How to prevent slope collapse during foundation pit excavation?
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I just saw news again about a collapse at a construction site in Zhengzhou, resulting in 2 deaths and 1 person buried: At 9:30 a.m. on the 12th, at the intersection of Dongfeng East Road and Jiuru East Road in Zhengdong New Area, Zhengzhou City, Henan Province, a collapse occurred at a construction site where work was being carried out to lay water pipes using tunneling techniques; 4 workers were buried in the rubble. More than 40 firefighters carried out emergency rescue efforts. As of 12:00, one person has been rescued, two have died, and another is still under search and rescue. http://news.sina.com.cn/c/2015-06-12/130231943936.shtml?cre=sinapc&mod=g&loc=9&r=u&rfunc=2 How can the risk of landslides during excavation work be prevented and avoided?
Protection techniques for trench excavation are no longer difficult to implement. Trench excavation is also a key focus of inspections by various organizations; if a collapse still occurs, it can no longer be considered an accident
In the southern regions, the groundwater level is high; often, additional support measures and dewatering methods using wells are required, making excavation relatively more difficult. Such a serious accident should not have happened in Zhengzhou. Our experience: if it is possible to create a slope, make the slope as steep as possible ； If there are no conditions for slope stabilization, do not focus on cost savings; instead, use professional support measures as much as possible ； The excavated soil should be kept at a certain distance from the foundation pit ； Provide access routes for easy entry and exit from the foundation pit.
The excavation plan is very important; the work may seem simple, but implementing safety measures is not easy. It’s possible that accidents such as landslides, water gushing out, falls, and broken underground pipelines could easily occur.
First, proper measures should be taken to stabilize the walls; second, the slope should be treated carefully. Third, the excavated soil must be piled up in accordance with relevant standards – it cannot be placed too close to the foundation pit nor at too great a height. Fourth, drainage measures should be implemented in advance, as collapses are usually caused by high groundwater levels.