Abstract Squeezing of weak rock is essentially associated with creep caused by exceeding a limiting shear stress.
In case of high in-situ stress, large deformation of surrounding rock may occur. During the deformation, a so called“genuine rock pressure”builds up and acts on the support structures according to“convergence-confinement”model. The load jointly borne by support and rock mass is different from the“discrete pressure”due to weight of discrete body and it might be called“genuine pressure”. Restrained by the understanding of discrete pressure load, it is difficult to find the reasonable means to deal with squeezing deformation. Several issues of the tunnel in squeezing rock mass are discussed in terms of the characteristics of genuine pressure, and it points out that the feasible solution in heavily squeezing ground is to release the genuine rock pressure by application of a yielding support system in combination with a certain amount of over-excavation, whereas the amount of over-excavation may be reduced by use of untensioned rock bolts.
Abstract：
Squeezing of weak rock is essentially associated with creep caused by exceeding a limiting shear stress.
In case of high in-situ stress, large deformation of surrounding rock may occur. During the deformation, a so called“genuine rock pressure”builds up and acts on the support structures according to“convergence-confinement”model. The load jointly borne by support and rock mass is different from the“discrete pressure”due to weight of discrete body and it might be called“genuine pressure”. Restrained by the understanding of discrete pressure load, it is difficult to find the reasonable means to deal with squeezing deformation. Several issues of the tunnel in squeezing rock mass are discussed in terms of the characteristics of genuine pressure, and it points out that the feasible solution in heavily squeezing ground is to release the genuine rock pressure by application of a yielding support system in combination with a certain amount of over-excavation, whereas the amount of over-excavation may be reduced by use of untensioned rock bolts.
WANG Jianyu
.The Key Way is to Release the Genuine Rock Pressure—Discussion on Problems of Tunnelling in Squeezing Ground[J] MODERN TUNNELLING TECHNOLOGY, 2020,V57(4): 1-11
2020, Vol. 57 