Heavy rainfall-related excavation failures in China during 1994 to 2018: An overview

• Published in: Engineering failure analysis 2021-11, Vol.129, p.105695, Article 105695
• Main Authors: Jiang, Weizhen, Tan, Yong
• Format: Article
• Language: English
• Subjects: China; Excavation; Failure; Heavy rainfall; Statistical pattern
• ISSN: 1350-6307; 1873-1961
• DOI: 10.1016/j.engfailanal.2021.105695

•170 rainfall-related excavation failure cases in China were collected for analyses.•10 conceptual models were developed for illustration of the excavation failures.•Soil conditions and technical factors involved in the failures were summarized. Over the last 30 years, intense rainfall events due to abnormal climate change have brought about numerous excavation failures in the urban areas of China. These heavy rainfall-related engineering failures, characterized by failure or collapse of retaining structures and/or retained slopes, have caused large-scale damages to urban environment as well as injuries and casualties. Thus, a summary of such failures along with corresponding statistical patterns and contributing factors is essential, which can help practitioners further understand the risk of excavation failures associated with heavy rainfall and then could develop or adopt appropriate measures for prevention of future failures. Based on these considerations, this paper reviewed 170 excavation failure cases occurring during 1994–2018 in China, using a method of descriptive statistics. The review mainly focused on their statistical failure patterns (temporal distributions of failures, types of failures and types of failed soil strata, etc.) and contributory factors (e.g., heavy rainfall influences and technical factors). It was disclosed that the failures occurred in those deep excavations in sandy soils during summer more frequently. In general, the failures can be categorized into six basic types, which are mainly governed by 11 kinds of adverse influences of heavy rainfall (e.g., seepage erosion under high hydraulic gradient, intense runoff scouring and water gushing impact from broken storm sewers nearby, etc.) and 16 technical factors (e.g., ignorance or improper protection of adjacent preexisting drainage structures, deficiencies in drainage or dewatering system, and poor construction quality of temporary retaining structures, etc.). The findings and lessons learned from this review are practically useful for designers and contractors to reduce the incidence of future excavation failures in the context of global climate change.