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Abstract Based on the construction need of shield cutting 14 large-diameter bridge piles in Suzhou subway，the field test of shield cutting two 1 200 mm diameter piles was carried out；the effect and mechanism of cutting piles，characteristics of cutting parameters and damage law of cutting tools were analyzed. Then，the feasibility and key technology of cutting large-diameter piles were studied. The test results show that shell cutter can be fit for cutting pile directly；it breaks concrete by the way of shear cutting and laterally squeezing to fracture；and its working mechanism of cutting rebar is shear cutting. The wrapped condition of rebar by surrounding concrete is the key factor determining whether rebar could be cut off effectively. The thrust value and torque value which acting on the pile have an approximately linear relationship with penetration. The alloys of cutting tools are easily cracked because of great fluctuation amplitude of advancing speed. Cutting side pile produces more damage on cutting tools than cutting central pile. According to test results，the configuration scheme of advancing shell cutter and the concept of cutting rebar with different times were presented；the setting value of advancing speed was suggested against exceeding 2 mm/min，and the cutterhead should rotate with medium speed. The test results were successfully applied to the Suzhou cutting piles engineering；the test and engineering practice jointly indicate that shield cutting large-diameter piles directly is feasible.
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Received: 20 February 2013
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2013, Vol. 32 
