Deformation control method of a large cross-section tunnel overlaid by a soft-plastic loess layer: a case study

Hong, Qiuyang; Lai, Hongpeng; Liu, Yuyang; Ma, Xiaoyan; Xie, Jing

doi:10.1007/s10064-021-02239-w

Cited by 27 publications

(9 citation statements)

References 40 publications

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“…The detailed mechanical parameters are shown in Figure 3. The lining structure adopts an elastic model [24], among which the initial support structure adopts C30 concrete with a thickness of 30 cm. The secondary lining structure adopts C40 concrete with a thickness of 50 cm [41], and its mechanical parameters are shown in Table 1.…”

Section: Analysis Of Deformation Mechanism Of Primary Support Structu...mentioning

confidence: 99%

“…Most loess tunnels are subject to waterfall erosion, lateral erosion, and headward erosion [22,23] due to surface water infiltration or groundwater erosion during the construction process, which in turn results in the reduction in the strength of the surrounding rock [24,25], large deformations, and wet subsidence of the loess [26][27][28]; therefore, the mechanism of structural failure in loess tunnels under different water contents is the focus of research. In addition, in groundwater flow simulation, the input parameters are Water 2024, 16, 581 2 of 16 uncertain [29] and certain methods are needed to predict the parameters [30].…”

Section: Introductionmentioning

confidence: 99%

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Stability Assessment of Tunnels Excavated in Loess with the Presence of Groundwater—A Case Study

Deng,

Zhang,

et al. 2024

Water

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The high water content of the surrounding rock in loess tunnels will lead to the deterioration of rock strength, causing deformation and damage to the initial support structure and thereby affecting safety during construction and operation. This article first analyzes the strength characteristics of loess under different water contents through indoor physical and mechanical tests. Secondly, based on numerical simulation results, the ecological environment, and design requirements, the water content threshold is determined. Finally, a reinforcement scheme combining surface precipitation measures and curtain grouting measures is proposed, and the reinforcement effect is analyzed based on on-site monitoring data. The results show that as the water content of loess increases, the cohesion, internal friction angle, and elastic modulus of the surrounding rock all decrease, leading to an increase in the sensitivity of the surrounding rock to excavation disturbances and a deterioration in strength. During the construction process, it shows an increase in the vault settlement and sidewalls’ convergence. During the process of increasing the distance between the monitoring section and the palm face, the settlement and convergence of the tunnel show a rapid growth stage, slow growth stage, and stable stage. The water content threshold is determined to be 22%. The reinforcement scheme of combining surface precipitation measures with curtain grouting measures not only meets the requirements of the ecological environment but also makes the settlement and convergence values lower than the yellow warning deformation values required by the design.

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Section: Analysis Of Deformation Mechanism Of Primary Support Structu...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stability Assessment of Tunnels Excavated in Loess with the Presence of Groundwater—A Case Study

Deng,

Zhang,

et al. 2024

Water

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“…Large cross-section tunnels have been widely adopted in highway tunnels because of their simplicity, high cost-effectiveness, and mechanized construction with the drill and blast method [2]. During the large cross-section tunnel construction, challenges include poor geological conditions, support structure parameters, and effects on the surrounding rocks [3,4]. To overcome all of these difficulties, artificial intelligence (AI) technology has been widely adopted in the tunnel construction process, specifically in the area of AI for poor geological prediction [5], disaster risk evaluation [6], construction decision-making [7], and deformation prediction [8].…”

Section: Introductionmentioning

confidence: 99%

The Construction and Application of a Deep Learning-Based Primary Support Deformation Prediction Model for Large Cross-Section Tunnels

Zhang,

Mei,

Wang

et al. 2024

Applied Sciences

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The deformation of tunnel support structures during tunnel construction is influenced by geological factors, geometrical factors, support factors, and construction factors. Accurate prediction of tunnel support structure deformation is crucial for engineering safety and optimizing support parameters. Traditional methods for tunnel deformation prediction have often relied on numerical simulations and model experiments, which may not always meet the time-sensitive requirements. In this study, we propose a fusion deep neural network (FDNN) model that combines multiple algorithms with a complementary tunnel information encoding method. The FDNN model utilizes Convolutional Neural Networks (CNNs) and Long Short-Term Memory (LSTM) networks to extract features related to tunnel structural deformation. FDNN model is used to predict deformations in the Capital Ring Expressway, and the predictions align well with monitoring results. To demonstrate the superiority of the proposed model, we use four different performance evaluation metrics to analyze the predictive performance of FDNN, DNN, XGBoost, Decision Tree Regression (DTR), and Random Forest Regression (RFR) methods. The results indicate that FDNN exhibits high precision and robustness. To assess the impact of different data types on the predictive results, we use tunnel geometry data as the base and combine geological, support, and construction data. The analysis reveals that models trained on datasets comprising all four data types perform the best. Geological parameters have the most significant impact on the predictive performance of all models. The findings of this research guide predicting tunnel construction parameters, particularly in the dynamic design of support parameters.

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“…Compared with the common loess tunnel construction methods such as the three-step method and CRD method, the slotted shield method can make full use of the advantages of the shield method and mining method (Liang et al, 2016;Zhou et al, 2020;Hong et al, 2021;Xu et al, 2021;An et al, 2022). In other words, before excavation, the cutters were inserted into the soil instead of the advanced small pipe for presupport, and the follow-up excavation and support work were carried out under the protection of the shield shell, which can significantly reduce the mutual interference between the various processes.…”

Section: Introductionmentioning

confidence: 99%

Study on the construction deformation of a slotted shield in loess tunnels with different buried depths and large sections

Han

Fang

et al. 2023

Front. Earth Sci.

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Since there is no precedent for the use of slotted shield tunneling in the large section of high-speed railways in China, the relevant technological accumulation and systematic research achievements are few. Therefore, this paper provides theoretical support for loess tunnel construction decision-making through the study of slotted shields and is expected to promote the mechanization and even intelligent construction of a high-speed iron-loess tunnel. Taking the Luochuan tunnel of the Xiyan high-speed railway as the engineering background, this paper uses the numerical simulation software packages of ANSYS and FLAC3D to study the tunnel deformation (surface settlement, vault settlement, tunnel bottom uplift, and horizontal convergence) caused by the slotted shield construction in three different buried depths of 30, 40, and 50 m surrounding rock. The deformation law and mechanical characteristics of a cutter shield construction of large cross-section loess tunnels under the influence of different buried depths are put forward. Results showed that 1) the mutual interference between the working procedures can be significantly reduced by inserting the cutting tool into the soil instead of the advanced tubule before excavation; 2) the settlement in the upper part of the longitudinal axis of the tunnel is the largest; the greater the depth of the tunnel is, the smaller the surface settlement is; and 3) the horizontal deformation of the arch waist and foot of the tunnel under different buried depths is symmetrically distributed into the tunnel during the whole process of slotted shield tunneling.

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Deformation control method of a large cross-section tunnel overlaid by a soft-plastic loess layer: a case study

Cited by 27 publications

References 40 publications

Stability Assessment of Tunnels Excavated in Loess with the Presence of Groundwater—A Case Study

Stability Assessment of Tunnels Excavated in Loess with the Presence of Groundwater—A Case Study

The Construction and Application of a Deep Learning-Based Primary Support Deformation Prediction Model for Large Cross-Section Tunnels

Study on the construction deformation of a slotted shield in loess tunnels with different buried depths and large sections

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