Cutting device with function of changing diameter in small range for soft rock shield machine

A cutting device for a tunnel boring machine, comprising:

• a cutting head having a plurality of grooves radially formed thereon;
• a plurality of peripheral cutters mounted on said cutting head at outer end portions of said grooves, wherein every two of said peripheral cutters are symmetrically mounted on said cutting head at two sides of one of said grooves correspondingly, such that said outer end portion of each of said grooves is located between two of said peripheral cutters;
• at least one peripheral cutter driving mechanism provided on said groove, wherein said peripheral cutters are connected with said peripheral cutter driving mechanism;
• a hydraulic control system driving said peripheral cutter driving mechanism to move, so as to drive said peripheral cutters to move correspondingly;
• and
• a monitoring system which comprises a detection probe provided on said cutting head and an alarm device linked to said detection probe, wherein said detection probe and said peripheral cutters are made of the same material and have the same material strength and properties, wherein during cutting operation of said peripheral cutters, said detection probe has the same wear ability of said peripheral cutters, such that when said detection probe is worn over a predetermined threshold, said alarm device is arranged for generating an alarm signal to protect said peripheral cutters being totally worn off.