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During the excavation of a water-conveyance tunnel in Tertiary soft rocks in China, significant deformation of the surrounding rocks and damage to the support were observed. Substantial horizontal deformation, reaching magnitudes of meters, was observed in the right side wall after a certain period of tunnel excavation. Extensive investigations, including field surveys, monitoring data analysis, laboratory tests, and numerical simulations, were conducted to understand the underlying mechanisms of this large deformation. The section of the tunnel with large deformation consisted of Tertiary sandy mudstone, mudstone interbedded with marl, and glutenite. Laboratory tests and mineral composition analysis revealed that the sandy mudstone and mudstone interbedded with marl exhibited low strength, which was closely related to the water content of the rock specimens. The compressive strength gradually decreased with increasing water content, and when the water content of mudstone interbedded with marl reached 26.96%, the uniaxial compressive strength decreased to only 0.24 MPa. Additionally, sandy mudstone and mudstone interbedded with marl contained a significant amount of hydrophilic minerals, with montmorillonite constituting 30% and 34% of the two rock samples, respectively. The tunnel passed beneath a perennially flowing gully, and a highly permeable glutenite layer was present in the middle of the tunnel. This resulted in groundwater seepage from the inverted arch during excavation, leading to the softening effect on the mudstone interbedded with marl in the lower part of the tunnel. Through numerical simulation and back-analysis techniques, the varying degrees of softening induced by groundwater were quantitatively analyzed in the surrounding rocks on the left and right sides. The study revealed that the large deformation of the tunnel was triggered by two factors: the plastic flow caused by tunnel excavation under the low strength of the surrounding rocks and the softening effect of groundwater. The damage to the support system was primarily attributed to the squeezing and swelling deformation of the surrounding rocks and the non-uniform deformation between different rock layers. [ABSTRACT FROM AUTHOR]

To recommend the excavation procedures and design parameters for underground powerhouses, excavation procedures of fifty-one underground powerhouses in China were summarized and analyzed based on in situ stress conditions. Firstly, the complex stress environment in China was introduced and fifty-one underground powerhouses with their engineering scale, size, lithology, rock classification and in situ stress level were listed in detail. Subsequently, to evaluate the influence of in situ stress levels on excavation procedure design, the correlation between excavation procedures and in situ stress level in three main excavation zones were analyzed accordingly. Moreover, to provide the excavation design recommendations, the strength–stress ratio (SSR) was promoted to analyze and recommend the design parameters, and the blasting excavation design based on the stress transient unloading control was also supplemented. The results show that excavation procedures have different priorities under different in situ stress levels, and the design parameters show an obvious relationship with in situ stress levels. Moreover, the excavation procedure parameters are suggested to adjust accordingly under different SSR. The discussion of influencing factors and specification ensures its rationality and accuracy. It is believed that the summary and recommendations can provide a good reference for excavation procedure optimization of underground powerhouse under high in situ stress. [ABSTRACT FROM AUTHOR]

In this paper, a new safety control method of the jointed slope under blasting excavation is presented. The spatial distribution of blasting damage and time-history characteristic of dynamic stability around the joint were investigated carefully based on the secondary development of the explicit FE code, LS-DYNA. Results clearly indicated that the evolution law of damage and stability are opposite with the change of joint angle, and the dual-controlled mechanism of damage extension and stability fluctuation exists in the safety control of the high rock slope with joints. Then a new safety control method is proposed by implementing the equivalent Blasting Safety Control Standard (BSCS) which includes coupled effects of damage and stability. Results reveal that a critical joint angle exists, and if the inclination is larger than the threshold value, the BSCS depends on damage extension, otherwise it was determined by stability fluctuation. Finally, site experiments are implemented carefully based on the blasting excavation of the famous Baihetan high rock slope with columnar joint in China to verify the rationality of the new control approach. Sonic wave test, displacement measurement and blasting vibration test are implemented for nearly two years to track the evolution process of damage and stability of the jointed slope. Experimental results demonstrate that the new approach could improve the accuracy rate of control by 40%. [ABSTRACT FROM AUTHOR]

• Stability problems caused by lower bench excavation were analysed. • A new support system controlling squeezing deformation was proposed during the lower bench excavation of the headrace tunnel. • Polar coordinate description methods for the maximum displacement and associated position were presented. Jinping II hydropower station in Sichuan Province, China, is one of the largest tunnel groups in the world. The tunnel was excavated using bench excavation with a top heading and a bench. Severe squeezing problems were reported immediately after the excavation of the top heading when crossing the chlorite schist stratum at Ch.1+537 m. Squeezing deformation could last for a long period during tunnelling, similar to the problem of rockburst reported in the marble stratum distributed in the middle and east of the headrace tunnels. One year after the top heading excavation, the profile of the top heading still violated the profile tolerance and had to be reshaped due to the large convergence. A new support scheme was proposed to ensure the stability of the surrounding rock mass and control the excessive squeezing deformation during the bench excavation. For this, laboratory triaxial tests were first conducted under saturated and dry conditions to acquire the mechanical properties of chlorite schist. Then, the mechanical parameters of intact and damaged surrounding rock mass were determined using Hoek empirical estimation and a displacement inversion method, respectively. Next, initial support design was re-reviewed and evaluated based on the field displacement measurements, and the potential for squeezing in the overstressed rock mass was estimated. Thereafter, 10 supplementary support schemes were proposed using the numerical method in combination with laboratory data and field observations. Finally, the optimised support scheme was selected based on the results of comparative analysis. Field application of the suggested scheme showed that the convergence was controlled to within an acceptable level throughout the entire period of excavation of the lower bench. The experiences of controlling excessive squeezing deformation and optimisation of the support scheme for rock strata in a high geo-stress environment provide a reference for similar projects in the presence of soft rocks. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to explore the mediating role of resilience and resignation coping in the relationship between consultation empathy and depression in patients with COVID-19., Design: Cross-sectional study., Setting: Participants were recruited from a tertiary hospital in Guangzhou, Guangdong province., Participants: A total of 215 patients were recruited for this study., Outcome Measures: A total of 215 patients completed the Consultation and Relational Empathy Measure, Connor-Davidson Resilience Scale, Medical Coping Modes Questionnaire and Hospital Anxiety and Depression Scale. PROCESS 4.1 model 6 was used to analyse the moderated mediating effects., Results: Consultation empathy had a positive correlation with resilience (r=0.34, p<0.001), and a negative correlation with resignation (r=-0.288, p<0.001) and depression (r=-0.379, p<0.001). Resilience had a negative correlation with resignation (r=-0.463, p<0.001) and depression (r=-0.605, p<0.001). Resignation had a positive correlation (r=0.547, p<0.001) with depression. In the moderated mediating model, consultation empathy had significant indirect predictive effects on depression through resilience (95% CI -0.093 to -0.030) or resignation (95% CI -0.043 to -0.005). Consultation empathy had significant indirect predictive effects on depression through both resilience and resignation (95% CI -0.030 to -0.008)., Conclusions: Consultation empathy not only predicted depression directly, but also indirectly predicted depression through the chain mediating effects of resilience and resignation coping., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: To translate the Information Needs in Cardiac Rehabilitation (INCR) tool into Chinese and evaluate its cultural adaptation and psychometric properties of this Chinese version. The INCR uses a Likert-type scale that aims to assess information needs in cardiac rehabilitation (CR) patients., Methods: The initial Chinese INCR tool was generated by forward/backward translation and evaluation of face and content validity. The internal consistency was assessed by Cronbach α, item-to-total correlations, interitem correlations, and test-retest reliability using intraclass correlation coefficient. The construct validity was tested by principal component analysis and known-group validity by t test. A total of 296 CR patients were recruited from 2 university-affiliated hospitals in Guangzhou, China, using a convenience sample., Results: The Chinese INCR tool included 10 subscales with 55 items. Cronbach α of 10 subscales ranged from 0.68 to 0.90. Intraclass correlation coefficients of 55 items were between 0.62 and 0.89. The item-to-total correlations for all items were between 0.23 and 0.73 and interitem correlations of 80% items ranged from 0.30 to 0.70. The content validity index was 0.91. Ten factors were extracted by principal component analysis, which together accounted for 66.74% of total variance. The mean total scores of Chinese INCR tool in CR patients with less than high school education were higher than scores in those with high school education and above, and there was a statistically significant difference (t = 2.95, P = .021)., Conclusions: The Chinese version of INCR tool has strong psychometric properties, providing preliminary evidence of the reliability and validity of INCR tool to assess information needs in Chinese CR patients.

Objectives: To test the effects of group-based Tai chi on health-status outcomes among older adults with hypertension., Background: A high-quality study exploring the effects of Tai chi on physical and psychosocial health for older adults with hypertension is needed in China. The long-term effects of group-based Tai chi in Chinese older adults with hypertension remain unclear., Methods: A randomized controlled trial was conducted. The group-based Tai chi training and practice were implemented in older adults over six-month., Results: The Tai chi (TC) group showed significantly lower blood pressure and body mass index than the usual care (UC) group. The TC group participants showed greater improvements in social support, quality of life, and reduction in depressive symptoms over a six-month intervention than UC group. TC group showed significant group-by-time interactions in these variables., Conclusion: Group-based Tai chi is effective in the enhancement of health-status outcomes for older Chinese adults with hypertension., (Copyright © 2018 Elsevier Inc. All rights reserved.)