Identifying Critical Factors Influencing the Safety of Chinese

This paper has been published: Zhang, S., Sunindijo, R.Y., Loosemore, M., Wang, S., Gu, Y. and Li, H. (2020), "Identifying critical factors influencing the safety of Chinese subway construction projects", Engineering, Construction and Architectural Management, https://doi.org/10.1108/ECAM-07-2020-0525.

Identifying critical factors influencing the safety of

Chinese subway construction projects

Shang Zhang - Suzhou University of Science and Technology, Suzhou, China Riza Yosia Sunindijo - Faculty of Built Environment, UNSW Sydney, Sydney, Australia Martin Loosemore - School of the Built Environment, University of Technology Sydney, Sydney, Australia Shejiang Wang and Yajun Gu - Suzhou Rail Transit Group Co., Ltd, Suzhou, China Hongfei Li - China Railway 12th Bureau Group Co., Taiyuan, China

Purpose - The image of the construction industry in China, as in many other countries, is tarnished by its poor safety record. With the rapid development of subway systems in Chinese urban areas, construction workers are being exposed to new risks which are poorly understood and managed. Subway construction projects are large scale and scattered over many construction sites, and involve numerous stakeholders and sophisticated technologies in challenging underground environments. Accident rates are high and have significant economic and social consequences for the firms and people involved. Addressing the gap in research about the safety risk in these projects, the purpose of this paper is to advance understanding of the factors influencing the safety of Chinese subway construction projects with the overall objective of reducing accident rates.

Design/methodology/approach - A survey was conducted with 399 subway construction professionals across five stakeholder groups. Follow-up interviews were also conducted with five experienced experts in safety management on subway projects to validate the results.

Findings - It was found that the eight most critical factors perceived by stakeholders to influence

1 safety risks on Chinese subway projects are: project management team; contractor-related factors; site underground environment; safety protection during the use of machines; safety management investment; site construction monitoring and measurement; hazard identification and communication; and use of machines in all stages. This indicates that in allocating limited project resources to improve the safety of subway projects, managers should focus on: developing safety knowledge and positive attitudes in leadership teams; formulating effective risk management systems to identify, assess, mitigate, measure and monitor safety risks on site; improving communications with stakeholders about these risks; and effectively managing plant, equipment and machinery.

Originality/value - This research contributes a new multi-stakeholder perspective to the lack of safety research in Chinese subway construction projects. The research findings provide important new insights for policymakers and managers in improving safety outcomes on these major projects, producing potentially significant social and economic benefits for society and the construction industry.

Keywords: Safety; Risk management; Subway project; China; Stakeholder management

Introduction

The subway system is considered as the primary public transportation option in major cities in

China. A recent report released by the China Association of Metros (2020) showed that by the end of 2019, 40 cities in mainland China operate 208 urban rail lines with a total length of 5180.6 km.

Furthermore, the addition of the urban rail line systems in 65 cities have been approved by the national and local governments, and 63 of them are in progress, with a total length of 7339.4 km.

2 This rapid development, unfortunately, also corresponds to a large number of accidents, which has significant negative economic and social consequences for the Chinese construction industry and society more broadly. For example, in 2014-2018, 108 accidents occurred which caused 142 fatalities in urban rail projects (Yu et al., 2019).

Subway construction projects mainly include three parts (train parking area, stations and subway line section between stations) and involve many disciplines such as power, telecommunication and rail construction. In China, a typical subway line is about 30 km long, which is broken down into around 10 sub-projects as independent bid packages (a bid package has a total investment of less than 1 billion Yuan) to be contracted to different contractors. Given the underground nature of the construction activities, these are uniquely complex projects with a very high level of safety risk over a long period – often up to ten years. Adding to this risk, these projects also involve many hundreds of people working across many construction sites and require the collaboration of numerous stakeholders and the combination of many sophisticated technologies (Seo and Choi, 2008; Zhou et al., 2015a; Wang et al., 2017). In addition to the complicated project system, subway construction activities are usually performed deep underground with complex hydrogeological conditions, passing through dense urban areas with significant amount of structures or penetrating important urban utilities such as power system, gas piping system, as well as water supply and drainage systems (Yu et al., 2014). During the underground construction process, there are many safety risks involved, including collapse, landslide, seepage, structure failure, pipe breaks, high ground water table, toxic gas leakage, pipe blasting, poor ventilation and fire (Zou and Li, 2010). Environmental conditions, such as heavy rainfall, adverse hydrogeological conditions and soft soil layers, can increase the level of safety

3 risk, and collapse is the primary type of accident in tunnel construction, accounting for 60% of the total accidents (Qian and Lin, 2016). In addition, during underground excavation, the settlement of the ground may cause the surface subsidence of adjacent buildings or structures (Xing et al., 2016).

For example, a quicksand disaster occurred during the excavation of the tunnel in the Shanghai

Subway Line 4 construction project on July 1, 2003, which resulted in the collapse of 210-meter long tunnel and three buildings. On November 11, 2008, a foundation collapse happened in the

Xianghu Station of Hangzhou Subway Line 1, which was considered as the worst accident in the

Chinese subway construction history. This accident resulted in the loss of 21 lives and four additional injuries, with additional direct economic loss of around 49 million Yuan (Yu et al.,

2014).

As a result of all of the above factors, subway construction remains one of the most dangerous construction activities in China (Ding et al., 2013). While there has been a considerable amount of research into the factors influencing safety performance in the construction industry (Boadu et al.,

2020), safety research in a subway construction project context is scant, despite the unique risks these projects pose to safety. The few exceptions include Wu et al. (2012) who undertook research into the organizational factors influencing the safety of subway construction projects, Wang et al.

(2017) who investigated the human-related safety risk factors in subway construction, and Yu et al.

(2014) who focused on the identification of subway safety factors in the preconstruction stage.

While this limited research is useful, it fails to address the comprehensiveness of numerous underlying safety risk factors in subway construction and in particular the perspectives of the varied stakeholders involved, who need to collaborate in managing safety risks. There is also a paucity of research in the Chinese context which presents specific organizational and cultural

4 challenges compared to other countries (Loosemore et al., 2020). The aim of this research is to address these gaps in knowledge by exploring, from a multi-stakeholder perspective, the critical factors perceived to influence the safety of Chinese subway construction projects. This research is significant in addressing an important gap in safety research and in informing more effective measures to improve the safety performance of Chinese subway construction projects.

Literature review

As noted above, in recent years, a small number of academics have begun to explore safety management of subway construction projects. Zhou et al. (2012) developed a subway construction incident database (SCID), which can be used as a qualitative tool in identifying precursor safety risk factors and as a quantitative tool in safety evaluation and management. Ding et al. (2012a) illustrated the safety risk identification system (SRIS) of subway construction projects based on construction drawings, which can be used in the preconstruction risk assessment stage to identify potential safety hazards and achieve dynamic risk early warning and control. They categorized the risk factors into four types: project features, construction technology, hydrological geology and construction environment. Yu et al. (2014) investigated the safety factors in the preconstruction stage of Chinese subway construction projects to identify critical safety factors and measure the ranking consistency among the main stakeholders, including clients, consultants, designers, contractors and engineering consultants (Jianli in Chinese). They found five critical influencing factors, including safety attitude, construction site safety, government supervision, market restrictions and task unpredictability. Similarly, Wang et al. (2017) analyzed human safety risk factors in Chinese subway construction projects and their interactions from the perspectives of

5 three project stakeholders, including client, designer and general contractor. Zhou et al. (2015b) employed network theory to explore the complex subway construction accident network to achieve prompt safety management. The results indicated that five types of causal safety risk factors are involved, including human, environment, geology, machine and material factors.

Through analyzing the Hangzhou subway construction collapse accidents, Zhou and Irizarry (2016) noted that people, material, machine and environment are direct and immediate factors of accidents, while management is an intermediate factor. Li et al. (2018) explored the safety risk identification system (SRIS) and early warning system (SREWS) for Chinese subway construction projects using Building Information Model (BIM). Zhang et al. (2019) developed a model to identify potential safety risks among the numerous risk factors during tunnel construction in real time, considering the complex and uncertain environment in a subway construction project adjacent to existing structures. They grouped the safety risks into three categories: geological, technical and environmental risks. Yan et al. (2019) proposed a vague fuzzy matter-element risk assessment model through combining vague set and matter-element theory. In the model, the types of risks were divided into five categories according to the 4M1E (man, machine, material, method and environment) thinking.

The above research is useful in mapping-out the various factors which affect safety in a subway construction context. However, it has been undertaken in isolation and consequently there is currently no comprehensive framework to help researchers and practitioners understand the range of safety risks involved in a typical subway construction project. Furthermore, as stated in the introduction, existing research failed to capture insights from multiple stakeholders to produce an integrated account of the safety risks on these major complex projects. Such an account is critical

6 to facilitate the cross-disciplinary collaboration which is required to address safety (Biggs et al.,

2005). To address this problem, Table 1 synthesises the dimensions identified in previous subway safety research resulting in a new conceptual framework (called the PE3M Framework) of 32 factors, which was refined by eight experienced subway construction and management experts through a pilot survey process. They include two project managers of subway clients, two safety management department directors of subway clients, two safety engineers of subway contractors, one project manager of subway contractor, and one safety engineer of subway client. Each expert has at least five years of working experience on subway construction projects with sufficient accumulated knowledge in safety management. The verified PE3M Framework comprises 32 influencing factors organized into five main categories of risk - people, environment, machine, material, and management.

7 8 Table 1 Preliminary factors influencing the safety in subway construction projects Dimensions and factors Literature source Description This dimension is concerned with project stakeholders and participants involved throughout the 1. People lifecycle of subway construction projects. • In Chinese subway construction projects, the client is working on behalf of the local Sun et al., 2008; Yu et al., 1.1 Client-related factors government and responsible for the lifecycle management of subway system, from financing 2014; Deng et al., 2010; (including qualification, to operation. MOHURD and AQSIQ, capabilities, experience and • The client's qualification, capabilities, experience, accountability and policy towards safety 2011a; Ding et al., 2011; accountability) have a significant impact on safety performance, since the client makes critical decisions on Wang et al., 2017 the design, selection of project participants and resources to implement safety measures. • The quality of design and design management process have a critical impact on project Seo and Choi, 2008; Zhou et safety. Due to the complex system involved in the design process, a design management 1.2 Surveyor/designer-related al., 2009; Deng et al., 2010; company is normally contracted by the client for coordinating various designers and, factors (including qualification, MOHURD and AQSIQ, sometimes, for conducting geological surveys. . capabilities, experience and 2011a; Ding et al., 2011; Yu • Unforeseeable site conditions, as well as the technical know-how, the qualification, accountability) et al., 2014; Wang et al., capabilities, experience and accountability of the surveyor and designer have a paramount 2017 influence on the quality of their work and project safety. Sun et al., 2008; Zhou et al., • Contractors are the primary stakeholder responsible for the implementation and management 1.3 Contractor-related factors 2009; Deng et al., 2010; of site construction works. (including qualification, MOHURD and AQSIQ, • Contractor's qualification, capabilities, experience and accountability have a significant and capabilities, experience and 2011a; Wu et al., 2012; Ding direct influence on safety, particularly in this complex project environment. accountability) et al., 2011; Yu et al., 2014; • As managing and coordinating subcontractors is in the scope of the contractor's work, Wang et al., 2017 subcontractor-related factors are included in this item. 1.4 Engineering consultant-related Sun et al., 2008; Deng et al., • Engineering consultants act as the client’s representative to daily supervise and inspect factors (including qualification, 2010; MOHURD and contractor’s site operations to ensure that project objectives are achieved. capabilities, experience and AQSIQ, 2011a; Wu et al., • In subway construction projects, they have a significant influence on site management,

9 accountability) 2012; Ding et al., 2011; especially on quality and safety. Wang et al., 2017 • Since subway construction is important public infrastructure projects, the government pays special attention on them. 1.5 Government-related factors Sun et al., 2008; Deng et al., • Major decisions have to be approved by the government at national, provincial and/or local (including regulation, supervision 2010; Yu et al., 2014; Wang levels before being implemented. and emphasis on safety) et al., 2017 • Governments in different cities normally issue specific directives regulating the management of subway projects. • The project management team's capabilities, experience and accountability have a direct and 1.6 Project management team MOHURD and AQSIQ, significant impact on safety performance. (including capabilities, experience 2011a; Wu et al., 2012; • All the stakeholders should be involved in establishing a project management team with an and accountability) Wang et al., 2017 experienced project manager in charge. This dimension is concerned with the project environments, including site construction 2. Environment environment, surrounding environment, underground environment, natural environment and weather conditions. 2.1 Site construction enviornment Zhou et al., 2009; Ding et al., A favorable site construction environment facilitates the improvement of construction (lighting, power, transportation, 2011; Wu et al., 2016 productivity and guarantees the safe operation of construction activities. etc.) Zhou et al., 2009; Ding et al., • In most cases, subway stations are constructed in densely populated areas and the 2012a; Wu et al., 2012; Ding construction of line sections is performed through these areas, thus, affecting existing 2.2 Site surrounding environment and Zhou, 2013; Yu et al., structures and facilities. (roads, buildings, etc.) 2014; Xing et al., 2016; Wu • The surrounding environments increase task unpredictability, which tends to negatively et al., 2016; Li et al., 2018; affect safety. As such, the employment of professional companies to investigate the Zhang et al., 2019 surrounding conditions is important. 2.3 Site underground environment Zhou et al., 2009; Deng et • The majority of subway construction works are underground. The availability of real-time (underground water, urban utility al., 2010; MOHURD and and accurate information about underground utilities, soil and other geological conditions is

10 pipelines, soil, etc.) AQSIQ, 2011a; Ding et al., a precondition of working safely. 2012a; Ding and Zhou, 2013; • Survey investigation methods should be used to improve the quality of data. Yu et al., 2014; Xing et al., • The client should employ professional companies to investigate underground conditions 2016; Qian and Lin, 2016; with sufficient details. Wu et al., 2016; Li et al., 2018; Zhang et al., 2019 • Extreme weather conditions have a strong negative influence on the safety of subway Zhou et al., 2009; Wu et al., projects. Heavy rains may lead to the rising of underground water table and soften the soil, 2.4 Site natural environment and 2013; Yu et al., 2014; Wu et thus increasing the risk of collapse. weather conditions al., 2016 • Relevant countermeasures can be undertaken to prevent incidents with timely and accurate information of weather conditions. This dimension is related with the safety of using various machines in subway construction 3. Machine activities. • As a heavy construction project, subway construction uses various specialized and large 3.1 Use of machines in all stages Zhou et al., 2009; Ding et al., construction machines/equipment. (including installation, operation 2012a; Wu et al., 2016; • Appropriate installation, operation and dismantling of these machines/equipment contribute and dismantling) Zhang et al., 2019 to safety. 3.2 Safety protection during the • Safety test should be implemented before the operation of machines. use of machines (including safety Deng et al., 2010; Wu et al., • Safety protection measures should be undertaken during operation. test, safety protection measures 2016 • The limiting device prevents overloads during machine operation. Ensuring the functionality and limiting device functioning) of this device is critical. • Unqualified, defective or untested machines/equipment are not allowed to enter the site. Zhou et al., 2009; Deng et 3.3 Professional inspection, test • Inspection, test and acceptance are important measures to prevent accidents due to the al., 2010; MOHURD and and acceptance for specialized failure of machines/equipment. AQSIQ, 2011a; Wu et al., machines • For important and high-risk specialized machines/equipment, their operation cannot start 2016 before approvals from professional agencies are obtained.

11 Seo and Choi, 2008; Zhou et al., 2009; Deng et al., 2010; 3.4 Machine’s applicability and The applicability and reliability of machines facilitate the quality of construction works and safe Ding et al., 2012a; Ding reliability operation of these machines. and Zhou, 2013; Yu et al., 2014 Zhou et al., 2009; Deng et 3.5 Regular test, calibration and Testing, calibration and maintenance of construction machines/equipment should be done al., 2010; MOHURD and maintenance of machines regularly to ensure their normal and safe operation. AQSIQ, 2011a This dimension is concerned with the safety factors of various materials used in subway 4. Material construction projects. 4.1 Material use and storage (including labeling, use, storage Zhou et al., 2009; Deng et The standardized labeling, use, storage and protection of construction materials facilitate the and semi-finished products al., 2010 improvement of the quality of construction works and reduce the occurrence of safety hazards. protection) Zhou et al., 2009; Deng et • Unqualified or poor-quality construction materials increase safety risks in subway al., 2010; Wu et al., 2012; construction projects. 4.2 Material quality and test MOHURD and AQSIQ, • For innovative construction materials, their function and quality should be approved by 2011a authorized agencies before use. This dimension is concerned with the safety factors of various management activities in subway 5. Management construction projects. • Construction preparedness is an independent stage in the lifecycle of subway projects. During this stage, all stakeholders should ensure that every aspect is ready for construction. Jin et al., 2010; Ding et al., • The client shall submit relevant safety documents and plans to the government for review 5.1 Construction preparedness 2011; MOHURD and and approval. AQSIQ, 2011a • The contractor shall make safety measures and personnel on duty ready for construction. • The engineering consultant shall review the contractor's construction plan and safety

12 management measures, investigate the site and underground conditions, and organize relevant stakeholders to attend orientation and other meetings. • A construction plan determines the use of construction methods, processes, activities, machines/equipment and corresponding safety risks. Therefore, a reasonable construction plan is important for safe construction. 5.2 Construction plan MOHURD and AQSIQ, • The client should take a leading role in establishing a technical committee, with the chief development (including safe work 2011a; Ding et al., 2012a; engineer or technical director as the responsible person to review and make decisions on the method statements for various Wu et al., 2012; Yu et development of the construction plan. activities) al.,2014; Zhang et al., 2019 • The engineering consultant can request contractors to implement site construction works according to the approved construction plan. Any changes to the construction plan should be resubmitted and approved by the chief engineering consultant and site engineering consultants. Data collected through site construction monitoring and measurement enables stakeholders to 5.3 Site construction monitoring Jin et al., 2010; Ding et al., make sure that construction activities are performed safely and be informed timely about any and measurement 2011; Yu et al., 2014 unfavorable site conditions or events, so that immediate measures to prevent safety accidents can be taken. 5.4 Management of high-risk Aksorn and Hadikusumo, construction works (including 2008; Jin et al., 2010; Major risk events and factors should be identified and assessed, and safety risk management construction plan development, MOHURD and AQSIQ, plans should be developed to mitigate safety risks. peer-reviewing and process 2011a; Wu et al., 2012 supervision) • The project team should focus on identifying safety hazards and risks, and facilitating Deng et al., 2010; Jin et al., effective communication between stakeholders. 5.5 Hazard identification and 2010; Ding et al., 2011; • The engineering consultant shall conduct inspections during the execution of important communication MOHURD and AQSIQ, construction works. If any potential safety hazard is identified on site, the relevant works 2011a; Yu et al., 2014 should be suspended and rectified.

13 Jin et al., 2010; MOHURD 5.6 Organizational factors for and AQSIQ, 2011a; Ding et Client, engineering consultant and contractor should jointly establish project safety management on-site safety management al., 2011; Ding et al., 2012a; organizations, develop safety performance assessment policy and determine safety (including organizational Wu et al., 2012; Yu et al., responsibilities of stakeholders. structure and safety personnel) 2014; Zhang et al., 2019 Zhou et al., 2009; Jin et al., • Safety rules and regulations are very important for accident prevention. 2010; Ding et al., 2011; Wu 5.7 Safety rules and regulations • Safety rules and regulations should be enforced to ensure that all activities are implemented et al., 2012; Zhou et al., safely. 2015b; Wu et al., 2016 5.8 Site safety risk management Ding et al., 2011; MOHURD Dynamic safety management policy should be implemented throughout the lifecycle of subway system (including risk and AQSIQ, 2011a,b; Wu et construction projects. Site safety risk management system, including risk management management organization, al., 2012; Wu et al., 2016; organization, procedure and responsibility, is an important and integral part of this effort. procedure and responsibility) The number of accidents is related with the level of standardization and on-site housekeeping. 5.9 Site construction management Zhou et al., 2009; Deng et The project stakeholders in China have realized the importance of this factor and invested more standardization al., 2010; Zhang et al., 2019 resources in this area to improve the safety performance. • Reasonable time available for construction works is important for the safe delivery of subway construction projects. Some major accidents in Chinese subway construction 5.10 Site construction schedule projects were due to unreasonable construction schedule. MOHURD and AQSIQ, (reasonable time available for all • The client should develop the master schedule for the overall project before design 2011a; Yu et al., 2014 the construction works) development according to the feasibility study approved by the government. • Other stakeholders follow the master schedule and develop respective and integrated detailed implementation plans. 5.11 Safety management MOHURD and AQSIQ, • The site shall be equipped with sufficient safety and fire protection instruments, emergency investment (including safety 2011a; Wu et al., 2012; Yu et escape route and other safety protection facilities. facilities and protection al., 2014 • The safety investment directly influences the quality and availability of safety instruments

14 instruments) and facilities. Seo and Choi, 2008; Zhou et • The contractor is responsible for carrying out safety training for construction workers. 5.12 Safety training (including al., 2009; MOHURD and • The frequency, personnel/parties involved and effectiveness of safety training have an frequency, personnel/parties AQSIQ, 2011a; Yu et al., important impact on strengthening safety awareness and regulating safety behavior. involved and effectiveness) 2014 • Safety training should also be extended to front-line workers and senior managers. • Safety meeting proves to be effective to reinforce the communication between stakeholders 5.13 Safety meeting (including at different levels (from management to operatives). frequency, personnel/parties Jin et al., 2010 • These meetings include daily, weekly, monthly, seasonal and yearly meetings, as well as involved and effectiveness) special meetings when necessary. • Safety inspection proves to be an effective tool to identify unsafe and risky works or events during construction. 5.14 Safety inspection (including Zhou et al., 2009; Jin et al., • These inspections might be carried out on daily, weekly, monthly, seasonal and yearly basis, frequency, personnel/parties 2010; Wu et al., 2012; Yu et as well as special inspections when necessary. involved and effectiveness) al., 2014 • The safety inspection can be organized by the government, client, engineering consultant, contractor or other stakeholders at different levels. • Accident prevention and emergency management enable stakeholders to effectively manage unforeseeable events during construction. 5.15 Accident prevention and Jin et al., 2010; MOHURD • A three-level accident prevention and emergency management policy should be established, emergency management and AQSIQ, 2011a; Wu et involving the government, client and other stakeholders. (including organization and al., 2012; Zhang et al., 2019 • Special accident prevention and emergency management plan should be developed for practicing for preparedness) high-risk works/events, which should be reviewed and approved by relevant experts and authorities before construction activities start.

15 16 Research methodology

The research process includes the following four steps:

1. A critical literature review on subway safety risks was conducted to identify 5 dimensions and

32 preliminary factors influencing safety in subway construction projects, which form the conceptual PE3M Framework.

2. Questionnaire survey was distributed to subway construction professionals. Statistical analysis of quantitative data was carried out to prioritize the magnitude of the 5 dimensions and 32 safety risk factors.

3. Interviews with subway construction professionals were conducted to gain deeper insights on influence of the factors in the PE3M Framework on safety in subway construction projects.

4. Quantitative and qualitative data were triangulated to present and discuss the results, and draw a conclusion.

The following section describes the survey and interview processes in detail.

Questionnaire survey

Using Table 1 as the conceptual framework, a questionnaire survey was used to collect quantitative data from construction professionals working in subway construction projects in

China. The questionnaire comprised three sections. The first section sought to collect the demographic information of the respondents, including type of company, years of working in the construction industry and current position. The second section asked respondents to rank the importance of each of the 32 global safety influencing factors in the verified PE3M Framework on a seven-point Likert scale ranging from 1 (very un-influential) to 7 (very influential). The third

17 section included an open-ended question for the respondents to comment on other factors that influence safety management in Chinese subway construction projects. Safety risk identification for subway construction projects is a knowledge-intensive process involving a variety of stakeholders and communities (Xing et al., 2019), hence, in this research, construction professionals were sampled from different stakeholder groups involved in these projects. These included professionals working in client organizations, contractors, design companies, engineering consultants and subcontractors/suppliers.

The questionnaire was distributed through both face-to-face and online mediums. Face-to-face surveys were distributed using random sampling at the 2019 Annual Subway Conference in

Jiangsu Province in China. This conference was chosen because it is the most influential academic gathering with participants from the subway authorities and high-profile management of various stakeholders in subway projects in Jiangsu Province. The online survey was administered in 2020 by using a purposeful sampling approach of respondents working on live subway construction projects in Shanghai and four cities in the Jiangsu Province (i.e. Nanjing, Suzhou, Wuxi and

Changzhou), through formal established networks with the research team. One hundred and twenty respondents were invited to participate in the face-to-face survey and 101 surveys were gathered (the response rate was 84.17%). In terms of on-line survey, 556 surveys were collected. It is impossible to calculate the on-line response rate because the number of potential respondents reached through the online link is not identifiable. In total, 657 survey responses were received, of which 399 were valid which included 88 and 311 valid responses from face-to-face survey and on-line survey, respectively.

Like all methods, it is recognized that on-line surveys have their limitations. Although one may

18 have access to greater numbers of participants over wide geographical areas and although online surveys are suited to the types of respondents targeted in this research, self-selection can sometimes bias results. However, Couper’s (2000) research into the merits and disadvantages of online surveys showed that self-selection is no more problematic in online surveys than in mail and telephone surveys. Gosling et al.’s (2004) research also indicated that in terms of sample representativeness, online surveys also compare favorably to research using other methods. In addition, a very strict standard was employed to screen the survey data, for example, if one particular respondent chose the same value for all the questions in section 2, the data will be discarded. It is also a necessary method to collect data considering the outbreak of Coronavirus epidemic in China. So having employed all these safeguards, the researchers are confident that the survey sample is representative and generates reliable results.

Interview

Following statistical analysis of the questionnaire survey data, semi-structured interviews were conducted with five experienced safety management practitioners working on subway construction projects (See Table 2 for details). The purpose of these interviews was to present the survey results and to capture further qualitative insights about the ranking and importance of the influencing factors. The interview results were used to complement and verify the quantitative analysis results. Interviewees were purposefully sampled based on their working experience and accumulated knowledge in safety management of subway construction projects.

19 Table 2 Interviewee sample structure Interviewee Brief description Project manager of a subway client, with about 15 years of working experience in Participant 1 subway construction management field. Director of safety management department of a subway client, with about 15 years Participant 2 of working experience in subway construction management field. Director of safety management department of a subway client, with over 10 years of Participant 3 working experience in subway construction management field. Project manager of a large state-owned subway contractor, with about 15 years of Participant 4 working experience in subway construction management field. Project engineer of a subway client, holding master degree in construction Participant 5 management, with over 10 years of working experience in the construction industry and 5 years of working experience in subway construction management field.

During the investigation, potential problems of social desirability bias, which are possible in

research on sensitive areas like construction safety (Loosemore and Lim, 2017), were controlled

by ensuring that the survey was anonymous. In addition, respondents were provided with

assurance that their responses would be treated with strict confidentiality and would not be seen by

their employers and supervisors. Finally, according to ethical clearance requirements, all

respondents were offered with an explanation of the research including the objectives of the

research, why they had been selected for survey, and the opportunity to stop their participation and

withdraw their data at any time during or after the research.

Data analysis

Respondents' profile and data reliability

The demographic profile of the respondents is presented in Table 3.

Table 3 Demographic profile of the respondents Category Profile Number of respondents Percentage Client 47 11.78% Type of Contractor 311 77.94% company Designer 21 5.26% Engineering consultant 10 2.51%

20 Category Profile Number of respondents Percentage Subcontractor/supplier 6 1.50% Others 4 1.00% Less than 5 years 149 37.34% Years of 6-10 years 100 25.06% working in the 11-15 years 66 16.54% construction 16-20 years 43 10.78% industry 21-25 years 10 2.51% More than 25 years 31 7.77% Staff 166 41.60% Foreman/department head 188 47.12% Position Project manager/high-rank 39 9.77% manager in the company Others 6 1.50%

The majority of the respondents were working for contractors and clients (89.72%). Over 60% of the respondents had more than 5 years of working experience in the construction industry and over 55% of them held management positions.

Cronbach’s alpha, a coefficient of reliability, was employed to test the reliability of the questionnaire data. The values of Cronbach’s alpha for the five dimensions (i.e. people, environment, machine, material and management) of safety influencing factors in the survey are

0.830, 0.875, 0.922, 0.850 and 0.958, respectively. All the values were considered excellent since they far exceed the threshold of 0.70 (George and Mallery, 2003).

General analysis results

The mean value of each dimension and factor were calculated and used to prioritize the importance of the five dimensions and 32 global factors. Table 4 shows the mean values and ranks of the five dimensions.

21 Table 4 Mean values and ranks of the five dimensions Dimension Mean value Rank Machine 6.40 1 Management 6.36 2 People 6.35 3 Environment 6.25 4 Material 6.21 5

Table 4 indicates that while all factors were highly ranked, the most influential factors that were perceived to influence safety in subway construction projects relate to machine, followed by management and people. The prominence of machines reflects the high-tech nature of subway projects and supports previous research which reported that in Chinese subway construction projects, 14.3% of fatalities were caused by mechanical, lifting and transportation operations (Yu et al., 2019). As one interviewee mentioned:

"...... During peak construction time, there could be 100 pieces of machines/equipment working on site. When these machines are not operated properly or in a safe condition, they pose serious threats to the safety of participants ...... " (Participant 4)

The results relating to management and people support Yu et al. (2014), who argued that they are two of the most critical factors influencing subway construction accidents in China.

Management factors are particularly important in high power distance culture, such as that in

China (Hofstede, 1984) where operatives are less likely to question management decisions. This is echoed by one interviewee:

"...... if the project manager places high importance on safety, the other participants will follow his example...... " (Participant 1)

The mean value of each safety factor is presented in Table 5.

22 Table 5 Statistical analysis results of influential factors Dimensions and factors Mean value Rank 1. People ------1.1 Client-related factors 6.32 22 1.2 Surveyor/designer-related factors 6.23 25 1.3 Contractor-related factors 6.69 1 1.4 Engineering consultant-related factors 6.02 30 1.5 Government-related factors 6.24 24 1.6 Project management team 6.59 2 2. Environment ------2.1 Site construction environment 6.17 27 2.2 Site surrounding environment 6.35 19 2.3 Site underground environment 6.50 4 2.4 Site natural environment and weather conditions 5.99 31 3. Machine ------3.1 Use of machines in all stages 6.46 9 3.2 Safety protection during the use of machines 6.49 5 3.3 Professional inspection, test and acceptance for specialized 6.38 14 machines 3.4 Machine’s applicability and reliability 6.30 23 3.5 Regular test, calibration and maintenance of machines 6.35 20 4. Material ------4.1 Material use and storage 6.06 28 4.2 Material quality and test 6.35 18 5. Management ------5.1 Construction preparedness 6.34 21 5.2 Construction plan development 6.46 10 5.3 Site construction monitoring and measurement 6.49 6 5.4 Management of high-risk construction works 6.48 7 5.5 Hazard identification and communication 6.46 8 5.6 Organizational factors for on-site safety management 6.41 12 5.7 Safety rules and regulations 6.38 16 5.8 Site safety risk management system 6.39 13 5.9 Site construction management standardization 6.44 11 5.10 Site construction schedule 6.38 15 5.11 Safety management investment 6.52 3

23 Dimensions and factors Mean value Rank 5.12 Safety training 6.36 17 5.13 Safety meeting 5.99 32 5.14 Safety inspection 6.06 29 5.15 Accident prevention and emergency management 6.20 26

In order to evaluate the similarity between the rankings of each factor in Table 5 among the five main project stakeholders, the Spearman’s rank correlation test was conducted. The results are shown in Table 6.

Table 6 Spearman’s rank correlation test results Engineering Subcontractor/ Client Contractor Designer consultant supplier Client 1.000 Contractor .696** 1.000 Designer .599** .769** 1.000 Engineering consultant .542** .587** .740** 1.000 Subcontractor/supplier .352* .269 .184 .209 1.000 ** Correlation is significant at 0.01 level (two-tailed). * Correlation is significant at 0.05 (two-tailed).

From Table 6, it can be seen that the similarity of rankings between the client, contractor, designer and engineering consultant are strongly significant. Interestingly, subcontractor/supplier perceptions are different to other groups apart from the client. This is important and interesting since it reflects recent research by Loosemore (2014) and in particular Lingard et al. (2019) who noted subcontractor's disempowerment in construction projects, the practice of subcontracting as a contributing factor in poor safety performance, the tendency for different sub climates to develop in project supply chains and the need for better safety-related communication between group members, to reduce the potentially damaging variance in perceptions.

Critical safety factors

24 Based on the results in Table 6 and considering majority of the respondents were working for contractors (77.94%), it is necessary to capture the insights on the critical influential factors from all the important stakeholders to obtain unbiased findings. As such, in order to identify the critical factors that influence safety of subway construction projects, the first ten factors (rank 1-10) perceived by each type of stakeholder were obtained, resulting in a total of 50 factors. Among them, the frequency of each factor was counted and accumulated. The eight factors with high frequency (agreed by over three types of stakeholders) are shown in Table 7.

Table 7 Critical factors influencing the safety of Chinese subway construction projects Surveyor Engineering Subcontractor Factors (factor code in Table 1) Client Contractor /Designer consultant /supplier Project management team (1.6) √ √ √ √ √ Contractor-related factors (1.3) √ √ √ √ Site underground environment (2.3) √ √ √ √ Safety protection during the use of √ √ √ √ machines (3.2) Safety management investment (5.11) √ √ √ Site construction monitoring and √ √ √ measurement (5.3) Hazard identification and √ √ √ communication (5.5) Use of machines in all stages (3.1) √ √ √ Note: "√" means that the factor was perceived by the particular stakeholder as very influential (rank 1-10) among the 32 global factors.

Among these factors, two factors (i.e. project management team, and contractor) are related with the people dimension and take the first two positions in the rank of importance. This aligns with a view which indicates that human error is a major cause of accidents in many heavy engineering industries (Garrett and Teizer, 2009). In addition, one factor (i.e. site underground environment) is related with the environment dimension, two factors (i.e. safety protection during the use of machines and use of machines in all stages) are related with the machine dimension and the remaining three factors (i.e. safety management investment, site construction monitoring and

25 measurement, and hazard identification and communication) are related with the management dimension. The following sections elaborate each of the eight critical influencing factors in detail.

Project management team

Project management team was considered as the most critical factor influencing the safety of Chinese subway construction projects by all five types of stakeholders. The project management team is responsible for developing a practical safety plan, allocating adequate resources, monitoring and assessing site safety conditions, initiating and attending regular safety meetings and training, and coordinating all project stakeholders to ensure their active involvement in managing safety (Mohurd and Aqsiq, 2011a). Due to the high level of risk and complex multi-stakeholder environments in subway construction projects, the project management team's capabilities, experience and accountability is likely to have a more significant impact on safety management performance

(Sunindijo et al., 2017). Therefore, selecting project management team members with the right skill profile is a key success factor to influence safety. Zou and Sunindijo (2013) argued that in order to perform their safety leadership role, project management personnel needs foundational skills, comprising self-awareness, visioning and apparent sincerity; personal skills, comprising scoping and integration, and self-management; and social skills, comprising social awareness, social astuteness, and relationship management. Under such a leadership, the project management team can analyze and assess safety risks from an interrelated network perspective and try to seek collaborative countermeasures to mitigate risks as a whole in subway construction projects (Wang et al., 2017).

Contractor-related factors

26 As presented in Table 5, this factor was also ranked first by all the respondents. Wu et al. (2012) indicated that contractors have a much higher-level of importance to facilitate a safe construction than the other project stakeholders. In subway projects, Sun et al. (2008) stated that over half of the critical safety risk factors are related with contractors and subcontractors. Indeed, the majority of safety risks occurred in the construction stage and the contractors are responsible for managing the majority of these risk factors (Zou et al., 2007). As addressed by one interviewee:

"...... the client may have a high level of safety management standard and a perfect safety management plan, but the contractor is responsible to manage the numerous site activities in construction. The contractor's capabilities of safety planning, execution, monitoring, control, and quick response to emergency are all very important for accident prevention...... " (Participant 2)

Despite the importance of contractors in managing safety risks, research has shown that managing these risks early in the project lifecycle is a way to reduce risk exposure in the construction stage, particularly in complex projects. Construction clients have important roles to play in selecting the best contractors for the work to ensure safety. The construction industry in general prefers to use the competitive tendering procurement method. This method, together with the practice of awarding contracts based on the lowest tender price, may compel contractors to cut corners when implementing safety measures to reduce costs (Boadu et al., 2020). In this case, value for money is an alternative procurement method where the quality of the contractor and its safety capability and records are factors taken into consideration when evaluating tenders. Early contractor involvement in the design stage is another proven procurement approach to improve constructability and safety in complex projects.

27 Site underground environment

Underground construction, with extremely high-risk due to unpredictable hydrological and geological conditions (Ding et al., 2012a), is a unique feature that differentiates subway construction with other construction projects. Therefore, comprehensive identification of critical safety risks in underground construction and their respective mitigation strategies are important for safety management. Specifically, three groups of safety risks should be considered in subway underground construction: (1) technical risks, which refers to construction activities to be done, such as excavation, foundation construction and wall construction (Zhou et al., 2017); (2) management and human safety risks, such as schedule pressure, constructability, supervision and training (Wang et al., 2017); and (3) environmental risks, such as geological and hydrogeological conditions, existing utilities and buildings and weather conditions (Fang et al., 2011). This indicates that project stakeholders need to conduct comprehensive and detailed underground surveys before and during construction to enable them to make a more informed construction plan and implement construction activities more safely.

Safety protection during the use of machines

This factor was considered critical by the client, contractor, engineering consultant and subcontractor/supplier. As stated earlier, many heavy machines are involved in subway construction projects, thus their safe operation and conditions are paramount to ensure safety

(MOHURD and AQSIQ, 2011a). Inspections and tests are needed to make sure that these machines are safe and that appropriate protection measures are effective to guarantee the safety of the operators and public. In addition, many lessons indicate that operating the equipment beyond their

28 limits frequently leads to serious accidents. In 2003 and 2006, respectively, accidents occurred in

Beijing Line 5 and Line 10 construction projects because of machine failure (Wu et al., 2016).

One interviewee suggested a best practice to improve safety performance in this aspect:

"...... an automatic safety early warning system to send timely information to management or operator is very helpful to prevent safety accidents because of machine operation failure in subway projects. For some important and hazardous areas, integral safety alarming measures, including alarming color, alarming light and alarming noise, are effective to protect the public......

"(Participant 3)

Safety management investment

Safety investment proves to have a positive impact on overall project cost performance due to reduced accident costs, better productivity and improved reputation (Zou and Sunindijo, 2015).

However, many construction clients, including those in Chinese subway construction projects, prefer to use competitive tendering and lowest price method when procuring services from contractors. This practice leads to poor safety performance, which is also detrimental to overall project performance. In fact, this is contradictory to the regulations of the Chinese government, which specified that safety investment should be an independent non-competition item in tenders in subway construction projects (MOHURD 2010). As further complemented by one interviewee:

''...... In our projects, the safety investment is included as a fixed item in the contract price. Every month, our team will audit the contractors' expenditure on safety facilities and protection instruments. The result will be the basis for monthly payment and contractors' reputation evaluation.

For the contractor, if the safety investment can be guaranteed, the safety performance will be enhanced

29 effectively...... " (Participant 3)

As such, integrating safety into subway construction projects, which is facilitated by adequate safety investment, is particularly important in subway construction. The top management of all stakeholders, especially the client and contractors, should commit to provide necessary and adequate safety investments, which enable the allocation of sufficient safety resources to carry out daily activities, and to achieve both short-term and long-term goals (Aksorn and Hadikusumo,

2008).

Site construction monitoring and measurement

Real-time monitoring and measurements aim to collect accurate and sufficient dynamic data, such as ground settlement and movement, excavation and underground utilities, to enable the early implementation of relevant measures to prevent incidents. This factor is very critical in subway construction, especially in dense urban areas (Ding et al. 2013). A foundation collapse in

Hangzhou Subway Line 1 was due to the ignorance of early warning information from the data collected (Zhou and Irizarry, 2016). Grabowski et al. (2007) also noted that identifying signals and alerts before an accident provides the opportunity to improve safety performance. In Chinese subway construction projects, in order to ensure the availability of correct and sufficient real-time data, the client frequently engages an independent agency to provide professional service in addition to the contractors' monitoring and measurement. After collecting and analyzing data from the two parties, the project management team can determine the level of safety risks during daily construction activities. As noted by one interviewee:

"...... In subway projects, accurate and timely data about underground conditions, supporting

30 structures and other utility piping systems are very important for safe construction. We rely on the data to make critical decisions and to determine the extent of safety risks...... " (Participant 4)

Hazard identification and communication

This factor again highlights the importance of effective risk identification and communication between project stakeholders and participants, which also support the arguments of Yu et al. (2014) and Ding et al. (2012b). In practice, an entire subway line project is divided into different sections, which are undertaken by different construction contractors. Even in one section, several contractors might be involved and working in the same space. In this case, a contractor in one section needs the safety risk data of related sections from other contractors (Xing et al., 2019). Effective and open communication, therefore, is critical to jointly identify safety hazard and share safety information.

This is in contrast to adversarial relationships often attributed to the construction industry. One interviewee shared a best practice:

"...... In order to foster proactive hazard identification and information sharing between the contractors working in the same space, we request these contractors to sign a multi-party safety technical management contract, specifying the work undertaken by each contractor, interface between the contractors, potential safety risks, and safety communication and joint safety management responsibilities...... " (Participant 5)

Use of machines in all stages

The influence of heavy machines on safety is demonstrated in this factor again. For example, the tunnel shield facilitates tunnel construction rapidly without affecting the road traffic, which is also one of the most important machines in subway construction (Qiu et al., 2020). Furthermore, about half of the machines are very large, requiring complex installation and dismantling processes.

31 Therefore, accidents can occur not only during the operation of these machines, but also before and after their use. The best practice is that a manual standard should be developed for each machine/equipment before arriving on site, and managers should ensure that these standards are strictly followed (Mohurd and Aqsiq, 2011a). However, this is also very challenging, as explained by one interviewee:

"...... since many machines are working simultaneously on site and generally we are very busy, it is impossible to pay attention to every piece of machine/equipment. This is also one of the reasons for this type of safety accident...... "(Participant 4)

Based on above research results, the final PE3M Framework is illustrated in Figure 1.

32 3. Machine 3.1 Use of machines in all stages*** 3.2 Safety protection during the use of machines*** 3.3 Professional inspection, test and acceptance for specialized machines

3.4 Machine’s applicability and reliability

3.5 Regular test, calibration and maintenance of machines

5. Management 1. People 5.1 Construction preparedness 1.1 Client-related factors 5.2 Construction plan development

1.2 Surveyor/designer-related factors 5.3 Site construction monitoring and measurement*** 1.3 Contractor-related factors*** 5.4 Management of high-risk construction works PE3M 1.4 Engineering consultant-related factors 5.5 Hazard identification and communication*** 1.5 Government-related factors 5.6 Organizational factors for on-site safety management

1.6 Project management team*** 5.7 Safety rules and regulations 5.8 Site safety risk management system 2. Environment 5.9 Site construction management standardization 2.1 Site construction environment 5.10 Site construction schedule

2.2 Site surrounding environment 5.11 Safety management investment*** 2.3 Site underground environment*** 5.12 Safety training 2.4 Site natural environment and weather conditions 5.13 Safety meeting

5.14 Safety inspection 4. Material 5.15 Accident prevention and emergency management 4.1 Material use and storage

4.2 Material quality and test

Note: (1) Critical factors influencing safety are highlighted with ***. (2) Each dimension is positioned according to the rank of its mean value (see Table 4), from top to bottom. Figure 1 Final PE3M Framework

Conclusion

Considering the rapid development of subway construction and its poor safety record in China, this research has identified the critical factors influencing the safety of subway construction projects to facilitate effective measures to improve safety performance in this context. Based on extensive literature review and pilot survey, 32 global safety influencing factors were identified and categorized into a five-dimensional PE3M Framework, which includes people, environment,

33 machine, material and management. The results indicated that the eight most critical influencing factors for the Chinese subway construction safety are project management team, contractor-related factors, site underground environment, safety protection during the use of machines, safety management investment, site construction monitoring and measurement, hazard identification and communication, and use of machines in all stages. This indicates that in allocating limited project resources to improve safety on subway construction projects, managers should focus on: developing safety knowledge and positive attitudes in leadership teams; formulating effective risk management systems to identify, assess, mitigate, measure and monitor safety risks on site; improving communications with stakeholders about these risks; and effectively managing plant, equipment and machinery.

The identified critical safety factors can also be used by construction practitioners as an effective decision support tool in tailor-making safety management plans to effectively manage safety in both subway construction projects and other similar complex infrastructure projects, such as tunnels, coal mining and dams.

It is important to point out that the empirical investigation of this research was conducted in

Jiangsu province and Shanghai, where over 10% of the length of Chinese subway lines was under construction in 2019. As the most wealthy and developed areas in China, the safety management level is relatively high in the region, and the standards and construction practices might be different from the rest of China. Therefore, further research is needed in other Chinese cities to obtain a broader understanding on these risks. Furthermore, it would be interesting to use the

PE3M Framework in other countries to better understand the cultural and regulatory influences (if any) on the risk factors posed by such projects. Finally, while the PE3M Framework has been

34 developed to reflect the specific risks posed by subway projects in China, it would be useful to test it in other project contexts to explore whether it could provide a useful basis for a more generic safety assessment framework.

References:

Aksorn T., Hadikusumo, B.H.W. (2008). Critical success factors influencing safety program

performance in Thai construction projects. Safety Science, 46, 709-727.

Biggs, H.C., Dingsdag, D.P., Sheahan, V.L., and Stenson, N.J. (2005). The role of collaboration in

defining and maintaining a safety culture: Australian perspectives in the construction sector. In:

Khosrowshahi, F (Ed.), Proceedings 21st Annual ARCOM Conference, 7-9 September 2005,

London, UK. Association of Researchers in Construction Management, 1, 137-46.

Boadu, E.F., Wang, C.C., and Sunindijo, R.Y. (2020). Characteristics of the construction industry

in developing countries and its implications for health and safety: An exploratory study in

Ghana. International Journal of Environmental Research and Public Health, 17(11), 4110.

China Association of Metros. (2020). Statistic and analysis report of metro system in 2019. China

Association of Metros Information, 25, 1-54. In Chinese

Couper, M.P. (2000). Web surveys: A review of issues and approaches. Public Opinion Quarterly,

64, 464-494.

Deng, X., Li, Q., and Zhou, Z. (2010). Statistical analysis on subway construction safety accidents

regularity. Statistics and Decision-making, 309, 87-89. In Chinese

Ding, L.Y., Wu, X., Luo, H., and Fu, F. (2011). Research on standard for construction safety

assessment of metro engineering. China Civil Engineering Journal, 44(11), 121-127. In

35 Chinese

Ding, L.Y., Yu, H.L., Li, H., Zhou, C., Wu, X.G., and Yu, M.H. (2012a). Safety risk identification

system for metro construction on the basis of construction drawings. Automation in

Construction, 27, 120-137.

Ding, L.Y., Zhou, Y., Luo, H.B., and Wu, X.G. (2012b). Using nD technology to develop an

integrated construction management system for city rail transit construction. Automation in

Construction, 21, 64-73.

Ding, L.Y., and Zhou, C. (2013). Development of web-based system for safety risk early warning

in urban metro construction. Automation in Construction, 34, 45-55.

Ding L.Y., Zhou C., Deng Q.X., Luo H.B., Ye X.W., Ni Y.Q., and Guo P. (2013). Real-time safety

early warning system for cross passage construction in Yangtze Riverbed Metro Tunnel based

on the internet of things. Automation in Construction, 36, 25-37.

Fang, Q., Zhang, D., and Wong, L.N.Y. (2011). Environmental risk management for a cross

interchange subway station construction in China. Tunnelling and Underground Space

Technology, 26(6), 750-763.

Garrett J.W., and Teizer J. (2009). Human factors analysis classification system relating to human

error awareness taxonomy in construction safety. Journal of Construction Engineering and

Management, 135(8), 754-763.

George, D., and Mallery, P. (2003). SPSS for windows step by step: A simple guide and reference.

11.0 update, 4th Ed., Allyn and Bacon, Boston.

Gosling, S.D., Vazire, S., Srivastava, S., and John, O.P. (2004). Should we trust web-based studies?

A comparative analysis of six preconceptions about internet questionnaires. American

36 Psychologist, 59(2), 93-104.

Grabowski, M., Ayyalasomayajula, P., Merrick, J., Harrald, J. R., and Roberts, K. (2007). Leading

indicators of safety in virtual organizations. Safety Science, 45, 1013-1043.

Hofstede, G. (1984). Culture's consequences: international differences in work-related values (2nd

ed.). Beverly Hills CA: SAGE Publications.

Jin, H., Zhang, C., Ma, X., Zhong, Q., Wu, F., and Li, J. (2010). Development of safety risk

technical management system of urban rail transit. Urban Rapid Rail Transit, 23(1), 34-37.

In Chinese

Li, M., Yu, H., Jin, H., and Liu, P. (2018). Methodologies of safety risk control for China’s metro

construction based on BIM. Safety Science, 110, 418-426.

Lingard, H., Pirzadeh, P., and Oswald, D. (2019). Talking safety: Health and safety

communication and safety climate in subcontracted construction workgroups. Journal of

Construction Engineering and Management, 145(5).

Loosemore, M. (2014). Improving construction productivity: A subcontractor's perspective.

Engineering, Construction and Architectural Management, 21(3), 245-60.

Loosemore, M., and Lim, B. (2017). Linking corporate social responsibility and Organizational

performance in the construction industry. Construction Management and Economics, 35(3),

95-105.

Loosemore, M., Sunindijo, R., and Zhang, S. (2020). A comparative analysis of safety in the

Chinese, Australian and Indonesia construction industries. Journal of Construction

Engineering and Management. In Press

MOHURD (Ministry of Housing and Urban-Rural Development of China). (2010). Interim

37 measures for safety and quality management of urban rail transit project (Construction

Quality [2010] NO. 5), http://www.mohurd.gov.cn/wjfb/201001/t20100119_199326.html,

accessed on June 26, 2020. In Chinese

MOHURD, and AQSIQ (General Administration of Quality Supervision, Inspection and

Quarantine of China). (2011a). Code of project management for urban rail transit construction

(GB 50722-2011). China Architectural and Building Press, Beijing, China. In Chinese

MOHURD, and AQSIQ. (2011b). Code for risk management of underground works in urban rail

transit (GB 50652-2011). China Architecture and Building Press, Beijing, China. In

Chinese

Qian, Q., and Lin, P. (2016). Safety risk management of underground engineering in China:

Progress, challenges and strategies. Journal of Rock Mechanics and Geotechnical Engineering,

8, 423-442.

Qiu, J., Qin Y., Feng Z., Wang, L., and Wang, K. (2020). Safety risks and protection measures for

city wall during construction and operation of Xi'an Metro. Journal of Performance of

Constructed Facilities, 34(2): 04020003, 1-13.

Seo, J.W., and Choi, H.H. (2008). Risk-based safety impact assessment methodology for

underground construction projects in Korea. Journal of Construction Engineering and

Management, 134(1), 72-81.

Sun Y., Fang, D., Wang, S., Dai M., and Lv, X. (2008). Safety risk identification and assessment

for Beijing Olympic venues construction. Journal of Management in Engineering, 24(1),

40-47.

Sunindijo, R.Y., Zou, P.X.W., and Dainty, A.R.J. (2017). Managerial skills for managing

38 construction safety. Civil Engineering Dimension, 19(2), 63-72.

Wang, X., Xia, N., Zhang, Z., Wu, C., and Liu, B. (2017). Human safety risks and their

interactions in China's subways: Stakeholder perspectives. Journal of Management in

Engineering, 33(5):05017004, 1-15.

Wu, X., Liu, H., Zhang, L., Yao, C., and Jiang, X. (2012). Survey and analysis on organizational

management factors of metro engineering. Journal of Civil Engineering and Management,

29(4), 79-83. In Chinese

Wu, X., Wu K., Shen M., Chen, Y., and Zhang L. (2016). Research on coupling of safety risks in

metro construction based on N-K model. China Safety Science Journal, 26(4), 96-101. In

Chinese

Wu, X., Zeng, T., Zhang, L., and Song, R. (2013). Research on safety management of adjacent

underground pipelines in metro construction. Journal of Railway Engineering Society, 9,

127-132. In Chinese

Xing H., Xiong, F., and Wu, J. (2016). Effects of pit excavation on an existing subway station and

preventive measures. Journal of Performance of Constructed Facilities, 30(6): 04016063, 1-9.

Xing, X., Zhong, B., Luo,H., Li, H., and Wu, H. (2019). Ontology for safety risk identification in

metro construction. Computers in Industry, 109, 14-30.

Yan, H., Gao, C., Elzarka, H., Mostafa, K., and Tang W. (2019). Risk assessment for construction

of urban rail transit projects. Safety Science, 118, 583-594.

Yu, H., Peng, Y., Zhang L., Wang, R., and Wang Q. (2019). Statistical analysis on urban metro

accidents during construction period. Chinese Journal of Underground Space and Engineering,

15, 852-860. In Chinese

39 Yu, Q.Z., Ding L.Y., Zhou, C., Luo H.B. (2014). Analysis of factors influencing safety

management for metro construction in China. Accident Analysis and Prevention, 68, 131-138.

Zhang S., Shang, C., Wang, C., Song R., and Wang, X. (2019). Real-time safety risk identification

model during metro construction adjacent to buildings. Journal of Construction Engineering

and Management,145(6): 04019034, 1-14.

Zhou, Y., Su, W., Ding, L., Luo, H., and Love, P.E.D. (2017). Predicting safety risks in deep

foundation pits in subway infrastructure projects: Support vector machine approach. Journal of

Computing in Civil Engineering, 31(5), 04017052.

Zhou, Z., Goh, Y.M., and Li, Q. (2015a). Overview and analysis of safety management studies in

the construction industry. Safety Science, 72, 337-350.

Zhou, Z., and Irizarry, J. (2016). Integrated framework of modified accident energy release model

and network theory to explore the full complexity of the Hangzhou subway construction

collapse. Journal of Management in Engineering, 32(5): 05016013, 1-9.

Zhou, Z., Irizarry, J., Li, Q., and Wu, W. (2015b). Using grounded theory methodology to explore

the information of precursors based on subway construction incidents. Journal of Management

in Engineering, 31.04014030, 1-10.

Zhou, Z., Li, Q., Deng, X., and Cai, Y. (2009). Analysis of metro collapse accidents based on

accident mechanism and management factors with the collapse of Hangzhou Metro as an

example. China Safety Science Journal, 19(9), 139-145. In Chinese

Zhou, Z., Li, Q., and Wu, W. (2012). Developing a versatile subway construction incident database

for safety management. Journal of Construction Engineering and Management, 138(10), 10,

1169-1180.

40 Zou, P.X.W., and Li, J. (2010). Risk identification and assessment in subway projects: Case study

of Nanjing Subway Line 2. Construction Management and Economics, 28(12), 1219-1238.

Zou, P.X.W., and Sunindijo, R.Y. (2013). Skills for managing safety risk, implementing safety task,

and developing positive safety climate in construction project. Automation in Construction, 34,

92-100.

Zou, P.X.W. and Sunindijo, R.Y. (2015). Strategic safety management in construction and

engineering. Chichester, UK, Wiley Blackwell.

Zou, P.X.W., Zhang, G., and Wang, J. (2007). Understanding the key risks in construction projects

in China. International Journal of Project Management, 25(6), 601-614.