Safety Risk Control Technology of Urban Subway with Shallow Tunnel Construction Method

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‰.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.