Page 62 - 2025年第56卷第11期

Variations patterns of sediment discharge capacity during the continuous channel
adjustments of the Lower Yellow River

1 1 1 2 3 4

CHENG Yifei ，XIA Junqiang ，ZHOU Meirong ，FANG Hongwei ，WAN Zhanwei ，CHEN Jianguo

（1. State Key Laboratory of Water Resources and Hydropower Engineering Science，Wuhan University，Wuhan 430072，China；

2. Southern University of Science and Technology，Shenzhen 518055，China；

3. Yellow River Engineering Consulting Co.，Ltd.，Zhengzhou 450003，China；4. State Key Laboratory of Water Cycle and

Water Security，China Institute of Water Resources and Hydropower Research，Beijing 100038，China）

Abstract：The incoming flow regime and channel boundary conditions in the Lower Yellow River （LYR）have under‐

gone drastic changes over the past 50 years，owing to intense human activities such as reservoir construction in the
upper and middle reaches. The channel in the LYR experienced continuous aggradation and subsequent continuous
degradation，but the trend slowed down in recent years. Based on the measurements of hydrological data，cross-

sectional profiles and bed material，the variation in channel erosion efficiency was firstly calculated and analyzed. A

calculation method of channel erosion efficiency considering the influences of various factors was then proposed.
Finally the critical flow regime was determined to keep the equilibrium of channel evolution under continuous channel
adjustment. The results indicate that：（1）the channel evolution processes could be divided into four periods after

1970，including a slow aggradation period，a rapid aggradation period，a rapid degradation period，and a slow degra‐

dation period. The channel erosion efficiency during the later sediment detention stage （2008-2022） has been

.
reduced to half of that during the initial sediment detention stage （2000-2007） （2）The temporal decreases in these

factors，including the incoming sediment coefficient，bed material supply，and geomorphic coefficient，resulted in a

temporal decline in channel erosion efficiency. An empirical relationship was further established between channel ero‐
sion efficiency and these factors，with the determination coefficient being equal to 0.80，which is able to reflect the

temporal variation in channel erosion efficiency. （3）The critical incoming sediment coefficient varied with the chan‐

nel adjustment，and the critical incoming sediment amount was reduced by 25% during the later sediment detention
stage compared with that during the initial sediment detention stage.

Keywords：incoming flow regime；channel geometry；bed material composition；channel erosion efficiency；equilib‐

rium sediment transport；Lower Yellow River

（责任编辑：鲁 婧）
（上接第 1442 页）
Effect of initial crack morphology on meso-scale hydraulic fracturing in concrete
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3

LÜ Congcong ，YANG Guodong ，WU Zhenchao ，LI Zongli ，LU Xiaochun ，TIAN Bin 1，2

（1. Hubei Key Laboratory of Construction and Management in Hydropower Engineering，China Three Gorges University，

Yichang 443002，China；2. College of Hydraulic and Environment Engineering，China Three Gorges

University，Yichang 443002，China；3. College of Water Conservancy and Architectural

Engineering，Northwest A&F University，Yangling 712100，China）

Abstract：To investigate the propagation and evolution patterns of hydraulic fracturing cracks in concrete at the

meso-scale，the relationship between the permeability coefficient of mortar and the internal damage evolution of the

matrix was introduced，and a meso-concrete pore pressure cohesion model that can reflect the seepage-stress cou‐
pling effect was established. This study examined the effects of initial crack dip angle，initial crack length，multiple

initial cracks，and special initial cracks on hydraulic fracturing failure at the meso-scale. The results indicate that the

differences in the initial fracture dip angle can cause the deviation of the penetration point of the main crack. As the
initial crack length increases，the critical cracking water pressure decreases. Particularly，when the crack length

increases from 5 mm to 20 mm，the critical cracking water pressure drops significantly. Compared to a single initial

crack，the presence of multiple initial cracks not only weakens the splitting resistance of concrete but also induces

non-periodic severe fluctuations in the water pressure for steady propagation of the cracks. Additionally，it is con‐
cluded that special initial cracks can affect the connection between cracks and the interfacial transition zone at the

meso-scale，potentially inducing more complex cracking patterns. The morphology of initial cracks significantly influ‐
ences the critical cracking water pressure and crack propagation path of concrete hydraulic fracturing. The research
provides a reference for predicting and preventing hydraulic fracturing failure in concrete structures.

Keywords：initial crack；hydraulic fracturing of concrete；meso-scale；cohesive element；critical cracking water
pressure
（责任编辑：王 婧）
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