Zhaogeng Wang

This paper comprehensively summarizes and discusses the latest research progress in the underwater concrete structure damage repair technology of infrastructures. The prompt application of underwater concrete structure repair technology can effectively deal with the damaged parts of underwater concrete structures, and it can ensure the safe and stable operation of infrastructure and extend its service life. Firstly, this study uses bibliometric methods to analyze the characteristics of the literature on research into underwater concrete repair in the past 30 years (1993–2023), and expounds the research status and hotspots of this field. Then, we conduct a comprehensive classification and discussion of the underwater concrete structure damage repair technologies at the current stage. This technology can be divided into two major types: direct underwater type and dry environment type. Further, the development history of these technologies is systematically sorted out and, combined with practical engineering application cases, the operation processes, applicability, limitations, and economy of these technologies are analyzed. Finally, the challenges and future development trends of the current underwater concrete structure damage repair technology are pointed out, which provides a direction for future research on the intelligent maintenance of underwater concrete structures.

Trees play important roles in urban stormwater management; through the loosening of soils by root growth, they increase infiltration and reduce runoff, helping to mitigate flooding and recharge groundwater. Malus baccata with fibrous roots and Sophora japonica with tap roots were studied experimentally to assess their enhancement of soil infiltration. A blank test without a tree was conducted for comparison. Steady-state soil infiltration rates at the bottom of test tanks were measured as 0.28 m/d, 0.33 m/d, and 0.61 m/d for the blank test, M. baccata, and S. japonica, respectively. This represents a 19% increase in the infiltration rate by planting M. baccata and a 118% increase by planting S. japonica. A larger increase in the infiltration rate by S. japonica is consistent with the effects of deeper and more vertical roots that help loosen deeper soils. Spatial variations in soil infiltration rates were also measured. Infiltration rates for M. baccata (1.06 m/d and 0.62 m/d) were larger than those for S. japonica (0.91 m/d and 0.51 m/d) at the same depths (0.35 m and 0.70 m); this is consistent with the expected effects of the shallower and more lateral roots of M. baccata. This study furthers our understanding of the roles of trees in watersheds and urban environments.