In this study, the technical schemes of rectangular
pipe jacking machine in different composite strata are discussed. Based on the
underpass expressline tunnel project at Tiangong
Palace in Chongqing, China, the design and application of key systems such as
excavation and mucking of rectangular pipe jacking machines in soft soil and
rock composite strata are introduced. A layered excavation method for composite
strata is proposed for the first time, and a blind area excavation device (rockbreaking roller) is developed. Based on finite element and
industrial test analysis, the feasibility of the layered excavation method of
composite multicutterhead + roller is verified, realizing the highefficiency cutting of 30MPa rock strata in
the blind area and successfully implementing rectangular pipe jacking in fullface composite strata of soft soil and rock. Meanwhile, the combined
mucking technology of the roller and the screw conveyor is developed for mixing
and mucking in the lower part of the excavation chamber in composite formation.
The mucking characteristics of the roller are analyzed based on computational
fluid dynamics. The results show that the maximum mucking efficiency is
achieved when the twinscrew 〖JP2〗mucking structure is adopted with a distance of ~900 mm〖JP〗 between the two screws. Finally, the
feasibility of layered excavation and combined mucking technology in composite
formation is validated through an industrial test, presenting a new solution
for the application of rectangular pipe jacking machines in composite formation.
FAN Lei
,
XUE Guangji
,
SHE Yuebin
,
CHEN Wentao
,
FENG Meng
. Key Technologies of Rectangular Pipe Jacking Machine in
Composite Strata and Its Application in Tiangong Palace
Underpass ExpressLine Project in Chongqing, China[J]. Tunnel Construction, 2023
, 43(9)
: 1605
-1613
.
DOI: 10.3973/j.issn.2096-4498.2023.09.018
