Page 123 - 水利学报2021年第52卷第1期

Study on the gravity wave induced by the diurnal variation of outflow discharge
in the Three Gorges Reservoir

1，2 1 1，2 1
JI Daobin ，ZHOU Zhexuan ，YANG Zhongyong ，LONG Lianghong ，WANG Yaoyao
（1. College of Hydraulic and Environmental Engineering，China Three Gorges University，Yichang 443002，China；
2. Hubei Field Observation and Scientific Research Stations for Water Ecosystem in Three Gorges Reservoir，
China Three Gorges University，Yichang 443002，China）

Abstract： Diurnal variation of water level has been observed in Three Gorges Reservoir （TGR）， which is
driven by the outflow discharge fluctuation， and would travel toward upstream along TGR as a gravity
wave. The mechanism of generation and propagation along the reservoir is still unclear. To study the genera⁃
tion mechanism and propagation process of this gravity wave， the field data of discharge and water level
during January and October， 2018 was analyzed with methods of wavelet transform and filter analysis. The
main results included：（1） the amplitudes of diurnal wave were proportional to accumulated discharge，and
inverse proportional to background water level，which can be evaluated by a formula derived in this paper；
（2） The wave amplitude experienced a decrease-increase process， while the phase increased gradually， in
the process of upstream travelling， under the influence of bottom friction， transverse section， discharge
from branches，as well as background water level.
Keywords：Three Gorges Reservoir；outflow discharge fluctuation；gravity wave；wave propagation in a res⁃
ervoir
（责任编辑：李福田）

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Experimental study on the electro-thermal performance
of ERCC and its power supply mode analysis

1
1
1
ZHANG Mengxi ，LI Mingchao ，ZHANG Jinrui ，HU Yu 2
（1. State Key Laboratory of Hydraulic Engineering Simulation and Safety，Tianjin University，Tianjin 300350，China；
2. State Key Laboratory of Hydroscience and Engineering，Tsinghua University，Beijing 100084，China）
Abstract： Engineering experience indicates that temperature cracking is easy to occur near the height of
overwintering layer of RCC dams under the low temperature. More dams are being constructed in China’s
frigid region， which puts forward higher requirements for temperature control of concrete dams. The laying
and dismantling of the traditional external insulation measures on the large warehouse surface will inevitably
increase the cost and reduce efficiency in construction. In view of the above problems，a new type of elec⁃
i
trically conductive roller compacted concrete （ERCC）s introduced in this paper. The electric temperature in⁃
crease of large-scale ERCC layer specimen was tested， and the thermal conductivity and specific heat ca⁃
pacity of ERCC was inversed according to the test data. Then，the quantitative calculation model of voltage
required to resist the cold wave （U）and the temperature difference inside and outside the dam （ ΔT）are de⁃
duced according to the heat flow balance. The evolution process of temperature field and stress field of over⁃
wintering layer under the action of sudden temperature drop was simulated by the coupling method of elec⁃
tricity-heat-structure. The power supply mode is optimized with the temperature stability of typical measur⁃
ing points as the objective function. The reliability of the U- Δ T model has been verified by the optimiza⁃
tion results. Comparing the temperature， stress and cost of 9 schemes for temperature control， including
“thin layer surface protection+ERCC electrified heating” and“conventional insulation materials”， the power
supply mode has a favorable effect in improving the temperature and stress distribution，which can provide
a new way to solve the problem of temperature control of overwintering layer.
Keywords： RCC dam； ERCC； overwintering layer； temperature control； U- Δ T model； power supply
mode；structural-thermoelectric simulation
（责任编辑：杨 虹）

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