Guang’an: a dramatic retaining wall failure video

Youtube has a cool video showing the impact of a retaining wall failure in the city of Guang’an in Sichuan Province, China. The event reportedly occurred early in the morning yesterday (6:50 am on 1st July 2018):

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The event reportedly involved the failure of a 50 m section of retaining wall during heavy rainfall. Interestingly, Liveleak has a second video that shows a part of the failure of the wall from the foot of the slope. This still is taken from that video:-

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I am not quite sure what to make of the images from the videos of the state of the materials behind the unfailed sections of the wall after the failure:-

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The resultant landslide was a classic slump, with the roadway moving downwards and outwards as the support at the toe of the slope failed. The Chengdu Economic Daily has an article about the landslide (in Mandarin). This article indicates that cracks had started to appear in the fill behind the wall on 22nd June, and that the authorities had been aware of the problem. These cracks enlarged rapidly on the day of the failure, such that local people were able to provide warnings that a failure night occur. The landslide occurred in several phases, starting at 6:50 am, and there was a significant failure at about 11 am too. In total about 50 households have now been evacuated. The slope was reportedly about 30 m in tall. Interestingly there is quite a large section of this wall that remains standing, as the still below shows:

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Managing the remaing sections of that wall will be challenge in the forthcoming rainy season.