Abstract:

In order to effectively reduce the damage degree of the shield cutter caused by boulder or bedrock encountered during shield tunneling in complex marine strata, reduce the construction risk and improve the construction efficiency, the distribution law of boulder and bedrock of marine water conveying tunnels #1 and #2 of Taishan Nuclear Power Station is determined by geological drilling and geophysical exploration, and the treatment of drilling blasting on land and sea surface is formulated. The driving parameters of the shield, i.e. driving speed, driving time per cycle and driving force, before and after blasting of boulder and bedrock section are compared and analyzed. The analytical results show that: (1) After blasting of the bedrock section, the driving speed of the shield is increased by 68.2%, the average driving time per cycle is reduced by 45.1%, and the average driving force is reduced by 11.5%. (2) The driving parameters of the shield in blasting section and normal tunneling section of the boulder group section are basically the same. (3) The blasting of the boulder group and bedrock has achieved the expected effect, which eliminates the threat of bedrock and boulder group to shield tunneling, and ensures the smooth construction of shield tunneling.

Key words: marine strata, boulder and bedrock, blasting treatment, slurry shield, driving parameter