The mountain tunnel drainage may change the ambient
groundwater seepage field and even drain groundwater resources, which threatens
terrestrial vegetation. In order to quantitatively analyze the impact of tunnel
drainage on terrestrial vegetation, the soil water matric potential is selected
as an indicator for plant survival state to build an analysis model of tunnelsoilplantatmosphere continuum (TSPAC). In the
model, the Richards equation is utilized to describe the moisture movement in
the root zone. The atmosphere and the groundwater seepage model are input to
the Richards equation as top and bottom boundary conditions. Then, the soil
matric potential distribution of the root zone is secured by solving the
Richards equation. Based on matric potential distribution within the root zone,
the plant dynamic wilting process can be evaluated and its survival state can
be judged. The method is applied to Mingtangshan Tunnel in Dabieshan Mountains
to analyze its drainage impact on terrestrial vegetation. The applicable
results show that: (1) The response of matric potential in the plant root zone
to variations in groundwater levels and atmospheric conditions is lagged and
nonuniform, thus the plants wilt gradually instead of withering immediately
after the groundwater table descends. (2) The atmospheric conditions play the
dominant role in vegetation survival in this region. (3) The drainage impact of
the tunnel on surrounding plants is relatively small and different for various
vegetation. The TSPAC analysis method innovatively introduced tunnelgroundwater seepage model to traditional SPAC models. By integrating
factors that represent tunnels and environment, the approach analyzed the whole
process of “tunnel drainagegroundwater
recessionvegetation withering”.
The method integrates tunnel, soil, vegetation and atmosphere as a whole to
analyze the ecoenvironmental impacts of tunnel
drainage. The approach can provide a novel thought of facilitating tunnel
engineering environmentally friendly.
LI Xiaojun
,
XU Hao
,
GOKDEMIR Cagri
,
WANG Fei
,
HUANG Xuewen
.
TSPAC Analysis Method for Impact of Groundwater
Drawdown Induced by
Tunnel Drainage on Terrestrial Vegetation
[J]. Tunnel Construction, 2020
, 40(9)
: 1261
-1271
.
DOI: 10.3973/j.issn.2096-4498.2020.09.003
