Evaluation of orderliness of underground workplace system based on occupational ergonomics: A case study in Guangzhou and Chengdu metro depots

Abstract

BACKGROUND:

An underground workplace (UGW) is a complex system with multiple subsystems that interact with each other. However, the research on UGW from a systemic perspective has not received due attention.

OBJECTIVE:

This study constructs an evaluation approach to the orderliness of UGW and systematically evaluates the UGW with Guangzhou and Chengdu metro depots as case studies.

METHODS:

First, the evaluation index system is established based on occupational ergonomics. Second, the system entropy model is constructed based on information entropy. Third, a dissipative structure judgment model is built based on the Brusselator. Fourth, the orderliness evaluation model is constructed based on information entropy and synergetics.

RESULTS:

The UGW of the metro depot has not yet reached the dissipative structure and is in a medium-order state. But the system is in the trend of orderly development. The entropy increase caused by the physical environment and health status is the main obstacle for the system to move toward order. The equipment configuration is an essential source of system negative entropy. The coordination between equipment configuration, health status, and physical environment is low, and that of work effectiveness, equipment aging and failure, and organizational environment is high.

CONCLUSIONS:

Equipment configuration cannot fully cope with the harsh physical environment and meet the needs of underground workers. Safety security equipment has more room for improvement. Humanized support facilities can introduce more negative entropy to the system. Organizational intervention can reduce the negative impact of adverse factors on the system.

Keywords

Underground workplace occupational ergonomics work environment equipment staff system orderliness

1 Introduction

The demand for land space in large cities is increasing, and underground space (UGS) is considered a significant resource to relieve land pressure [1]. The functions and scenes of modern UGS show a diversified development trend [2]. More and more workers are transferred from aboveground space (AGS) to UGS for work [3]. Compared with AGS, UGS is usually characterized by poor ventilation, dim light, humidity, and claustrophobia [4], which makes the occupational hazards faced by underground workers much higher than those of aboveground workers [5]. Therefore, before massive investments and master plans are made, assessing whether the underground workplace (UGW) complies with occupational efficacy factors to ensure that it can provide healthy, comfortable, safe, and productive spaces for underground workers is a major priority.

UGW is a complex system that contains multiple subsystems that interact with each other, such as people, environment, and equipment, and each subsystem includes multiple interacting elements [6]. However, the research on UGW from a systemic perspective has not received due attention, not to mention the lack of systematic evaluation of UGW [7]. The orderliness degree is one of the metrics that characterize the system’s complexity. Generally, the greater the system’s orderliness, the less chaotic it is and the better it operates [8]. Evaluating the orderliness of UGW enables us to understand the coordination and adaptation among the system’s elements and subsystems and predict the system’s operation status and development trend. This is an effective way to prevent, control, and eliminate occupational hazards in UGW and realize the unification of safety, health, and work effectiveness of underground workers’ occupational activities.

Existing research mainly uses entropy theory to evaluate system orderliness [9]. One of the key issues is identifying the evaluation index system that both characterizes the occupational ergonomics of UGW and reflects the interactions among elements and subsystems from a system perspective. Occupational ergonomics is an essential branch of ergonomics application, focusing on occupational groups and studying the interrelationship between people, mechanical equipment, and the environment, aiming to guarantee people’s health, safety, and comfort at work while maintaining optimal work efficiency [10]. It covers the core subsystems and elements of UGW and pays attention to their coordination and interaction, which can appropriately reflect the entropy changes of the system. For example, good “human-equipment” interaction can help workers better match and handle work tasks and improve work efficiency, which can introduce negative entropy to the UGW.

Therefore, this study aims to evaluate the orderliness of UGW. Compared with previous studies, this study attempts to enrich relevant research from the following three aspects. First, instead of treating individual elements in the workplace as a single research object [11], this paper takes the human, equipment, and environment as a complete system, which helps us understand the organization and orderliness of the structure and the function of UGW. Second, in contrast to the index system determined based on experience [12], this study constructs the evaluation index system based on occupational ergonomics. This is more in line with the systemic perspective and helps us assess whether UGW can meet workers’ needs from a humanistic perspective. Third, compared with the traditional adoption of the Brusselator model as the criterion of system orderliness [13], this study further establishes the orderliness calculation function of each subsystem and calculates the compound orderliness of the system by introducing the synergistic degree model, which overcomes the shortcoming of the traditional method that cannot precisely judge the system orderliness degree. In addition, this method can also comparatively analyze the synergy between the subsystems and identify their adverse factors to help managers and decision-makers formulate targeted improvement measures for UGW.

2 Methodology

2.1 Research design

Firstly, this study constructs an evaluation index system from three dimensions of “human, equipment, and environment” according to occupational ergonomics. Then, this study builds an evaluation model of the orderliness of UGW based on information entropy, Brusselator model, and synergetics. Precisely, the model consists of three modules. The first is the system entropy model based on information entropy. This module is mainly used to calculate the entropy value of UGW. The second is a dissipative structure judgment model based on Brusselator. This module can judge whether the UGW reaches the dissipative structure according to the entropy value. The third is the orderliness evaluation model based on information entropy and synergetics. This module can accurately evaluate the orderliness of the UGW, considering the synergistic effects between various elements and subsystems. Finally, this study takes the UGW of metro depots in Guangzhou and Chengdu, China, as a case to evaluate the orderliness to provide empirical evidence for improving the orderliness and promoting the sustainable development of the system.

2.2 Evaluation index analysis

According to occupational ergonomics, a UGW contains three core subsystems: the underground staff, equipment, and the environment (including physical and organizational environments), which interact [10], as shown in Fig. 1. The state of the staff will affect their use of the equipment and the adaptation and transformation of the work environment. The setting and layout of equipment and the work environment will affect the staff’s health, safety, and efficiency. The work environment conditions will affect the life and layout of equipment, while a reasonable equipment configuration and layout can improve the work environment conditions.

Fig. 1

UGW subsystems and their interrelationships based on occupational ergonomics.

2.2.1 Classification of evaluation indicators

(1) Underground work environment

The work environment affects the UGW system’s orderliness mainly through the physical and organizational environments [14]. The physical environment dramatically impacts the staff’s physical and mental health and sensory comfort. According to occupational ergonomics, light is a prerequisite for all work operations, especially for the UGW. The light environment of UGS mainly relies on the artificial light source, which has the disadvantages of single, static, and insufficient light, making people prone to visual fatigue [15]. Properly introducing natural light can mitigate the negative impact of artificial light on health [16]. In addition, ergonomic factors such as odor, noise in terms of occupational hazards and ventilation, temperature, and humidity in terms of building sanitation are also factors of general interest to scholars in studies related to UGS. For example, a survey of nonresidential buildings in Chongqing, China, showed that people are more sensitive to odor and noise in the UGS and are less satisfied with the wind and noise environment [17]. A thermal performance test conducted by Zhu and Tong on underground dwellings showed that a stuffy underground environment significantly reduced the thermal comfort of the human body [18]. At the same time, air humidity affects the ability of the human body to maintain thermal comfort through sweat evaporation [19]. In addition, the dark, claustrophobic UGS will also affect people’s direction sense. The rational design of the guiding sign’s color, content, and location significantly improves the guidance effect [20]. Based on this, this paper intends to evaluate the physical environment of the UGW from five aspects: ventilation environment, noise environment, light environment, humidity and heat environment, and signage environment.

According to occupational ergonomics, organizational environment, such as organizational structure, management mechanism, incentive mode, and humanistic care, as factors of psychosocial dimensions, significantly impact the psychological load, working state, and efficiency of staff [21]. Some scholars believe that organizational structure is the core of organizational management [22], and improving organizational structure also implies improving the management model [23]. Scientific organizational structure design, rational leadership and management, and efficient communication and feedback mechanisms help employees relieve stress and improve their work efficiency [24]. In addition, the institutional environment is also an essential part of the organizational environment. A study on family enterprises showed that greater institutional and rule-based management adoption significantly improved workers’ effectiveness [25]. The perfection of the management system, rationality of performance appraisal and fairness of salary treatment significantly impact employees’ fairness perception and work enthusiasm [26]. In the organizational environment, soft humanistic management has always been an important factor influencing the cohesion of employees’ goals and the improvement of employees’ self-worth perception [27]. Good corporate culture [28], bright career prospects [29], harmonious interpersonal relationships [30], and humanistic care [31] can motivate staff to overcome difficulties and improve their work performance. Therefore, this paper intends to evaluate the organizational environment of the UGW from three aspects: organizational structure, institutional system, and humanistic management. Among them, the rationality of organizational structure design, the scientificity of leadership and management, and the efficiency of communication and feedback mechanisms are used to measure the organizational structure. The rationality and perfection of work management system, performance appraisal system, and welfare system are used to measure the institutional system. The corporate culture, career prospects, interpersonal relationships, and organizational humanistic care are used to measure humanistic management.

(2) Underground equipment

For the UGW, the configuration and layout of the equipment will directly or indirectly affect its orderliness. Occupational ergonomics considers the quality of equipment, facilities, and tools crucial to workers’ safety and health, especially their operation ability [32]. On the one hand, appropriate setting and layout of equipment following relevant design standards of UGS can effectively prevent occupational hazards [33] and directly affect the safety and health of workers and the work environment. The configuration of ventilation and exhaust equipment, lighting equipment, dehumidification equipment, temperature regulation equipment, noise and sound reduction equipment, etc., can effectively improve the poor physical environment such as poor ventilation, dimness, humidity, and stuffiness in UGS, increase people’s physiological and psychological comfort, and improve their job satisfaction [4]. On the other hand, whether the design of the operating equipment follows the basic principles of the working system and adapts to the operation of underground workers, whether the supporting equipment for production and living can meet the daily needs of workers will indirectly affect the interaction and efficiency of the “human-machine” system in UGW [34]. Therefore, this paper intends to evaluate the rationality of underground equipment configuration through ventilation and exhaust equipment, lighting equipment, dehumidification equipment, temperature regulation equipment, noise reduction equipment, operation system equipment, and production and living support equipment. Among them, the operation system equipment and production and living support equipment can be set with specific measurement indicators according to different UGW.

It is worth noting that the wet physical environment will accelerate the aging and failure of underground equipment, shorten their service life, and bring more significant health and safety risks to underground workers [35]. Monitoring and evaluating the efficacy, stability, and safety of equipment can effectively reduce the uncertainty caused by the aging and failure of equipment [36]. Equipment efficacy reflects the effectiveness and usefulness of the equipment. The worse the efficacy, the lower the availability of the equipment, and the less convenience and comfort the equipment brings to people [37]. The failure frequency reflects the stable performance of the equipment. The higher the failure frequency, the worse the stability and the lower the reliability of the equipment [38]. In addition, the frequency of safety accidents during the use of the equipment reflects the safety performance of the “human-machine” interaction, and equipment with frequent safety accidents exposes the user to more significant safety risks [39]. Therefore, this paper intends to evaluate the aging and failure of equipment by using equipment efficacy, equipment aging degree, equipment failure frequency, and the frequency of equipment safety accidents.

(3) Underground staff

Staff is the most concerned factor of occupational ergonomics and the most essential and core element in the UGW, which mainly includes physical and mental health status and work efficiency [32]. Their physiological and psychological characteristics and matching with work tasks will affect the orderliness of the UGW system through their occupational safety, health, and working status. These indicators mainly evaluate the adaptability of underground staff and occupational activities, aiming to eliminate human hazards in the work system from the prevention perspective.

According to occupational ergonomics, the workers’ respiratory, excretory, cardiovascular, and psychological systems will undergo corresponding changes in the operational labor process. The poor work environment will aggravate their adverse physiological and psychological reactions [40]. Relevant research has shown that people are prone to fatigue and emotional problems when working in a hot and humid environment [41]. For example, a study in the United States showed that living in a dark and humid environment for long periods was associated with a 15.8% incidence of depression [42]. Moreover, the poorly ventilated, humid, and claustrophobic physical environment causes poor air quality in underground places, making personnel in long-term underground environments susceptible to dizziness, respiratory infections, pneumonia, and other diseases [43]. A review of 11 longitudinal studies on miners conducted by the World Health Organization found that the risk of lung cancer increased by 16% for every 100 Bq/m3 increase in radon exposure concentration under mines [44]. In addition, a study of air quality and psychiatric hospitalization rates in Shanghai, China, showed that air pollution increases the risk of psychiatric disorders such as anxiety and irritability [45]. Light is an essential factor affecting human biorhythms, and light exposure in the daily light-dark cycle in the UGW will affect people’s sleep rhythm and metabolism [5]. In addition, light can also affect people’s emotional cognition, leading to psychological problems such as loss of interest, dissatisfaction with the status quo, and frustration and emptiness [46]. Therefore, this paper intends to measure the physiological health status of underground staff by investigating their fatigue, dizziness, respiratory and pulmonary diseases, insomnia, and metabolism, and their psychological health status by examining their depression, anxiety, diminishing interest, dissatisfaction with status quo, and emptiness.

Work effectiveness is a comprehensive reflection of the attitudes people display and the efficiency and effectiveness they achieve to achieve their work goals [47]. Occupational ergonomics argues that workers’ attitude, satisfaction, and performance toward work largely reflect their work effectiveness [48]. A positive attitude toward work can counteract the emotional exhaustion caused by work pressure and enhance work effectiveness [49]. Job satisfaction is people’s evaluation of their work, an emotional state with a significant positive correlation with work effectiveness [50]. The performance measures work effectiveness from the perspective of goal realization [51]. Therefore, this paper intends to measure the work effectiveness of underground staff in three aspects: work attitude, job satisfaction, and work performance.

2.2.2 Construction of evaluation index system

The exceptional physical environment of the UGW harms underground workers’ physical and mental health and safety, making the UGW system generate positive entropy flow. The organizational environment can provide material and spiritual support for underground workers, motivate their work, relieve their psychological pressure, improve their work effectiveness, and bring negative entropy flow to the UGW system.

The reasonable layout and setting of underground equipment can improve the work environment, enhance the coordination and adaptability of the “human-machine-environment” system, and bring negative entropy flow to the UGW. The aging and failure of equipment make the equipment have uncertain factors, threatening the health and safety of underground workers and causing an increase of positive entropy flow in the UGW system.

The underground staff’s physiological and psychological sub-healthy state makes them less adaptable to the working system, reduces their work effectiveness, and causes a rise of positive entropy flow in the UGW system. The positive work attitude, higher job satisfaction, and work efficiency of underground staff can overcome the discomfort caused by their subhealth state, improve their work effectiveness, and introduce negative entropy flow to the UGW system. The entropy flow direction of orderliness evaluation indicators of the UGW system is shown in Fig. 2.

Fig. 2

The entropy flow direction of orderliness evaluation indicators of UGW system.

Based on the above analysis, the orderliness evaluation index system of UGW is constructed as shown in Table 1.

Table 1

The orderliness evaluation index system of UGW based on occupational ergonomics

Subsystem	Element	Indicator	Metrics of indicator	Entropy
				flow
				direction
Underground work environment	Physical Environment ( PE )	Ventilation environment ( PE ₁)	Ventilation and exhaust effect ( PE ₁₁)	Positive
		Noise environment ( PE ₂)	Working noise intensity ( PE ₂₁)	Positive
		Light environment ( PE ₃)	Natural lighting suitability ( PE ₃₁)	Positive
			Artificial lighting suitability ( PE ₃₂)	Positive
		Humidity and heat environment ( PE ₄)	Body surface temperature suitability ( PE ₄₁)	Positive
			Relative humidity suitability ( PE ₄₂)	Positive
		Signage environment ( PE ₅)	Color discrimination ( PE ₅₁)	Positive
			Content readability ( PE ₅₂)	Positive
			Location Reasonableness ( PE ₅₃)	Positive
	Organizational Environment ( OE )	Organizational structure ( OE ₁)	Organizational setup ( OE ₁₁)	Negative
			Leadership and management ( OE ₁₂)	Negative
			Communication and feedback mechanisms ( OE ₁₃)	Negative
		Institutional system ( OE ₂)	Management system ( OE ₂₁)	Negative
			Performance appraisal system ( OE ₂₂)	Negative
			Welfare system ( OE ₂₃)	Negative
		Humanistic management ( OE ₃)	Corporate culture ( OE ₃₁)	Negative
			Career prospects ( OE ₃₂)	Negative
			Interpersonal relationships ( OE ₃₃)	Negative
			Organizational humanistic care ( OE ₃₄)	Negative
Underground Equipment	Equipment Configuration ( EC )	Ventilation and exhaust equipment ( EC ₁)	Ventilation equipment setting ( EC ₁₁)	Negative
			Exhaust equipment setting ( EC ₁₂)	Negative
		Lighting equipment ( EC ₂)	Lighting equipment setting ( EC ₂₁)	Negative
		Dehumidification equipment ( EC ₃)	Dehumidification equipment setting ( EC ₃₁)	Negative
		Temperature regulation equipment ( EC ₄)	Air conditioning, fan and other equipment setting ( EC ₄₁)	Negative
		Noise reduction equipment ( EC ₅)	Noise reduction equipment setting ( EC ₅₁)	Negative
		Soundproofing equipment setting ( EC ₅₂)	Negative
		Operation system equipment ( EC ₆)	Operation system equipment setting ( EC _6x)	Negative
		Production and living support equipment ( EC ₇)	Production and living support equipment setting ( EC _7x)	Negative
	Equipment Aging and Failure ( EA )	Equipment efficacy ( EA ₁)	Efficacy of the use of equipment ( EA ₁₁)	Positive
		Equipment aging ( EA ₂)	Equipment aging degree ( EA ₂₁)	Positive
		Equipment failure frequency ( EA ₃)	Frequency of equipment failure ( EA ₃₁)	Positive
		Equipment safety accident frequency ( EA ₄)	Frequency of safety accidents on equipment ( EA ₄₁)	Positive
Underground Staff	Health Status ( HS )	Fatigue ( HS ₁)	Fatigue and decreased energy ( HS ₁₁)	Positive
		Dizziness ( HS ₂)	Dizziness and lightheadedness ( HS ₂₁)	Positive
		Respiratory and pulmonary diseases ( HS ₃)	Respiratory and pulmonary diseases ( HS ₃₁)	Positive
		Insomnia ( HS ₄)	Sleep disorders ( HS ₄₁)	Positive
		Metabolism ( HS ₅)	Constipation and other metabolic abnormalities ( HS ₅₁)	Positive
		Depression ( HS ₆)	Often feel depressed and frustrated ( HS ₆₁)	Positive
		Anxiety ( HS ₇)	Easy to get angry and anxious ( HS ₇₁)	Positive
		Diminishing interest ( HS ₈)	Uninterested in anything ( HS ₈₁)	Positive
		Dissatisfaction with status quo ( HS ₉)	Dissatisfaction with status quo ( HS ₉₁)	Positive
		Emptiness ( HS ₁₀)	Feeling the emptiness of life ( HS ₁₀₁)	Positive
	Work Effectiveness ( WE )	Work attitude ( WE ₁)	Continuous learning of new knowledge and technology ( WE ₁₁)	Negative
			Be proactive at work ( WE ₁₂)	Negative
		Job satisfaction ( WE ₂)	work environment satisfaction ( WE ₂₁)	Negative
			Wage satisfaction ( WE ₂₂)	Negative
			Job content satisfaction ( WE ₂₃)	Negative
		Work performance ( WE ₃)	Get the job done efficiently ( WE ₃₁)	Negative
			Complete performance appraisals with high quality ( WE ₃₂)	Negative

2.3 Computational model

2.3.1 Calculation of entropy value of UGW

We use the questionnaire survey method to analyze the evaluation indices quantitatively. The design of the questionnaire adopts the Likert five subscale method (completely inconsistent, not very consistent, general, relatively consistent, and completely consistent), so the probability of the index i in five grades is $P_{I_{ij}} x = I_{ij} / \sum_{j = 1}^{5} I_{ij}$ , (Where I_ij represents the value of the index I_i on the level j, j = 1, 2, 3, 4, 5). Based on information entropy theory, we define the entropy calculation formula of the index i of the UGS system as: $S_{I_{i}} = - k_{I_{i}} \sum_{j = 1}^{5} P_{I_{ij}} \log_{2} P_{I_{ij}}$ (1)

Where i = 1, 2, ⋯ , m. k_{I
_i} = 1/log₂5 and 0 ⩽ S_{I
_i} ⩽ 1 when I_i is positive entropy, k_{I
_i} = -1/log₂5 and -1 ⩽ S_{I
_i} ⩽ 0 when I_i is negative entropy.

To ensure that the positive and negative entropy values are in the same number field, we define the redundancy of the index I_i as: $d_{I_{i}} = {\begin{matrix} 1 - S_{I_{i}}, when I_{i} is positive entropy \\ 1 + S_{I_{i}}, when I_{i} is negative entropy \end{matrix}$ (2)

Then, the weight of the index I_i is: $λ_{I_{i}} = \frac{d_{I_{i}}}{\sum_{i = 1}^{m} d_{I_{i}}}$ (3)

Therefore, the calculation formula for the entropy of a UGW is: $S = \sum_{i = 1}^{m} λ_{I_{i}} S_{I_{i}}$ (4)

2.3.2 Dissipation structure judgment model based on Brusselator

According to the Brusselator model proposed by the Belgian Brusselator school, we construct a translated Brusselator model based on positive and negative entropy values for a UGW, that is: $\begin{matrix} A (Positive entropy) \to k_{1} X (Quantifiable factor of \\ the positive entropy indices) \\ B (Negative entropy) + X \to k_{2} Y (Quantifiable \\ factor of the negative entropy indices) \\ + D (Non - dissipative structure) \\ Y + 2 X \to k_{3} 3 X (Non - linear mechanism of action \\ of quantifiable factors) \\ X \to k_{4} E (Dissipative structure) \end{matrix}$ (5)

A and B are the components of the entropy of a UGW, where A is the positive entropy, and B is the negative entropy. D and E are the two possible structural states a UGW reaches in the evolution process, where D is the non-dissipative structure, and E is the dissipative structure. X and Y are quantifiable factors, where X is the quantifiable factor of the positive entropy indices, and Y is the quantifiable factor of the negative entropy indices.

According to the Brusselator reaction mechanism, the kinetic equation is established: ${\begin{matrix} dX / dY = A + X^{2} Y - BY - X \\ dY / dt = BX - X^{2} Y \end{matrix}$ (6)

Solving formula (6), we can find that there is a unique uniform stationary solution: $\begin{matrix} X_{0} = A \\ Y_{0} = B / A \end{matrix}$ (7)

Therefore, the dynamic critical value of a dissipative structure is: $B > 1 + A^{2}$ (8)

Therefore, the dissipation structure of the UGW system is judged based on the following: $| B | - (1 + A^{2}) {\begin{matrix} < 0 non - dissipative structure \\ = 0 critical state \\ > 0 dissipative structure \end{matrix}$ (9)

2.3.3 UGW orderliness evaluation model

To concretely and accurately assess the orderliness of UGW, we need to calculate the orderliness of the UGW. Firstly, according to the information entropy theory, the orderliness calculation function of the positive and negative entropy flow index system of each subsystem in UGW is defined as follows: $R = 1 - \frac{S}{S_{\max}}$ (10)

Where R is the measurement index of orderliness, 0 ⩽ R ⩽ 1. S is the actual comprehensive entropy of the index, and S_max is the maximum entropy of UGW system. According to the maximum entropy theorem [52], when the distribution of each index on each level in the Likert five-point scale has an equal probability, the system entropy value reaches the maximum, that is, $S_{\max} = - (1 / \log_{2} 5) * \sum_{j = 1}^{5} 5^{- 1} \log_{2} 5^{- 1} = 1$ .

As there are non-linear interactions between the elements and subsystems of the underground working system, the coordination between them affects the orderliness of the overall system. Therefore, based on synergetics, we define the composite orderliness function of the system based on the coordination degree between subsystems: $CR = \sqrt[q]{\prod_{p = 1}^{q} R_{p}}, p = 1, 2, \dots q$ (11)

Where CR represents the composite orderliness based on the coordination degree between subsystems, R_p represents the orderliness of subsystem p, and q represents the number of subsystems.

To analyze and evaluate the degree of the system orderliness more accurately, we divide CR into four equal parts between 0 and 1, which tend to disorder (0 ⩽ CR < 0.25), low-order (0.25 ⩽ CR < 0.5), medium-order (0.5 ⩽ CR < 0.75) and high-order (0.75 ⩽ CR ⩽ 1).

2.4 Data source

With the advance of the development process of the properties on top of the metro depot, after adding the “cover” above the metro depot, the work environment of the UGW is worse. The humid and sultry workplace has caused great trouble to the job operation of workers, which has seriously affected their occupational safety, health, and daily work. Therefore, this paper chooses the UGW of metro depots in Chengdu and Guangzhou as analysis cases.

From June to August 2021, the research group members and we conducted an on-the-spot investigation and interviews at Chuanshi depot, Huilong depot, Dongsi depot, Cuijiadian parking lot of Chengdu Metro and Zhenlong depot, Luogang depot and Guanhu depot of Guangzhou Metro in China. According to the survey, the operation equipment required by the underground workers in the metro depot for daily inspection and maintenance of trains mainly includes boarding ladders, maintenance tracks, train condensate drainage equipment, and safety protection equipment. Meanwhile, the work of underground workers is dirty and tiring, and their demand for toilets and showers is more significant in their daily work life. Most depot workers are male and tend to smoke to relieve fatigue and pressure in their spare time. The setting of the smoking area can provide a space for workers to communicate and reduce stress, and it can also prevent the safety risks caused by workers throwing cigarette butts. Therefore, according to the characteristics of the UGW in the metro depot, this study concretizes the measurement indicators of the operation system equipment into the boarding ladder setting (EC₆₁), the maintenance tracks setting (EC₆₂), train condensate drainage equipment (EC₆₃) and safety protection equipment (EC₆₄), and concretizes the measurement indicators of the production and living supporting equipment into the setting of toilets (EC₇₁), showers (EC₇₂), and smoking areas (EC₇₃). We distributed 400 questionnaires to the staff and collected 385 questionnaires, of which 352 were valid. Since the measurement of Equipment aging and failure (EA) and Health Status (HS) are negative. In contrast, the measurement of other indicators is positive. The metrics of EA and HS are transformed into positive indicators.

3 Results

3.1 Reliability and validity test

Reliability and validity are the key indicators of data analysis. The reliability aims to evaluate the quality of a scale, reflecting the degree to which random errors affect measurement results. The validity seeks to assess the accuracy of a scale’s measurement content, reflecting the scale data’s effectiveness corresponding to the survey questions and the rationality of each dimension and question item [53]. Therefore, this study first conducted reliability and validity tests on the overall and three subsystem dimensions of the scale to ensure the reliability and validity of the model.

Reliability is tested by Cronbach’s α coefficient [54], and validity is tested by KMO values and Bartlett’s spherical [55] in our study, and the results are shown in Table 2. The results in column (1) indicate that Cronbach’s α coefficient for the overall scale is 0.908, and that of work environment, equipment, and staff are 0.887, 0.804, and 0.804, respectively, all greater than 0.8. This indicates that the overall scale and the subsystem dimensions have high internal consistency and reliability [56]. The results in columns (2)-(5) show that the KMO values of the overall scale and each subsystem dimension are greater than 0.8, and the results of Bartlett’s spherical test are highly significant (p = 0.000), indicating that the overall structure and each dimension structure of the scale are reasonably and have good validity [57].

Table 2
The results of reliability and validity test

(1) (2) (3) (4) (5)

Cronbach’s α KMO Chi-square Dof. Sig

Overall 0.908 0.878 7941.171 1431 0.000

Underground work environment 0.887 0.877 3321.892 171 0.000

Underground equipment 0.804 0.843 1312.531 153 0.000

Underground staff 0.804 0.823 1312.198 136 0.000

	(1)	(2)	(3)	(4)
Overall	0.908	0.878	7941.171	1431
Underground work environment	0.887	0.877	3321.892	171
Underground equipment	0.804	0.843	1312.531	153
Underground staff	0.804	0.823	1312.198	136

3.2 Entropy value of UGW

According to equation (1)-equation (4), the entropy value of the UGW system of the metro depot is calculated, and the results are shown in Table 3. Positive entropy flow A = 1.0814 and negative entropy flow B = –1.0722 for the UGW system of the metro depot. According to equation (9), |B| - 1 + A² = | - 1.0722| - 1 +1 . 0814² = -1.0972 < 0, which shows that the UGW of the metro depot is in a non-dissipative structural state, and the main reason is that the negative entropy flow of the system is small, which is insufficient to offset the entropy increase caused by the positive entropy flow. However, the total entropy value of the system S_S = A + B = 1.0814 + -1.0722 = 0.0092 → 0 indicates that the system is developing in an orderly direction.

Table 3
Entropy values of UGW systems in metro depot

Subsystem Element Indicator Metrics of indicator Entropy weight Comprehensive entropy

Underground work environment PE PE₁ PE₁₁ 0.0896 0.0567

PE₂ PE₂₁ 0.0576 0.0440

PE₃ PE₃₁ 0.0639 0.0472

PE₃₂ 0.0662 0.0482

PE₄ PE₄₁ 0.0829 0.0547

PE₄₂ 0.0926 0.0574

PE₅ PE₅₁ 0.0501 0.0398

PE₅₂ 0.0445 0.0364

PE₅₃ 0.0644 0.0474

OE OE₁ OE₁₁ 0.0335 –0.0289

OE₁₂ 0.0420 –0.0347

OE₁₃ 0.0392 –0.0329

OE₂ OE₂₁ 0.0431 –0.0355

OE₂₂ 0.0332 –0.0287

OE₂₃ 0.0319 –0.0277

OE₃ OE₃₁ 0.0455 –0.0370

OE₃₂ 0.0302 –0.0265

OE₃₃ 0.0471 –0.0380

OE₃₄ 0.0422 –0.0349

Underground Equipment EC EC₁ EC₁₁ 0.0363 –0.0290

EC₁₂ 0.0618 –0.0406

EC₂ EC₂₁ 0.0469 –0.0347

EC₃ EC₃₁ 0.0639 –0.0412

EC₄ EC₄₁ 0.0430 –0.0327

EC₅ EC₅₁ 0.0491 –0.0357

EC₅₂ 0.0442 –0.0333

EC₆ EC₆₁ 0.0634 –0.0411

EC₆₂ 0.0452 –0.0339

EC₆₃ 0.0516 –0.0368

EC₆₄ 0.0288 –0.0242

EC₇ EC₇₁ 0.0709 –0.0430

EC₇₂ 0.0775 –0.0441

EC₇₃ 0.0784 –0.0443

EA EA₁ EA₁₁ 0.0680 0.0423

EA₂ EA₂₁ 0.0565 0.0388

EA₃ EA₃₁ 0.0618 0.0406

EA₄ EA₄₁ 0.0527 0.0373

Underground staff HS HS₁ HS₁₁ 0.0824 0.0529

HS₂ HS₂₁ 0.0709 0.0490

HS₃ HS₃₁ 0.0732 0.0499

HS₄ HS₄₁ 0.0760 0.0509

HS₅ HS₅₁ 0.0805 0.0523

HS₆ HS₆₁ 0.0731 0.0499

HS₇ HS₇₁ 0.0599 0.0443

HS₈ HS₈₁ 0.0657 0.0469

HS₉ HS₉₁ 0.0620 0.0453

HS₁₀ HS₁₀₁ 0.0720 0.0495

WE WE₁ WE₁₁ 0.0364 –0.0306

WE₁₂ 0.0502 –0.0392

WE₂ WE₂ ₁ 0.0431 –0.0350

WE₂₂ 0.0283 –0.0248

WE₂₃ 0.0424 –0.0346

WE₃ WE₃₁ 0.0429 –0.0349

WE₃₂ 0.0411 –0.0337

Positive entropy 1.0814

Negative entropy –1.0722

Total entropy 0.0092

Subsystem	Element	Indicator	Metrics of indicator	Entropy weight	Comprehensive entropy
Underground work environment	PE	PE₁	PE₁₁	0.0896	0.0567
		PE₂	PE₂₁	0.0576	0.0440
		PE₃	PE₃₁	0.0639	0.0472
			PE₃₂	0.0662	0.0482
		PE₄	PE₄₁	0.0829	0.0547
			PE₄₂	0.0926	0.0574
		PE₅	PE₅₁	0.0501	0.0398
			PE₅₂	0.0445	0.0364
			PE₅₃	0.0644	0.0474
	OE	OE₁	OE₁₁	0.0335	–0.0289
			OE₁₂	0.0420	–0.0347
			OE₁₃	0.0392	–0.0329
		OE₂	OE₂₁	0.0431	–0.0355
			OE₂₂	0.0332	–0.0287
			OE₂₃	0.0319	–0.0277
		OE₃	OE₃₁	0.0455	–0.0370
			OE₃₂	0.0302	–0.0265
			OE₃₃	0.0471	–0.0380
			OE₃₄	0.0422	–0.0349
Underground Equipment	EC	EC₁	EC₁₁	0.0363	–0.0290
			EC₁₂	0.0618	–0.0406
		EC₂	EC₂₁	0.0469	–0.0347
		EC₃	EC₃₁	0.0639	–0.0412
		EC₄	EC₄₁	0.0430	–0.0327
		EC₅	EC₅₁	0.0491	–0.0357
			EC₅₂	0.0442	–0.0333
		EC₆	EC₆₁	0.0634	–0.0411
			EC₆₂	0.0452	–0.0339
			EC₆₃	0.0516	–0.0368
			EC₆₄	0.0288	–0.0242
		EC₇	EC₇₁	0.0709	–0.0430
			EC₇₂	0.0775	–0.0441
			EC₇₃	0.0784	–0.0443
	EA	EA₁	EA₁₁	0.0680	0.0423
		EA₂	EA₂₁	0.0565	0.0388
		EA₃	EA₃₁	0.0618	0.0406
		EA₄	EA₄₁	0.0527	0.0373
Underground staff	HS	HS₁	HS₁₁	0.0824	0.0529
		HS₂	HS₂₁	0.0709	0.0490
		HS₃	HS₃₁	0.0732	0.0499
		HS₄	HS₄₁	0.0760	0.0509
		HS₅	HS₅₁	0.0805	0.0523
		HS₆	HS₆₁	0.0731	0.0499
		HS₇	HS₇₁	0.0599	0.0443
		HS₈	HS₈₁	0.0657	0.0469
		HS₉	HS₉₁	0.0620	0.0453
		HS₁₀	HS₁₀₁	0.0720	0.0495
	WE	WE₁	WE₁₁	0.0364	–0.0306
			WE₁₂	0.0502	–0.0392
		WE₂	WE₂ ₁	0.0431	–0.0350
			WE₂₂	0.0283	–0.0248
			WE₂₃	0.0424	–0.0346
		WE₃	WE₃₁	0.0429	–0.0349
			WE₃₂	0.0411	–0.0337
Positive entropy	1.0814
Negative entropy	–1.0722
Total entropy	0.0092

As shown in Fig. 3, the entropy values of the underground work environment and the underground staff are both positive (0.1069 for the underground work environment and 0.2578 for the underground staff), which means that the environment and the staff are currently in an entropy-increasing state, and their subsystems are in a trend of developing towards disorder. Among them, for the underground work environment, the entropy increase brought by the physical environment is larger (0.4317), while the negative entropy flow introduced by the organizational environment (–0.3248) is not enough to offset the entropy increase. For the underground staff subsystem, the negative entropy flow (–0.2329) introduced by their work effectiveness is also insufficient to offset the positive entropy (0.4907) caused by their physiological and psychological sub-health state. The entropy value of the underground equipment subsystem is negative (–0.3556) because the negative entropy flow (–0.5145) brought by the reasonable configuration and layout of the equipment is enough to offset the entropy increase (0.1589) caused by the aging failure of the equipment, indicating that the underground equipment is in a state of entropy reduction. Its subsystem is in a trend of orderly development.

Fig. 3

Positive and negative entropy values of subsystems.

3.3 Evaluation of the orderliness of UGW

According to equation (11) the orderliness of the UGW system of the metro depot is calculated, and the results are shown in Table 4. The composite orderliness of the UGW of the metro depot is 0.6278, among which the composite orderliness of the work environment subsystem is 0.6194, that of the equipment subsystem is 0.6390, and that of the staff subsystem is 0.6251. It shows that the UGW of the metro depot is in a medium-order state at present, and all its subsystems are also in a medium-order state, which means that the degree of the orderliness of UGW is not high. Some undesirable factors within the system cause entropy to increase. The subsystems may be in the mutual influence and friction stage, with lower coordination among the elements.

Table 4
The orderliness of metro depot UGW system

Subsystem Element Element orderliness Subsystem orderliness System orderliness

Underground work environment PE 0.5683 0.6194 0.6278

OE 0.6752

Underground equipment EC 0.4855 0.6390

EA 0.8411

Underground staff HS 0.5093 0.6251

WE 0.7671

Subsystem	Element	Element orderliness	Subsystem orderliness	System orderliness
Underground work environment	PE	0.5683	0.6194	0.6278
	OE	0.6752
Underground equipment	EC	0.4855	0.6390
	EA	0.8411
Underground staff	HS	0.5093	0.6251
	WE	0.7671

Combined with the equipotential diagram of the orderliness evaluation of UGW in Fig. 4, we can see the local orderliness state of UGW. The orderliness of the physical environment is 0.5683, which is in a medium-order state. The orderliness of the organizational environment is 0.6752, which is also in a medium-order state. The orderliness of equipment configuration is 0.4855, which is in a low-order state, and the orderliness of equipment aging and failure is 0.8411, which is in a high-order state. The orderliness of the health status of staff is 0.5093, which is between low and medium orderliness, and the orderliness of work effectiveness is 0.7671, between medium and high orderliness.

Fig. 4

The equipotential diagram of the orderliness evaluation of UGW system.

3.4 Evaluation of subsystem coordination adaptability and identification of adverse factors

3.4.1 Evaluation of subsystem coordination adaptability

To consider the coordination adaptability among subsystems in the UGW of the metro depot, we further calculated the coordination orderliness among the elements, as shown in Table 5. The results show that the coordination between the health status of staff, equipment configuration, and physical environment is low (0.4972, 0.5252, 0.5380, respectively), indicating that the harsh underground physical environment harms workers’ physical and mental health and poses a challenge to the configuration of underground equipment. And the underground equipment is currently unable to respond to the needs of workers fully. The coordination between the work effectiveness of staff, equipment aging and failure, and organizational environment is high (0.8033, 0.7536, and 0.7197, respectively). This indicates that the organizational management environment can help underground staff overcome difficulties and discomfort, improve their work effectiveness, contribute to the maintenance and update of equipment, delay their aging failure, and reduce the adverse impact of equipment on people’s work effectiveness.

Table 5
Coordination of the elements in the UGW of the metro depot

Subsystem Underground work environment Underground Equipment Underground Staff

Element PE OE EC EA HS WE

Underground work PE /

environment OE 0.6194 /

Underground Equipment EC 0.5252 0.5725 /

EA 0.6913 0.7536 0.6390 /

Underground Staff HS 0.5380 0.5864 0.4972 0.6545 /

WE 0.6603 0.7197 0.6103 0.8033 0.6251 /

Subsystem		Underground work environment	Underground Equipment	Underground Staff
Underground work	PE	/
environment	OE	0.6194	/
Underground Equipment	EC	0.5252	0.5725	/
	EA	0.6913	0.7536	0.6390	/
Underground Staff	HS	0.5380	0.5864	0.4972	0.6545	/
	WE	0.6603	0.7197	0.6103	0.8033	0.6251	/

3.4.2 Identification of adverse factors

According to the above evaluation results, the orderliness of the equipment configuration, health status of staff, and physical environment are not high, and the coordination between them is low. Further analysis of the main adverse factors affecting the orderliness of the above indicators is necessary to provide targeted information for the planning and design, transformation and improvement, and organizational management of UGW.

(1) Adverse factors affecting the equipment configuration

The entropy contribution rate of each element is calculated based on the comprehensive entropy of elements in equipment configuration. Since these are negative entropy indicators, they are ranked according to the principle of low to high contribution of negative entropy to identify the factors that lead to a lower negative entropy value of equipment configuration. The results are shown in Fig. 5. As can be seen from the figure, the negative entropy flow introduced by the equipment configuration related to the occupational safety and physiological needs of workers, such as EC₆₄, EC₁₁, and EC₄₁, is small (the contribution rate of entropy is only 16.69%). These are the main adverse factors causing the small negative entropy value and low orderliness of underground equipment configuration.

Fig. 5

Ranking of the entropy contribution of the indicators of Equipment Configuration.

(2) Adverse factors affecting the health status of staff

Each element’s entropy contribution rate is calculated according to the comprehensive entropy of elements in health status. Since these are positive entropy indicators, the contribution rates of positive entropy are sorted from high to low to identify the factors that lead to higher positive entropy of the health status of staff, and the results are shown in Fig. 6. The figure shows that the physiological subhealth states such as HS₁₁, HS₅₁, HS₄₁, and HS₃₁ are the main adverse factors contributing to the entropy increase of the underground staff subsystem (the entropy value contributes up to 42%).

Fig. 6

Ranking of the entropy contribution of the indicators of Health Status of staff.

(3) Adverse factors affecting the physical environment

Each element’s entropy contribution rate is calculated according to the comprehensive entropy of elements in the physical environment. Since these are positive entropy indicators, they are ranked according to the principle of positive entropy contribution rate from high to low to identify the adverse factors that cause the higher positive entropy of the physical environment. The results are shown in Fig. 7. As can be seen from the figure, PE₄₂, PE₁₁, PE₄₁, and PE₃₂ are the main factors causing the entropy increase in the physical environment (the entropy contribution rate is as high as about 50%), which is consistent with the characteristics of the humid, sultry, and dark underground environment.

Fig. 7

Ranking of the entropy contribution of the indicators of Physical Environment.

4 Discussion

The development and utilization of UGW have become very common and varied in large cities. Compared to traditional UGW, such as mining and storage [1], modern UGW can include offices, workshops, control rooms, utility infrastructure, and shopping centers [58]. It is essential to determine that the UGW is consistent with occupational ergonomic considerations to safeguard workers’ occupational safety and health [59]. Previous studies have examined environmental conditions [60], design layout [61], psychological [62], and health [58] associated with UGW, but mainly employing relatively mono-disciplinary approaches and methodologies, many times in a non-systematic way [63]. However, the UGW is a complex system, and the traditional reductionist that parts constitute the whole cannot grasp the essence of the development of the system [6]. Therefore, this study aims to evaluate the orderliness of UGW from a system perspective to understand the synergy of subsystems and elements and to predict the system’s operational status and development trend. Combined with the findings of previous studies, we discuss our results as follows.

First, the UGW system of the metro depot has not yet reached the dissipative structure, and the system is in a medium-order state. The main reason is that the system’s positive entropy is high, and the negative entropy is low. The entropy increase caused by the physical environment and staff’s health status is the main obstacle for the system to move toward order. We can interpret this in terms of the characteristics of the underground physical environment. Due to the specific spatial location, the underground physical environment has peculiarities, and they are always negative, such as humid and stuffy, poorly ventilated, dark, and claustrophobic [64]. Long-term adverse environmental exposure is also associated with biorhythm disturbances, vitamin D deficiency, and radon exposure in underground workers, thus increasing their health risks [43]. In addition, UGW can reduce people’s perceived control over their surroundings, leading to disengagement, lack of concentration, and anxiety [63]. These factors significantly increase the entropy increase of the system. However, the total entropy value tends to be 0, indicating that the system is on a trend of orderly development. At this point, increasing the introduction of negative entropy can promote the non-equilibrium phase transition of the system to enter an ordered structural state [65]. The analysis of negative entropy indicators shows that equipment configuration is the most significant development power source of UGW. Proper equipment configuration and design layout, such as an effective ventilation system [66], safe marking evacuation system [67], and comfortable lighting system [5], can not only improve the underground environment but also enhance the staff’s perception of control over the environment, and thus improve the performance and satisfaction of them [43], offsetting the system entropy increase.

Second, the orderliness of equipment configuration, health status, and physical environment are lower, and their coordination is poor. This indicates that the equipment configuration in the UGW of the metro depot cannot fully cope with the harsh physical environment and meet the needs of underground workers. The analysis of adverse factors shows that the negative entropy contribution rate of safety security equipment is the lowest, which means that improving the safety of UGW is an effective way to enhance the orderliness of the system [67]. With the increasing demand for UGS construction, we need to change the public’s negative attitude toward the safety of underground structures [68]. Improving the safety of UGS is a crucial factor in achieving the most comfortable and efficient use for the public [61]. Notably, we found that the humanized support facilities, such as shower rooms and smoking areas, can introduce more negative entropy flow into the UGW, which is generally ignored by existing studies. Existing research on UGS planning and design mainly focuses on constructing sound, light, heat, and other environments to meet people’s basic physiological needs [4]. However, relevant studies show that satisfying people’s psychological needs and preferences will alleviate and eliminate their inherent biases towards UGW, promoting their attitude change and acceptance of UGW [59], taking smoking areas as an example. According to our research, most underground staff in the metro depot are male, and smoking is the primary way for them to relieve pressure and communicate. Establishing smoking areas based on standardized ventilation and fire safety can eliminate the safety risks brought by smoking and provide informal channels for workers to rest, communicate, and relax. Venugopal et al. emphasized the importance of informal communication in UGW, discussing how rest areas can be effective spaces for staff to communicate with each other and with people outside of work [69]. By promoting communication among workers, it provides space for rest, rejuvenation and recovery from workplace pressure, humanized supporting facilities such as smoking areas, rest areas and fitness areas are important factors in improving workers’ fitness and satisfaction with their jobs [70].

Third, the coordination between work effectiveness, equipment aging and failure, and organizational environment is high, which reflects the non-linear interaction between them. This can help us understand the relationship between occupational ergonomic factors and organizational management and determine which factors can be controlled through organizational intervention so that managers can identify essential themes [71]. When the coordination between equipment aging and failure and the organizational environment is low, organizations can extend the life-cycle of underground equipment through equipment management, such as detecting, repairing, and updating, to solve the challenges of underground equipment [72]. Similarly, when the coordination between work effectiveness and organizational environment is low, organizations can promote better interaction between staff and work content through staff management, such as regular skill training, stress relief, continuous health education, and health promotion [73]. These measures can reduce the impact of social and psychological factors, improve their work efficiency, and prevent occupational ergonomic-related diseases [74]. These help to provide information for organizational-level interventions to guide the evolution of UGW systems toward a more orderly direction.

4.1 Limitations

The limitations of this study should be pointed out. First, the sample of this study has some limitations. Taking the data collected from the UGW of the metro depot as a case may lead to sample bias. In particular, as we pointed out earlier, the measurement indicators of operation system equipment and production and living support equipment in the equipment configuration need to be explicitly set according to different UGW properties. In the future, we hope to be able to survey a variety of UGW of other properties to reduce the bias of the results caused by different works.

Second, our measurement of staff’s health status and work effectiveness is subjective. Considering Chinese people’s traditional prejudice and resistance to “mental illness,” the answers to their mental health status questions may be concealed or evaded, leading to subjective bias in the data. Multi-source data acquisition methods can be tried to overcome this difficulty in the future.

5 Conclusion

With the increasing development and application of UGW, the systematic evaluation of UGW systems from the perspective of occupational ergonomics is a necessary prerequisite for promoting their orderly development in compliance with the human-oriented concept. By constructing an evaluation approach focusing on the orderliness of UGW, this study comprehensively evaluates the UGW system in three dimensions: human, equipment, and environment. Taking the UGW of seven metro depots in Guangzhou and Chengdu, China, as the case background, we have drawn the following conclusions:

First, the negative entropy flow of the UGW is insufficient to compensate for positive entropy, and the system has not reached the mutation threshold to form a dissipative structure. However, the comprehensive entropy reflects that the system is evolving from disorder to order. Increasing the introduction of negative entropy flow by improving the equipment configuration, optimizing the organizational environment, and enhancing the staff’s work effectiveness can enhance the fluctuation of the system and promote it to enter an orderly structure.

Second, the UGW is in a medium-order state. Its subsystems are also in a medium-order state, but their evolutionary trends are different. Since the harsh physical environment and the staff’s sub-health state cause large positive entropy, both the work environment and the staff subsystems are entropy-increasing and developing towards disorder. The configuration and layout of the equipment bring a sizeable negative entropy, causing the equipment subsystem to be entropy-decreasing and evolve in an orderly direction.

Third, the equipment configuration is the most important source of negative entropy flow in the system, but its coordination with the physical environment and staff’s health status is low, and it cannot fully cope with the harsh physical environment and meet the needs of underground workers. Among them, the safety security equipment has the smallest negative entropy and requires significant improvement. The humanized support facilities can introduce more negative entropy. When designing or optimizing the UGW of the metro depot, decision-makers and designers should pay attention to these factors that are easily ignored.

Fourth, organizational intervention can reduce the negative impact of adverse factors. Regarding the physical environment, emphasis should be placed on improving the humid and thermal, ventilation, and light environment. Simultaneously, in the organizational management process, attention should be focused on staff’s physiological health and regular medical checkups, especially increasing special examinations about fatigue and weakness, metabolism, sleep disorders, and lung diseases.

Overall, these findings can provide new ideas and insights for the systematic evaluation of UGW and help to identify essential intervention projects and themes to guide the UGW system to evolve more orderly.

Ethical approval

This study did not involve human experimentation, and the study data were gathered with the informed consent of the anonymous individual participants. No ethical reviews were necessary at the time of data gathering within the involved workplace.

Informed consent

The introduction of the questionnaire provides the purpose of the study, social value, scope of information collection, potential risks, and countermeasures. Signatures and contact details of the researcher and the research organization were also included. All participants were asked to read the introduction of the questionnaire and complete a written informed consent form.

Conflicts of interest

The authors declare that they have no conflict of interest.

Footnotes

Acknowledgments

The authors have no acknowledgments.

Funding

This research was funded by the Scientific Research Project of China Railway First Survey and Design Institute Group Co., Ltd. (20200397).

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	(1)	(2)	(3)	(4)	(5)
	Cronbach’s α	KMO	Chi-square	Dof.	Sig
Overall	0.908	0.878	7941.171	1431	0.000
Underground work environment	0.887	0.877	3321.892	171	0.000
Underground equipment	0.804	0.843	1312.531	153	0.000
Underground staff	0.804	0.823	1312.198	136	0.000

Evaluation of orderliness of underground workplace system based on occupational ergonomics: A case study in Guangzhou and Chengdu metro depots

Abstract

BACKGROUND:

OBJECTIVE:

METHODS:

RESULTS:

CONCLUSIONS:

Keywords

1 Introduction

2 Methodology

2.1 Research design

2.2 Evaluation index analysis

2.2.2 Construction of evaluation index system

2.3.1 Calculation of entropy value of UGW

3 Results

3.1 Reliability and validity test

Table 4 The orderliness of metro depot UGW system Subsystem Element Element orderliness Subsystem orderliness System orderliness Underground work environment PE 0.5683 0.6194 0.6278 OE 0.6752 Underground equipment EC 0.4855 0.6390 EA 0.8411 Underground staff HS 0.5093 0.6251 WE 0.7671

3.4.1 Evaluation of subsystem coordination adaptability

4.1 Limitations

5 Conclusion

Ethical approval

Informed consent

Conflicts of interest

Footnotes

Acknowledgments

Funding

References

Table 4
The orderliness of metro depot UGW system

Subsystem Element Element orderliness Subsystem orderliness System orderliness

Underground work environment PE 0.5683 0.6194 0.6278

OE 0.6752

Underground equipment EC 0.4855 0.6390

EA 0.8411

Underground staff HS 0.5093 0.6251

WE 0.7671