This study aims to solve the problem of the frequent TBM jamming caused by the large squeezing deformation of surrounding rock around the water diversion tunnel from Datong river into Huangshui river in Qinghai province. Based on the constitutive model of squeezing deformation and the shield jamming prediction theory

we developed a procedure to calculate squeezing deformation and shield jamming. The main conclusions are drawn as follows. When TBM advances through F5 fault section and the overcut gap is 10 cm

the friction on the shield reaches the maximum thrust supplied by the propulsion system

which may result in shield jamming. As the growth of the downtime

the squeezing deformation

the contact area between surrounding rock and shield

and the friction on the shield increase with the stoppage. The growth rate is getting greater on the first day. However

the creep rate of surrounding rock and its friction growth rate decrease from the seventh day. The interaction between surrounding rock and shield reaches a balance until the thirteenth day

and the friction on the shield becomes stable. The above results are consistent with observed data in the field. Furthermore

to prevent and control shield jamming

we provide the following advice for optimal overcut and permissible downtime for further tunnelling. The over gap should be larger than 15 cm

under which the shield will not be jammed at the tunnelling unloading instant

and the permissive downtime is 2 days. When the overcut increases to 18 cm

the allowable stoppage is 4 days. While the over gap reaches 20 cm

shield jamming will not happen on the whole within 7 days under the surrounding rock condition

which also can be easily overcome. These control measures are substantially significant in the safety and efficiency of TBM tunnelling

which are also verified by the engineering practice.