Search

This research explores the potential for the evaluation and prediction of earth pressure balance shield performance based on a gray system model. The research focuses on a shield tunnel excavated for Metro Line 2 in Dalian, China. Due to the large error between the initial geological exploration data and real strata, the project construction is extremely difficult. In view of the current situation regarding the project, a quantitative method for evaluating the tunneling efficiency was proposed using cutterhead rotation (R), advance speed (S), total thrust (F) and torque (T). A total of 80 datasets with three input parameters and one output variable (F or T) were collected from this project, and a prediction framework based gray system model was established. Based on the prediction model, five prediction schemes were set up. Through error analysis, the optimal prediction scheme was obtained from the five schemes. The parametric investigation performed indicates that the relationships between F and the three input variables in the gray system model harmonize with the theoretical explanation. The case shows that the shield tunneling performance and efficiency are improved by the tunneling parameter prediction model based on the gray system model.

A multi-purpose prototype test system is developed to study the mechanical behavior of tunnel supporting structure, including a modular counterforce device, a powerful loading equipment, an advanced intelligent management system and an efficient noncontact deformation measurement system. The functions of the prototype test system are adjustable size and shape of the modular counterforce structure, sufficient load reserve and accurate loading, multi-connection linkage intelligent management, and high-precision and continuously positioned noncontact deformation measurement. The modular counterforce structure is currently the largest in the world, with an outer diameter of 20.5 m, an inner diameter of 16.5 m and a height of 6 m. The case application proves that the prototype test system can reproduce the mechanical behavior of the tunnel lining during load-bearing, deformation and failure processes in detail.