Axisymmetric Failure Mechanism of a Deep Cavity in Layered Soils Subjected to Pore Pressure

Three-Dimensional Upper Bound Limit Analysis on the Collapse of Shallow Soil Tunnels considering Roof Stratification and Pore Water Pressure

“…Further, Table 1 lists the corresponding calculation results of the two mechanisms. As can be seen from Table 1, when l 1 � 0, the calculation results in this paper are the same as those in Yang and Yao [23] and the corresponding two collapse mechanisms are consistent, thus verifying the validity of the proposed method in this paper.…”

“…On the contrary, when the burial depth H > H c , the failure of the soil masses will not penetrate the ground surface and the collapse arch may be formed inside the roof to resist the surrounding rock pressure from the soil masses above, thus presenting failure characteristics of the deep tunnel. For example, Yang and Yao [23] once adopted the nonlinear MC failure criterion to put forward the three-dimensional collapse mechanism of deep soil tunnels and investigated the influence laws of varying parameters on the collapse area of the tunnel roof. Accordingly, in order to verify the validity of the proposed method in this paper, we conduct the following comparison in this section based on the collapse characteristics of deep and shallow tunnels and Yang and Yao [23].…”

“…For example, Yang and Yao [23] once adopted the nonlinear MC failure criterion to put forward the three-dimensional collapse mechanism of deep soil tunnels and investigated the influence laws of varying parameters on the collapse area of the tunnel roof. Accordingly, in order to verify the validity of the proposed method in this paper, we conduct the following comparison in this section based on the collapse characteristics of deep and shallow tunnels and Yang and Yao [23]. Specifically, as shown in Figure 2, when the fracture width at the top of the collapsed soil masses is equal to zero, both sides of the collapsed surfaces intersect, thus forming a collapse arch within the roof surrounding soils.…”

“…Specifically, as shown in Figure 2, when the fracture width at the top of the collapsed soil masses is equal to zero, both sides of the collapsed surfaces intersect, thus forming a collapse arch within the roof surrounding soils. en, we can convert the mechanism proposed in this paper into that put forward by Yang and Yao [23]. Further, Table 1 lists the corresponding calculation results of the two mechanisms.…”

“…Other factors like the pore water pressure and ground overload also have a direct impact on tunnel failure and stability. Yang et al [23][24][25] as well as Qin et al [26][27][28][29] once incorporated the nonhomogeneous and stratified characteristics of the strata into their analysis of the roof collapse, which may provide a good theoretical basis for this paper; however, their research is only applicable to deep tunnels.…”