Assessing the causes of project overruns in tunnel construction projects in Pakistan

Tunnel construction is considered a bottleneck point in mega construction projects because of higher associated risks and uncertainties. This study is an attempt to identify and rank the causes project overruns in tunnel construction projects in Pakistan and propose a mitigation strategy to minimize their effects. For the given purpose, a total of 32 key causes were obtained from the literature and discussion with a team of experts and practitioners. A web-based questionnaire survey was used for data collection. About 55 complete responses were received from the practitioners working as clients, consultants, and contractors in Pakistan. The identified causes were ranked using frequency, severity, and relative importance indexes. The most important causes were found to be inexperienced and incompetent contractors, ignoring consultants' instructions by contractors, inadequate project estimates, delay in issuance of funds to the contractors, and low bids. This study can be employed for controlling the leading causes of overruns in tunnel construction projects. Moreover, it can serve as a guide in further investigation of the causes of project overruns in tunneling in different countries.

隧道工程因伴随较高风险与不确定性，被视为大型基建项目中的关键瓶颈环节。本研究旨在识别并排序巴基斯坦隧道工程项目中导致项目超支的各类成因，并提出缓解策略以降低其影响。基于该研究目标，本研究通过文献调研及与专家、从业者团队的研讨，共梳理得到32项关键成因。本次数据采集采用网络问卷调查法，共回收巴基斯坦地区业主、咨询方及承包商等从业者的有效问卷55份。研究通过频率、严重程度及相对重要性指数对识别出的成因进行排序，最终得到的首要成因包括：承包商经验不足且能力欠缺、承包商无视咨询方指令、项目估算不足、向承包商拨付资金延迟以及低价竞标。本研究可用于管控隧道工程项目中超支的主要成因，同时也可作为不同国家隧道工程项目超支成因后续研究的参考指南。