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Testing the Key Performance of Mobile Flood Protection System

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Mobile flood protection systems provide a standardized flood protection method with high reliability. A comprehensive test site for mobile flood wall was established with the support of real applications, which provided opportunities to perform various tests. The anchor plate installation, seepage characteristics, and stress behavior of mobile flood protection systems were investigated through a process test, a water impounding test, and a post loading/unloading test. Test results indicated that installing anchor plates either by direct fixing or by preopened slots and eyes satisfy the construction and normal work requirements. However, the former is preferable over the latter. The mobile flood protection wall leaks when filled with water, and the leakage changes exponentially with the level. The leakage accelerates when the water level exceeds 1.5 m, thus registering 300 L/h at the 1.7 m level. In the post loading test (0–100 kN), concrete plastic deformation was first observed. Then, residual displacement was developed in the posts. The stressing process indicated that the failure process in the post, anchor plate, and base concrete system propagates from the concrete on both sides of the anchor plates toward the water side.
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Research Article
Testing the Key Performance of Mobile Flood Protection System
Shoukai Chen,
1
Huimin Li ,
1
Lei Guo,
2
,
3
Lunyan Wang,
4
and Yongchao Cao
1
1
School of Water Conservancy, North China University of Water Resources and Electric Power, Zhengzhou 450045, China
2
Academician Workstation of Water Environment Governance and Ecological Restoration, Zhengzhou, Henan 450002, China
3
Henan Key Laboratory of Water Environment Simulation and Treatment, Zhengzhou 450045, China
4
Collaborative Innovation Center of Water Resources Efficient Utilization and Protection Engineering, Zhengzhou,
Henan 450045, China
Correspondence should be addressed to Huimin Li; lihuimin3646@163.com
Received 24 March 2018; Accepted 20 May 2018; Published 2 July 2018
Academic Editor: Flavio Stochino
Copyright ©2018 Shoukai Chen et al. is is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Mobile flood protection systems provide a standardized flood protection method with high reliability. A comprehensive test site
for mobile flood wall was established with the support of real applications, which provided opportunities to perform various tests.
e anchor plate installation, seepage characteristics, and stress behavior of mobile flood protection systems were investigated
through a process test, a water impounding test, and a post loading/unloading test. Test results indicated that installing anchor
plates either by direct fixing or by preopened slots and eyes satisfy the construction and normal work requirements. However, the
former is preferable over the latter. e mobile flood protection wall leaks when filled with water, and the leakage changes
exponentially with the level. e leakage accelerates when the water level exceeds 1.5 m, thus registering 300L/h at the 1.7 m level.
In the post loading test (0–100 kN), concrete plastic deformation was first observed. en, residual displacement was developed in
the posts. e stressing process indicated that the failure process in the post, anchor plate, and base concrete system propagates
from the concrete on both sides of the anchor plates toward the water side.
1. Introduction
Today, there are more than 400 cities worldwide with one
million or more population [1]. More than half of the world’s
population lives in cities which provide job opportunities
and quality life. Historically, major cities are located along
rivers and coastal areas. is makes them and their pop-
ulations vulnerable to natural disasters such as flood. Fur-
thermore, natural disasters and weather-related disasters
have been occurring at an increased frequency during the
last decade [2].
is upward trend in losses has been mainly attributed to
socioeconomic developments, such as economic and pop-
ulation growth in disaster-prone areas, which have increased the
exposure of properties that can be damaged by natural hazards
over time [3, 4]. Moreover, future natural disaster losses are
expected to increase in many regions around the world [5, 6].
e high-level urban flood control system is the basic
guarantee for the sustainable development of modern
cities, and the beautiful water environment and river
landscape are the important symbols of modern cities. e
need of protection is increasing with rising population
density and concentration of valuables in low-lying coastal
and river areas in the last decades [7]. Nevertheless, a fact
frequently overlooked is that small local events cause ap-
proximately 50% of total flood damage [8]. For example,
the flooding caused by the hurricane can be assumed as the
flooding with the highest economical losses for more than
$81 billions at the US coast [9]. Tropical Storm Irene and
spring flooding in 2011 exposed the vulnerabilities of
mobile home parks in Vermont when 154 mobile homes in
parks were destroyed [10].
Beneath dykes and floodwalls, mobile constructions are
a solution for flood protection especially in densely popu-
lated areas where no space for permanent structures is
available. In addition, permanent structures may obstruct
heavily the view onto the water body. In these cases, mobile
flood protection measures may be a solution to fit both
Hindawi
Advances in Civil Engineering
Volume 2018, Article ID 5641385, 11 pages
https://doi.org/10.1155/2018/5641385
requirements: protection in case of flooding and open access
to the floodplain over the remaining time. Furthermore,
mobile protective systems can be used as an emergency tool
against flooding in unprotected low-lying areas and for
heightening of permanent flood protection structures in
extreme events [11].
Greening flood protection (GFP) is increasingly recog-
nized as an adaptive and flexible approach to water man-
agement that is well suited to addressing uncertain futures
associated with climate change. In the last decade, GFP
knowledge and policies have developed rapidly, but
implementation has been less successful and has run into
numerous barriers [12].
erefore, the demand for technical protection measures
is growing. It means that the construction of flood control
projects should not only meet the requirements of urban
construction, but also meet the requirements of water and
shore two-way landscape viewing and residents’ and tourists’
visiting [13]. Recently, more and more mobile protection
schemes are on the market promising to fit both re-
quirements: protection in case of flooding and open access to
the floodplain in the remaining time. With the severe sit-
uation of urban flood protection in China [14], mobile flood
protection systems can satisfy the different quality of life and
safety requirements for the urban residents. e mobile
flood protection method has been successfully applied in
many American and European countries [15]. For example,
in 1984, Cologne City, first installed the mobile flood
protection baffle to protect against river flood. In 2005,
Czech built a 17.2 km long and 6.0 m high mobile flood
protection system, which is one of the largest urban flood
protection systems in the world. After the flood protection
exercise, 310 fire protection volunteers completed the in-
stallation of the entire system in 11 hours. Grein City in
Austria also introduced flood protection equipment which
successfully resisted the maximum rainfall record in the area
in June, 2013. In recent years, mobile flood protection
systems have been implemented by important flood pro-
tection cities in Heilongjiang province and Zhejiang prov-
ince in China. However, these flood protection systems have
not met the flood.
Mobile floodwalls can be installed at river dams, large-
size port piers, railway tunnel portals, culvert openings of
expressways, openings of civil air defense structures, and
urban large-scale communities to prevent flood disasters.
Compared with the traditional flood protection method,
mobile floodwalls have the advantages of low-labor intensity,
high-work efficiency, and small seepage over traditional
flood protection methods [15]. Mobile floodwalls improve
the standard of urban flood protection and can effectively
prevent flood disasters under the requirement of preserving
the urban landscape [16]. Mobile floodwalls usually com-
prise posts (including center post and end posts), dam
beams, ground seal, bolts, pressing tool, and anchor plate
[17–19]. For mobile floodwalls, reinforced concrete plinths
embedded with anchor plates are constructed in advance at
the site of floodwalls. e posts should be installed on the
anchor plates before flooding occurs, and the dam beams
and ground seal should be installed among the posts to form
a closed wall to prevent flooding. When flooding occurs,
water enters the vacuum dam beams through the contact
parts of the dam beams and the vertical posts. en, the self-
weight and stability of floodwalls are improved. After the
flood recedes, all components are reversely removed and
orderly stored in a warehouse.
During a flood, several causes of failure may occur re-
lated to the flood protection system. Failure types can be
distinguished into five general situations: (1) sliding/rolling,
(2) seepage, (3) leakage, (4) tilting, and (5) collapse. Every
flood protection system has the possibility of failure.
erefore, it is important to design the system in a way that
minimizes the possibility to meet one or several failure types.
Wind, floating elements, bad design, vandalism, and human
failure are all factors that may cause failure of the flood
protection system [16]. Obviously, it is important to try
avoiding the mentioned failure types. During the design
phase of a flood protection system, the engineers should
consider the risk of failure and put it up against properties
that the system should hold. For instance, large and heavy
systems provide stability and robustness, but on the con-
trary, they will be more difficult and expensive to produce,
store, and transport. erefore, it is important to consider
which strengths the flood protection system should get and
which to neglect [20].
Two problems should be considered for such a combined
flood protection system. e first one is the installation
precision of anchor plates as the key control components for
the assembly and force transmission of floodwalls in which
the anchor plates are embedded in reinforced concrete
plinths for connecting fixed columns. Ensuring the in-
stallation precision of anchor plates without deviation
during concrete pouring is crucial because the control
precision of concrete pouring is in millimeter accuracy, and
the installation precision of anchor plates should be con-
trolled in centimeter accuracy. e second problem is the
seepage and safety of flood protection systems, which is
the primary concern of practical and research [7]. However,
the seepage and safety of flood protection systems have not
been studied in the literature. Considering the two problems,
this study used the mobile flood wall from IBS company
through the construction of experimental bases and in-
vestigated the installation technology of anchor plates, the
leakage characteristics of mobile flood protection systems,
and the stress conditions of posts and anchor plate bases to
provide a reference for the application and promotion of
mobile floodwalls in China.
2. Test Scheme of Mobile Floodwalls
2.1. Product Characteristics. e mobile flood wall used in
this study is obtained from IBS Company, Germany, and has
been applied in Germany, Austria, UK, and China. e
installation effect is shown in Figure 1. e posts (including
center posts and end posts) and dam beams of the system are
made of aluminum alloy (with a tensile strength of
200 N/mm
2
and yield strength of 165 N/mm
2
). e pressure
tools and anchor plates are made of stainless steel (with
a tensile strength of 500 N/mm
2
and yield strength of
2Advances in Civil Engineering
190 N/mm
2
). e type and materials of their components are
shown in Table 1, and the main structure parts are shown in
Figure 2. In this research, the single span and the height of
maximum water level for the system are 3.0 m and 1.8 m,
respectively.
2.2. Test Design. Figure 3 shows the layout of mobile
floodwalls at the test site. e test site is divided into three
areas: water storage, post damage destructive, and standby
areas. e test site is 10.4 m long and 10.0 m wide. ree
spans, two end posts, two center posts with an anchor plate,
and three-span dam beams (27 dam beams) were designed
for the floodwalls in the prototype test area. e destructive
test area comprises a center post and its anchor plates.
e base plate in the test site was 30 cm thick, and
a layer of V18 reinforcing mesh with a spacing of 20 cm was
installed inside. e reservoir wall was a standard rein-
forced concrete U-shaped shear wall, which was 250 mm
thick and 2.4 m high. e base of the anchor plates for the
center posts was 10.4 m (length) ×1.2 m (width) ×1.0 m
(height), and the reinforced concrete posts of the anchor
plates for the end posts were 0.8 m (length) ×0.8 m
(width) ×1.8 m (height). When water is impounded to the
designed height of 1.8 m, the volume of the impounding
reservoir is 55.341 m
3
.
e test site was built using C25 reinforced concrete and
completed in two layers. e first layer comprised the base
plate and the base of the anchor plates, and the second layer
comprised the reservoir walls.
2.3. Test Procedures and Method. After the test site is con-
ducted according to the design, the following are performed:
(1) e installation methods for the test of anchor plates:
two methods are adopted for the installation of
anchor plates. e first one is the direct installation
method; that is, the anchor plates are installed and
fixed. en, concrete is poured after the steel bars are
assembled. e second one is the reserved slot
method; that is, the anchor plates are installed, and
slots are reserved on the base after the poured
concrete reaches a certain age.
(2) After the anchor plates are installed, the steel bar
meters and the strain meters are arranged as shown
in Figure 4. R1–R5 are steel bar meter number, and
S1–S3 are strain gauge number. e steel bar and
strain meters are obtained from Geokon Instruments
Co., Ltd. Full-automatic wireless collection devices
are used for real-time collection, and they recorded
data once every 3 mins.
(3) Concrete is poured and cured for 28 d. Subsequently,
reaction frames, the waterproof impounding reser-
voir, water inlet and outlet pipelines, and the ceiling
are installed and erected. en, the construction of
Table 1: Main structure parts and materials of mobile floodwalls.
Class Model Material
Center post MS100K-T05-1865 Aluminum alloy
EN AW 6005
End post E100K-T01-1865 Aluminum alloy
EN AW 6005
Dam beam DBAL100 ×200–2.5
(width: 3000 mm)
Aluminum alloy
EN AW 6063 T66
Ground
seal BD100K (width: 3000 mm) PE/PU
Pressing
tool VS 100K Stainless steel
SS304
Anchor plate AP 100K-T05 Stainless steel
SS304
Center post
Dam beam
Anchor plate
Figure 2: Structure of main parts.
Figure 1: Mobile flood wall.
Advances in Civil Engineering 3
the test site is completed such that the ceiling can
prevent the influence of sunlight or rainfall during
the leakage test.
(4) Water storage and post loading tests are performed.
3. Installation Technology of Anchor Plates
3.1. Installation Precision of Anchor Plates. e precision of
anchor plates’ installation depends on the designed water
level. Considering the water retaining height of 1.8 m as
an example, the tolerances of all directions are shown in
Figure 5. e control tolerances in the axis direction of the
anchor plates are ±5 mm and ±10 mm in the vertical di-
rection, 3°of the horizontal angle, 0.15% of the vertical
angle, ±3 mm of the interval errors for the contiguous an-
chor plates, and ±5 mm interval errors for the interval
anchor plates, perspective.
3.2. Installation Technology of Anchor Plates. Two in-
stallation methods, namely, the direct installation method
and reserved slot method, are used for anchor plate’s in-
stallation for this test. For the direct installation method,
U-shaped steel bars are arranged firstly at the installation
position (Figure 6), and the anchor plates and U-shaped steel
bars are welded. e foundation steel bars are assembled,
and concrete is poured all at once. e advantage of the
direct installation method is the integrity of the anchor
plates, steel bars, and base concrete. However, the in-
stallation precision of anchor plates cannot be easily con-
trolled because the anchor plates easily deviate when
concrete is poured. And their surrounding concrete cannot
be easily vibrated and compacted.
For the reserved slot method, concrete should be poured
one time at the lifting elevation of the foundation and slots
should be reserved in the concrete foundation according to
10,400 mm
3800 mm
C25 reinforced concrete wall
Center postEnd post Dam beam
Pool
250 mm
800 mm
800 mm 3000 mm
Direct installation of
anchor plate
Reserved slot installation of
anchor plate
Figure 3: Test site layout.
16Φ12 @ 100
10Φ12 @ 100
8Φ10 @ 150 R5
R3
R1 R4
20Φ14 @ 100
(a)
360.5 mm
R5
S1
R3
245.5 mm
258.5 mm
S3
S2 R2
45 mm
495 mm
Central axis
318.5 mm
4Φ16 @ 150
R4
R1
3Φ12 @ 150
(b)
Figure 4: Layout of reinforcing steel bars, steel bar meters, and strain meters. R1–R5 are steel bar meter number, and S1S3 are strain gauge
number. e same as in Figure 4(b). 3Φ12 @150 refers to three steel bars with diameter 12 mm and spacing 150mm, the same as in Figure 4(a).
4Advances in Civil Engineering
the requirement and water level of the flood period during
construction. e steel bars around the anchor plates cannot be
arranged in advance. However, U-shaped steel bars are welded
with the anchor plates completely in advance (Figure 7(a)).
en, the second-stage concrete is poured after the anchor
plates are fixed by an adjusting device (Figure 7(b)). In the
reserved slot method, the base concrete can be constructed
firstly, and thus, the installation is convenient and precision can
be easily controlled. However, the periphery of slots is pro-
cessed as construction joints, and leakage channels can be easily
formed at the joints.
e two methods have been applied on-site for this
research.
4. Analysis of Test Results
4.1. Water Storage Test. After civil engineering is completed,
the mobile floodwalls are installed for the water storage test,
as shown in Figure 8. e measured values of steel bar meters
of the two installation methods are shown in Table 2. e
strain gauge measured values of two installing methods are
shown in Table 3. e layout of the steel bar and strain
meters of the base is shown in Figure 4.
e stresses on all parts are changed after water storage
with water pressure, water weight, and deadweight of the
flood protection system. e stress condition of the direct
installation method is as follows: maximum tensile stress
appears at R1 and R4 positions where a tensile stress of
0.9 MPa was recorded; moreover, R3 and R5 positions are
compressed, reaching a compression stress of 5.8 MPa.
Compared with the direct installation method, the stress
characteristics of R1, R3, and R4 positions are consistent.
At the same time, the stress features of concrete under the
two installation methods are consistent, but the strain
generated by the latter is higher; for instance, S2 generates
tension strains 5.45 με (direct installation method) and
1.39 με (reserved slot method). e analysis indicates that
the integrity of anchor plates installed via the reserved slot
Horizontal
positioning line
≤3°
System axis
Deviation ± 10 mm Deviation ± 10 mm Gradient 0.15%
Deviation ± 5 mm
±3 mm ±3 mm
±5 mm
Figure 5: Installation tolerances of anchor plates.
(a) (b)
Figure 6: Direct installation method. (a) Anchor plate fixation. (b) Reinforced bar assembly.
Advances in Civil Engineering 5
method is low, which just like anchor plates and slot concrete
form a member that is embedded into the base. en, the stress
state of the reserved slot method is clearly different from the
direct installation method. So, the direct installation method is
apparently safer than the reserved slot method. e actual
stress values of impounding of the two installation methods
are lower than the allowable values of reinforced concrete
plinths.
4.2. Leakage Test. e seepage test was performed when the
level of stored water reached 1.78 m. After 3 h, the water level
(a) (b)
Figure 7: Reserved slot installation method. (a) Reinforced bar arrangement. (b) Adjusting device and anchor plate fixation.
(a) (b) (c)
Figure 8: Water storage testing of mobile flood wall storage. (a) Overall view. (b) Pool (not storage). (c) Pool (stored water at 1.8 m).
Table 2: Measured values of steel bar meters of the two installation methods (unit: MPa).
Number of steel bar meter Time of measurement Direct installation method Reserved slot method
Actual measured value Variation value Actual measured value Variation value
R1 (V14) Before storage 4.32 0.90 2.83 1.04
Storage to 1.8 m 5.22 1.79
R2 (V12) Before storage 15.96 0.49
Storage to 1.8 m 15.47 —
R3 (V12) Before storage 14.35 5.71 22.93 5.64
Storage to 1.8 m 8.64 17.29
R4 (V16) Before storage 3.44 0.87 6.25 1.39
Storage to 1.8 m 4.31 7.64
R5 (V16) Before storage 22.87 5.92 6.38 0.82
Storage to 1.8 m 16.95 7.20
6Advances in Civil Engineering
decreased to 1.75 m. Given 1.75 m as time 0, the observation
frequency was measured every 6–2 h, until 150 h was
reached. en, the water level was 1.37 m at 300 h. e
observation times and corresponding observation levels are
shown in Tables 2 and 3. e variation in the actual mea-
sured level with time did not exhibit a linear correlation. e
following regression formula was obtained by origin re-
gression analysis:
H0.202et/18.79 +0.217et/182.02 +1.327,(1)
where His the water level (m) and tis the time (h), when
t0 and H1.75 m.
Fitting testing was conducted via (1). e correlation
coefficient was 0.995, and the fitting effect was good. For-
ward and backward predictions were performed to verify the
accuracy of the relation formula. e calculation results
indicated that the Hvalue was 1.784 m (the actual measured
value was 1.78 m) when the time was moved back by 3 h
(t3 h in the calculation), and the calculation value was
1.369 m (the actual measured value was 1.37 m) when the
time was moved forward to 300 h. us, the consistency of
the result was good. e decrease of water level is caused by
the leakage in the mobile floodwalls, and the critical water
level is 1.327 m.
e seepage rule for mobile floodwalls has not been from
the literature. Generally, seepage only occurs at contact
positions, which are the positions between dam beams and
posts, the positions between the bottom dam beams and the
foundation, and the positions among dam beams. Consid-
ering the current test condition, the leakage amount of all
parts cannot be obtained through the test. Under the re-
quirement of ignoring the influence of water evaporation at
the reservoir surface, the leakage amount of mobile flood-
walls is calculated according to the following formula:
q1000 Av 1000 AdH
dt ,(2)
where qis the leakage amount (L/h) and Ais the reservoir
area (m
2
). For the test conducted, A30.745 m
2
and vis the
seepage velocity (m/h), vdH/dt.
After the derivation of (1), the seepage velocity is
obtained. e variation rule for the average leakage
amount at different water levels is obtained after sub-
stitution in (2). en, the average leakage amounts are
compared with the average leakage amount after the
conversion of the actual measured water level (Figure 10).
Figures 9 and 10 show that the range of water level var-
iation becomes fast and the seepage rate becomes large,
which is more than 50 L/h, when the water level exceeds
1.7 m, and the seepage rate can exceed 300 L/h when the
water level exceeds 1.5 m. Seepage quantity is an important
aspect to consider when floodwalls increase the flood
protection height.
4.3. Post Loading Test. Section 4.2 indicates that under the
normal hydrostatic pressure, the base of the mobile flood
wall is slightly stressed and generally cannot damage the
concrete. However, the hydrodynamic action or the impact
of foreign objects should be considered during the process of
flood resistance. At this time, the post, anchor plate, and base
system ensure the safety of flood protection.
Table 3: Strain gauge measured values of two installing methods (unit: με).
Number of steel bar meter Time of measurement Direct installation method Reserved slot method
Actual measured value Variation value Actual measured value Variation value
S1 Before storage 41.31 8.68
Storage to 1.8 m 49.99
S2 Before storage 79.97 5.45 4.75 11.95
Storage to 1.8 m 85.42 16.70
S3 Before storage 63.32 25.84 12.33 26.32
Storage to 1.8 m 37.48 13.90
1.3
1.4
1.5
1.6
1.7
1.8
1.9
45 95 145 195 245 295 345 395 445 495
Water level (H/m)
Measure time (t/h)
H= 0.202e
(–t/18.79)
+ 0.217e
(–t/182.02)
+ 1.327
R
2
= 0.995
Measured values-1 Measured values-2
Fitted values Predicted values
Figure 9: Variation rule of water level with time.
0
50
100
150
200
250
300
350
1.4 1.45 1.5 1.55 1.6 1.65 1.7 1.75
Leakage (q/L/h)
Water level (H/m)
q= 330.52e(–t/18.79) + 36.65e(–t/182.02)
R2 = 0.951
Measured water level conversion values
Calculated values
Figure 10: Leakage variation rule with the change of water level.
Advances in Civil Engineering 7
e post loading test site, layout of its loading
devices, displacement meters, and strain plates are shown in
Figures 11 and 12. And the layout of the base steel bar and
strain meters is shown in Figure 4. In Figure 12, strain meters
C1 and C2 are arranged at the side of the posts, which is
1.02 m away from the base surface, to observe the self-
deformation of the posts. Displacement meters A1, A2,
and A3 are arranged at the downstream surface of the posts,
which are 0.25, 1.02, and 1.57 m away from the base surface,
respectively, to measure the overall displacement of the posts.
e steel bar and strain meters are arranged in the same way
as that in Section 4.1. e test adopted the hydraulic jack
continuous loading mode, the set load limit was 100 kN, and
all measurement equipment was measured once at 0, 25, 50,
75, and 97 kN. e loading and unloading process lines of all
monitoring devices are shown in Figures 1316.
e oblique strains (C1 and C2) of the post show a linear
variation with the load during the loading process. e
loading and unloading curves are basically consistent, and
the directions and values of C1 and C2 are opposite and
similar, respectively. Under loading of 50 and 97 kN, the
strain values are approximately 500 and 1000 με, re-
spectively, which indicate that the posts are consistently in
the elastic phase during the loading process. e overall
radial displacement of the posts shows that one of the upper
parts is higher than that of the lower part, and the maximum
value appears at the upper parts of the posts. For instance,
the displacement meter A3 is 9.8 mm when the load is 50 kN,
and displacement meter A3 is 17.1 mm when it is 97 kN. e
radial displacement of the posts shows a nonlinear variation
with the load variation, and the actual measured residual
displacements of A1, A2, and A3 are 0.17, 0.36, and 0.50mm,
respectively, after unloading. e values are in linear re-
lationship with the heights where the displacement meters
are located (as showing in Figure 17); that is, the posts are
also at the elastic stage. us, residual displacement shall be
generated by the reinforced concrete plinth of the anchor
plates.
Considering the concrete load-strain curve, concrete
enters the plastic stage from the elastic stage when the load is
approximately 25 kN. For example, S1 and S2 reach 97.34
and 389.47 με when loaded to 7 kN. At this time, S1 is close
to the ultimate tensile deformation value of concrete, and the
residual strains are 6.50 and 26.39 με, respectively, after
unloading. is condition can also be observed from the
load-stress curve of steel bar meters. Stress shows a linear
variation with the load when the load does not exceed 25 kN,
which indicates that the steel bars and concrete are in the
elastic stage of coordinative deformation at this time. Stress
shows a nonlinear variation with the load when it is loaded
continuously, and residual stresses are found, which are
0.39 MPa (R1), 0.20 MPa (R2), 0.16 MPa (R3), and 0.10 MPa
(R4), after unloading. Unfortunately, R5 was broken, so the
record cannot be gotten. e stress of the loaded steel bar is
lower than the yield condition because the test uses HRB335
steel bars. us, the residual stresses displayed by steel bar
meters are caused by the plastic deformation of concrete. In
addition, the strain rule of steel bar meters is
R2 >R1 >R4 >R3. For example, when the loading is up to
97 kN, the actual maximum measured stress values of R1 to
R4 are 8.50, 12.50, 2.70, and 3.63 MPa, respectively, which
indicates that the side surface of the anchor plates is in
maximum stress. us, crack starts from the two sides of the
anchor plates and then develops to the positive side of the
water gradually if damage occurs.
5. Conclusions
Mobile floodwalls can be installed at river dams, large-size
port piers, railway tunnel portals, culvert openings of ex-
pressways, openings of civil air defense structures, and urban
large-scale communities to prevent flood disasters. Mobile
floodwalls improve the standard of urban flood protection
and can effectively prevent flood disasters under the re-
quirement of preserving the urban landscape. In order to
investigate the safety of mobile flood wall, the anchor plate
installation, seepage characteristics, and stress behavior of
mobile flood protection systems were investigated through
a process test, a water impounding test, and a post
loading/unloading test. Test results indicated the following:
(1) e installation precision of anchor plates ensures
the rapid assembly and normal operation of mobile
flood protection systems. Combined with engi-
neering characteristics, the technologies of the direct
installation and reserved slot methods are studied.
e two methods are assumed capable of satisfying
the construction requirements after technical testing.
However, the integrity of the former is better than
the latter. e impounding test also proved that the
two methods can satisfy the requirements of normal
operation. However, the stress condition of the direct
installation method is better than that of the reserved
slot method. So, direct installation method is rec-
ommended for the actual project.
Figure 11: Post loading test.
8Advances in Civil Engineering
0
10
20
30
40
50
60
70
80
90
100
–1500 –1250 –1000 –750 –500 –250 0 250 500 750 1000 1250 1500
Load (kN)
Strain (με)
C1 loading curve
C2 loading curve
Unloading curve
Figure 13: Relationship between post oblique strain and load.
A1
A2
C1/C2
250 mm
1020 mm
1570 mm
1865 mm
1200 mm
Loading by hydraulic jack
Center post
Concrete floor
Fixed steel pipe
P
Reinforced
concrete plinth
A3
Figure 12: Layout of displacement meter, strain meter, and loading.
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 101214161820
Load (kN)
Displacement (mm)
A1 loading curve
A2 loading curve
A3 loading curve
Unloading curve
Figure 14: Relationship between displacement and load.
0
10
20
30
40
50
60
70
80
90
100
–400 –350 –300 –250 –200 –150 –100 –50 0 50 100
Load (kN)
Strain (με)
S1 loading curve
S2 loading curve
Unloading curve
Figure 15: Relationship between concrete strain and load.
Advances in Civil Engineering 9
(2) e leakage characteristic of the mobile flood pro-
tection system should be considered during flood
prevention. e impounding test for the reservoir of
three-span mobile flood protection system indicated
the actual measured water level and time, and the
leakage amount and water level are in the index
variation relationship. e leakage amount, which is
higher than 50 L/h, will rapidly increase when the
water level is higher than 1.5 m. For example, the
leakage amount can be 300 L/h when water level is
1.7 m, which indicates that the leakage should be
solved when the water retaining height of the mobile
flood protection system increases.
(3) In the entire mobile flood protection system, the
post-anchor plate-reinforced concrete plinth system
ensures the safety of flood protection. e post
loading and unloading tests (the limited load is
100 kN at this time) indicate that the plastic de-
formation of concrete around the anchor plates
occurs when the load is up to 25 kN. When the load is
reaching 97 kN, the concrete would be close to ul-
timate tensile deformation. However, the posts and
steel bars are all in the elastic stage during the en-
tire loading process. e actual measured residual
displacements of posts and residual stress of steel
bars are caused by the plastic deformation of con-
crete after unloading. In addition, the stress analysis
of the loading and unloading processes shows that
the damage of the post-anchor plate-foundation
system will start from the concrete around the an-
chor plate and gradually develop toward the surface
of the water surface until the whole is destroyed.
erefore, the mobile flood control system engi-
neering should pay full attention to the construction
quality of concrete around the anchor plate.
Data Availability
e data used to support the findings of this study are
available from the corresponding author upon request.
Conflicts of Interest
e authors declare that they have no conflicts of interest.
Acknowledgments
is research was financially supported by the National
Natural Science Foundation of China (nos. 51309101 and
51679092).
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Advances in Civil Engineering 11
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