Tunnelling and Underground Space Technology最新文献_第2页

Experimental study on smoke movement characteristics and temperature distribution in high geothermal tunnel fire during construction with shaft structures

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

Tunnelling and Underground Space Technology

Pub Date : 2025-02-12 DOI: 10.1016/j.tust.2025.106470

Chuangang Fan , Maozhen Liu , Xiaoxian Fei , Jiayi Ha , Linbo Du , Ao Jiao , Yuhao Li

With the growing scale of construction tunnels in areas with complex geological conditions, the fire risk in this tunnels cannot be ignored and its control is facing the challenge of complex environments such as high geothermal hazards. In this work, a series of tests were conducted to investigate the smoke movement and temperature distribution in construction tunnel fire under the geothermal condition and natural ventilation through shafts. Results show that the air is heated by the high-temperature walls, which forms thermal airflow and an initial temperature field within the tunnel, resulting in the accelerated smoke spread. The construction shaft can mitigate the effect of geothermal environment and restrict the smoke movement. The maximum smoke temperature rise of the fire located in the geothermal area is affected by the geothermal temperature and a corrected prediction model is established. The smoke temperature distribution along the tunnel can be divided into three regions based on the fire source and construction shaft. With the increasing geothermal temperature, the overall smoke temperature rise increases and the temperature attenuation rate decreases. However, only smoke temperature rise at the downstream of the shaft drops rapidly with the increasing shaft height. Furthermore, exponential function formulas are established to describe the smoke temperature distribution. This study can provide references for risk identification and resilience improvement of tunnels during construction in complex natural environments.

{"title":"Experimental study on smoke movement characteristics and temperature distribution in high geothermal tunnel fire during construction with shaft structures","authors":"Chuangang Fan , Maozhen Liu , Xiaoxian Fei , Jiayi Ha , Linbo Du , Ao Jiao , Yuhao Li","doi":"10.1016/j.tust.2025.106470","DOIUrl":"10.1016/j.tust.2025.106470","url":null,"abstract":"<div><div>With the growing scale of construction tunnels in areas with complex geological conditions, the fire risk in this tunnels cannot be ignored and its control is facing the challenge of complex environments such as high geothermal hazards. In this work, a series of tests were conducted to investigate the smoke movement and temperature distribution in construction tunnel fire under the geothermal condition and natural ventilation through shafts. Results show that the air is heated by the high-temperature walls, which forms thermal airflow and an initial temperature field within the tunnel, resulting in the accelerated smoke spread. The construction shaft can mitigate the effect of geothermal environment and restrict the smoke movement. The maximum smoke temperature rise of the fire located in the geothermal area is affected by the geothermal temperature and a corrected prediction model is established. The smoke temperature distribution along the tunnel can be divided into three regions based on the fire source and construction shaft. With the increasing geothermal temperature, the overall smoke temperature rise increases and the temperature attenuation rate decreases. However, only smoke temperature rise at the downstream of the shaft drops rapidly with the increasing shaft height. Furthermore, exponential function formulas are established to describe the smoke temperature distribution. This study can provide references for risk identification and resilience improvement of tunnels during construction in complex natural environments.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"159 ","pages":"Article 106470"},"PeriodicalIF":6.7,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395786","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

Deformation and protection of tunnels influenced by excavation dewatering in soft soil strata with leaky aquifers

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

Tunnelling and Underground Space Technology

Pub Date : 2025-02-12 DOI: 10.1016/j.tust.2025.106468

Qinghan Li , Gang Zheng , Xuesong Cheng , Xiaorui Shi , Na Zhang , Shilong Zhou , Wenlong Cheng

Deep excavation engineering often causes deformation and destruction of adjacent existing shield tunnels. In previous studies, the influence of deep excavation on tunnel was mainly concentrated on tunnel deformation caused by retaining structure deformation, and the maximum range of the influence zone was approximately 4 times the excavation depth (4H_e). However, there has been little research on tunnel deformation caused by groundwater drawdown when tunnels are located outside the traditional influence range (4H_e) of the excavation. In this study, the deformation and damage characteristics of tunnels caused by dewatering in a deep excavation project were analysed using field data, and control methods of tunnel deformation caused by excavation dewatering in leaky aquifers were proposed and discussed. In this project, the maximum settlement reached 8.23 mm for tunnel at the location far than 4H_e from the excavation, and the influence range of the dewatering on tunnel was nearly 8H_e. Furthermore, the higher stiffness of the station reduced the settlement and convergence but aggravated the dislocation of the tunnels within approximately 40 m from the station, causing many leakage points. To protect the tunnels, groundwater recharge and deep-shallow-well dewatering scheme (dewatering wells in phreatic aquifer and confined aquifer were set independently) were proposed and applied during subsequent construction, which effectively avoided further tunnel settlement. Groundwater recharge also induced slight uplift and horizontal deformation of the tunnels to the opposite side of the excavation. In addition, recharge should be started in advance and remain in operation until the groundwater level was fully restored. For deep excavations near important infrastructures in soft soil strata with leaky aquifers, the same dewatering and recharge system in this case study is suggested to adopted.

{"title":"Deformation and protection of tunnels influenced by excavation dewatering in soft soil strata with leaky aquifers","authors":"Qinghan Li , Gang Zheng , Xuesong Cheng , Xiaorui Shi , Na Zhang , Shilong Zhou , Wenlong Cheng","doi":"10.1016/j.tust.2025.106468","DOIUrl":"10.1016/j.tust.2025.106468","url":null,"abstract":"<div><div>Deep excavation engineering often causes deformation and destruction of adjacent existing shield tunnels. In previous studies, the influence of deep excavation on tunnel was mainly concentrated on tunnel deformation caused by retaining structure deformation, and the maximum range of the influence zone was approximately 4 times the excavation depth (4<em>H</em><sub>e</sub>). However, there has been little research on tunnel deformation caused by groundwater drawdown when tunnels are located outside the traditional influence range (4<em>H</em><sub>e</sub>) of the excavation. In this study, the deformation and damage characteristics of tunnels caused by dewatering in a deep excavation project were analysed using field data, and control methods of tunnel deformation caused by excavation dewatering in leaky aquifers were proposed and discussed. In this project, the maximum settlement reached 8.23 mm for tunnel at the location far than 4<em>H</em><sub>e</sub> from the excavation, and the influence range of the dewatering on tunnel was nearly 8<em>H</em><sub>e</sub>. Furthermore, the higher stiffness of the station reduced the settlement and convergence but aggravated the dislocation of the tunnels within approximately 40 m from the station, causing many leakage points. To protect the tunnels, groundwater recharge and deep-shallow-well dewatering scheme (dewatering wells in phreatic aquifer and confined aquifer were set independently) were proposed and applied during subsequent construction, which effectively avoided further tunnel settlement. Groundwater recharge also induced slight uplift and horizontal deformation of the tunnels to the opposite side of the excavation. In addition, recharge should be started in advance and remain in operation until the groundwater level was fully restored. For deep excavations near important infrastructures in soft soil strata with leaky aquifers, the same dewatering and recharge system in this case study is suggested to adopted.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"159 ","pages":"Article 106468"},"PeriodicalIF":6.7,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386597","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

Research on the influence of high-altitude tunnel environment on gas explosion characteristics and explosion limits

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

Tunnelling and Underground Space Technology

Pub Date : 2025-02-11 DOI: 10.1016/j.tust.2025.106435

Hongyun Yang, Chuandong Jiang, Yongchao Ding, Zhi Lin, Xiang Chen, Zihan Wang, Huaizhang Gong

Gas explosions in tunnels often result in significant casualties and economic losses. As gas tunnels are increasingly being constructed in high-altitude areas, safety concerns are becoming more critical. The environmental parameters in high-altitude regions, such as temperature, oxygen content, and air pressure, differ significantly from those in low-altitude areas. These differences greatly affect the environment, gas explosion characteristics, and explosion limits in tunnels, yet relevant research is limited. This paper presents findings from measurements and theoretical analysis. The results are as follows: (1) The equations for estimating atmospheric pressure and oxygen content were derived through measurement, achieving a high degree of accuracy. (2) For a high-altitude tunnel with a 3 km long flat guide and inclined shaft, the internal air pressure remains constant as the distance from the cave entrance increases. However, the ambient temperature rises by 6–––8 °C, the oxygen content reduces by 1.6 %, and with the continuous excavation of long tunnels, related factors will undergo significant alterations. (3) From 0 to 4 km altitude, the maximum explosion shock wave pressure decreases by up to 26.78 %. Conversely, the maximum flame propagation speed increases by up to 21.04 %. The peak flame temperature effect becomes more pronounced, and the adiabatic flame temperature lowers. Atmospheric pressure and oxygen content significantly impact explosive properties, while ambient temperature has minimal effect. (4) As altitude increases from 0 to 4 km, the lower explosive limit rises, and the upper explosive limit decreases. The explosion limit range narrows from 5 %-16 % to 5.4928 %-14.9448 %, reducing by 16.45 %. The explosion limit effect coefficient based on altitude is proposed, and the minimum gas concentration value of railway and highway tunnel at 4 km is recommended. These findings are crucial for ensuring the safe construction and operation of high-altitude gas tunnels.

{"title":"Research on the influence of high-altitude tunnel environment on gas explosion characteristics and explosion limits","authors":"Hongyun Yang, Chuandong Jiang, Yongchao Ding, Zhi Lin, Xiang Chen, Zihan Wang, Huaizhang Gong","doi":"10.1016/j.tust.2025.106435","DOIUrl":"10.1016/j.tust.2025.106435","url":null,"abstract":"<div><div>Gas explosions in tunnels often result in significant casualties and economic losses. As gas tunnels are increasingly being constructed in high-altitude areas, safety concerns are becoming more critical. The environmental parameters in high-altitude regions, such as temperature, oxygen content, and air pressure, differ significantly from those in low-altitude areas. These differences greatly affect the environment, gas explosion characteristics, and explosion limits in tunnels, yet relevant research is limited. This paper presents findings from measurements and theoretical analysis. The results are as follows: (1) The equations for estimating atmospheric pressure and oxygen content were derived through measurement, achieving a high degree of accuracy. (2) For a high-altitude tunnel with a 3 km long flat guide and inclined shaft, the internal air pressure remains constant as the distance from the cave entrance increases. However, the ambient temperature rises by 6–––8 °C, the oxygen content reduces by 1.6 %, and with the continuous excavation of long tunnels, related factors will undergo significant alterations. (3) From 0 to 4 km altitude, the maximum explosion shock wave pressure decreases by up to 26.78 %. Conversely, the maximum flame propagation speed increases by up to 21.04 %. The peak flame temperature effect becomes more pronounced, and the adiabatic flame temperature lowers. Atmospheric pressure and oxygen content significantly impact explosive properties, while ambient temperature has minimal effect. (4) As altitude increases from 0 to 4 km, the lower explosive limit rises, and the upper explosive limit decreases. The explosion limit range narrows from 5 %-16 % to 5.4928 %-14.9448 %, reducing by 16.45 %. The explosion limit effect coefficient based on altitude is proposed, and the minimum gas concentration value of railway and highway tunnel at 4 km is recommended. These findings are crucial for ensuring the safe construction and operation of high-altitude gas tunnels.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"159 ","pages":"Article 106435"},"PeriodicalIF":6.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386596","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

Strength evaluation method for circumferential joint of shield tunnel under seismic loading

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

Tunnelling and Underground Space Technology

Pub Date : 2025-02-11 DOI: 10.1016/j.tust.2025.106432

Xiangyu Guo , Ping Geng , Guanxiong Zeng , Xu Chang , Qipeng Cai

Currently, there is no well-established method for assessing the seismic safety of circumferential joints in shield tunnels. To address this gap, this paper, based on the seismic response characteristics of shield tunnels, first studies the structural characteristics of circumferential joints and categorizes their failure modes into bolt failure and segment failure. For the straight bolt circumferential joint, the bolt failure occurs along the entire screw, while the segment failure takes place in the hand hole area where the bolt head compresses the segment concrete in conjunction with the washer; for the oblique bolt circumferential joint, bolt failure occurs near the bolt head and sleeve-port, while the segment failure occurs in the bolt-sleeve-segment connection area. Based on these findings, the circumferential joint strength evaluation method for shield tunnel that considers the structural characteristics of circumferential joints is proposed. Subsequently, this paper uses the submodel method and full-scale failure tests of circumferential joints to verify the applicability of the proposed strength evaluation method. The theoretical solutions are more conservative and secure but still closely align with the numerical results, with difference rates ranging from 0-25 % (In fact, the difference between the numerical results and the theoretical solutions of the straight bolted joint under axial force are less than 10 %.); Additionally, the full-scale tests confirm the predicted failure modes, thereby validating the method’s engineering applicability. The comparison of load at failure for different types bolt circumferential joints with theoretical solutions shows good agreement. Specifically, for the straight bolt circumferential joint, when the joint fails, the ultimate load-bearing capacity of the test segment is recorded as 527.2 kN, while the theoretical solution is 257.1 kN. Considering that the damage state of the segment develops over time, the joint failure correction coefficient is introduced, denoted as μ = 2.1. This study further expands the applicability of the longitudinal equivalent continuous model and serves as a valuable reference for the longitudinal seismic design of shield tunnels.

{"title":"Strength evaluation method for circumferential joint of shield tunnel under seismic loading","authors":"Xiangyu Guo , Ping Geng , Guanxiong Zeng , Xu Chang , Qipeng Cai","doi":"10.1016/j.tust.2025.106432","DOIUrl":"10.1016/j.tust.2025.106432","url":null,"abstract":"<div><div>Currently, there is no well-established method for assessing the seismic safety of circumferential joints in shield tunnels. To address this gap, this paper, based on the seismic response characteristics of shield tunnels, first studies the structural characteristics of circumferential joints and categorizes their failure modes into bolt failure and segment failure. For the straight bolt circumferential joint, the bolt failure occurs along the entire screw, while the segment failure takes place in the hand hole area where the bolt head compresses the segment concrete in conjunction with the washer; for the oblique bolt circumferential joint, bolt failure occurs near the bolt head and sleeve-port, while the segment failure occurs in the bolt-sleeve-segment connection area. Based on these findings, the circumferential joint strength evaluation method for shield tunnel that considers the structural characteristics of circumferential joints is proposed. Subsequently, this paper uses the submodel method and full-scale failure tests of circumferential joints to verify the applicability of the proposed strength evaluation method. The theoretical solutions are more conservative and secure but still closely align with the numerical results, with difference rates ranging from 0-25 % (In fact, the difference between the numerical results and the theoretical solutions of the straight bolted joint under axial force are less than 10 %.); Additionally, the full-scale tests confirm the predicted failure modes, thereby validating the method’s engineering applicability. The comparison of load at failure for different types bolt circumferential joints with theoretical solutions shows good agreement. Specifically, for the straight bolt circumferential joint, when the joint fails, the ultimate load-bearing capacity of the test segment is recorded as 527.2 kN, while the theoretical solution is 257.1 kN. Considering that the damage state of the segment develops over time, the joint failure correction coefficient is introduced, denoted as <strong><em>μ</em></strong> = 2.1. This study further expands the applicability of the longitudinal equivalent continuous model and serves as a valuable reference for the longitudinal seismic design of shield tunnels.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"159 ","pages":"Article 106432"},"PeriodicalIF":6.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386595","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

Mechanisms of interaction and influence zone partitioning of high geo-stress twin tunnels in complex mountainous regions

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

Tunnelling and Underground Space Technology

Pub Date : 2025-02-11 DOI: 10.1016/j.tust.2025.106462

Fangyin Wu , Chuan He , Wenbo Yang , Jincheng Nie , Chaofan Yao , Feng Yang

In challenging mountainous regions under high geo-stress, the construction of twin tunnels faces unique interaction issues, which is a systemic risk arising from the coupling of stress fields, surrounding rock conditions, and twin-tunnel clear spacings. Compared to single tunnels, the disaster mechanisms and evolution patterns are more complex. Existing studies and standards on the classification of interaction degrees between twin tunnels remain insufficient. Due to the singularity of geological conditions, vagueness in the scope of influence, and lack of consideration for geo-stress levels, adequate support for the design and construction of twin tunnels under multivariate geotechnical conditions in challenging mountainous regions is not provided. This study focuses on the interaction patterns and influence zone partitioning of high geo-stress twin tunnels under multivariate geotechnical conditions. By integrating scaled model tests with numerical simulations, this study employs the plastic zone and secondary stress field distribution from numerical results as qualitative indicators, while using maximum tunnel peripheral displacement, maximum principal stress, and asymmetry coefficient as quantitative metrics. Additionally, failure patterns and structural stress patterns from model tests are used as supplementary evidence to comprehensively assess the interaction degree of twin tunnels. Based on these findings, the interaction patterns after excavation of high geo-stress twin tunnels are proposed, along with a classification standard suitable for multi-geological conditions. The interaction effects are categorized into four levels: severe, moderate, minor, and none. In engineering applications, appropriate twin-tunnel categories can be selected based on specific geo-stress and surrounding rock conditions to achieve better design rationality and economic efficiency.

{"title":"Mechanisms of interaction and influence zone partitioning of high geo-stress twin tunnels in complex mountainous regions","authors":"Fangyin Wu , Chuan He , Wenbo Yang , Jincheng Nie , Chaofan Yao , Feng Yang","doi":"10.1016/j.tust.2025.106462","DOIUrl":"10.1016/j.tust.2025.106462","url":null,"abstract":"<div><div>In challenging mountainous regions under high geo-stress, the construction of twin tunnels faces unique interaction issues, which is a systemic risk arising from the coupling of stress fields, surrounding rock conditions, and twin-tunnel clear spacings. Compared to single tunnels, the disaster mechanisms and evolution patterns are more complex. Existing studies and standards on the classification of interaction degrees between twin tunnels remain insufficient. Due to the singularity of geological conditions, vagueness in the scope of influence, and lack of consideration for geo-stress levels, adequate support for the design and construction of twin tunnels under multivariate geotechnical conditions in challenging mountainous regions is not provided. This study focuses on the interaction patterns and influence zone partitioning of high geo-stress twin tunnels under multivariate geotechnical conditions. By integrating scaled model tests with numerical simulations, this study employs the plastic zone and secondary stress field distribution from numerical results as qualitative indicators, while using maximum tunnel peripheral displacement, maximum principal stress, and asymmetry coefficient as quantitative metrics. Additionally, failure patterns and structural stress patterns from model tests are used as supplementary evidence to comprehensively assess the interaction degree of twin tunnels. Based on these findings, the interaction patterns after excavation of high geo-stress twin tunnels are proposed, along with a classification standard suitable for multi-geological conditions. The interaction effects are categorized into four levels: severe, moderate, minor, and none. In engineering applications, appropriate twin-tunnel categories can be selected based on specific geo-stress and surrounding rock conditions to achieve better design rationality and economic efficiency.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"159 ","pages":"Article 106462"},"PeriodicalIF":6.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386399","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

Nonlinear seismic response analysis of underground structures considering spatial variability of soil parameters

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

Tunnelling and Underground Space Technology

Pub Date : 2025-02-11 DOI: 10.1016/j.tust.2025.106445

Wenhao Zhang , M. Hesham El Naggar , Pinghe Ni , Mi Zhao , Xiuli Du

Investigations of seismic response of underground structures often assume homogeneous or layered homogeneous sites. However, significant spatial variability in soil parameters may lead to vastly different underground structure performance from that obtained for homogeneous sites. Based on random field theory, this study models the spatial variability of the soil elastic modulus, cohesion, and friction angle using the Karhunen–Loève (K-L) expansion method. Target acceleration response spectra are generated according to standards, and the trigonometric series method is employed to create artificial seismic waves of four different intensities. Nonlinear dynamic analyses of underground structures under deterministic and random field conditions are conducted using ABAQUS software. The study comprehensively analyzes the structural damage state, internal forces, inter-story displacement, and drift ratio to evaluate the station structure’s performance under different seismic intensities. Results show that the spatial variability of soil parameters significantly impacts the dynamic response of underground structures, especially for stronger earthquakes. The variability of soil stiffness and strength parameters leads to greater fluctuations and uncertainties in displacement and internal force responses, exacerbating structural damage. It is recommended that when the peak ground acceleration (PGA) reaches or exceeds 0.5 g, the spatial variability of soil parameters should be incorporated into the analysis to ensure a reliable assessment of the structural seismic performance.

{"title":"Nonlinear seismic response analysis of underground structures considering spatial variability of soil parameters","authors":"Wenhao Zhang , M. Hesham El Naggar , Pinghe Ni , Mi Zhao , Xiuli Du","doi":"10.1016/j.tust.2025.106445","DOIUrl":"10.1016/j.tust.2025.106445","url":null,"abstract":"<div><div>Investigations of seismic response of underground structures often assume homogeneous or layered homogeneous sites. However, significant spatial variability in soil parameters may lead to vastly different underground structure performance from that obtained for homogeneous sites. Based on random field theory, this study models the spatial variability of the soil elastic modulus, cohesion, and friction angle using the Karhunen–Loève (K-L) expansion method. Target acceleration response spectra are generated according to standards, and the trigonometric series method is employed to create artificial seismic waves of four different intensities. Nonlinear dynamic analyses of underground structures under deterministic and random field conditions are conducted using ABAQUS software. The study comprehensively analyzes the structural damage state, internal forces, inter-story displacement, and drift ratio to evaluate the station structure’s performance under different seismic intensities. Results show that the spatial variability of soil parameters significantly impacts the dynamic response of underground structures, especially for stronger earthquakes. The variability of soil stiffness and strength parameters leads to greater fluctuations and uncertainties in displacement and internal force responses, exacerbating structural damage. It is recommended that when the peak ground acceleration (PGA) reaches or exceeds 0.5 g, the spatial variability of soil parameters should be incorporated into the analysis to ensure a reliable assessment of the structural seismic performance.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"159 ","pages":"Article 106445"},"PeriodicalIF":6.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378572","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

Stress redistribution in some supported subway station tunnels within Upper-Soft and Lower-Hard strata during Excavation: A physical model study

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

Tunnelling and Underground Space Technology

Pub Date : 2025-02-11 DOI: 10.1016/j.tust.2025.106466

Feng Huang , Xingchen Liu , Chuangzhou Wu , Wei Tang , Aichen Zheng

The disturbance mechanism between adjacent tunnels and the rules for stress redistribution in upper-soft and lower-hard strata remain unclear. This study designed and carried out a scale model test to simulate the excavation process of adjacent tunnels with the double side heading method in upper-soft and lower-hard strata. The mutual disturbance mechanism between adjacent tunnels and the evolution law of surrounding rock stress were investigated. The results show that the vertical and horizontal asymmetric deformation characteristics of tunnels surrounding rock were influenced by the lithology and integrity of the upper-soft and lower-hard strata. The process of stress redistribution in the surrounding rock exhibits stress concentration and local stress release at the interface due to mutual disturbance among tunnels. During the excavation of adjacent tunnels, the thickness of the stress loosening zone (SLZ) gradually increases at the vault and decreases at the sidewalls. In the upper-soft and lower-hard strata, the distribution range of the SLZ above the interface was smaller (about 479 mm), while the SLZ below the interface was larger (>1000 mm). When the interface is positioned above the tunnel vault, only a small range of SLZ vertically expands and crosses the interface, while a large range of SLZ horizontally expands along the interface.

{"title":"Stress redistribution in some supported subway station tunnels within Upper-Soft and Lower-Hard strata during Excavation: A physical model study","authors":"Feng Huang , Xingchen Liu , Chuangzhou Wu , Wei Tang , Aichen Zheng","doi":"10.1016/j.tust.2025.106466","DOIUrl":"10.1016/j.tust.2025.106466","url":null,"abstract":"<div><div>The disturbance mechanism between adjacent tunnels and the rules for stress redistribution in upper-soft and lower-hard strata remain unclear. This study designed and carried out a scale model test to simulate the excavation process of adjacent tunnels with the double side heading method in upper-soft and lower-hard strata. The mutual disturbance mechanism between adjacent tunnels and the evolution law of surrounding rock stress were investigated. The results show that the vertical and horizontal asymmetric deformation characteristics of tunnels surrounding rock were influenced by the lithology and integrity of the upper-soft and lower-hard strata. The process of stress redistribution in the surrounding rock exhibits stress concentration and local stress release at the interface due to mutual disturbance among tunnels. During the excavation of adjacent tunnels, the thickness of the stress loosening zone (SLZ) gradually increases at the vault and decreases at the sidewalls. In the upper-soft and lower-hard strata, the distribution range of the SLZ above the interface was smaller (about 479 mm), while the SLZ below the interface was larger (>1000 mm). When the interface is positioned above the tunnel vault, only a small range of SLZ vertically expands and crosses the interface, while a large range of SLZ horizontally expands along the interface.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"159 ","pages":"Article 106466"},"PeriodicalIF":6.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378571","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

Model test study of punching shear failure mode of the bearing stratum induced by tunneling beneath an existing pile

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

Tunnelling and Underground Space Technology

Pub Date : 2025-02-10 DOI: 10.1016/j.tust.2025.106459

Fu Huang , Yongtao Wang , Min Zhang , Wangtao Jiang , Hengbo Ji , Qiujing Pan

With the increase of the density of subway line in big cities, it is common for newly built shield tunnels to cross beneath the existing pile foundations at short distances. When the disturbance generated during the construction of the shield tunnels is transmitted to the bearing stratum of the existing pile tip, a punching shear failure may occur in the bearing stratum. To study the evolution process and final form of the punching shear failure of the bearing stratum, a scaled model test based on the Particle Image Velocimetry (PIV) technology is designed. By using PIV technology to analyze deformation images of the bearing stratum, the failure range and shape of the bearing stratum between the pile tip and tunnel induced by excavation are obtained. Using the failure shape of the bearing stratum provided by the model test, a theoretical failure mechanism based on the spatial discretization technique is constructed. The limit analysis theorem is employed here to calculate the theoretical solution of the punching shear failure surface of the bearing stratum. The good agreement of the failure range for the bearing stratum between the model test and theoretical result indicates that the model test presented here is effective.

{"title":"Model test study of punching shear failure mode of the bearing stratum induced by tunneling beneath an existing pile","authors":"Fu Huang , Yongtao Wang , Min Zhang , Wangtao Jiang , Hengbo Ji , Qiujing Pan","doi":"10.1016/j.tust.2025.106459","DOIUrl":"10.1016/j.tust.2025.106459","url":null,"abstract":"<div><div>With the increase of the density of subway line in big cities, it is common for newly built shield tunnels to cross beneath the existing pile foundations at short distances. When the disturbance generated during the construction of the shield tunnels is transmitted to the bearing stratum of the existing pile tip, a punching shear failure may occur in the bearing stratum. To study the evolution process and final form of the punching shear failure of the bearing stratum, a scaled model test based on the Particle Image Velocimetry (PIV) technology is designed. By using PIV technology to analyze deformation images of the bearing stratum, the failure range and shape of the bearing stratum between the pile tip and tunnel induced by excavation are obtained. Using the failure shape of the bearing stratum provided by the model test, a theoretical failure mechanism based on the spatial discretization technique is constructed. The limit analysis theorem is employed here to calculate the theoretical solution of the punching shear failure surface of the bearing stratum. The good agreement of the failure range for the bearing stratum between the model test and theoretical result indicates that the model test presented here is effective.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106459"},"PeriodicalIF":6.7,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377811","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 of the Bond–slip performance of grouted rockbolt structures under the coupling effects of temperature and corrosion

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

Tunnelling and Underground Space Technology

Pub Date : 2025-02-10 DOI: 10.1016/j.tust.2025.106467

Shuisheng Yu , Hongsen Zhang , Yuzhou Sun , Yi Zhao , Honghao Yang , Shucan Lu , Fuzhou Qi

Due to the “three high and one disturbance” effect, the high-temperature and humid environment in deep tunnels leads to the corrosion of rockbolts, decreases the stability of support structures, and endangers tunnel safety. Therefore, the stability of grouted rockbolt structures in high-temperature and humid environments must be addressed. In this work, rockbolts were corroded for different time periods and at different temperatures to study the bond–slip performance of corroded grouted rockbolt structures. Based on the load evolution process and failure mechanism of the grouted rockbolt interface, a bond–slip model considering temperature and corrosion was constructed. The results indicate that the coupling effect of temperature and corrosion exacerbates the deterioration of bond performance of the bond interface; as the temperature increases, the ultimate load of the corroded grouted rockbolt structure first increases but then decreases. When the temperature was 35 °C, the maximum limit load was reached. The bond strength and peak slip length of rockbolts significantly decrease under high corrosion rates. The rust expansion effect of rockbolts increases the radial pressure at the grouted rockbolt interface, leading to changes in the failure mode of rockbolts. The proposed bond–slip model, which considers the temperature and corrosion rate, can accurately reflect the actual load transfer behavior of rockbolts in complex environments.

{"title":"Study of the Bond–slip performance of grouted rockbolt structures under the coupling effects of temperature and corrosion","authors":"Shuisheng Yu , Hongsen Zhang , Yuzhou Sun , Yi Zhao , Honghao Yang , Shucan Lu , Fuzhou Qi","doi":"10.1016/j.tust.2025.106467","DOIUrl":"10.1016/j.tust.2025.106467","url":null,"abstract":"<div><div>Due to the “three high and one disturbance” effect, the high-temperature and humid environment in deep tunnels leads to the corrosion of rockbolts, decreases the stability of support structures, and endangers tunnel safety. Therefore, the stability of grouted rockbolt structures in high-temperature and humid environments must be addressed. In this work, rockbolts were corroded for different time periods and at different temperatures to study the bond–slip performance of corroded grouted rockbolt structures. Based on the load evolution process and failure mechanism of the grouted rockbolt interface, a bond–slip model considering temperature and corrosion was constructed. The results indicate that the coupling effect of temperature and corrosion exacerbates the deterioration of bond performance of the bond interface; as the temperature increases, the ultimate load of the corroded grouted rockbolt structure first increases but then decreases. When the temperature was 35 °C, the maximum limit load was reached. The bond strength and peak slip length of rockbolts significantly decrease under high corrosion rates. The rust expansion effect of rockbolts increases the radial pressure at the grouted rockbolt interface, leading to changes in the failure mode of rockbolts. The proposed bond–slip model, which considers the temperature and corrosion rate, can accurately reflect the actual load transfer behavior of rockbolts in complex environments.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106467"},"PeriodicalIF":6.7,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377810","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

Optimizing seepage control for underground powerhouse caverns near a large-scale fault

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

Tunnelling and Underground Space Technology

Pub Date : 2025-02-10 DOI: 10.1016/j.tust.2025.106456

Kai-Kun Chen , Yao-Lai Liu , Ji-Yuan Yu , Yi-Feng Chen , Ran Hu , Zhibing Yang , Jia-Qing Zhou

Seepage control is a critical issue for construction of underground powerhouse caverns, especially when the caverns are located near large-scale, water-conductive faults that provide flow channels into the cavern area. Grouting and draining have been considered as the most effective measures for regulating leakage into the caverns, which usually calls for an optimization design to achieve a balance between the performance and cost. This study proposes to optimize both the location of an underground cavern system and the design parameters (depth and/or spacing) of seepage control system located near a large-scale fault by numerical simulations. A comprehensive site characterization is performed to quantify the permeability of the surrounding rocks, and the excavation-induced permeability variation is characterized with a strain-dependent model. The groundwater flow is described by a steady-state flow model with unilateral boundary condition for rigorous simulation of drains. It is found that both the location of caverns and the layout of grout curtains and drains can be effectively optimized in terms of the metrics including the pore water pressure distribution, the discharge into the cavern area, and the stability of fault against seepage erosion. This work underscores the importance of optimization design in regulating the groundwater flow around underground caverns located near permeable faults.

{"title":"Optimizing seepage control for underground powerhouse caverns near a large-scale fault","authors":"Kai-Kun Chen , Yao-Lai Liu , Ji-Yuan Yu , Yi-Feng Chen , Ran Hu , Zhibing Yang , Jia-Qing Zhou","doi":"10.1016/j.tust.2025.106456","DOIUrl":"10.1016/j.tust.2025.106456","url":null,"abstract":"<div><div>Seepage control is a critical issue for construction of underground powerhouse caverns, especially when the caverns are located near large-scale, water-conductive faults that provide flow channels into the cavern area. Grouting and draining have been considered as the most effective measures for regulating leakage into the caverns, which usually calls for an optimization design to achieve a balance between the performance and cost. This study proposes to optimize both the location of an underground cavern system and the design parameters (depth and/or spacing) of seepage control system located near a large-scale fault by numerical simulations. A comprehensive site characterization is performed to quantify the permeability of the surrounding rocks, and the excavation-induced permeability variation is characterized with a strain-dependent model. The groundwater flow is described by a steady-state flow model with unilateral boundary condition for rigorous simulation of drains. It is found that both the location of caverns and the layout of grout curtains and drains can be effectively optimized in terms of the metrics including the pore water pressure distribution, the discharge into the cavern area, and the stability of fault against seepage erosion. This work underscores the importance of optimization design in regulating the groundwater flow around underground caverns located near permeable faults.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"158 ","pages":"Article 106456"},"PeriodicalIF":6.7,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377809","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