Abstract:

The geological condition in Shenzhen is so heterogeneous that the shields to be used in Shenzhen should have special design and type selection requirements. In the paper, the characteristics of the design and type selection of two shields made by CREG used for No. 9 line and No. 11 line of Shenzhen rail transit system are presented. Special design is made for these two shields in order to solve such problems as cutterhead clogging, abnormal damage of cutterheads and cutting tools and jamming of cutterhead and shield shell. These shields have been used in the tunneling of Shenzhen rail transit system. Conclusions drawn are as follows: Regarding the heterogeneous geological conditions in Shenzhen, the shields designed should have good geological adaptability, enough driving torque, enough rock breaking capacity, good wearing resistance, good cutterhead clogging prevention capacity, good muck burst prevention capacity and good hyperbaric cutting tool replacing function. Furthermore, some proposals are made on shield boring management and shield design modification. 

Key words: Shenzhen rail transit system, heterogeneous ground, EPB (Earth Pressure Balanced) shield, design, type selection