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• The role of TBM tail-grouting on surface settlement in coarse-grained soils was investigated. • The field test was executed to show how surface settlement is controlled by TBM tail-grouting. • Influence of asymmetric tail-grouting on settlement trough was explored. This paper examines the role of TBM tail-grouting on surface settlement of coarse-grained soils in urban area. The influence of tail grouting on the ground surface settlement is firstly demonstrated through a challenging shield-driven tunnel project in Beijing City, China. FEA modelling incorporating the excavation sequence and tail grouting details is then set up to support the field observations, based on which the influences of different TBM tail-grouting parameters on ground settlement are investigated, especially the asymmetric tail-grouting in which one of the two grouting openings at the upper part of the shield tail is malfunctioned. It is shown that the grouting volume variation is inconsistent with the development of the grouting pressure, and the ground deformation in coarse-grained soils is directly related to the tail-grouting pressure rather than the grouting volume ratio. Asymmetric tail-grouting will result in notable offset of the maximum surface settlement point in settlement trough from tunnel centerline which correlates exponentially with the parameter ξ defined to represent the asymmetry ratio of the grouting pressure. [ABSTRACT FROM AUTHOR]

Background: The outbreak of the COVID-19 pandemic has caused extensive public health concerns, posing significant challenges to healthcare services. One particular area of concern is the mental health of patients with mental disorder, who are often a neglected group. The aim of this study was to investigate the prevalence of, and associated factors for symptoms of post-traumatic stress disorder (PTSD) among patients with mental disorder in China during the COVID-19 pandemic. Methods: Self-reported questionnaires were distributed to patients in four psychiatric hospitals in Beijing, China, between April 28th and May 30th, 2020. Information regarding sociodemographic characteristics, COVID-19 related factors, support, psychosomatic factors, and PTSD symptoms were collected using a series of scales, such as the Impact of Event Scale-Revised, the 7-item Generalized Anxiety Disorder Scale, the 9-item Patient Health Questionnaire depression scale, and so on. Multivariate regression was used to identify factors related to PTSD symptoms. Results: A total of 1,055 patients with mental disorder were included in the final sample. The prevalence of PTSD symptoms was 41.3%. Hierarchical linear regression demonstrated that fear of the pandemic and anxiety were shared associated factors for both symptoms of PTSD and their subscales. Additionally, age was an associated factor for the total PTSD (β = 0.12, p < 0.01), intrusion (β = 0.18, p < 0.001), and avoidance (β = 0.1, p < 0.05) symptoms; depression was an associated factor for the total PTSD (β = 0.13, p < 0.001), intrusion (β = 0.11, p < 0.01), and hyperarousal (β = 0.19, p < 0.001) symptoms. Conclusions: The prevalence of PTSD symptoms was high among patients with mental disorder during the COVID-19 pandemic in China. This study found that age, fear of the pandemic, anxiety and depression are significant associated factors of PTSD symptoms in patients with mental disorder during the pandemic. We call for higher awareness and introduction of PTSD interventions to relieve the psychological stress in these patients. [ABSTRACT FROM AUTHOR]