Underground structures are currently widely used and are built as urbanism develops. The interactions between perpendicularly crossing and parallel tunnels in the Tehran region are investigated by using a full three-dimensional (3D) finite difference analysis with elastic-plastic material models. Special attention is paid to the effect of subsequent tunneling on the support system, i.e., the shotcrete lining and rock bolts of the existing tunnel. Eventually, as the tunnels are excavated at certain levels, the interaction between the tunnels will certainly have a significant influence on both stress distribution and consequently deformations. Since multilayer tunneling is a three-dimensional phenomenon in nature, 3D numerical solutions must be utilized for analyzing effect of perpendicularly crossing tunnels at various levels. As Tohid twin tunnels and Line 7 pass beneath the Line 4 metro tunnel, changes in stress distribution, deformations, and surface settlements are studied for various conditions and the results are presented in this paper. Consequently, it is shown that there is a significant interaction between tunnels that necessitate certain preventive measures to maintain a stable tunneling operation.
Underground structures are currently widely used
and are built as urbanism develops. The interactions between
perpendicularly crossing and parallel tunnels in the Tehran
region are investigated by using a full three-dimensional (3D)
finite difference analysis with elastic-plastic material models.
Special attention is paid to the effect of subsequent tunneling on
the support system, i.e., the shotcrete lining and rock bolts of
the existing tunnel. Eventually, as the tunnels are excavated at
certain levels, the interaction between the tunnels will certainly
have a significant influence on both stress distribution and
consequently deformations. Since multilayer tunneling is a
three-dimensional phenomenon in nature, 3D numerical solutions
must be utilized for analyzing effect of perpendicularly
crossing tunnels at various levels. As Tohid twin tunnels and
Line 7 pass beneath the Line 4 metro tunnel, changes in stress
distribution, deformations, and surface settlements are studied
for various conditions and the results are presented in this
paper. Consequently, it is shown that there is a significant
interaction between tunnels that necessitate certain preventive
measures to maintain a stable tunneling operation.
