Investigation of the long-term settlement of a cut-and-cover metro tunnel in a soft deposit

2016 ◽  
Vol 204 ◽  
pp. 33-40 ◽  
Author(s):  
Honggui Di ◽  
Shunhua Zhou ◽  
Junhua Xiao ◽  
Quanmei Gong ◽  
Zhe Luo
Keyword(s):  
Metro Tunnel ◽  
Soft Deposit

scholarly journals Long-Term Deformation Monitoring of Metro-Tunnel Airshaft Excavation during Construction Stage

2012 ◽  
Vol 8 (10) ◽  
pp. 972893 ◽  
Author(s):  
L. Ran ◽  
T. H. Yi ◽  
X. W. Ye ◽  
X. B. Dong
Keyword(s):  
Deformation Monitoring ◽  
Geological Condition ◽  
Building Structures ◽  
Construction Site ◽  
Construction Stage ◽  
Transit System ◽  
Depth Direction ◽  
Metro Tunnel ◽  
Metro Systems

The project of Hangzhou Metro Line 1 is the first metro line of the urban rapid rail transit system in Hangzhou, China, which is one of the largest municipal projects of Hangzhou and is being constructed commencing from March 28, 2007 and expected to be completed by October 1, 2012. This metro line has a total length of 48 km and 34 stations, connecting Hangzhou downtown with the suburban area of the city. Owing to the complex geological condition, harsh construction situation, and immature computational methodology, construction of metro systems is often subjected to considerable sources of uncertainties. To ensure the safety of the adjacent building structures, it is a vital necessity to monitor deep excavations of metro tunnels at their in-construction stage. This paper introduces the instrumentation system for settlement monitoring of a metro-tunnel airshaft of the project of Hangzhou Metro Line 1 during the construction of deep excavation. The long-term settlement data monitored by the measurement markers installed at the surface ground and in the depth direction of the airshaft excavation construction site are analyzed and presented in detail. The obtained results indicate that the settlements at the instrumented locations of the construction site during different construction steps vary steadily in an allowable variation range.

scholarly journals Fatigue Life Characteristics of Segmental Lining Structure for the Shallow Buried Metro Tunnel under the Dynamic Load of a High-Speed Railway

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Wangping Qian ◽  
Taiyue Qi ◽  
Qing Zhao ◽  
Bingrong Pu ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
Dynamic Load ◽  
High Speed ◽  
Dynamic Loads ◽  
High Speed Railway ◽  
Segmental Lining ◽  
Lining Structure ◽  
Metro Tunnel

Shallow buried shield metro tunnels constructed underneath subgrade project of high-speed railways are becoming increasingly common in China, but the lower metro tunnel bears the fatigue effect of dynamic load induced by the upper high-speed railway, so the long-term durability of segmental lining is a nonnegligible problem. The segmental lining structure of metro tunnel is in a state of static-dynamic loads for a long time, especially when a high-speed railway passes above the metro line, and the long-term durability of segmental lining needs further research. Based on theoretical analysis, the effect of different forms of loads on the fatigue life was analyzed, the change law of the static-dynamic loads on segmental lining was summarized, and the method was put forward to evaluate the fatigue life characteristics of segmental lining. The research results reveal that the additional dynamic load is the fundamental reason for the fatigue failure of the structure, and the existence of static load can cause and accelerate the occurrence of structural fatigue failure simultaneously. The results indicate that the fatigue life decreases gradually with the increase of static-dynamic load. Based on coupling analysis of static-dynamic loads of segmental lining, the fatigue life increases first and then decreases with the increase of buried depth of metro tunnel, and it remains unchanged when the depth exceeds a certain value. According to the actual metro tunnel engineering, by using ABAQUS software, a three-dimensional numerical simulation was carried out to analyze the characteristics of the fatigue life and evolution rules of segmental lining. Based on the modified fatigue life formula and metro service life, the optimization design of the buried depth was carried out to determine the most reasonable range of the buried depth. This study provides a valuable reference for safe operation and long-term durability of metro tunnels under high-speed railways.

scholarly journals Dynamic response and long-term settlement of a metro tunnel in saturated clay due to moving train load

2017 ◽  
Vol 57 (6) ◽  
pp. 1059-1075 ◽  
Author(s):  
Qiang Huang ◽  
Hong-wei Huang ◽  
Bin Ye ◽  
Dong-mei Zhang ◽  
Lin-lin Gu ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Saturated Clay ◽  
Metro Tunnel ◽  
Moving Train

scholarly journals Study on the influence of supertall building load on adjacent tunnel subsidence

2020 ◽  
Vol 382 ◽  
pp. 219-224
Author(s):  
Yan Xu ◽  
Xuexin Yan ◽  
Tianliang Yang
Keyword(s):  
Pile Foundation ◽  
Soft Soil ◽  
Monitoring Data ◽  
Building Load ◽  
Long Term Monitoring ◽  
Metro Tunnel ◽  
Subsidence Monitoring ◽  
Underlying Soil ◽  
Term Monitoring

Abstract. With the rapid growth of economy in coastal megacities, the construction of supertall buildings with deep pile foundations adjacent to tunnels in soft soil is inevitable. The additional subsidence of tunnel and long-term subsidence of soft soil was appeared caused by the supertall building load transferred through pile foundation. In this paper, a typical case in Shanghai where deep piles of supertall building group adjacent to a metro tunnel was selected, and the long-term monitoring data of tunnel deformation was collected and analysed. The layered subsidence of surrounding soft soil was analysed by using the monitoring data of extensometers in a land subsidence monitoring station near the study area. The results of data analysis showed that the construction of supertall building had a significant impact on the adjacent tunnel subsidence. Moreover, with the increase of the load transferred from building structure to pile foundation, the adjacent tunnel appeared sustained uneven subsidence. And the subsidence of tunnel in the study area mainly depended on the deformation of underlying soil.

Automatic Detection of the Grout Layer of Metro Tunnel by GPR

2014 ◽  
Vol 556-562 ◽  
pp. 2719-2722
Author(s):  
Cun Chang Qin ◽  
Hui Lin Zhou ◽  
Qi Ming Yu ◽  
Xi Yuan
Keyword(s):  
Ground Penetrating Radar ◽  
Automatic Detection ◽  
The Other ◽  
Shield Tunnel ◽  
Jiangxi Province ◽  
Tunnel Construction ◽  
Term Basis ◽  
Metro Tunnel ◽  
Ground Penetrating

The grout behind the lining segments have a powerful influence on the long-term basis in shield tunnel construction in gravel sand and round gravel layers. Grouting layer detection in the shield construction is important. Two aspects are usually be used to evaluate the effectiveness of the grout treatment, one is the thickness of the Grouting layer and the other is to determine the presence and distribution of any damage in grouting layer. This study reports on the applications of the ground penetrating radar (GPR) and associated work carried out on Nanchang Metro line 1, Jiangxi province of China. After raw data preprocessing the results of the radar image are used to evaluate the thickness and hidden trouble of the grout layer automatically.

Therapy and prevention for mental health: What if mental diseases are mostly not brain disorders?

2019 ◽  
Vol 42 ◽  
Author(s):  
John P. A. Ioannidis
Keyword(s):  
Mental Health ◽  
Mental Disease ◽  
Brain Disorders ◽  
Social Stressors ◽  
Labor Education ◽  
Mental Diseases ◽  
Long Term Follow Up ◽  
Political Decisions

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.

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