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Bolt into holes difficulties in view of the cohesive soil layer of soil tunnel construction methods , supporting opportunity , construction techniques , system Bolting effect , and high water content , poor grouting anti- pulling force , low defects , this article days Hengshan road tunnel project relying raised no system in the high moisture content of cohesive soil tunnel anchor , initial support using concrete reinforcing mesh shaped steel gantry (grid Gongjia ) injection locking pin anchor tube longitudinal connecting bars composed new Support Structure . In order to evaluate the force of this new type of supporting structure , deformation characteristics and reliability of the lining structure , through field tests and finite element simulation are two ways to do a comprehensive analysis of the surrounding rock and lining structure security , stability , economy . Field trials Ⅴ, Ⅵ level surrounding rock rely measurement including the initial support clearance convergence , arch sinking rock pressure and stress of sprayed concrete , steel gantry stress longitudinal connecting bar stress , initial support times lining contact pressure , the secondary lining concrete stress , steel stress of secondary lining and secondary lining clearance convergence . The monitoring results show no systematic bolts , tunnel support structure deformation and stress within the allowable range , initial support and secondary lining work in good condition , there are sufficient safety reserves . The application of finite element analysis software (MIDAS / GTS) analysis of the the Ⅵ level surrounding rock no deformation of the tunnel support system in case of system anchor force . The analysis results show that , the shotcrete and secondary lining structure with a large safety factor , the force of the anchor pipe steel arch with locking pin , the stability of the surrounding rock deformation . Site monitoring data and finite element simulation results show that The new support structure deformation and stress in the allowable range , the secondary lining in good working condition , there are sufficient safety reserves . To the Ⅵ level rock ( high water content clayey soil ) , for example , to cancel systematic bolts to 8.9 per cent of the project cost savings , can be shortened by about 10 % of the construction period .
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