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Foundation pit engineering has been developing rapidly with the challenges associated with modern urbanization. As a result, deep excavations can now be performed at the heart of coastal metropolises with dense existing structures and adverse soil and hydraulic conditions. On the other hand, foundation engineering is challenged with sustainability and economic viability such that cost-effectiveness is a key factor provided that the robustness and safety requirements are fully satisfied. This paper presents the design of the retaining system for a deep foundation excavation that is located in a second-tier inland city with less crowed existing structures and good soil and hydraulic conditions. This is representative of the current trend of the suburban development of major cities and the development of below first-tier cities, as a response to the saturating of the major cities. Different designs are reviewed for this case in order to strike the balance between structural capability and cost-effectiveness. The analysis indicates that a hybrid solution is particularly suitable for such type of construction. Specifically, results show that the maximum displacement, bending moment, and shear force in the pit can be reduced by over 50%, 40%, and 30%, respectively, by the combination of soil nailing wall and pile anchor compared with a single support solution. And for the combination of non-prestressed anchor bolts and prestressed anchor cables can effectively save the cost while improving the safety factor of foundation pit during excavation. The findings are instructive to similar projects with cost-effectiveness as a major factor. [ABSTRACT FROM AUTHOR]

• Indoor and outdoor PM 2.5 concentrations were monitored for a year. • The indoor and outdoor PM 2.5 concentration in the university area was analyzed. • DALYs and USEtox models were used to evaluate the health hazards of college students. Campus environment, especially campus indoor environment, will directly affect the health of college students. Through one-year real-time monitoring of PM 2.5 indoor and outdoor in colleges and universities in Northeast China, the annual PM 2.5 indoor and outdoor concentration was analyzed. Questionnaires were used to investigate students' lifestyles, and the health effects of PM 2.5 pollution on students in university packed areas were assessed using the DALY model and the USEtox model. The monitored results show that PM 2.5 concentration was the highest in winter, 41.59 μg/m3 indoor and 105.85 μg/m3 outdoor, the lowest concentration was 11.15 μg/m3 and 18.71 μg/m3 in summer. There is a significant Correlation between indoor and outdoor PM 2.5 concentrations. The contribution value of outdoor PM 2.5 to indoor air pollution was 11.22 μg/m3 and 14.28 μg/m3 respectively in autumn and winter, and 7.30 μg/m3 and 3.61 μg/m3 respectively in spring and summer. The contribution rate of autumn and winter was 26.47% and 27.00% respectively, and that of spring and summer was 48.13% and 65.63% respectively. Among 145,200 students in this area, 109–134 died prematurely due to PM 2.5 pollution, 71–75 of which were attributed to indoor PM 2.5 pollution. Indoor and outdoor PM 2.5 pollution resulted in 42 chronic bronchitis, 2565 medical outpatient visits, 19 cardiovascular diseases and 5 respiratory diseases. These findings should further arouse our attention to come up of effective solutions for indoor air pollution control, such as sources control, purification equipment mounting etc.. [ABSTRACT FROM AUTHOR]