2019 International Conference on Civil and Hydraulic Engineering
IOP Publishing
IOP Conf. Series: Earth and Environmental Science 304 (2019) 042035
doi:10.1088/1755-1315/304/4/042035
construction and reconstruction, and the continuous maintenance and reinforcement for many years, the
defects of the dam have been treated to a certain extent, and the aging process of the dam has been
alleviated. However, the low-strength concrete strength, leakage, high pressure, corrosion and frost
heaving affect the long-term safety of the dam, and it is urgent to fully evaluate the safety of the dam.
3. Technical route
The completion time of this project is relatively early. During the period, it has undergone continuous
construction, reconstruction, post-repair and reinforcement, and a large number of scientific research
and demonstration work. Therefore, the safety assessment needs to be based on engineering design,
construction, safety monitoring and testing and other relevant information, and comprehensively analyze
and summarize the previous research results, and carry out the necessary testing, calculation and analysis
to evaluate the dam safety. The main research work includes analysis and review of dam safety
inspection opinions and related research progress at home and abroad, engineering flood and flood
control capacity evaluation, engineering geological analysis and evaluation, dam observation results
analysis and evaluation, dam stability and stress state evaluation, metal Structural evaluation, hydraulic
machinery and electrical engineering evaluation, as well as strength, aging and durability evaluation of
concrete materials.
4. Safety assessment highlights and related technologies
4.1. Design flood control safety review
Due to the congenital deficiency in the design stage of the project and the changes in the hydrological
and engineering application conditions, the operational parameters of the reservoir are the content of
debates in previous dispatch meetings. The limited water level, the highest regulated water level and the
downstream flow of the reservoir have been changed several times and are not fixed until an upstream
reservoir is completed, and the joint design of the two reservoirs is completed. In this flood control
safety assessment, the storm flood characteristics and flood composition characteristics were analyzed
first. The design flood review was carried out using conventional methods and flood random simulation.
Then according to the design flood, storage capacity curve, discharge curve and other review results and
flood control principle, the actual flood control capacity is evaluated by comparing the water level with
the design flood control characteristics. The problems in the flood control safety of the reservoir include
the use of remote sensing technology to retest some of the storage capacity curves. The extension
between 264.0 m and 267.7 m is still derived from the actual storage capacity curve, which is an
uncertainty factor for flood control safety; The existence of reservoirs and ponds and dams in the basin
has a great influence on the runoff and catchment of the basin. The reservoir storage of large floods is
not yet clear. The accuracy and reliability of flood forecasting need to be verified; In the design flood
control calculations, all power generation and outflows are included, which does not meet the existing
specifications. Therefore, there are still some problems in flood control basic materials and flood control
forecasting. The flood control calculation does not meet the existing norm requirements, and the existing
flood discharge capacity of the reservoir cannot meet the flood discharge requirements of the once-in-
a-lifetime flood.
4.2. Engineering geological conditions evaluation and review of mechanical parameters
The rationality of engineering geological conditions and selection of mechanical parameters of rock and
soil were evaluated from the aspects of regional structural stability, geological analysis of engineering
area and stability of dam foundation rock mass. The basic intensity of the project area is VII degree, and
the seismic horizontal acceleration of the site surface with a 50% surpassing probability of 1% is 0.131
g. The dam foundation has a single lithology and consists of the Permian deep metamorphic
conglomerate with thick to thick layered structure. In addition to the influence of the F67 large fault
zone, the 34#~36# dam section has better engineering geological conditions and high compressive
strength of the rock mass, which can meet the dam bearing requirements. Most of the foundations of the
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