The engineering geological characteristics of the
waterrich moraine Milin tunnel on LhasaNyingchi
railway, causes of collapse, and corresponding countermeasures are studied in
detail. The research results show the following. (1) The waterrich moraine stratum in the plateau is characterized by good water
permeability and is prone to frost heaving at low temperatures. The shear
strength increases with the increasing rock content and density of surrounding
rocks, and decreases with the increasing fine particle content and water
content of surrounding rocks. The surface water and groundwater have strong
effects on the immersion, softening, migration, and destruction of surrounding
rocks. (2) The interaction between the high content of fine particles in the
moraine stratum and the development of groundwater would cause an instability
in the surrounding rock, and further cause the tunnel to collapse. (3) Grouting
reinforcement should be strengthened in the area of backfilling of the ballast
body and surrounding rock overhead, a safety arch protection and cavein drainage system should be set up, and rational excavation and support
methods should be adopted.
CHEN Tianming
. Causes and Countermeasures for Collapse in a WaterRich
Moraine Tunnel in a Plateau Area: a Case Study on
Milin Tunnel of LhasaNyingchi
Railway[J]. Tunnel Construction, 2021
, 41(2)
: 274
-282
.
DOI: 10.3973/j.issn.2096-4498.2021.02.014
