Page 78 - 2025年第56卷第10期

mance deterioration of the anti-seepage walls in earth-rock dams. The model is developed based on the theories of
saturated-unsaturated seepage and conventional calcium leaching，taking into account the effect of seepage on the

non-equilibrium dissolution of solid-phase calcium within the concrete. The model's validity is verified through labo⁃
ratory seepage-dissolution tests. The long-term seepage-dissolution evolution characteristics of the anti-seepage walls
in a specific earth-rock dam project are investigated. The performance evolution of the anti-seepage walls during the

seepage-dissolution process is analyzed，revealing the degradation patterns. A new criterion based on the critical
hydraulic gradient is proposed to estimate the safe service life of the concrete cutoff wall. The results show that cal⁃

cium leaching from the anti-seepage wall mainly occurs at the upstream water-facing surface，at the locations of seep⁃

age bypasses，and at the interface between adjacent soil layers. During the seepage-dissolution process，the leaching

of solid-phase calcium，the average porosity，the diffusion coefficient，and the permeability coefficient all increase

exponentially over time，leading to a gradual weakening of impermeability. For a completely dissolved concrete cutoff

wall，the porosity increases by approximately sevenfold，while the permeability and diffusion coefficients increase by

about 2-3 orders of magnitude. Throughout the dam's service life，the coupled effects of seepage and dissolution
result in an increasing hydraulic gradient within the anti-seepage wall. The critical hydraulic gradient-based method
provides a reliable estimate of the safe service life of the concrete cutoff wall.

Keywords：earth-rock dam；concrete cutoff wall；seepage dissolution；hydraulic gradient；safe service life

（责任编辑：尹 婧）
（上接第 1313 页）

Flow velocity compensation mechanism for delayed sexual maturation of migratory fish due
to cold water release from reservoirs

1 1 1，2 1 1
YANG Zefan ，YAN Xiaoyao ，TANG Jiaxuan ，ZENG Qinghui ，HU Peng

（1. State Key Laboratory of Water Cycle and Water Security in River Basin，China Institute of Water Resources and Hydropower Research，

Beijing 100038，China；2. School of Civil Engineering，Tianjin University，Tianjin 300072，China）

Abstract：Water temperature and cumulative temperature are key factors in determining the gonad development of

fish，but the temperature hysteresis effect in reservoirs delays the gonad development and sexual maturity of fish. Con⁃
sidering the crucial role of water flow stimulation in the natural reproduction of migratory fish，this paper proposes a

mechanism to mitigate the adverse effects of low-temperature water on fish gonad development by increasing flow

velocity. Furthermore，it explores the synergistic effects of water temperature and flow velocity on grass carp's sex hor⁃

mone secretion through mechanistic experiments，while analyzing changes in serum estradiol and testosterone concen⁃

trations. The key findings are as follows：when the water temperature reaches 14 ℃，increasing the flow velocity can

effectively mitigate the delaying effect of low water temperature on fish gonad development；in the temperature range

of 16-20 ℃ ，increasing flow velocity has the most favorable compensatory effect；by elevating the flow velocity to

0.9 m/s，the influence of low water temperature on fish gonad development can be significantly alleviated. This paper
preliminarily verified the feasibility of using high flow velocity to promote fish gonad development and compensate for
insufficient cumulative temperature for sexual maturity，providing a new idea for the ecological operation of reservoirs

for fish protection.

Keywords：gonad development；water temperature；flow velocity；estradiol；low-temperature discharge；ecological

operation
（责任编辑：尹 婧）
— 1325 —