A　variety　of　construction　problems,　such　as　bad　cutting　effects　of　cutters,　unreasonable　boring　parame-　ters　and　blowout,　are　often　encountered　during　shield　tunnelling　under　unfavorable　geological　conditions.　Aimed　at　these　construction　difficulties　of　high　pressure,　abundant　underground　water,　fractured　rock　stratum,　long　distance　and　small-radius　curves　of　Fuzhou　metro,　the　mechanical　behaviors　of　cutting　tools　were　analyzed　through　theoreti-　cal　calculations　of　cutter　cutting　force,　then　the　reasonable　cutter　configuration,　tunneling　parameters　and　the　proper　time　for　cutter　replacement　were　presented.　Some　measures,　such　as　screw　conveyor　renovation,　mucking　control　and　lowering　of　groundwater,　were　adopted　for　controlling　blowout　based　on　practice.　The　stability　of　excavation　face　was　analyzed　by　numerical　simulation,　and　the　measures　for　shield　boring　and　posture　control　in　the　long　distance　and　small　radius　curved　tunnels　were　summarized.　The　conclusions　are　as　follows:　1)　when　shield　machine　is　driven　in　fractured　stratum,　the　effect　of　lateral　impact　force　produced　by　spalling　rock　on　cutter　will　be　very　large　and　rein-　forcement　is　needed　for　cutter;　2)　cutter　replacement　should　be　taken　at　proper　time　based　on　muck　samples　in　con-　ditions　of　increasing　of　total　shield　thrust　by　4　000-7　000　kN,　cutter　torque　by　1　000-1　500　kN•m　and　driving　speed　smaller　than　10　mm/min;　3)　adopting　screw　conveyor　device　with　innovative　anti-blowout　devices　and　control　measures　for　ground　precipitation　and　mucking,　it　controls　blowout　effectively;　4)　the　maximum　axis　offset　and　the　height　offset　of　segment　meet　the　requirements　of　shield　construction　specifications　during　shield　construction　of　long　distance　small-radius　curved　tunnel.　©　2018,　Editorial　Office　of　＂Modern　Tunnelling　Technology＂.　All　right　reserved.