To realize efficient drainage of water-rich
tunnels in high-altitude environments and ensure
construction safety and progress, the extra-long
Milashan tunnel of the Nyingchi-Lhasa highway in Tibet,
China is investigated. The characteristics of water inflow in high-altitude water-rich tunnels, efficiency
reduction characteristics of pumping and drainage machinery, and principle of
equipment selection and configuration are analyzed through theoretical analysis
and field tests. The pumping and drainage scheme of the main tunnel drainage
assisted by an inclined shaft is designed, and the displacement and pump head
are calculated. The results show the following: (1) the Milashan tunnel passes
through a water-rich fault, and there is a large volume
of water inflow, long water inflow time, and uneven water distribution; and (2)
highaltitude environments affect pumping and drainage
machinery and equipment. The test results show that the maximum output power of
the generator set and pumping unit is only 66.2% and 90% of the rated power,
respectively. Therefore, three levels of fixed pump stations are set in the
construction section of the main tunnel assisted by the inclined shaft, and the
pumping equipment of the pump station is composed of pumps and booster pumps of
different power. Matching calculations show that the selection of water pipes
and the pump head meet the requirements.
YANG Yang
,
TANG Ke
,
GONG Bin
,
YAN Jian
,
WANG Bo
. Drainage Technology of Main Tunnel Construction
Assisted by Inclined Shaft in High-Altitude Water-Rich Tunnels: a Case Study on
Extra-Long -Milashan Tunnel of
Nyingchi-Lhasa Highway in Tibet, China[J]. Tunnel Construction, 2021
, 41(12)
: 2171
-2177
.
DOI: 10.3973/j.issn.2096-4498.2021.12.019
