation and internal forces.

Prediction of ground settlements induced by twin shield tunnelling in rock and soil--A case study

Ground movements caused by the construction of tunnels and excavation are inevitable.Estimation of such movements is a very important for risk management in tunnel design.This paper presents a case study of ground settlements induced by twin shield tunnelling in Copenhagen using analytical and numerical methods and their predictions.The predictions are compared with the monitored settlements.The comparison shows that the predictions are sufficiently conservative.

A continuum method for granular collapse with μ(I)-rheology-based dynamic earth pressure coefficient

In this paper,a continuum model with dynamic earth pressure coefficient is established to describe the granular slump process by introducingμ(I)rheology.This rheology is adopted to quantify the normal stresses in our proposed model rather than shear stresses in classical models.The constitutive laws of different depth-averaged continuum approaches including the hydrodynamic,Savage–Hutter and proposed models are comparatively investigated in terms of the rheological effects on the spread of a granular column.The simulation results indicate that the proposed dynamic model captures some significant features during granular slump on inclined planes with different inclination angles(for example,the runout distance,runout time,and final profile).The proposed model can also reproduce the inner static sided axisymmetric region observed in tests when the granular column's initial aspect ratio(ratio of height to radii)is small.