This paper reports on a water inrush hazard, which occurred during the construction of the Chaoyang tunnel in Libo County, Guizhou Province, China. On 10 June 2018, a continuous water inflow of about 57 thousand m³ of water within 40 min took place at the tunnel excavation face, resulting in three casualties. The objectives of this study are to investigate and discuss the water inrush process of this atypical case. Further, an inclusive description of the implemented emergency responses will be provided. The principal causes of this tunneling incident include the karst geological condition at the construction field, hydraulic conductivity induced by the connection between karst water system and surface water body, and effects of excavation and precipitation. Moreover, based on a preliminary investigation and analysis, three main control measures to overcome similar incidents in the future are proposed: (1) Performing “water inrush risk grading” in areas prone to water inrush; (2) undertaking comprehensive geological forecast for a synthetic analysis; and (3) employing a monitoring system during the construction, and educating workers on self-protection skills. These effective management measures are bound to benefit underground engineering constructions with regard to water inrush risks.

This paper presents a comprehensive review on subsea jet trenching technology via a critical analysis of its principle, mechanism, devices, modeling approaches, as well as properties of subsea sediments. This review shows that the success of jet trenching operations is closely related to some key factors including the soil conditions, trencher specifications, and characteristics of pipelines or cables. Three case histories are presented to demonstrate the importance of these key factors and their interrelationships. This paper also points out a number of challenges pertaining to the implementation of the jet trenching method in carbonate sediments, as well as some limitations and gaps in the existing modeling approaches. Future perspective researches that are recommended to develop: (1) promising theories, like turbulent submerged flow, and (2) robust numerical approaches, such as the smoothed particle hydrodynamics (SPH) and material point method (MPM) to substantiate the experimental experience and reveal possible hidden mechanisms.

This paper reports on a large-scale landslide with a movement of 48 thousand m³ of soil and rock that occurred in Sichuan, China. This catastrophic landslide occurred in Aidai village, Ganluo County, at 12:44 on 14 August 2019, blocking a section of the railway between Lianghong station and Aidai station. This landslide resulted in 12 deaths and five people missing. This report describes the preliminary investigation, the rescue activity, topographic survey and analysis as well as the main predisposing and triggering factors. The combined effects of steep topography, continuous rainstorms, floods eroding the foothills of the mountain and human activity were the main influencing factors that triggered this landslide. To reduce the possibility of casualties resulting from large geological disasters, such as landslides and mudslides, in this region in the future, some recommendations are proposed to systematically reduce potential human casualties and economic losses.

Water quality is one of the most essential factors to influence human daily life and environment health. Risk assessment of water quality has critical significance to sustainable development of human society and natural systems. Set pair analysis (SPA) methods are widely used in risk assessment, especially in water resources. The essence of SPA is to classify assessment samples consider the uncertainties exist in risk assessment system based on the viewpoints of unity, difference, and opposition. The existing SPA methods are classified into two types, including (i) original SPA and (ii) comprehensive SPA. Both the original and comprehensive SPA methods have the following limitations: (i) it is need to judge whether the assessment factor belongs to type I or type II; (ii) it is need to judge whether the assessment factor is positive or negative. This method article gives a detailed description of the application of the existing SPA method. The method article is a companion paper with the original article [1].