Page 167 - Water Standards
P. 167

3   5   3  The lining of in⁃situ concrete shall be in accordance with the
                       following requirements:
                           1  The construction procedure of lining. The operations of tunnel
                       lining and excavation can be carried out in the same sequence or in
                       parallel and overlapping way, to be decided according to specific a⁃
                       nalysis of the factors of tunnel length, section size, surrounding rock
                       characteristic, construction equipment and construction period re⁃
                       quirement.
                           2  Concrete lining subsection. The subsection of concrete lining
                       shall be decided according to comprehensive analysis of the
                       surrounding rock condition, concrete supply capability, lining speed
                       and form structure, as well as the requirement of hydraulic structures.
                       When there is no design regulation, a length of 9-15m can be adopt⁃
                       ed.
                           3  Concrete blocking. The blocking of tunnel lining sections
                       shall be decided according to conditions such as the surrounding rock
                       condition, tunnel  section  shape  and  size, form  structure,
                       construction method and organization.
                             1) Lining the whole section in one time: suitable for tunnels
                                with small and medium⁃sized sections, with high speed
                                lining and good geological conditions. When the geological
                                conditions are bad, shotcrete⁃bolt support can be done be⁃
                                fore the whole section lining (secondary lining).
                             2) Two parts divided into as bottom arch, side wall and roof
                                arch: pouring the bottom arch before the side and roof arch
                                is suitable for various kinds of section tunnel with good ge⁃
                                ological condition. Pouring of side wall and roof arch
                                before the bottom arch is suitable for various geological
                                conditions and large section tunnels.
                             3) Four parts divided into as roof arch, two side walls and
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