Modeling microtunnel boring machine penetration rate using a mechanistic approach

Predicting the productivity of microtunneling construction projects is challenging, due to the complexities of this trenchless excavation method. One of these complexities is estimating the microtunnel boring machine (MTBM) penetration rate due to the complex nature of the interactions between the MTBM and the ground. In the present study, a novel mechanistic approach based on the theory of contact mechanics is proposed to determine the underlying mechanics of the MTBM penetration rate. Using the proposed mechanistic approach, an analytical model of the MTBM penetration rate is developed, and a mechanistic relationship between the MTBM penetration rate and its influential factors, namely soil properties, operational loads, and cutterhead characteristics, is established. The proposed approach is expected to provide substantial mechanistic insight with respect to MTBM penetration rates by (1) modeling penetration rates of MTBMs into soils, (2) identifying the factors that influence penetration rates based on a fundamental theoretical approach, and (3) providing a useful tool for evaluating MTBM penetration rates based on the combined influences of ground properties, operational loads, and cutterhead characteristics.