(1. Tunnel and Underground Engineering Research Center of Ministry of Education,Beijing Jiaotong University,Beijing 100044,China;2. China Railway Shisiju Group Corporation,Tai¢an,Shandong 271000,China)
Abstract:Based on the Nanjing Yangtze River slurry shield tunnelling project,the investigations on the subsidence,horizontal displacement of soil,earth pressure and pore water pressure are conducted by setting up corresponding equipments. Then,the underlying laws,influential range,and influence degree for soil disturbance exerted by different stages of slurry shield tunnelling are analyzed. In addition,according to the stress variation in soil,the relevant mathematical relations between stress disturbances degree and distances are proposed;and it is found that the shield driving can affect stress disturbance of soil(disturbance degree is larger than 5%) at a range of 16 m from shield(approximately the hole diameter). After that,based on field test data,the Peck formulae are improved by establishing the mathematical model of hydraulic pressure on kerf,the synchronous grouting pressure,and ground subsidence. The model gives better prediction on subsidence caused by slurry shield tunnelling. Finally,with careful consideration on shield tunnelling data,some measures to reduce soil disturbance are also presented.