Search Results (7)

This study investigates the deformation characteristics and control measures for existing metro shield tunnels induced by large-section rectangular pipe jacking over-crossing, focusing on the Chengbei Road Comprehensive Utility Corridor project in Suzhou. A 9.1 m × 5.5 m pipe gallery was installed 73.6 m through clay strata over operational subway tunnels, with a minimum clearance of 4.356 m above the tunnel. Finite element simulations and field monitoring were employed to analyze the deformation of the existing tunnels, particularly the effectiveness of anti-uplift counterweights. The results revealed that excavation-induced unloading caused significant tunnel uplift, with maximum vertical displacements of 5.51 mm and 4.95 mm for the down line (DL) and up line (UL) tunnels, respectively. The addition of counterweights reduced these displacements by 30.3% and 37.1%, while also decreasing lateral displacements by up to 61.6% and bending moments by approximately 33%. The study demonstrates that counterweights, combined with slurry lubrication, real-time monitoring, and over-excavation control, effectively mitigate deformation and stress variations during large-section pipe jacking. The successful completion of the project without disrupting subway operations highlights the practical applicability of these measures. Full article

With the increasing utilization of urban underground space, new tunnels frequently intersect with existing tunnels and operational railways. However, sometimes the excavation and unloading of new tunnels can cause deformation of adjacent existing tunnels and railways, significantly affecting their normal operation. We used finite element software to predict the influence of new tunnel construction on overcrossing existing tunnels and down-traversing operational railways by a dynamic tunneling model based on a connection channel project of the east and west squares of a railway station. This article is not only control the distance between the two tunnels, but the new tunnel and the existing tunnel, as well as the new tunnel and the operation of the railway, the positional relationship between the three, the deformation laws of existing tunnels and operational railways during the construction of new tunnels with different buried depths are analyzed. The results show that the deformation curves of existing tunnels and operational railways present a normal distribution. The maximum deformation position is at the intersection with the new tunnel upon completion of the new tunnel excavation construction. Moreover, an increase in the buried depth of the new tunnel increases the deformation of the operational railway and the existing tunnel. The influence of the depth change of the new tunnel on the settlement of the operational railway is greater than that of the existing tunnel. Full article

As urban underground spaces continue to develop, new engineering projects are increasingly closer to existing operating tunnels. This study focuses on the impact of excavation work, such as a new tunnel or deep excavation, on an existing shield tunnel. However, few studies have examined the simultaneous effects of excavation and over-crossing tunneling on operational tunnels. This paper presents a case study of Section 2 of Hangzhou Metro Line 7, employing MIDAS GTS to simulate the settlement of the existing tunnel and analyze the data collected through automatic measurements. Both methods demonstrated that excavating a foundation pit near the existing tunnel results in the tunnel’s settlement while over-crossing tunneling of the new tunnels leads to the uplift of the existing tunnel. The excavation prompted the existing tunnel to move horizontally toward the foundation pit, whereas over-crossing tunneling pushed it horizontally away. The numerical simulation revealed minor vertical displacement but significant horizontal displacement, aligning closely with the measured data. The impacts of foundation pit excavation and over-crossing tunneling on the vertical and horizontal displacement of existing tunnels are contrary, suggesting that the two construction stages will offset each other. Full article

This study aims to assess and identify the role of disruptive/digital technologies in financial innovation strategies as part of social innovations at both the firm and country level. The analysis proposed by the present study brings useful theoretical/pragmatic insights on the application of financial technologies in the context of the “fintech” revolution, as a disruptive innovation. There are few studies of this type that “cross-examine” technical/social innovative capacity at the firm level vs. the same innovative capacity at the level of the world’s major countries. Our proposed study brings some novel elements to the literature on this topic. First, the study synthesizes the factors/variables explaining technical/social innovative capacity as ranked by the GCI (Global Competitiveness Index) and GII (Global Innovation Index) at the country level and then correlates informal/empirical variables with the factors explaining innovative capacity for the 50 companies in the BCG (Boston Consulting Group) ranking. Second, the study identifies three “driving forces” (digital technologies, managers, and the market) as the main variables determining financial innovativeness (fintech revolution) at the firm level. Third, based on the “over-cross assessment” (non- statistical) of the information/data provided by the BCG study vs. the GII and GCI studies, the study suggests some ways to delineate and quantify financial innovation as part of social innovation (e.g., it is argued that up to 80% of the social innovation achieved annually by a firm relates to the financial relationships engaged by the firm with various categories of stakeholders). Finally, the study is also important from a pragmatic point of view as it suggests/proposes a number of principles that can be considered by managers for building a KM (knowledge management) and continuous financial innovation strategy. From a theoretical perspective, the study provides a starting point for further research aimed at explaining firm-level financial innovation (fintech as a disruptor) through the massive use of disruptive technologies. Full article

Diffuse midline glioma (DMG) is a heterogeneous group of aggressive pediatric brain tumors with a fatal prognosis. The biological hallmark in the major part of the cases is H3K27 alteration. Prognosis remains poor, with median survival ranging from 9 to 12 months from diagnosis. Clinical and radiological prognostic factors only partially change the progression-free survival but they do not improve the overall survival. Despite efforts, there is currently no curative therapy for DMG. Radiotherapy remains the standard treatment with only transitory benefits. No chemotherapeutic regimens were found to significantly improve the prognosis. In the new era of a deeper integration between histological and molecular findings, potential new approaches are currently under investigation. The entire international scientific community is trying to target DMG on different aspects. The therapeutic strategies involve targeting epigenetic alterations, such as methylation and acetylation status, as well as identifying new molecular pathways that regulate oncogenic proliferation; immunotherapy approaches too are an interesting point of research in the oncology field, and the possibility of driving the immune system against tumor cells has currently been evaluated in several clinical trials, with promising preliminary results. Moreover, thanks to nanotechnology amelioration, the development of innovative delivery approaches to overcross a hostile tumor microenvironment and an almost intact blood–brain barrier could potentially change tumor responses to different treatments. In this review, we provide a comprehensive overview of available and potential new treatments that are worldwide under investigation, with the intent that patient- and tumor-specific treatment could change the biological inauspicious history of this disease. Full article

The rectangular utility tunnels have been increasingly built in urban areas in recent decades. In this paper, a case of jacked box tunnels built closely over-crossing the existing subway tunnels in Suzhou, China, is presented. The tunneling-induced deformation of the subway tunnels is measured and analyzed. The measurement indicates that the subway tunnels are uplifted and subjected to the overcrossing box tunneling. As compared, the longitudinal deformation of the range that locates under the box tunnels is more significant than that outside the range. The tunneling-induced deformation of the left subway tunnel is relatively higher than that of the right one. The numerical simulation is performed for validation. The numerical result is agreed with the in-situ measurements. Moreover, the simulation reveals that the presence of friction in jacked tunnels causes the extra uplift deformation of subway tunnels. The higher the friction, the is the deformation. It is affirmed that using the effective lubrication not only facilitates the tunnel jacking but also inabilities the tunneling-induced deformation of underlying tunnels Full article

High-precision positioning with low-cost global navigation satellite systems (GNSS) in urban environments remains a significant challenge due to the significant multipath effects, non-line-of-sight (NLOS) errors, as well as poor satellite visibility and geometry. A GNSS system is typically implemented with a least-square (LS) or a Kalman-filter (KF) estimator, and a proper weight scheme is vital for achieving reliable navigation solutions. The traditional weight schemes are based on the signal-in-space ranging errors (SISRE), elevation and C/N0 values, which would be less effective in urban environments since the observation quality cannot be fully manifested by those values. In this paper, we propose a new multi-feature support vector machine (SVM) signal classifier-based weight scheme for GNSS measurements to improve the kinematic GNSS positioning accuracy in urban environments. The proposed new weight scheme is based on the identification of important features in GNSS data in urban environments and intelligent classification of line-of-sight (LOS) and NLOS signals. To validate the performance of the newly proposed weight scheme, we have implemented it into a real-time single-frequency precise point positioning (SFPPP) system. The dynamic vehicle-based tests with a low-cost single-frequency u-blox M8T GNSS receiver demonstrate that the positioning accuracy using the new weight scheme outperforms the traditional C/N0 based weight model by 65.4% and 85.0% in the horizontal and up direction, and most position error spikes at overcrossing and short tunnels can be eliminated by the new weight scheme compared to the traditional method. It also surpasses the built-in satellite-based augmentation systems (SBAS) solutions of the u-blox M8T and is even better than the built-in real-time-kinematic (RTK) solutions of multi-frequency receivers like the u-blox F9P and Trimble BD982. Full article