7, it can be seen that the annual variation of the temperature inside the insulation layer is smaller than that outside, and the time response of the temperature in the insulation layer is a little hysteretic than that outside. Bui, K.-T.T., Tien Bui, D., Zou, J., Van Doan, C. & Revhaug, I. Fract. Su H, Li X, Yang B, Wen Z. Wavelet support vector machine-based prediction model of dam deformation. In practical engineering, there are the following two situations regarding the layout of thermometers: (1) When sufficient thermometers are embedded in the dam body and foundation, temperature component T can also be calculated with measured temperature in HTT models. As for the buttresses, the crest of the buttress is displaced upstream when temperature rises (cf, Fig. Dam safety monitoring by instruments is the most important project of dam operation management1,2. Temperature component T describes the thermal displacement caused by the temperature variations of the dam body and foundation. (9) can be obtained by the least square method. Foziling Reservoir. Integration of artificial neural networks with radial basis function interpolation in earthfill dam seepage modeling. In addition, consolidation grouting and curtain reinforcement were carried out on the dam foundation, and dam monitoring facilities were added. Credit: unknown on TT ( Just dm for removal ) Foziling dam is worthy of being the first dam in new china and the first arch dam in Asia#shorts #adventure #earth #explore #shortvideo #aquarium #dam #china Eng. 17a), the resultant line of the action, which is transmitted from the upstream water pressure through the arch to the buttress, passes upstream of the midpoint of the buttress-foundation surface, a counterclockwise bending moment is generated, and the crest is displaced downstream. Softw. Fig. The data set of radial displacement, a period of 13years (May 2006July 2018, 624 observations) is selected for modeling. Earth is not a perfect sphere. Foziling dam is worthy of being the first dam in new china and the first arch dam in Asia #foziling #whatshop #subscribe #status #zone Luan. 22 buttresses are greater than others. Foziling is a reservoir based project. (4) Dam safety automation monitoring system and other management facilities were added. Appl. By submitting a comment you agree to abide by our Terms and Community Guidelines. 12 and 13 buttresses, tensile stress occurs. Mech. The tangential displacement is almost entirely induced by temperature. It is necessary to point out that the harmonic function in HST models cannot effectively interpret the thermal displacement caused by the short-term dynamic temperature variations. 12 buttress and (iv) No. In order to solve the problems of cavitation and vibration of steel pipes in the buttresses and cracks leakage, the reservoir was emptied, the reinforced arches were poured at the bottom of No. Sometimes it is considered that this verse has connection with Qiyamat. Foziling . Jul 07, 2019. & Loh, C.-H. It is a large multi-arch dam reservoir designed by China in the early days of the founding of the People's Republic of China with the advanced international level at that time. Similar to radial displacements analysis, the contributions of water level, temperature and time to the annual amplitude of tangential displacements (PL13-1, PL21) are calculated based on the HTT model. Figure1 shows the top, upstream, and downstream views of the dam. Control Health. Auction Venue/Sale . Download scientific diagram | Foziling muli-arch dam: (a) top view; (b) upstresm view; (c) downstream view. Control Health. 19, the three-dimensional finite element mesh of the Foziling multi-arch dam is established, in which 508,094 elements and 568,417 nodes are included. From the data of thermometers inside and outside the insulation layer shown in Fig. where m2 is taken as 1or2; b1i and b2i are the statistical coefficients; \(s = 2\pi t/365\), and t is the number of accumulated days from the initial monitoring date. With the development of artificial intelligence technology, machine learning algorithms offer new ways to establish dam behavior prediction models. Media in category "Foziling Dam" The following 2 files are in this category, out of 2 total. And the other part called irreversible displacement is caused by creep, alkali-aggregate reaction and other inelastic effects 6,29. is (m1) residual error between the measured displacements and the model predicted displacements. Due to the great tensile stresses that occurred close to the crown of No. Jeon J, Lee J, Shin D, Park H. Development of dam safety management system. The thermometers numbered T13-1T13-16 are newly added in this reinforcement, and the thermometers numbered T13011T13102 are original. Therefore, the flood control standard of the reservoir was improved. The observations from May 2006 to November 2016 are selected for training the model, while the observations from December 2016 to July 2018 are selected for testing the model. (7), the HTT displacement health monitoring model (M1) based on measured concrete temperature is established. https://doi.org/10.1016/j.engfailanal.2015.02.020 (2015). Maozedong foziling.jpg 320 423; 98 KB. (2) The tangential displacements are cyclical, especially for the buttresses on banks, and the closer to the banks, the greater displacements occur. contribute to editing and reviewing the improvement of the manuscript. Principal stresses under loading C2: (a) maximum and (b) minimum principal stresses on (i) arches, (ii) buttresses, (iii) No.12 buttress and (iv) No.13 buttress (unit: Pa). The water pressure component, temperature component and aging component of displacement observation points (PL3, PL13-1) are calculated based on Eqs. (2) The tangential displacements are cyclical, especially for the buttresses on banks, and the closer to the banks, the greater displacements occur. The Foziling multi-arch dam, the first reinforced concrete multi-arch dam after the founding of the People's Republic of China, built-in 1952, is located on the Bi River in Anhui Province. 12 and 13 buttresses are 3.41 Mpa and 3.46 Mpa, respectively (cf. https://doi.org/10.1016/j.ymssp.2018.03.022 (2018). Air temperature and concrete temperature at selected typical measured points. Huoshan. 101, 178184. (2) When there are no thermometers or few thermometers in the dam body and foundation, thermal displacement is generally assumed to follow the season evolution. It is an annual regulating reservoir with comprehensive utilization benefits of flood control, irrigation, power generation, and water supply. You are using a browser version with limited support for CSS. To obtain {"type":"entrez-protein-range","attrs":{"text":"T13011-T13102","start_term":"T13011","end_term":"T13102","start_term_id":"7487382","end_term_id":"7444591"}}, Influence of temperature variation on radial displacement: (. First of all, an HTT displacement model is established based on monitoring data over the past 13years. Article The Foziling multi-arch dam, one of the few multi-arch dams in the world, was built on the bedrock with complicated geological conditions. Struct. https://doi.org/10.1016/j.engstruct.2019.05.043 (2019). Therefore, the objective of this study is to put forward a method for evaluating the safety of Foziling Muti-arch Dam based on displacements observation and simulated stresses, while the methods can also be applied to other concrete dams. The data set of radial displacement, a period of 13years (May 2006July 2018, 624 observations) is selected for modeling. The actual area controlled is 1270 square kilometers. Finally, a numerical model is established to investigate the stress state of the dam in different load cases. And the maximum values reach 1.46 Mpa and 1.27 Mpa, respectively. A compression-shear fracture growing on an arch-gravity dam. 13 buttress (cf. https://doi.org/10.1016/j.camwa.2011.09.057 (2011). The total reservoir capacity of the reservoir 4.96 billion cubic meters, corresponding flood level of 130 meters, the flood season xingli reservoir capacity 1.2 billion cubic meters, the dead reservoir capacity 1.25 billion cubic meters, flood control standard is a thousand years. https://doi.org/10.1109/access.2020.3029562 (2020). It illustrates how temperature affects radial displacement, that is, the crest is displaced downstream when the temperature rises, and the crest is displaced upstream when the temperature drops. flights. Google Scholar. As the proportion of the water pressure component is relatively small, the water pressure component separated from the model established by using the whole data is biased. Thus, the Foziling multi-arch dam behavior can be further analyzed. The above analysis results illustrate that temperature has the greatest influence on displacement. and D.Y. Finally, the dam stress state is evaluated by establishing a dam finite element model and simulating the stress distribution in various operating conditions. In addition, consolidation grouting and curtain reinforcement were carried out on the dam foundation, and dam monitoring facilities were added. 91, 2639. https://doi.org/10.1007/s00603-018-1435-z (2018). Eng. Thus, there are four loading combinations, which are listed in Table 4. After the model is reached equilibrium under gravity, water pressure is applied at the upstream surface by hydrostatic loading. Figs. Greater tensile stress occurs in the middle of the crest of No. Integration of artificial neural networks with radial basis function interpolation in earthfill dam seepage modeling. X is an (m(i+j+3)) matrix of the independent variables expressed in H, T, and . Wang Q, Wang J-T, Jin F. Equivalent simulation of dam heat insulators and their effect analysis. Control Health 21, 423437. A majority of the annual precipitation occurs from May to August. The high similarity between displacement and temperature indicates that displacement is greatly affected by temperature. Here, high and low temperatures refer to the average monthly maximum and minimum temperature. X.L. Thermal displacements of concrete dams: Accounting for water temperature in statistical models. When the temperature rises, the dam body is heated and expanded, pushing the buttresses to the banks, so the buttresses on the left bank move towards the left bank, while the buttresses on the right bank move towards the right bank. Neural Comput. A hybrid model based on a swarm optimized neural fuzzy inference system performed better than multilayer perceptron neural networks and Gaussian processes in forecasting the horizontal displacement of a rockfill dam19. Xi, G.-Y., Yue, J.-P., Zhou, B.-X. Although the application of steel fiber reinforced concrete in the region of high stress can effectively alleviate the generation of fatigue cracks, more attention should be paid to the weak parts of the dam. The direction of water pressure is perpendicular to that of tangential displacement, and the dam has been in operation for many years, so the water pressure and time have little effect on the tangential displacement. (3) The radial displacements of the buttresses on the riverbed are more affected by water pressure but less affected by temperature than buttresses on the banks, and there is little difference in the effect of time on them. 3. conceives the study and is responsible for the methodology and original draft. Adv. Earth's rotation changes frequently, with many different variables added into the equation. 12 and 13 buttresses reach 1.54 Mpa and 1.55 Mpa, respectively (cf. 2 and 22 arches from the foundation to the 127.46m elevation are reinforced by steel fiber shotcrete in the reinforcement. Valente, S., Capriulo, C. & He, Q. X.L. Thus, as the water level and temperature change continuously, fatigue cracks tend to occur on the No. For the great tensile stress areas on the upstream concrete face and sidewalls of each buttress, steel fiber concrete was sprayed for thickening from the inside of the buttress. Due to the small storage capacity, the large variation range of water level, complex terrain and geological conditions of the dam foundation, and insufficient temperature control during the construction, the dam has undergone three times large-scale maintenance and reinforcement since it was put into service35. (4) The regression coefficients of Eq. 816 buttresses) as the midpoint, the tangential displacements of the buttresses on the left bank (No. It is not repeated here. Sign up for the Nature Briefing newsletter what matters in science, free to your inbox daily. (2)The tangential displacement is almost entirely induced by temperature. From the dam crest down, the arch section gradually thickens, with a thickness of 0.6m at the dam crest and 2.0m at the elevation of 70.0m away from the top. However, when they are viewed separately, their respective effects on the dam displacement are quite different. Comput. & Xu, L.-Q. Struct. Earth rotates eastward, in prograde motion. The vertical cross of No.13 buttress (unit: m). https://doi.org/10.1038/s41598-022-13073-9, DOI: https://doi.org/10.1038/s41598-022-13073-9. 3,13 and 21 buttresses. Dam safety is closely related to property safety, economic development, and the ecological environment in the area around the dam. The MLSR model has shown that, compared with the water pressure and temperature component, the aging component is negligibly small and tends to be stable. Therefore, the objective of this study is to put forward a method for evaluating the safety of Foziling Muti-arch Dam based on displacements observation and simulated stresses, while the methods can also be applied to other concrete dams. Salazar F, Toledo MA, Oate E, Morn R. An empirical comparison of machine learning techniques for dam behaviour modelling. The statistical models based on multiple linear regression (MLR) and stepwise regression (SR) are widely used for predicting dam behavior due to their simple formulation and fast calculation speed11,12. Article It can be concluded that the multi-arch dam is quite sensitive to temperature fluctuation, and the drastic fluctuation of temperature is a disadvantageous factor for dam safety. All authors reviewed the manuscript. However, there is a shortcoming that over-fitting may occur. Figure5 shows the water level fluctuation after the reinforcement. The average contributions of water level, temperature and time to the tangential displacement. Kang, F., Li, J., Zhao, S. & Wang, Y. Sale Date. As a result, No. Although the dam has been reinforced twice, serious cracks still existed. It can be seen that: (1) There is a significant correlation between the radial displacements and season. Day and night happen due to this rotational motion of the earth. Arab. Precession and nutation can be modeled and predicted precisely using time-dependent harmonic series expansions. from publication: Multi-arch dam safety evaluation based on statistical analysis and . The average contributions of each component in the last 11years (2007 to 2017) are shown in Fig. Fig. The performance criteria for model performance evaluation include the coefficient of determination (R), the mean absolute error (AEmean), and the root means squared error (RMSE). However, due to the uncertainty of dam body and foundation materials, it is very difficult to accurately predict dam behavior by FEM. For instance, it is provided that the models based on the artificial neural network are more accurate in the prediction of the dam displacement than the MLR model13,14,15. The effect of thermal expansion and contraction is the fundamental cause of dam tangential displacement. Structural health monitoring of concrete dams using long-term air temperature for thermal effect simulation. 6. Article Although the application of steel fiber reinforced concrete in the region of high stress can effectively alleviate the generation of fatigue cracks, more attention should be paid to the weak parts of the dam. 19, the three-dimensional finite element mesh of the Foziling multi-arch dam is established, in which 508,094 elements and 568,417 nodes are included. Application of advanced statistical methods for extracting long-term trends in static monitoring data from an arch dam. > FOZILING RESERVOIR SAVE ARTWORK FOLLOW ARTIST. It can be seen as follows: (1) Taking the buttresses riverbed (No. Two thermometers (TQ13_1, TQ13_2) monitoring the air temperature nearby are respectively installed at the front and tail of the cavity formed by the No.13 arch and the buttresses connected to it. 2 and 22 arches, as well as the foundation of the arches and buttresses in C1 and C3, exceeding the allowable tensile strength, the load case of high water level+temperature drop is regarded as the most disadvantageous operating load combination for thedam safety. https://doi.org/10.1016/j.advengsoft.2008.10.009 (2009). (7) and (8) extend to a generalized form of an MLSR model, which can be written in matrix notation as. 15b). 3D Rendering animation using satellite imagery. (9) can be obtained by the least square method. International Earth Rotation and Reference Systems Service, Formation and evolution of the Solar System, List of important publications in geology, Fallexperimente zum Nachweis der Erdrotation, "Parameters of Common Relevance of Astronomy, Geodesy, and Geodynamics", "Historical eclipses and Earth's rotation", "The Earth is spinning faster now than at any time in the past half century", "Humans Contribute to Earth's Wobble, Scientists Say", "Ibn Sn: Ab Al alusayn ibn Abdallh ibn Sn", "www.pierpaoloricci.it/dati/giorno solare vero VERSIONE EN", "INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE: EARTH ORIENTATION PARAMETERS: EOP (IERS) 05 C04", "Prediction of Universal Time and LOD Variations", "Topographic core-mantle coupling and fluctuations in the Earth's rotation", IERS Excess of the duration of the day to 86,400s since 1623, "Excess to 86400s of the duration day, 19951997", Sumatran earthquake sped up Earth's rotation, "Pleistocene deglaciation and the earth's rotation: a new analysis", "NASA Details Earthquake Effects on the Earth", "System-specific systematic errors in earth rotation parameters derived from GPS, GLONASS, and Galileo", "Solar and lunar eclipses recorded in medieval Arab chronicles", "Ancient eclipses show Earth's rotation is slowing", "Measurement of the Earth's rotation: 720 BC to AD 2015", "Earth's Rotation Is Mysteriously Slowing Down: Experts Predict Uptick In 2018 Earthquakes", IERS Earth Orientation Center: Earth rotation data and interactive analysis, International Earth Rotation and Reference Systems Service (IERS). Rock Eng. FOZILING RESERVOIR, 1956 Ink on paper Works on Paper. Adv. In the middle and lower areas of No. and D.Y. Struct. Due to the small storage capacity, the large variation range of water level, complex terrain and geological conditions of the dam foundation, and insufficient temperature control during the construction, the dam has undergone three times large-scale maintenance and reinforcement since it was put into service35. 9. Wang, Z., Liu, S., Vallejo, L. & Wang, L. Numerical analysis of the causes of face slab cracks in Gongboxia rockfill dam. The second reinforcement was carried out from June 1982 to June 1986. Foziling Reservoir, the eighth batch of national key cultural relics protection units. Maximum and minimum principal stresses in C3 and C4. Adv. Original name of this place (including . The difference in stiffness between them is so great that the end connected to the gravity dam is more constrained and subjected to greater forces. 62, 39803986. As for the No. 12 and 13 buttresses reach 1.54 Mpa and 1.55 Mpa, respectively (cf. Due to the flood overtopping accident in July 1969, in which the highest reservoir water level exceeded the top of the wave wall by 1.08m, the dam was increased by 1.5m and one additional spillway was built. Water pressure component H represents the displacement of the dam body and foundation caused by reservoir hydrostatic pressure, and it is calculated as. 27, 183195. Overview Nearby Reviews Win Prizes Details Recommended. The tensile stress of arches and buttresses generally decreases in C2 compared with that in C1. Parameters about the dam body concrete and foundation rock, determining the stress strength and deformation characteristic, are important foundations for obtaining reliable results by numerical modeling. In dam safety evaluation, the numerical simulation based on finite element models is often used to obtain the actual dam operation behavior3034. LOGIN . The results indicate that (1) the dam is currently in an elastic state after the last reinforcement; (2) temperature contributes the most to the displacement, and the drastic fluctuation of temperature is the disadvantage factor for multi-arch dam safety; (3) the stresses generally can meet the requirements of code; and (4) the ideas and methods of the study can provide references for the safety evaluation of other concrete dams. The actual control area is 1,270 square kilometers. In order to solve the problems of cavitation and vibration of steel pipes in the buttresses and cracks leakage, the reservoir was emptied, the reinforced arches were poured at the bottom of No. 20 and and21).21). In addition, fatigue damage may occur in areas with large stress variation, probably leading to crack initiation. And the performance parameters of the dam health monitoring models based on MLSR are listed in Table 2. The Foziling multi-arch dam, one of the few multi-arch dams in the world, was built on the bedrock with complicated geological conditions. The average contributions of water level, temperature and time to the tangential displacement. Anhui. In winter, the temperature near the downstream of the arch is lower than that on the upstream side, but in summer it is the opposite. Foziling zhu.jpg 3,039 1,246; 470 KB. Loh C-H, Chen C-H, Hsu T-Y. This research was substantially supported by National Natural Science Foundation of China (Grant No. Can a dam slow the rotation of the earth? (4) The radial displacement is the most affected by temperature, followed by water level and then time. (2) The radial displacements of the buttresses on the riverbed (e.g., PL13_1 and PL13_2) are larger than those on the bank (e.g., PL3 and PL21). From Wikimedia Commons, the free media repository. China. MathSciNet 3, 13, and 21 buttresses over time. 3). car rental. Therefore, the flood control standard of the reservoir was improved. Eng. 3 buttress, the water pressure component accounted for 4.136.66%, the temperature component accounted for 91.8994.37%, and the aging component accounted for 1.31.5%, with the average values of 93.11%, 5.45% and 1.44%, respectively. The data on water level, temperature, stressstrain, and seepage is important monitoring variables in the safety evaluation of concrete dams. (2) In the annual amplitude of the radial displacements of No.13 buttress, the water pressure component accounted for 18.5027.90%, the temperature component accounted for 69.5879.82%, and the aging component accounted for 1.213.43%, with the average values of 22.58%, 74.65% and 2.77%, respectively. A novel hybrid artificial intelligent approach based on neural fuzzy inference model and particle swarm optimization for horizontal displacement modeling of hydropower dam. Deep learning is an extension of machine learning. Anhui. NASA has calculated that the dam only slows the rotation by 0.06 microseconds, which is six hundredths of a millionth of a second.Our planet's rotation speed actually fluctuates fairly often, as it can be influenced by earthquakes, the moon, and the climate change-induced movement of the North Pole. Therefore, in order to highlight the effect of water pressure on the radial displacement as much as possible, the measured values corresponding to the air temperature between 20 and 23 C are selected, and the water pressure component is separated by the MLSR method. Greater tensile stresses mainly occur close to the crown of No.2 and 22 arches and the bottom of arches and buttresses, especially in low temperature and high water level load cases. \({{\varvec{\upalpha}}}\) is a ((n+i+3)1) vector of the regression coefficients. 17b), the resultant action line passes downstream of the midpoint of the buttress-foundation surface, a clockwise bending moment is generated, and the crest is displaced downstream. How long is a full rotation on Earth? Tangential displacements of the No. Earth Rotation. Foziling Reservoir Dam. C.G., S.V. Subsequently, contributions of water level, temperature and time to the annual amplitude of displacement are also obtained. J. Comput. The dam holds water at a level that is 175 meters above sea level. The greater tensile stress occurs in the middle of the buttress upstream panels, and none of them exceeds the allowable tensile stress. 321 arches mainly occur at the elevation near 1/3 of the water depth in C1, and the maximum value reaches 3.54 Mpa, which is very similar to the distribution of the maximum compressive stress of buttresses. Displacement observation, which is intuitive and reliable, and can explain the dam behavior itself, has been widely used in practice1,7,8. The performance criteria for model performance evaluation include the coefficient of determination (\(R\)), the mean absolute error (\(AE_{mean}\)), and the root means squared error (\(RMSE\)). Monitoring date, MLSR model results for radial displacements at PL3, PL13-1 and PL21. The buttress is displaced downstream (upstream) when the temperature rises (drops). It can be seen as follows: (1) Taking the buttresses riverbed (No. 12. The North and South Poles are defined as the two points on the Earth's surface where the axis of rotation emerges. So the hydrostatic-season-time (HST) model is widely used, in which the temperature component T is usually simulated with a one-year or half-year period harmonic function. On the other hand, it also shows that the methods proposed in this paper have the value of engineering popularization and application to other concrete dams. The upstream concrete face was thickened by 0.5m, the bottom (below elevation 79.56m) was thickened by 0.7m, and the left and right side walls were thickened by 0.4m. Moreover, the compressive strength of steel fiber concrete is 48.0Mpa, the tensile strength is 3.5Mpa and the bond strength with old concrete is 2.53.0Mpa35. Foziling Reservoir Dam. Foziling Reservoir discounts - what to see at Huoshan - check out 124 reviews and 23 photos for Foziling Reservoir - popular attractions, hotels, and restaurants near Foziling Reservoir The calculations of these models are in the "black box", and no specific mathematical analytic expressions can be obtained to interpret the physical meaning of dam behavior. This comprises motions of the Earth rotation axis with respect to the space-fixed system with periods from a few days to 18.6 years, caused by gravitational influences of sun, moon, and the planets of our solar system. For optimal irrigation and electricity generation, the water level is operated at elevations between 105.0 and 125.0m. The monitoring data of air temperature is shown in Fig. What is needed to point out is that some thermometers are not working, so data from 57 thermometers are selected as input temperature data for the establishment of HTT and MLSR models. The maximum compressive stress of No. In addition, fatigue damage may occur in areas with large stress variation, probably leading to crack initiation. where m2 is taken as 1or2; b1i and b2i are the statistical coefficients; s=2t/365, and t is the number of accumulated days from the initial monitoring date. Thus, there are four loading combinations, which are listed in Table Table44. 26 buttresses) are closely and positively correlated with temperature, while they are the opposite to the tangential displacements of the buttresses on the right bank (No. It can be seen that: (1) In the annual amplitude of the radial displacements of the No. The measured and modeled displacements are shown in Fig. Dam displacement is composed of two parts, one is reversible displacement caused by the fluctuations of reservoir water level and temperature. Dam safety monitoring by instruments is the most important project of dam operation management1,2. The temperature field of the dam is essentially caused by the alternation of temperature with the seasons during the operation period, so the thermal displacement can be also calculated by the measured air temperature1,4,21.
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