Analysis Of Split Lining Structure Bearing Capacity And Model Test Study On Large Scale

With the expanding range of high-speed road network,China has gradually become the country of greatest demand for conservation in tunnel engineering instead of the country of largest and fastest-growing in tunnel engineering in the world.The massive project instances have indicated,by the influence of topographical condition,survey and design,construction quality,load condition and so on,lining appears cracking,which could not only affect the capacity of structure bearing,but also raise the secondary disease evil of structure such as leading the block falls and water leaks from lining when the highway tunnel in operation.Reling on “disease tunnel model test technology and system research and development”,which is of the specific content of applied basic research project of the Ministry of transport,this article studies on bearing capacity of tunnel lining structure with crack by methods including theoretical analyses,large scale model test and numerical simulation.The main content of this paper is divided into the following aspects:First,existing statistical analysis on lining cracks of highway tunnel shows that fracture distribution density of holes figure larger than the entrance.In various shapes crack,the number of circumferential crack is in the largest proportion.In the cross section of the lining,cracks is more probably distributed in the arch.Second,based on similar principles,this paper drawed up the mixture ratio of similar material and considered sand,cement,gypsum and water as the material of the physical model by strength tests of sample.According to the size of highway tunnel under V level of adjacent formation,this paper formulated the size of lining sample according to 1:10 of the zoom scale.Third,by carring on the physical model loading test to the non-destructive lining work as well as the lining with cracks,the result indicated that damage displacement and damage load of measuring points of the linig with cracks relative to the non-destructive lining,and there is a obvious downward trend when the vault crack depth achieves 20% of the lining sample thickness.Forth,by establishing numerical models through finite element software ANSYS corresponding to the physical test models and taking comparative analysis to them,the result indicated that there is few difference in vault damage displacement and vault damage load between numerical models and physical test models,and the rules are basically same.Fifth,this paper established lining numerical mode with different depth cracks in vault and waist lining numerical model to study on bearing performance of lining with cracks.Research indicates that:With the increase of crack depth,vault damage displacement and vault damage load are a clear downward trend and fell by 78.20% and 78.17% relative to non-destructive lining respectively when the vault crack depth is less than 20% of the prototype lining thickness.As the crack depth increases,the above two downward curve is gentle when the vault crack depth achieves 20% of the prototype lining thickness.Relatived to the non-destructive lining,the drop of vault damage displacement and vault damage load are grim and fell by 50.26% and 50.29% respectively when the vault crack depth achieves 4% of the prototype lining thickness.The drop slope of vault damage displacement and vault damage load has reduced when the waist crack depth exceed 4% of the prototype lining thickness.The residual strength of lining with vault crack whose depth achieves 4% of the prototype lining thickness is 16.36% of the non-destructive lining,and as the crack depth increases to 40% of the prototype lining thickness,the residual strength decrease to7.73% of the non-destructive lining.The residual strength of lining with waist crack whose depth achieves 4% of the prototype lining thickness is 33.64% of the non-destructive lining,and as the crack depth increases to 40% of the prototype lining thickness,the residual strength decrease to 9.09% of the non-destructive lining.With the increase of crack depth,the drop of the residual strength of the lining with waist crack are grim,and there is low diversity in residual strength compared with the lining with vault crack when the crack depth achieves 4% of the prototype lining thickness.