为了控制暗挖施工带来的环境风险,提出了以控制地层变形为核心,以保证既有结构安全为目的的风险管理体系.该体系包括:既有结构现状评估、施工影响预测、控制方案制定、监测反馈及工后评估与恢复,在目前国内最大的暗挖地铁换乘车站——北京地铁黄庄站得到了应用,从技术上保证了环境安全.根据监测数据,10号线双层段最终地表沉降全部控制在80 mm以内,其中控制在64 mm以内的测点占总测点数的93.6%;管线测点沉降值全部小于30 mm,最大差异沉降为1.123‰.表明风险控制中制定的控制标准是合理的,施工中采取的措施是有效的.
In order to guarantee environmental safety, risk management system which aims at ground settlement control and existing structure protection is proposed. It includes 5-stage technology-based steps: the current state evaluation of existing structures, forecast of construction effect, control schemes made, process control during construction and assessment & recovery after construction. This system is put into practice in Huangzhuang station, the biggest urban subway by using shallow tunnel method in China. Ground surface settlement of line 10 is successfully controlled within 80 mm, while 93.6% measuring points are controlled within 64 mm. The settlements of pipeline are below 30 mm and the max differential settlement is 1. 123%o. This risk control system works well in environment safety, structure safety and construction safety. Control standards are reasonable and the measures taken in construction are effective.