Research On EPB Shield Tunnelling Technique In Water-rich Cobble Ground In Nanchang

In company with scale-up of the Metro engineering construction at home, various safety violations happened in construction process have caused wide public concern over the recent years.The situation of construction safety in Metro engineering is hardly optimistic. There were a number of construction risks in Nanchang Metro engineering construction which adopted shield tunneling method. Based on the background of study on construction safety technologies in Water-rich Cobble Ground in Nanchang Metro engineering construction, a research was carried out to summarize the safety control techniques for lowering construction risks and avoiding safety violations in tunneling construction of the 6th contract section of Nanchang Rail Transit Line 1. The detailed works are as below.1. According to stratum adaptive conditions of different shield machine types and hydrogeological environment of the 6th contract section of Nanchang Rail Transit Line 1, type selection and parameters of shield machine was confirmed, and its cutter heads and cutters were designed with adaptability.2. According to geological conditions, the main parameters of shield machine were verified and compared with nominal parameters of the original design to confirm validity and adaptability of the type selection.3. By analyzing construction difficulties, pressure-keeping pump mucking technology, secondary grouting technology and high polymer injection system technology with independent intellectual property rights were proposed to deal with them. Key tunnelling technologies of safety control were investigated and summarized systematically.4. Combined with actual engineering case, causes of safety violation in the left line tunnel were investigated by doing statistical analysis and comparing the tunnelling parameters of the left line against the right line in environmentally-sensitive area which along the provincial government. Reasonable range of parameters concerning tunneling construction safety was put forward. Additionally, the operation and control effect of tunnelling safety control technique on project entity were analyzed to testify that tunnelling construction technique can provide references for later projects.