Study on creep characters of anchorage body in soft rock tunnel

Abstract：Creep is a key factor to the application of bolts in weak rock.The creep rule of anchorage body was studied in soft rock under different stress level, by means of analogue experiment.Soft rock was analogue by the mixture of wax, sand and vansline, bolt by fuse and resign by gypsum.Step loading was applied.Based on experimental results, creep regular patterns and expirical formula were obtained in different stress level.The creep character was described in Burgers model, then creep mechanical function deduced.According to creep expirical foumula, the raitional support time is 1000 to 1500 minutes when stress level is 1.1 times by using viscid and elastic analyses.

Keyword：weak rock;anchorage body;creep;analogue experiment;