Study On The Mechanism And Model Of Damage Of Lining Structure Under High Hydraulic Pressure In Mountain Tunnel

The lining of deep mountain tunnels would have to bear high water pressure acrossthe water-rich area inevitably, especially water-drainage pattern. Under the influence ofvarious environmental factors, the deterioration of mechanical properties of concretelining would be affecting its service performance. The factor of high water pressurewould be different mechanism compared to other loads. High hydraulic pressure inmountain tunnel concrete lining there is significant coupling between seepage andstress and damage. External water pressure and water to its permeability effect wouldhave a negligible impact to the damage of concrete. Researches on this paper are asfollows:â‘ According to constitutes a scientific and reasonable damage theory of fourelements, represent an analysis of damage mechanism of concrete structures; From amacroscopic and mesoscopic analysis of damage mechanism of concrete structure,based on typical stress-strain curves of concrete developmental stages of damageevolution of concrete structure that divides the linear elastic stage, nonlinear hardeningstage, divided into stages of stress drop and strain-softening stage; Thought on themeso-damage of concrete structure and its inhomogeneities and have strong relevanceto dehydration shrinkage in hardening process.â‘¡Under the action of water penetration through concrete permeability, waterpercolation of concrete fracture system and the interaction between the water and theconcrete research on the seepage field of concrete, and proposed formula of initialpermeability coefficient of concrete fracture systems. On permeation properties ofconcrete using a meso-macro analysis, and on the basis of the typical stress-straincurves of concrete permeability coefficients of divided in four phases, namely elasticstage of densification, compaction stage of stability, and softens the plastic jump phaseto level off; Building seepage-stress coupled model and a coupled seepage-damagemodel for osmosis damage characteristics of concrete structures under water pressure.â‘¢Based on deeply buried mountain circular tunnel lining the plane strainassumptions, use of external water pressure reduction coefficient calculation method tocalculate the external water pressure, establishment of external water pressuredistribution in concrete lining of formula; Proposed formula of internal water pressure on lining. Characterization by double scalar damage variables establishedElasto-plastic damage model of concrete structures, through the formula for Planarpolar coordinates the establishment of lining-damage coupled model of seepage-stress,based on previous studies, amending the coupled governing equations; And through theABAQUS finite element analysis software to analyze and validate the model, themodel can be used for concrete lining in the injury determination, provide technicalsupport for the maintenance of tunnel lining.