Abstract:

A computational model of tunneling load in soilrock interbedded strata is devised to sufficiently design the thrust and torque parameters and efficiently regulate the construction parameters of superlargediameter slurry shield. According to the characteristics of the slurry shield, the load components are analyzed and a mathematical model of tunneling load is established. Next, the load computational model is numerically simulated using the soilrock interbedded strata model and the cutterhead geometry model. Finally, the model is validated using construction data from the bedrock region of the Su′ai tunnel in Shantou, China, and the influence rules of factors such as bedrock invasion height, rock strength, and penetration degree on cutterhead torque are examined. The results indicate the following: (1) The error between theoretical thrust by the model and the measured value is -6.4%~5.6% and the error between theoretical torque of cutterhead and the measured value is -9.5%~9.0%, demonstrating the high precision of the model and the ability to meet the actual needs of equipment design and engineering application. (2) The thrust and torque rise with an increase in bedrock intrusion height and penetration degree, where the torque is more sensitive to the change of rock intrusion height and penetration degree. (3) The torque increases by approximately 7% (the strength is 50~100 MPa and the penetration degree is 5 mm/r) as the uniaxial compressive strength of rock increases every 10 MPa. (4) When the penetration degree is high, the rising amplitude of cutterhead torque increases drastically as the rock intrusion height grows. (5) The torque increase caused by rock height increment near the cutterhead 1/2 position is the most substantial. The equivalent torque estimated based on bedrock intrusion height, rock invasion strength, and penetration parameters discovered during construction by geological prospecting can be regarded as the driving control parameters in construction.

Key words:  , superlargediameter slurry shield, tunneling load, rocksoil interbedded strata, mathematical model, numerical simulation, thrust, cutterhead torque