| 摘要 |
896,096. Tunnel linings. MORGAN, H. D. June 5, 1958 [July 1, 1957], No. 20759/57. Class 85. A tunnel lining 1 is made up of an invert 11 and a series of pre-cast, interlocking concrete blocks 2, the upper and lower portions of the lining being separated by jacking blocks 15, 15<SP>1</SP> having slots 16, 16<SP>1</SP> for the jacks and the eventual reception of concrete. The lining may be provided with a side opening 18 by incorporating temporary blocks therein and special blocks 19 having recesses 20, shear pins and tie bars 23, see also Fig. 4 (not shown). |
