Impact of Conditioned Soil Parameters on Tool Wear in Soft Ground Tunneling

摘要

The use of mechanized shielded tunnel boring machines (TBMs), has grown rapidly in various soft ground tunneling projects. In the recent years, Earth Pressure Balance (EPB) shields have been successfully used in many tunneling projects in urban areas while the range of soil types that it can handle has expanded. One of the critical issues for successful EPB tunneling is the use of proper soil conditioning. The effects of soil abrasiveness on primary and secondary wear of tools and machine components is one of the most important aspects of soft ground tunneling, estimation and assessment of, costs, and schedule of a project. Among the parameters that can affect tool wear, soil conditioning is the most critical one that can be controlled by the operators. To assess the impact of the soil conditioning on tool wear, a new test apparatus with new propeller has been developed. Specific test procedure has been developed and many tests have been conducted. Review of the initial test results shows that soil conditioning reduces wear of tool and other machine parts. More tests are underway to evaluate the effect of soil conditioning on machine torque requirements through a parametric study.