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Tunnels
Follow the developments of tunnels, as they have gone deeper underground, have traveled further and helped us transport people, energy and goods through engineering skill, design, and ambition.
Book
Innovation in TBM traffic tunnels
Tunnel Boring Machine (TBM) constructed tunnels are widespread, and can deliver significant environmental and cost benefits. However, as noted in the noteworthy examples of TBM traffic tunnels presented in this book, there are still important challenges associated with them, linked in particular to structural safety in the event of earthquakes, as well as cost and safety issues during operation. To face these challenges, Innovation in TBM Traffic Tunnels presents three innovative concepts in the field of construction of TBM rail and road tunnels: the TISB concept that improves the structural safety of those built on soft soil in seismic areas, and the TMG and TMF concepts, for rail and road tunnels, respectively, that allow for significant reduction of their cost and the improvement of safety during operation. Examples of the application of these new concepts in the conceptual design of specific tunnel cases are presented and compared with solutions based on common approaches, demonstrating the additional benefits of these concepts. The book also draws attention to other innovations in TBM tunnelling that may improve the construction of tunnels in the future, especially when using the concepts mentioned above. Innovation in TBM Traffic Tunnels is aimed at professionals involved in the planning, design, and construction of tunnels for transport infrastructure, including authorities, consultants and construction companies, worldwide.
Book
Surgery versus corticosteroid injection for carpal tunnel syndrome (DISTRICTS): an open-label, multicentre, randomised controlled trial
Surgery and corticosteroid injections are established treatments for carpal tunnel syndrome, but the optimal treatment strategy remains unclear. This study aimed to compare starting treatment with surgery versus starting with a corticosteroid injection.
We conducted an open-label, randomised controlled trial across 31 hospitals in the Netherlands. Eligible patients, diagnosed with carpal tunnel syndrome for at least 6 weeks and confirmed by electrophysiological or sonographic testing, were randomly assigned (1:1) to start treatment with either surgery or an injection via a web-based system. Randomisation was stratified by unilateral or bilateral symptoms, carpal tunnel syndrome with or without concomitant disease as risk factor, and previous ipsilateral injections. If needed, additional treatments were allowed, such as additional injections or surgery. The primary outcome, assessed in the intention-to-treat population, was the proportion of patients who were recovered (defined as a score of less than eight points on the six-item carpal tunnel syndrome scale) at 18 months. The trial was preregistered with the ISRCTN Registry (ISRCTN13164336) and is now completed.
From Nov 7, 2017, to Nov 4, 2021, 934 participants (545 female and 389 male participants) were included. 468 were randomised to the surgery group and 466 to the injection group. At 18 months, 805 (86%) of 934 participants had primary outcome data. In the surgery group, 243 (61%) of 401 participants had recovered, significantly higher than the 180 (45%) of 404 participants recovered in the injection group (relative risk 1·36; 95% CI 1·19–1·56; p<0·0001). One or more adverse event occurred in 376 (86%) of 436 participants in the surgery group and in 384 (85%) of 453 participants in the injection group. One participant in the surgery group was hospitalised due to complications. No treatment-related deaths were reported.
In patients with carpal tunnel syndrome, initiating treatment with surgery offers a higher chance of recovery after 18 months compared with starting with a corticosteroid injection, even with the possibility of additional interventions.
The Netherlands Organization for Health Research and Development and Zorgverzekeraars Nederland.
Journal Article
Retracted: The Mechanical Performance of Shear Key of Immersed Tube Tunnel with Differential Foundation Settlement
At the request of the authors, the article titled “The Mechanical Performance of Shear Key of Immersed Tube Tunnel with Differential Foundation Settlement” [1] has been retracted. The authors found that there was an error in the method used for the data processing as temperature change was not considered, and the results were inconsistent with those in the thesis of Shengli [2], who was acknowledged in the article. Thus, the accuracy of the reported data and the conclusions of this article are not reliable.
Journal Article
Experimental and Numerical Studies of a Shield Twin Tunnel Undercrossing the Existing High-Speed Railway Tunnel
In order to study the influence of shield tunneling on existing high-speed railway lines. Combined with centrifuge test and three-dimensional numerical simulation, the dynamic response of shield tunnel undercrossing existing high-speed railway tunnel was studied, and the influence of settlement joint and steel pipe pile reinforcement on existing tunnel was analyzed. The results show that: (1) the construction joints of existing tunnels significantly reduce the shielding effect of existing high-speed railway tunnels on the ground; (2) The settlement value of the existing tunnel caused by double-line shield tunnel construction needs to be controlled by steel pipe pile reinforcement to meet the requirements of the specification; (3) The double-line shield tunnel construction has little effect on the internal force of the existing high-speed railway tunnel, and the reinforcement of the high-speed railway tunnel lining meets the stress requirements.
Journal Article
Study on Excavation Sequence of Pilot Tunnels for a Rectangular Tunnel Using Numerical Simulation and Field Monitoring Method
Cross diaphragm (CRD) method divides the tunnel into multiple pilot tunnels to reduce the span of a single excavation, which is beneficial to reduce the disturbance of excavation construction to surrounding rocks. In this method, the excavation sequence of pilot tunnels is a key factor affecting the excavation disturbance. In this study, two schemes of excavation sequence of pilot tunnels were simulated by numerical method, based on a newly built shallow buried rectangular tunnel using CRD method. By comparing and analyzing the vertical displacements of tunnel surrounding rocks, ground surface settlements, crown settlements and bending moment of the primary support structure, the surrounding rock deformation characteristics and trends of the tunnel were revealed, which determined the more reasonable excavation sequence scheme for the construction of the rectangular tunnel. By comparing with the field monitoring data, the numerical simulation results were verified to a certain extent. In addition, the comparison of calculation results obtained from the Mohr–Coulomb (MC) and the hardening soil small (HSS) constitutive models were discussed. The investigation results show that: (1) the displacement of surrounding rock and bending moment of the primary support structure are closely related to the excavation sequence of the pilot tunnels; (2) the deformation trends revealed by the numerical results are similar to those from the field data; (3) according to the field construction process, the asymmetric excavation sequence of \"left upper pilot tunnel—left lower pilot tunnel—right-upper pilot tunnel—right lower pilot tunnel\" is safe and reliable for the rectangular tunnel construction.HighlightsTwo different excavation sequences of a rectangular tunnel with CRD method were systematically compared and analyzed, and the recommended excavation sequence was proposed.The displacement of surrounding rock and bending moment of primary support structure were closely related to the excavation sequences of pilot tunnels.The details of the excavation and construction process of a rectangular tunnel using CRD method were shown by pictures.Compared with the HSS model, the Mohr Coulomb (MC) model may lead to larger deformation in significant unloading / reloading problems.
Journal Article