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Integration of ground reaction curve and equilibrium strain approach in designing tunnel support system in weak rock masses
a Institut Teknologi Bandung, Bandung, Indonesia
[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]© 2018 ISRM & SRMEG (Singapore).Tunnel collapse in weak rock masses occurs when the support pressure given by the installed support system is not adequate to sustain the weight of broken rock resulting from the excavation. Further, installation of support system will encounter great difficulty when the maximum allowable limit of strain before setting up the support is exceeded. This paper presents the results of numerical simulations in computer code FLAC to integrate the use of ground reaction curve and equilibrium strain approach for designing tunnel support system in a non-circular excavation. The equilibrium strain is used as one of the design tools because the final radial deformation of a supported tunnel occurs at the equilibrium between the support and the deforming ground, not at the time of support installation. The approach is demonstrated on a large cross-section road tunnel that is excavated through weak rock masses with varying qualities. Results from the FLAC model show that when the time to install support system is correctly estimated at the equilibrium strain eq of 1%, the amount of vertical deformation and the extent of the plastic zone around the tunnel decrease significantly. This correct estimation is made possible with the help from the ground reaction curve (GRC). Moreover, as shown by the support capacity diagrams, the induced bending moment, axial and shear loads in the tunnel lining are well inside the strength envelopes of the support system with factor of safety > 1.5. Results from this research indicate that the integrated use of GRC and equilibrium strain approach can be used as a tool to achieve a reliable tunnel support design.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Equilibrium strain,Ground reaction curves,Induced bending moments,Large cross-sections,Radial deformation,Strength envelope,Tunnel support design,Vertical deformation[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Equilibrium Strain,Ground Reaction Curve,Support Capacity Diagram,Tunnel Support Design[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text][/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]