Objective The accuracy of comprehensive dam safety assessment remains critical to national economic development and the safety of people's lives and property downstream. This study addresses the distortion of evaluation results caused by overlapping information among evaluation indices and the use of constant weights assigned manually in the comprehensive evaluation of the operational safety of earth and rock dams. An optimization weight approach is proposed to mitigate this issue. Methods The initial weights of the indices were calculated using the analytic hierarchy process, and the connections among the indices were analyzed with the help of the decision-making trial and evaluation laboratory. The initial weights were then corrected based on the independence of the indices from DEMATEL to reduce the effect of overlapping evaluation index information on the evaluation results. In addition, the safety state of the dam was a dynamic process that changed over time, and the deterioration of the dam often presented as local damage in the early stages. The use of constant weight can cause these disadvantageous indicators to be overshadowed by other advantageous indicators, thus failing to detect local damage problems. Therefore, it is necessary to revise the weights of the indicators based on the variable weight theory. The weights of the indicators were optimized based on their state values, resulting in an optimized weight that accounted for both the correlation of the indicators and their state values, to address the uncertainty in the monitoring information and evaluation process, the cloud model was adopted to extract the index characteristic values and carry out a comprehensive evaluation. The influence of the number of cloud drops on the comprehensive similarity was explored to resolve the issue that the selection of the number of cloud drops was mainly subjectively determined by the decision-maker and lacked a theoretical basis. The membership degree was calculated by generating different numbers of cloud droplets through the forward cloud generators, which were taken as the model solution under each number of cloud droplets. The expected value of the membership degree was derived based on the normal distribution probability density function and was taken as the theoretical solution. It was found that in 20 random experiments, the model solution consistently fluctuated around the theoretical solution under the same cloud droplet number. As the cloud droplet number increased from 500 to 10 000, this fluctuation decreased and gradually converged to the theoretical solution, with the corresponding variance decreasing from 20.86 to 0.80. Taking 95% engineering accuracy as the measurement standard, it was found that among these 20 random experiments, three experiments failed to satisfy the condition when the cloud droplet number was 2 000, and all experiments met the requirement when the cloud droplet number was 5 000. Since the error did not change significantly when the number of cloud drops continued to increase, 5 000 was taken as the optimal number of cloud drops to balance computational efficiency and accuracy. Results and Discussions The established evaluation model was applied to the earth and rock dam of the Helong Reservoir in Guangdong Province. The results showed that the optimization weight reduced the weights of indicators that were easily influenced due to a certain degree of information overlap between these indicators and others. Based on this, the variable weight theory was further integrated, and the weights of the advantageous indicators were reduced to prevent the disadvantageous indicators from being overshadowed. Therefore, the role of disadvantageous indicators in the evaluation was highlighted, and the operation status of the dam was reflected from a safer perspective. Most of the cloud drops generated by the evaluation cloud of the Helong Reservoir fell between "safety" and "basically safety". Combined with the results of the membership degree calculation, the membership degree of the Helong Reservoir Dam to "safety" and "basically safety" was 32.5% and 16.3%, respectively, and the evaluation result was determined to be "safety" by the principle of maximum similarity. Compared to the constant weights, the two evaluation results were the same, but the affiliation degree of "safety" was reduced from 40.7% to 32.5%, which reflected the influence of the correlation of the indicators and the state value of the indicators on the evaluation results. The method considers the correlation of the indices and the influence of the measured indices on the weights. It combines with the cloud model to evaluate the operation state of earth and rock dams from both quantitative and qualitative perspectives, which more realistically and effectively reflects the safety condition of the dams and provides a reference for the safety evaluation of the dam. Conclusions The results indicated that this method is applicable to the comprehensive evaluation of the operational safety of earth and rock dams. Fuzzy comprehensive evaluation and set pair analysis are utilized to compare the evaluation results with those of the proposed model to verify the reliability of the proposed model. All of the evaluation models indicate a status of "safety". The evaluation results are consistent and align with the actual condition of the dam, confirming the accuracy and feasibility of the proposed model.
ShengJinbao, LiHongen, ShengTaozhen.Statistical analysis of dam failure and its loss of life in China[J].Hydro-Science and Engineering,2023(1):1‒15. doi:10.12170/20220919001
ChenLonglong, LiJie, WangZhifeng,et al.Sustainable health state assessment and more productive maintenance of tunnel:A case study[J].Journal of Cleaner Production,2023,396:136450. doi:10.1016/j.jclepro.2023.136450
[4]
WenLifeng, YangYing, LiYanlong,et al.Comprehensive evaluation method for the concrete-face rockfill dams behavior based on the fuzzy recognition model[J].Journal of Performance of Constructed Facilities,2022,36(3):04022021. doi:10.1061/(asce)cf.1943-5509.0001734
[5]
JiangFuliang, WuHaonan, LiuYong,et al.Comprehensive evaluation system for stability of multiple dams in a uranium tailings reservoir:Based on the TOPSIS model and bow Tie model[J].Royal Society Open Science,2020,7(4):191566. doi:10.1098/rsos.191566
[6]
ShuXiaosong, BaoTengfei, XuRuichen,et al.Dam anomaly assessment based on sequential variational autoencoder and evidence theory[J].Applied Mathematical Modelling,2021,98:576‒594. doi:10.1016/j.apm.2021.05.021
[7]
JiaFan, YangMeng, LiuBingrui,et al.A comprehensive evaluation method study for dam safety[J].Structural Engineering and Mechanics,2017,63(5):639‒646.
[8]
WangXiaoling, YuHongling, LvPeng,et al.Seepage safety assessment of concrete gravity dam based on matter-element extension model and FDA[J].Energies,2019,12(3):502. doi:10.3390/en12030502
[9]
ChenAnyi, TangXianqi, ChengBochao,et al.Multi-source monitoring information fusion method for dam health diagnosis based on Wasserstein distance[J].Information Sciences,2023,632:378‒389. doi:10.1016/j.ins.2023.03.053
[10]
LiDeyi, LiuChangyu, DuYi,et al.Artificial intelligence with uncertainty[J].Journal of Software,2004,15(11):1583‒1594.
HeJinping, GaoQuan.An improved algorithm of cloud fusion for dam health diagnosis[J].Geomatics and Information Science of Wuhan University,2018,43(7):1022‒1029. doi:10.13203/j.whugis20160283
WangFei, ZhongDenghua, YanYuling,et al.Rockfill dam compaction quality evaluation based on cloud-fuzzy model[J].Journal of Zhejiang University:Science A,2018,19(4):289‒303. doi:10.1631/jzus.A1600753
[15]
JiangZhenxiang, ChenHui, ChenBoquan.Evaluation model of overall dam behavior based on cloud theory[J].Chinese Journal of Engineering,2022,44(3):464‒473.
FuHelin, HuangZhen, HuangHongwei,et al.Health diagnosis method of shield tunnel structure based on cloud theory[J].Chinese Journal of Engineering,2017,39(5):794‒801.
FuXiao, ZhaoGang, WangMaomei,et al.Comprehensive evaluation method for structural behavior of concrete dams in cold regions[J].Engineering Structures,2023,278:115435. doi:10.1016/j.engstruct.2022.115435
[20]
HaoTengteng, ZhengXin, WangHuiyu,et al.Development of a method for weight determination of disaster-causing factors and quantitative risk assessment for tailings dams based on causal coupling relationships[J].Stochastic Environmental Research and Risk Assessment,2023,37(2):749‒775. doi:10.1007/s00477-022-02316-w
[21]
LiZongkun, MoXiangming, GeWei,et al.Comprehensive evaluation of dam-break consequences based on variable weight set pair‒extenics coupling model[J].Advanced Engineering Sciences,2022,54(5):64‒71.
ChenXudong, XuPeng, LiuXinyi,et al.Comprehensive evaluation method for the safety state of RCC dams based on interval number theory[J].Water,2023,15(11):2089. doi:10.3390/w15112089
[24]
WangLei, WangXiaoling, ZhangJun,et al.Comprehensive evaluation method for dam safety considering fusion weight optimization and conflicting information sources[J].Journal of Tsinghua University(Science and Technology),2023,63(10):1566‒1575.
LiZongkun, JiangJingshan, WangGuangyin.Comprehensive assessment of observed behavior of earth-rockfill dams[J].Chinese Journal of Geotechnical Engineering,2007,29(2):255‒259.
LiYawei.Study on safe operation and evaluation of small and medium‒sized earth‒rock dams in cold regions[D].Changchun:Changchun Institute of Technology,2021.
[29]
李雅薇.寒区中小型土石坝安全运行与评价研究[D].长春:长春工程学院,2021.
[30]
HeJinping, GaoQuan, ShiYuqun.A multi-hierarchical comprehensive evaluation method of dam safety based on cloud model[J].Systems Engineering‒Theory & Practice,2016,36(11):2977‒2983.
LiSiguang, MaYonghong, ZhuEnjia.Analysis of institutional barriers to integrated innovation based on AHP-DEMATEL[J].Journal of Harbin Engineering University,2022,43(6):900‒906.
XueYanzhuo, ZhouYing, LuYang,et al.Risk assessment of ships stuck in ice in Arctic ice area based on fuzzy AHP‒DEMATEL[J].Journal of Harbin Engineering University,2022,43(7):944‒949.
DongKai, MiZhankuan, YangDewei.Comprehensive diagnosis method of the health of tailings dams based on dynamic weight and quantitative index[J].Sustainability,2022,14(5):3068. doi:10.3390/su14053068
[40]
LiYue, HuYuqi, CaiJing,et al.Hydroplaning risk of aircraft tire based on variable weight theory‒normal cloud model[J].Journal of Beijing University of Aeronautics and Astronautics,2023,49(9):2299‒2305.
LiangLi, XingGuanhua, WuFengyuan.The evaluation model and method based on cloud theory[J].Journal of Northeastern University(Natural Science),2019,40(6):881‒885. doi:10.12068/j.issn.1005-3026.2019.04.025
ChenXi, ZengYawu, LiuWei.Fuzzy AHP-based two-level fuzzy comprehensive evaluation on safety of reservoir dam in rural area[J].Water Resources and Hydropower Engineering,2019,50(2):168‒176.
GeWei, LiZongkun, LiWei,et al.Risk evaluation of dam-break environmental impacts based on the set pair analysis and cloud model[J].Natural Hazards,2020,104(2):1641‒1653. doi:10.1007/s11069-020-04237-9
[47]
LiDeshun.Research on system risk assessment based on generalized set pair analysis[D].Shenyang:Northeastern University,2010.