Construction Plan of Parallel Porous Small Clear Distance Tunnel Based on Analytic Hierarchy Process
To address the problem of selecting construction schemes for parallel multi-hole tunnels with small clear spacing,a hierarchical analysis method was applied to establish an evaluation system for the construction of parallel multi-hole tunnels.The system took into account the various influencing factors involved in tunnel construction.Weight values for each influencing factor were calculated,and numerical simulation results from finite element software were used to compare and analyze different construction schemes for parallel multi-hole tunnels.The study shows that,in the ranking of influencing factors for construction schemes with different numbers of holes in the same tunnel,displacement control is the main factor with a weight of 0.103 8.The subsequent factors,in descending order of weight,are blasting vibration,operation and maintenance factors,construction cost,cross-section size,and support measures,with calculated weights of 0.070 5,0.065 4,0.029 2,0.016 3,and 0.011 4,respectively.The finite element calculation results reveal that the final displacement values at various observation points increase with the grade of surrounding rock.Under the same grade of surrounding rock,the settlements of the crown and the upward bulge of the invert are larger in a two-hole tunnel compared to a four-hole tunnel,while the displacements of the left and right sidewalls are smaller in a two-hole tunnel compared to a four-hole tunnel.
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