Study on Impact Grab Ultra Large Diameter Drilling in Deep Gravel Boulder Formation and the Application

Abstract:

The paper presented the application of cone grab in grabbing gravel footage and combining with rotary drilling technology for ultra drilling in bored shaft with diameter of 8.3m and depth of 285m, and introduced the parameter selection for grabbing equipment, grabbing process and the determination of technical parameter.

Key words:gravel boulder; ultra large diameter drilling; drilling construction; grabbing process