To investigate the cracking characteristics of combined hydraulic tunnel linings with drainage board,a theoretical for-mula of multi-layer thick-wall cylinder model was derived.Based on a hydraulic tunnel in Pearl River water resources alloca-tion project,the stress analysis on combined linings with fully laid drainage board and without board installed was performed com-paratively.A numerical model based on LUSAS was established,and the deformation and stress evolution characteristics of steel tube and the cracking characteristics of self-compacting-concrete were investigated by using the plastic damage multi-crack concrete constitutive model.The results demonstrate that the steel tube without drainage board only bears a minor amount of inter-nal water pressure under the elastic state,while the steel tube with a full drainage plate bears one-third of internal water pres-sure,and the self-compacting-concrete has reached the fracture level.The cracking nonlinear analysis showed that the maxi-mum displacement of the steel tube was located at the waist near the end of the drainage board after damage and cracking of self-compacting-concrete take place,and the stress of the steel tube in the laying area reacheed one-third of the yield strength,which did not full play its total bearing capacity.The propagation of cracks in self-compacting concrete can be broken down into four stages:elastic stage,crack initiation stage,expansion stage,and wave stage.The new crack will quickly penetrate and cause two adjacent slight cracks close.The through-cracks are mainly located in the drainage board area.
维普
万方数据