As mining depth increases for coal and other mineral resources, so has the stress of coal-rock mass increased. The deep underground environment that coal-rock mass exists in has the typical characteristics of high water pressure, high ground pressure and high ground temperature. In addition, coal mining often causes additional characteristics, such as strong disturbance and strong ageing. These factors are causing an increasing number of serious underground dynamic disasters. In recent years, the construction of railways, roads, and water conservancy facilities has been carried out in high-altitude areas, such as China's Sichuan-Tibet railway (the highest point is 5,100 metres above sea level) and the water diversion project in central Yunnan province. There are numerous active fault zones and other geological hazards, including earthquakes, can be seen in these areas. At the same time, high in-situ stress in long tunnels, high seepage pressure of groundwater, high in-situ temperature and multi-field coupling of dynamic loads, are all leading to new characteristic scientific phenomena in the engineering response for deep rock mass.

For example, high temperature can change the mechanical properties of rock, such as the softening of hard rock due to the effects of thermal stress. Soft rock, such as mudstone and shale, is easily destroyed by accelerated creep under extremely high in-situ stress. Creep is also sensitive to high underground temperature and high permeability pressure. Moreover, dynamic water pressure generated by dynamic action has a significant influence on rock mass hydraulic fracturing and seepage deformation. Multi-field coupling of high ground stress, high ground temperature, high seepage pressure and dynamic load are all factors that can lead to water inrush, large deformation of soft rock and rock burst disaster, the mechanisms of which are all important in underground engineering. These factors will cause unprecedented technical challenges, meaning that disaster prevention and control methods need to be improved as soon as possible to ensure the safety of engineering and construction projects.

Underground engineering continues to progress at deeper levels with the challenging and characteristic environment of high temperature, high ground stress and high water pressure. In this Special Issue, we focus on the latest and most challenging research topics in the mechanisms and control of geological disasters in deep engineering, under coupled high temperature, high ground stress and high water pressure. We invite investigators to contribute to this special issue with original research articles as well as review articles on the mechanisms and control of geological disasters as well as their applications in solving engineering problems.

Potential topics include but are not limited to the following:

• Nonlinear mechanical characteristics and aging characteristics of deep rock mass
• Macroscopic and microscopic damage behaviour of deep rock mass
• Multi-field coupling failure mechanisms of deep rock mass
• Solid-liquid-gas multiphase coupling effect of deep rock mass
• Rock burst mechanisms and geological models under extremely high stress
• Large deformation mechanisms and models of soft rock under extremely high stress
• Mechanisms and processes of water gushing under high stress and high water pressure
• Prediction methods and active control technology for deep geological disasters
• Deterioration mechanisms of structure under high temperature and high pressure and optimal design of waterproofing and drainage