Tunnelling and Underground Space Technology最新文献_第8页

Study on construction mechanical characteristics and pinch rocks reinforcement schemes of honeycomb tunnel clusters in Mountainous City

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2025-01-21 DOI: 10.1016/j.tust.2025.106397

Hai Chen , Xiaohan Zhou , Xinrong Liu , Suliman Lojain , Qiang Xu , Lijun Ren

Due to the growing need for underground space and the acceleration of urbanization, narrow clearance tunnel clusters are being created, making construction more challenging. This paper investigated tunnel clusters consisting of five parallel tunnels at Hongyan Village in Chongqing as a background project. The mechanical behaviour of the clusters has been studied by using three main methods as the following: model test, theoretical analysis, and numerical simulation. The induced forces characteristics in the pinch rock based on the stress correlation theory have been accomplished, with establishing a pinch-rock yielding reserve (YR) model for different pinch-rock reinforcement schemes to be compared with the other ones. The results can be introduced as the following: (1) During the stage of temporary support removal, the incremental displacement of the crown of each tunnel accounted for 6.25 %∼60.53 % of the total displacement. Moreover, it seems that the temporary support has a significant influence on the stability of the surrounding rock. (2) The value of YR depends on the position of the shear and tensile damage line, the “centre” and the “radius” of the Mohr’s circle. A smaller value indicates a higher tendency towards instability. (3) For the left pinch rock that has been disturbed many times during the construction of the tunnel clusters, the combination of prestressed tie-back anchors- grouting is preferred, which raises the maximum value of the YR to 1,324.62 kN/m.

{"title":"Study on construction mechanical characteristics and pinch rocks reinforcement schemes of honeycomb tunnel clusters in Mountainous City","authors":"Hai Chen , Xiaohan Zhou , Xinrong Liu , Suliman Lojain , Qiang Xu , Lijun Ren","doi":"10.1016/j.tust.2025.106397","DOIUrl":"10.1016/j.tust.2025.106397","url":null,"abstract":"<div><div>Due to the growing need for underground space and the acceleration of urbanization, narrow clearance tunnel clusters are being created, making construction more challenging. This paper investigated tunnel clusters consisting of five parallel tunnels at Hongyan Village in Chongqing as a background project. The mechanical behaviour of the clusters has been studied by using three main methods as the following: model test, theoretical analysis, and numerical simulation. The induced forces characteristics in the pinch rock based on the stress correlation theory have been accomplished, with establishing a pinch-rock yielding reserve (<em>YR</em>) model for different pinch-rock reinforcement schemes to be compared with the other ones. The results can be introduced as the following: (1) During the stage of temporary support removal, the incremental displacement of the crown of each tunnel accounted for 6.25 %∼60.53 % of the total displacement. Moreover, it seems that the temporary support has a significant influence on the stability of the surrounding rock. (2) The value of <em>YR</em> depends on the position of the shear and tensile damage line, the “centre” and the “radius” of the Mohr’s circle. A smaller value indicates a higher tendency towards instability. (3) For the left pinch rock that has been disturbed many times during the construction of the tunnel clusters, the combination of prestressed tie-back anchors- grouting is preferred, which raises the maximum value of the <em>YR</em> to 1,324.62 kN/m.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106397"},"PeriodicalIF":6.7,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study on the deformation of existing tunnel under the combined effect of pit excavation and dewatering based on the Kerr foundation model

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2025-01-20 DOI: 10.1016/j.tust.2025.106382

Meng Fei, Qiao Shifan

There is a significant progression towards the trend of significant depth and extensive scale in foundation pit construction, where the excavation range is large and dewatering measures are usually required. To overcome the shortcomings associated with the complexity of the 3D numerical analysis model and the long period of on-site measurement in existing studies, a two-stage analysis method is proposed to consider the impacts on existing tunnels under the combined effects of pit excavation and dewatering. The first step involves calculating the additional stress imposed on the existing tunnel under the construction of pit bottom, pit side, and dewatering. Secondly, a differential equation describing the deformation effects on the existing tunnel is established based on the Kerr foundation model. Finally, the control equation is solved using the Galerkin method. Three engineering cases with different locations and tunnel parameters are selected to validate the proposed method. The effects of various factors on the deformation of the existing tunnel under the influence of pit excavation and dewatering are analyzed. Subsequently, an orthogonal experiment is designed to analyze the significant factors influencing the deformation of the existing tunnel and their prioritization, and an optimal parameter combination for controlling the existing tunnel deformation is obtained.

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引用次数: 0

Intelligent monitoring-based resilience assessment system for prefabricated underground structures based on restorability

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2025-01-20 DOI: 10.1016/j.tust.2025.106411

Tong Qiu, Xiangsheng Chen, Wei Rao, Dong Su, Xiaohua Bao, Chengyu Hong

In the context of low-carbon strategies, China has joined the global leadership series of prefabricated underground structures (PUS). However, PUS faces significant challenges in construction, maintenance, and restoration subjected to multi-hazard impacts, particularly at the assembled joints. Addressing this research gap, this study focuses on the PUS life-cycle resilience based on joint restorability. The full-scale experimental studies were conducted on typical assembled joint of PUS and its restored specimen. Integrating experimental results with intelligent monitoring techniques, a resilience assessment framework for the PUS was proposed. The effectiveness of this framework was validated through a case study. Key findings include: (1) Even with minor restoration level undetected rotations, the assembled joint can rapidly reach major restoration thresholds after cumulative operational impacts. (2) Intelligent monitoring techniques enable rapid and accurate responses to restoration needs. It reduces recovery time and cost by more than 10 times, with a 52 % resilience enhancement compared to traditional techniques. (3) The proposed joint restoration technology enhances the yield and ultimate load-bearing capacities by 11.8 % and 7.9 %, respectively, primarily owing to the enhancement of interface bond strength. (4) Restored joints exhibit higher resilience under subsequent daily operations and extreme conditions. Compared to original assembled joints, restored joints show 29 % improvements in rotation tolerance at minor restoration thresholds. Along with 22 % resilience enhancement, the restored joint significantly reduces more than 90 % restoration costs. This study not only provides key restoration technologies and intelligent resilience management methods for the life-cycle resilience of PUS, but also has significant practical application value and resilience enhancement implications.

{"title":"Intelligent monitoring-based resilience assessment system for prefabricated underground structures based on restorability","authors":"Tong Qiu, Xiangsheng Chen, Wei Rao, Dong Su, Xiaohua Bao, Chengyu Hong","doi":"10.1016/j.tust.2025.106411","DOIUrl":"10.1016/j.tust.2025.106411","url":null,"abstract":"<div><div>In the context of low-carbon strategies, China has joined the global leadership series of prefabricated underground structures (PUS). However, PUS faces significant challenges in construction, maintenance, and restoration subjected to multi-hazard impacts, particularly at the assembled joints. Addressing this research gap, this study focuses on the PUS life-cycle resilience based on joint restorability. The full-scale experimental studies were conducted on typical assembled joint of PUS and its restored specimen. Integrating experimental results with intelligent monitoring techniques, a resilience assessment framework for the PUS was proposed. The effectiveness of this framework was validated through a case study. Key findings include: (1) Even with minor restoration level undetected rotations, the assembled joint can rapidly reach major restoration thresholds after cumulative operational impacts. (2) Intelligent monitoring techniques enable rapid and accurate responses to restoration needs. It reduces recovery time and cost by more than 10 times, with a 52 % resilience enhancement compared to traditional techniques. (3) The proposed joint restoration technology enhances the yield and ultimate load-bearing capacities by 11.8 % and 7.9 %, respectively, primarily owing to the enhancement of interface bond strength. (4) Restored joints exhibit higher resilience under subsequent daily operations and extreme conditions. Compared to original assembled joints, restored joints show 29 % improvements in rotation tolerance at minor restoration thresholds. Along with 22 % resilience enhancement, the restored joint significantly reduces more than 90 % restoration costs. This study not only provides key restoration technologies and intelligent resilience management methods for the life-cycle resilience of PUS, but also has significant practical application value and resilience enhancement implications.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106411"},"PeriodicalIF":6.7,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Enhancing convergence speed and accuracy of virtual field optimization method for microseismic source location in tunnels

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2025-01-20 DOI: 10.1016/j.tust.2025.106366

Jian He , Huailiang Li , Binhong Li , Nuwen Xu , Junnan Wen , Yuedong Li

Accurate and rapid microseismic source location is the foundation for tunnel rockburst warning. Here, we present a novel location strategy that employs an improved mayfly algorithm (IMA) to enhance the convergence speed and accuracy of the virtual field optimization method (VFOM) for tunnel microseismic events. By optimizing the initial position of the mayfly population and the moving velocity of mayfly personals, we develop an IMA with superior convergence speed in searching for source locations. The proposed method utilizes paired microseismic receivers in the tunnel monitoring array to create hyperbolic surfaces. Then, the IMA is employed to rapidly and accurately determine the intersection point of all hyperbolic surfaces, defining it as the microseismic source location. We compare the IMA-VFOM with different error levels in seismic wave velocity or arrival time against other traditional location approaches based on travel time differences. The results confirm that the IMA-VFOM’s convergence speed is, on average, more than 4 times that of the MA-VFOM algorithm. Compared to conventional methods, the IMA-VFOM method demonstrates higher location accuracy and stability. The average location error of the proposed method is

4.0043 m

when applied to real rockburst microseismic events in tunnels.

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引用次数: 0

Tunnel intersection mechanics: Closed-form pseudo-3D approximations for deformation modeling and shear-failure prediction

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2025-01-20 DOI: 10.1016/j.tust.2025.106394

Andreas Michael

Deformation modeling of underground tunnel intersections attempts to provide answers on the occurrence of localized structural instabilities under different, and possibly dynamically-changing, in-situ conditions. Design decisions hinge on these findings; since much of the stresses underground are compressive, shear-failure predictions provide outlines for maintaining structural stability on the intersections of underground tunnel excavations in anisotropic rock masses, such as those made using tunnel-boring machines (TBMs).

Three-dimensional (3D) deformations around the circumference of the orthogonal intersection plane of two tunnels are modeled using a pseudo-3D approximation approach established in petroleum engineering, which adjusts for stress interferences coming from each tunnel. The rationale for such approach is that the normal stresses on the circumference of the primary “Tunnel A” are used as inputs to evaluate the stresses on the base of a smaller, secondary “Tunnel B” which approximates the two tunnels’ intersection plane.

The resultant closed-form expressions are used as a boundary condition in a Mohr-Coulomb-type model for shear failures, in a cylindrical coordinate system. Dimensionless plots (“allowable stress diagrams”) provide the means to visually recognize whether the induced stresses on the tunnel intersection can trigger shear failure, or not. The dynamic impact of sediment settling is quantitatively assessed and non-orthogonal tunnel intersections are discussed.

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引用次数: 0

Fine controlled blasting of subsurface excavation for subway stations in soft–hard mixed-medium rock mass

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2025-01-20 DOI: 10.1016/j.tust.2025.106407

Wanzhi Zhang , Jie Mei , Keguo Sun , Bangshu Xu

Drilling and blasting excavation methods along with primary arch-cover primary supports are frequently employed in the construction of urban subway stations. However, traditional blasting methods fail to control tunnel face flatness, overbreak, and underbreak in soft–hard mixed-medium rock mass owing to symmetric and invariable blasting parameters. The Shishan Road Station of Qingdao Metro Line 6 is located in a soft–hard mixed-medium rock mass. Traditional blasting excavation methods result in considerable over-excavation of the soft rock on the one side, forming a concave inside, and minor over- and under-excavation of the hard rock on the opposite side, forming a convex outside. Herein, numerical models were developed to analyze the rock damage caused by contour blasting in soft–hard mixed-medium rock mass. Different perimeter hole spacings, burden thicknesses, and charge weights were investigated to identify the optimal parameters. Based on these models, this study proposes an asymmetric blasthole pattern and charge parameters, such as a smaller spacing and charge weight on the soft rock side and deeper hole lengths on the hard rock side. In addition, higher delay times were suggested to control the blasting vibration. Field tests showed that the optimized blasting scheme effectively controlled the flatness, overbreak, and underbreak. The utilization rate of blast holes increased by 5%, the average overbreak area decreased by 57.3%, and underbreak did not occur. The blasting energy of a single initiation and the proportion of low-frequency energy decreased significantly, resulting in better control of rock damage caused by blasting vibrations.

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引用次数: 0

Time-dependent seismic fragility analysis of subway station structure subjected to chloride-induced corrosion

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2025-01-20 DOI: 10.1016/j.tust.2025.106376

Zilan Zhong, Jiaxi Guo, Bu Zhang, Xiuli Du

Subway station structures near coast are at risk of corrosion caused by chloride, resulting in material and structural component deterioration over time and impacting overall performance during earthquakes. This study proposes a numerical framework for the time-dependent seismic fragility analysis of subway station structures, considering chloride-induced corrosion, based on the IDA method. This study utilizes finite element simulations of typical subway station structures in Qingdao, Shandong, China, focusing on nonlinear dynamic interactions between soil and structure, as well as the impact of chloride-induced corrosion on aging effects. The time-dependent damage states within subway station structures are determined through a nonlinear static pushover analysis. Subsequently, the IDA method is employed to generate time-dependent seismic fragility curves and surfaces specific to subway station structures. The numerical results indicate that the impact of chloride-induced corrosion on the subway station structure cannot be ignored. In the corrosion environment, the seismic performance assessment of subway station structures must take into account time-dependent damage states resulting from the degradation of material properties and the reduction in seismic capacity. The probability of a subway station structure exceeding various damage states monotonically increases during its service life. The subway station structure primarily suffers minor to moderate damage under the ground motion with a return period of 2450 or 10000 years, as it reaches its design service life.

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引用次数: 0

Probability analysis on tunnels in heterogeneous strata based on borehole data-driven conditional random fields and convolutional neural network

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2025-01-18 DOI: 10.1016/j.tust.2025.106402

Gaoyu Ma , Chuan He , Zhengshu He , Rongmin Bai , Guowen Xu

Tunnels in heterogeneous strata always encounter spatially varied geological formations, causing asymmetric responses and localized failure in the supporting structure. The homogeneity assumption for surrounding strata, commonly adopted in tunnel design and construction, will neglect the inherent spatial uncertainty of rock mass and lead to the overestimation in tunnel bearing capacity. The conventional stochastic calculations for analyzing tunnel performance in heterogeneous strata also fail to reflect the statistical asymmetry in mechanical behaviors of supporting structure. With the application of mechanized equipment with built-in sensors in drilling and blasting construction, rock parameters at borehole locations can be promptly derived through the drilling data. This systematic on-site monitoring necessitates a rational and stationary extrapolation using rock parameters from the excavation face to the surrounding strata, as the inversion results provide a more precise depiction of the properties of surrounding strata and enable the dynamic design for supporting structure during construction. Therefore, an innovative approach was proposed in this research to conduct probability analysis on the mechanical behaviors of tunnels in heterogeneous strata based on conditional random field models. The statistical characteristics of random variables in these fields were constrained by the derived rock parameters on the excavation face using Hoffman method. The probability distributions of mechanical behaviors were analyzed for tunnels with both symmetric and asymmetric anchor cable systems. In addition, a trained convolutional neural network (CNN) model was implemented to reduce the computational resources required in massive numerical simulations. The tunnel deformation at different circumferential locations can be predicted with an acceptable accuracy and minimal time consumption that significantly facilitated the probabilistic assessments.

{"title":"Probability analysis on tunnels in heterogeneous strata based on borehole data-driven conditional random fields and convolutional neural network","authors":"Gaoyu Ma , Chuan He , Zhengshu He , Rongmin Bai , Guowen Xu","doi":"10.1016/j.tust.2025.106402","DOIUrl":"10.1016/j.tust.2025.106402","url":null,"abstract":"<div><div>Tunnels in heterogeneous strata always encounter spatially varied geological formations, causing asymmetric responses and localized failure in the supporting structure. The homogeneity assumption for surrounding strata, commonly adopted in tunnel design and construction, will neglect the inherent spatial uncertainty of rock mass and lead to the overestimation in tunnel bearing capacity. The conventional stochastic calculations for analyzing tunnel performance in heterogeneous strata also fail to reflect the statistical asymmetry in mechanical behaviors of supporting structure. With the application of mechanized equipment with built-in sensors in drilling and blasting construction, rock parameters at borehole locations can be promptly derived through the drilling data. This systematic on-site monitoring necessitates a rational and stationary extrapolation using rock parameters from the excavation face to the surrounding strata, as the inversion results provide a more precise depiction of the properties of surrounding strata and enable the dynamic design for supporting structure during construction. Therefore, an innovative approach was proposed in this research to conduct probability analysis on the mechanical behaviors of tunnels in heterogeneous strata based on conditional random field models. The statistical characteristics of random variables in these fields were constrained by the derived rock parameters on the excavation face using Hoffman method. The probability distributions of mechanical behaviors were analyzed for tunnels with both symmetric and asymmetric anchor cable systems. In addition, a trained convolutional neural network (CNN) model was implemented to reduce the computational resources required in massive numerical simulations. The tunnel deformation at different circumferential locations can be predicted with an acceptable accuracy and minimal time consumption that significantly facilitated the probabilistic assessments.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106402"},"PeriodicalIF":6.7,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Axial chain rockbursts in deep tunnels excavated via drilling and blasting

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2025-01-18 DOI: 10.1016/j.tust.2025.106395

Hong-Pu Li , Ben-Guo He , Xiang-Rui Meng , Shengcun Yan , Tao Chen

Chain rockbursts have a long duration and significant hazards, severely affecting construction progress, yet their occurrence patterns and formation mechanisms remain unclear. Monitoring was conducted on a deeply buried tunnel in southwest China for axial chain rockbursts (ACRs) occurrences. The recorded ACRs (23 weak, 3 moderate, and 3 intense) were analyzed to reveal their patterns of occurrence, geological characteristics, and mechanisms of formation. ACRs were studied through geological surveys, analysis of on-site failure characteristics, and a series of laboratory tests. The findings indicate that ACRs are most likely to occur near river valleys, faults, and geological contact zones, where the overburden is significant, and the direction of major stress is perpendicular to the tunnel axis. In ACRs-prone regions, the content of brittle minerals in the surrounding rock tends to be relatively high. At the site studied, the proportion of plagioclase in the diorite ranges from 55 % to 65 %. ACRs are likely to be triggered when the dip of structural planes forms a small angle with the principal stress, and when their strike is parallel (or nearly parallel) to the tunnel axis, or when a group of structural planes intersects the tunnel axis at a small angle and is distributed along it. During tunnel excavation in areas prone to ACRs, appropriate measures should be sufficiently robust and ductile, aimed at enhancing the strength and ductility of the surrounding rock, with support structures closely following the excavation face. This investigation contributes to our understanding of ACRs and may help in designing methods for predicting and preventing their occurrence.

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引用次数: 0

Two-scale basalt fibers reinforced concrete shield tunneling segments for underground constructions 地下建筑双尺度玄武岩纤维增强混凝土盾构管片

IF 6.7 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Tunnelling and Underground Space Technology

Pub Date : 2025-01-17 DOI: 10.1016/j.tust.2025.106383

Min Hou , Jiang Feng , Hougai Shi , Ruiyi Jiang , Hengyi Zhu , Hualin Fan

In this paper, two-scale Basalt fibers reinforced polymer (BFRP) rebars reinforced arch (BRRA) technique was developed through applying BFRP rebars to macroscopically reinforce concrete shield tunneling segments (STSs). BFRP minibars were mixed into concrete as the micro reinforcements. Six two-scale BRRAs were prepared with content of minibars changing from 0%, 0.5% to 1.5%. Full-scale flexural experiments were performed to reveal the mechanical performances of the BRRAs. With higher minibar content, the utilization ratio of the BFRP rebars is much greater and the BRRA has longer elastoplastic deformation, higher bearing capacity and better ductility. Long elastic deformation of BFRP rebars and reinforcing mechanism of BFRP minibars improve the bearing capacity and ductility of the BRRA.

本文通过将双尺度玄武岩纤维增强聚合物（BFRP）钢筋应用于混凝土盾构管段的宏观加固，发展了双尺度玄武岩纤维增强聚合物（BFRP）钢筋加固拱（BRRA）技术。将BFRP迷你棒掺入混凝土中作为微增强筋。制备了6种二标BRRAs，迷你棒的含量从0%、0.5%到1.5%不等。进行了全尺寸的弯曲实验，以揭示brra的力学性能。微棒含量越高，BFRP筋的利用率越高，BRRA的弹塑性变形时间越长，承载能力越高，延性越好。BFRP筋的长弹性变形和BFRP小筋的加固机理提高了BRRA的承载力和延性。

引用次数: 0