6
a critical value for settlement (EN 1997-1 2004). As illus-
trated above, after flooding the underground infrastructure
and rock mass, the downward movement is replaced by an
upward movement. In most cases, the maximum upsidence
is at a different location than the maximum subsidence
(Vervoort 2020b). Therefore, the curvatures for the sub-
sidence and upsidence profiles are different, meaning that
the tilt and induced strains are different. It also means that
the upward movement is not simply a rebound of part of
the downward movement. In conclusion, there is a great
variety and sequence of absolute and relative movements,
rotations and tilt, etc. All these phenomena induce stresses
and strains in structures (Boscardin and Cording 1989).
When studying damage to buildings and infrastructure, the
cumulative amount of the induced stresses and strains must
be taken into account. That is why a relatively small addi-
tional movement, e.g., in the upsidence phase, is sufficient
to induce new fractures, because in the previous phases a
certain amount of stresses and strains have already been
stored in the structure, but which did not lead to damage
in the previous phases.
Some examples of damage to buildings during the phase
of upsidence can be found in the literature (e.g., Baglikow
2011 Dudek et al. 2021 Vervoort 2022b). Three examples
of damage are shown below (Figures 6 to 8), which are
within the mined zone presented in Figure 3. The typical
damage for each case is illustrated with three images. The
variation of the vertical and of the horizontal movements
for the 4 data points closest to the building or road section
are presented as a function of time. The minimum, average
and maximum movement values of these four data points
are shown as a function of time (6 days frequency). These
graphs present the movements for the period 2016–2021,
available in the EGMS database (Costantini et al. 2021).
Only this database (of the three available for the study)
includes vertical and horizontal movements. The main
Figure 5. Vertical surface movements over 5-year periods along a north-south transect at a longitude of 5.495°. a. European
C-band ERS1/2 satellite images, period from June 1995 through June 2000 b. ENVISAT-ASAR satellite images, period from
August 2005 through August 2010 c. Interferometric C-band SAR Sentinel-1 images, period from November 2016 through
November 2021. (black dotted lines: mining limits in N and S blue dotted line: border between the two mines stars: average
position of double central shafts (Winterslag in purple and Zwartberg in brown)
(a) (b)
(c)
a critical value for settlement (EN 1997-1 2004). As illus-
trated above, after flooding the underground infrastructure
and rock mass, the downward movement is replaced by an
upward movement. In most cases, the maximum upsidence
is at a different location than the maximum subsidence
(Vervoort 2020b). Therefore, the curvatures for the sub-
sidence and upsidence profiles are different, meaning that
the tilt and induced strains are different. It also means that
the upward movement is not simply a rebound of part of
the downward movement. In conclusion, there is a great
variety and sequence of absolute and relative movements,
rotations and tilt, etc. All these phenomena induce stresses
and strains in structures (Boscardin and Cording 1989).
When studying damage to buildings and infrastructure, the
cumulative amount of the induced stresses and strains must
be taken into account. That is why a relatively small addi-
tional movement, e.g., in the upsidence phase, is sufficient
to induce new fractures, because in the previous phases a
certain amount of stresses and strains have already been
stored in the structure, but which did not lead to damage
in the previous phases.
Some examples of damage to buildings during the phase
of upsidence can be found in the literature (e.g., Baglikow
2011 Dudek et al. 2021 Vervoort 2022b). Three examples
of damage are shown below (Figures 6 to 8), which are
within the mined zone presented in Figure 3. The typical
damage for each case is illustrated with three images. The
variation of the vertical and of the horizontal movements
for the 4 data points closest to the building or road section
are presented as a function of time. The minimum, average
and maximum movement values of these four data points
are shown as a function of time (6 days frequency). These
graphs present the movements for the period 2016–2021,
available in the EGMS database (Costantini et al. 2021).
Only this database (of the three available for the study)
includes vertical and horizontal movements. The main
Figure 5. Vertical surface movements over 5-year periods along a north-south transect at a longitude of 5.495°. a. European
C-band ERS1/2 satellite images, period from June 1995 through June 2000 b. ENVISAT-ASAR satellite images, period from
August 2005 through August 2010 c. Interferometric C-band SAR Sentinel-1 images, period from November 2016 through
November 2021. (black dotted lines: mining limits in N and S blue dotted line: border between the two mines stars: average
position of double central shafts (Winterslag in purple and Zwartberg in brown)
(a) (b)
(c)