Abstract: Taking a karst tunnel as the engineering background,according to the principle of elastic similarity,model tests are carried out to study characteristic of the internal forces of secondary lining of the concealed bottom water-filled empty cavity tunnel.The results show that when the concealed empty cavity of the bottom of the tunnel is filled by water,the axial force of the arch shoulder,side wall and wall foot is negative,the axial force of vault and invert is positive,and the wall foot has the...