Going underground: Fatigue and sleepiness in tunnelling operations

Highlights

• Fatigue is a major problem in tunnelling; no single solution exists for reducing it.

• A more open industry-wide approach is required to make fatigue an acceptable event.

• Shift patterns vary greatly across sites; no one pattern is widely acceptable.

• Managers deem fatigue to be more of a safety concern than tunnellers do.

Abstract

This research represents one of the first qualitative studies to investigate fatigue in the tunnelling sector of the construction industry. It explores the opinions of tunnellers and their managers about how fatigue influences or is influenced by tunnelling, and how this is managed. Fatigue and sleepiness were discussed in six focus groups with frontline workers (n = 42) and 10 manager interviews. Fatigue was seen to be a problem, with all participants having experienced, or recognised in others, the feeling of sleepiness whilst at work. Fatigue and sleepiness are not commonly discussed between tunnelling workers and they do not feel comfortable reporting instances of fatigue. The research shows that workers in the tunnelling construction sector are exposed to a wide range of occupational factors that potentially increase their vulnerability to fatigue, including the physical environment, repetitive and monotonous tasks, variable shift patterns and manual work. Additionally, personal factors such as social and family demands, long commute times and living away from home, can increase the risk of fatigue. The construction industry in general has gone some way to address fatigue and there is opportunity to further improve fatigue management. However, a major shift is needed before workers will feel able to openly discuss fatigue with their employer.

Introduction

The personal consequences of working in general construction have been acknowledged by Sherratt and Turner (2018), who note that “construction work is unhealthy and bad for worker wellbeing. The industry structure results in insecure contracts, transient work, long working hours, stressful workplaces and poor occupational health” (p 283). In particular, the negative impact of fatigue and sleepiness on general safe operations across many industries is widely acknowledged (Gander et al., 2011) and there is currently no reason to believe that the tunnelling sector, a type of construction, is any different. Sleepy individuals exhibit impaired performance at a range of cognitive abilities, particularly higher order executive functions which engage the prefrontal cortex (Kilgore, 2010). This reduced ability, for example in decision making and ability to update strategies based on new information, can have serious consequences in safety critical situations (Whitney et al., 2015). Furthermore, fatigue and sleepiness pose unique issues for occupational safety and health (OSH) management, as they are influenced by both work-related and non-work-related factors (Gander et al., 2011).

It should be noted here that this research recognises that there is a difference between fatigue and sleepiness and both concepts were the focus throughout the research. As noted by Pilkington-Cheney et al. (2020), sleepiness is considered to result from insufficient sleep or circadian time of day, whereas fatigue is more broadly considered as resulting from work and task related activities. Relevant for this study is the fact that, in occupational settings, sleepiness and fatigue are often used interchangeably. Within the current work a single investigation is undertaken to investigate fatigue, while recognising that some aspects relate directly to sleepiness. This broad usage of the term fatigue to include sleepiness was employed during the data gathering.

Most published research into fatigue is focused on transport or medical personnel (see, for example, Filtness and Naweed, 2017; Anderson et al., 2012; Anund et al., 2018; Ku and Smith, 2010). Previous research which has examined fatigue in construction workers is more limited, relating largely to physical fatigue (see, for example, Maiti, 2008; Chang et al., 2009; Maman et al., 2017). Where studies have examined fatigue in the context of the psychosocial work environment, this has been in connection with specific trades such as bricklayers (see, for example, Boschman et al., 2013; Zhang et al., 2015). An exception can be seen in Jackson et al. (2013) which employed 20 interviews and a survey (n = 47) to find that worker and manager fatigue is a problem on rapid renewal highway construction sites and that it is exacerbated by construction practices such as night working. Notably, the existence of fatigue was widely acknowledged by both management and other workers. The study found that methods employed for dealing with fatigue were informal; a wide variability in attitudes relating to fatigue was also found.

Investigations relating to the wider construction industry are of relevance to this research. For example, with regard to the issue of fatigue in the conflict between work and family life in construction workers, Bowen et al. (2018) investigated the situation of South African construction professionals, examining the relationship between work contact, work–family conflict and consequent outcomes of psychological distress and sleep problems. Via an integrated model of these factors, the authors found that sleep problems are influenced by work–family conflict, work contact and psychological distress. Holguín-Veras et al. (2003) carried out field surveys and interviewed 30 construction employees working at night and found ample evidence that this kind of work has negative impacts on workers’ sleep patterns, body rhythms and social and family lives.

Dong (2005) aimed to examine work scheduling in the construction industry and to investigate whether there is a connection between work hours and safety outcomes among the workers in the industry. The study found that construction workers experience long work hours and irregular work schedules which have an adverse effect on worker safety. Such extreme working conditions were investigated by Kumar and Chaturvedi (2018); this research attempts to examine the challenges associated with maintaining work-life balance in the construction industry, specifically in relation to the associated under-representation of women. They concluded that work-life balance is equally important for the individual and the organisation.

Relatively little research has been conducted in tunnelling construction, particularly relating to the issue of fatigue. Workers in the tunnelling sector, however, are particularly vulnerable to fatigue due to the use of shift working (which is less common elsewhere in general construction work) and its associated impact on sleeping patterns. Bustamante (2016) used a range of methods (including actigraphy) and reported that many tunnelling workers slept less than 6 h between shifts, slept less when working night rather than day shifts, and that this had an adverse impact on cognitive performance. There is evidence from research with miners that “restricted sleep and quick shift-change periods may lead to long-term sleep loss and associated fatigue” (Paech et al., 2010) and that fatigue is associated with an increase in occupational accidents (Paech et al., 2010).

Studies by Karkoulias et al. (2012) and Lykouras et al. (2014) both recognise that working shifts leads to diminished time for sleeping and increased sleepiness and can be dangerous particularly in large scale construction, such as tunnels. Karkoulias et al.’s (2012) study of 42 male tunnelling workers examined whether sleep duration and daytime sleepiness differed between day and night shifts among these workers. They concluded that rotating shifts (as often found in tunnel construction) do not contribute significantly to daytime sleepiness. Lykouras et al. (2014) involved 44 tunnelling construction workers (42 male and 2 female) in their study which attempted to evaluate the impact of shifts on sleepiness and correlate sleepiness scores (ESS) (Johns, 1991) to the experience in a shift schedule. They concluded that workers who had been employed in the industry for a longer time had lower levels of sleepiness. However, they found no relationship between night shifts and sleepiness, which they related to workers' exposure to artificial lighting in the construction site.

Tunnellers have a specific skill set and way of working which sets them apart from workers within generic construction work, for example, it is very common for tunnelling construction to operate 24/7. This brings additional pressures in the process, which are less commonly experienced by the wider construction industry, for example, working in established small teams and travelling to remote locations to work for intense periods before moving on to another worksite. Forberg et al. (2010) found that a small group of tunnelling workers living in an isolated environment adapted relatively easily to shift changes in the absence of family responsibilities. However, most tunnellers still have everyday commitments even if they are living away from family, and they also face additional risks from commuting long distances between blocks of shifts (Jones et al., 2019).

Other key differences between tunnelling and construction and other general shiftwork include light exposure (including circadian rhythm as well as illumination), atmospheric pressure/decompression sickness (DCS), oxygenation/ventilation, physical work environment (e.g. noise and heat) and utilisation of powered haulage in small areas. Furthermore, DCS is worth mentioning as an occupational exposure unique to tunnelling (and a very limited number of other industries) of which fatigue can be a symptom (Francis and Mitchell, 2003). Additional impacts can arise from the poor diet and limited opportunity to exercise which are common in general construction work, particularly where working hours are long and time with family is limited (e.g. Lingard and Turner, 2017).

Further investigation within the specific context of tunnelling construction is needed to understand the causes and consequences of fatigue and sleepiness in these operations. As mentioned previously, fatigue and sleepiness are different concepts; fatigue includes the inability to continue or the impairment of performance at an activity because it has been going on too long (Bartley and Chute, 1947) whereas sleepiness is defined as a physiological urge to fall asleep resulting from sleep loss or circadian effects (Dement and Carskadon, 1982). The overall aim of this work was to improve the general construction industry's understanding of the prevalence of fatigue and sleepiness within 24-h operations using tunnelling as a case study. Furthermore, the work aims to investigate how fatigue and sleepiness relate to shift work patterns and non-work activities, and how the industry can better manage the risks involved.

Focus groups and interviews were used to investigate the personal experiences and opinions of tunnelling workers and managers relating to fatigue and thus to surface the hidden knowledge of these industry experts. It is particularly valuable to obtain the opinions of the workforce themselves since their day-to-day experiences can provide realistic and detailed data on the subject. The main tasks being undertaken by the participants were: sinking shafts ready to commence tunnelling, operating the tunnel boring machines (TBMs) and managing ‘muck away’ – removing the excavated material from the newly dug tunnel. The focus groups and interviews addressed the following research questions:

• Do tunnelling personnel believe fatigue/sleepiness to be a problem in their sector?

• What are the causes and consequences of fatigue/sleepiness in the tunnelling sector?

• How is fatigue/sleepiness managed in the tunnelling sector?