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Elastic modulus and temperature are the main influences of dam stress. In order to study the Dongjiang dam stress for crack controlling, the critical parts stress of dam under different elastic modulus and high-low temperature seasons is analyzed by the finite element method. The results show that: (1) the arch crown and abutment principal tensile stress at upstream face and principal compressive stress at downstream face under high temperature season are greater than the calculation results under low temperature season for the whole at the normal storage water level; (2) the influence on stress caused by elastic modulus are more significant under high temperature season compared to low temperature season at arch crown and abutment, the maximum stress increase with the increasing of elastic modulus. (3) Dongjiang arch dam should pay more attention to the safety control under high temperature season and surface crack prevention and control work in low temperature season.

The strain energy of dam body and its sensitivity to the deformation modulus of foundation are taken as objective functions, feasibility robust constraint of stress is taken into account with the consideration of uncertainty of foundation deformation modulus, and a robust optimization model for shape design of arch dams is established based on strain energy. A formula of sensitivity of dam strain energy to deformation modulus of foundation is derived and a relevant algorithm is proposed. The optimization of a planned arch dam indicates that, the dam strain energy and its sensitivity to foundation deformation modulus of optimal design are reduced 2.29% and 15.51%, respectively, of that of initial design, and the validity of the proposed model is demonstrated.

The paper introduces the distributed temperature sensor (DTS), analyzes the system veracity and the concrete temperature change compared with the conventional thermometer, shows that DTS can fast and accurately monitor the temperature of the dam and provide messages for the construction. It has great value in engineering application.

This paper makes analysis on accelerated speed overload and hydraulic pressure after earthquake, as well as the relationship between the ground motion peak acceleration and the dam body displacement, dam body damage volume ratio, and dam facing damage volume ratio. According to dam body partition, this paper takes the ratio of over stress accumulative duration and stress required capacity as parameters, and studies arch local earthquake damage evaluation of dam body partition. After analysis, it is found that after arch dam experiences different geological process, there are damages in both sides of dam abutment and upper part of dam body, overstressed area expands continuously and local damages take place.

The optimization design method was rarely used to design the gravity buttress of arch dam in the past. With this in mind, the parametric description of gravity buttress is given, and the auto-calculation of its exerting loads and the safety coefficient of anti-slide stability are realized subsequently. Then, the optimization design model of gravity buttress and the procedures of optimization design are presented using the asynchronous particle swarm optimization method. Finally, ODGB software, which is short for Optimization Design of Gravity Buttress software, is developed and verified.

With the development of 300m super-high dams are built in the southwest of China, reservoir water gravity will make the settlement of the reservoir basin, which will make dam tilt upstream. In the paper, reservoir settlement will be studied in-depth on the basis of monitoring data analysis and numerical simulation comprehensively. First, reservoir basin will be sinking with the rising of the upstream water gradually according to level monitoring data. Second, those affect factors of FEM calculation have been explored comparatively, such as displacement modes, element geometry and boundary conditions. Third, reservoir, dam and foundation are integrated into a whole to establish a wide spread finite element model. At last, reservoir deformation and its influence factors are determined through the simulation of the bedrock depth, the extending length of the upstream and downstream and different water levels. Those methods have been applied into an engineering project and analysis results show that the settlement of the reservoir will make high arch dam tilt upstream, the higher of the water level, the larger of the horizontal displacement. Accordingly, reservoir deformation should be considered deeply on the appraisement of super-high arch dam operating status in future.

An early-warning model of dam safety base on Dynamic FCM-LSSVM was supported to solve the traditional model failure over time. The training set was divided into subsets with different cluster centers method by using FCM algorithm, and then every subset was trained and modeled by using LS-SVM. When making forecasts, the category of the sample belongs was determined firstly. Then the corresponding sub-type model was used to predict and updated on-line. An arch dam safety warning model of deformation was established by using the proposed method. Compared with the standard LS-SVM model, the proposed hybrid model can significantly improve the generalization ability of the model.

The factors resulted in the cracking of Xiao-wan arch dam are extremely complicated. A numerical analysis based on elastic-viscoplastic mechanics theory has been developed to study the cracks in the middle diversion pier of Xiaowan Arch Dam. This analysis aims to investigate the cause of cracks and the reliability and accuracy of the analysis model have been examined. By using this analysis and the obtained results, the following conclusions are drawn: 1) cracks were not induced by a single cause, but a multitude of various effect such as stresses induced by thermal movements, the bond between the anchor cables and the surrounding concrete and the pressure due to the impounded water, amongst which the thermal stress is the most significant reason; and 2) with the presence of water in cracks, if the drainage hole continues to run overflowing water, the stress intensity factor of a crack tip will exceed the fracture toughness of the concrete. With the hydraulic fracture effect, the crack will grow continuously. The findings derived from this study will provide useful information for future projects of the similar nature.

The nonlinear finite element can precisely simulate practical work condition of arch dam, but also has some problems in the safety evaluation of high arch dam, mainly in different mesh size, different strength criteria and constitutive relations of dam corresponding to different results. This article first proposes determining method for reasonable mesh size describes three strength criterions of uniaxial, biaxial, triaxial, gives two constitutive relations of dam cracking, damage. Take a high arch dam as an example, has done some research on the above question, obtain some beneficial conclusions.

By utilizing the transverse joint opening and closing iteration technique and the finite element method based on the discontinuous deformation theory for manifolds, and with the help of measured data in situ of temperature, stress and displacement and so on during the construction period, the dynamic tracing feedback simulation/analysis was carried out to the temperature field and the stress field. On this basis, a series of effective safety control measures and methods were systematically put forward, which are beneficial to safety construction in the high temperature season and winter, improvement of the safety coefficient for restrained zones, lowering the cracking risk of low gradation concrete in portholes, ensuring the transverse joints aperture and groutability as well as effective control of the cantilever height and so on; and good effects have been obtained in the engineering practice and the important guarantee may be provided for the overall safety of Xiluodu Super-high arch dam.

The brittle failure finite element method is widely used in arch dam safety evaluation, but it also has some problems, the concrete strength criterion is different, the dam failure range is different. This article first introduces brittle failure constitutive relation and three strength criterions, then takes a high arch dam as an example to compute, obtains some conclusions that the relative failure range of foundation plane corresponds to blaxial strength criterion is slightly bigger than the result of uniaxial strength criterion, is almost the same as the result of triaxial strength criterion. Because the influence of the third principal stress is compressed stress to the dam crack is taken into account under multiaxial strength criterion, therefore using multiaxial strength criterion is more reasonable.

It is difficult to get a theoretic answer to the water flow load features of high dam flood discharge. Through direct measurement of water flow load features by arranging a surface pressure cell, the complicated point-surface conversion was avoided, and the shock load and surge load features were obtained. For the dam body outlet wall pressure, isolated the fluctuating load applied to the plunge pool floor and the downstream dam surface, the impact of the fluctuating load to the arch dam dynamic response at the flood discharge flow outlet was obtained, and then the equivalent fluctuating load on each discharge flow outlet was obtained by using flow-induced vibration back analysis. The test shows that the energy of the shock load and the surge load mainly centers in a frequency range between 0~1Hz, the shock load is about 2.5-6 times that of the surge load, and the surge load is about 4 times that of the outlet wall pressure.

The arch dam of Jinping I hydropower station is on obvious high ground area, and the foundation rock masses may relaxed while excavating. Limit tensile strain is put forward to be relaxation criterion. By three-dimensional elastic-plastic finite element method analyzing, and imitating the dam excavating steps, the maximum principle strain of the dam foundation rocks is obtained. The research indicates that the maximum principal strain of upstream side is greater than that of downstream side commonly, and some area would relaxed, with 41m maximal relaxed depth. By engineer analogical research with Xiaowan arch dam foundation rock mass, which have relaxed while excavating, the calculate method and criterion of this paper are reliable, and they can provide reference for engineer design.

It does numerical analysis on the overload of RCC arch dam named wanjiakouzi, through the analysis, we try to find the damage process of the dam. It does elastic-plastic analysis by FEM. Result shows that the horizontal cracks are usually a very important symbol, it means the dam will reach its ultimate capacity.

For a temperature rebound in the irrigated high arch dam during the construction period, using finite element method to research the influence of environment temperature to temperature rebound of the irrigated high concrete arch dam. Assuming that the initial temperature of the dam concrete is the joint grouting temperature. This paper presents a simulation of the temperature rebound of the high arch dam which is caused by the monthly average environment temperature, and performs sensitivity analysis to research the influence of thermal conductivity and surface heat preservation on the temperature rebound. According to the analysis,when the high arch dam sealing temperature is lower than the dam site annual average temperature, the dam site temperature inevitably would flow backward,slowly,to the irrigation area.The larger the thermal conductivity is,the quicker the temperature rebound speed will be. And benzene board insulation can reduce concrete temperature rebound rate, if the heat preservation benzene board is thicker,the temperature rebound rate is smaller.

Based on M language offered by Comsol Multiphysics analysis platform, a 3-D finite element model of a high arch dam was established. In this paper, a practical engineering was taken to be as a case.The coupled seepage-stress field was compared with uncoupled condition under normal storage level. The seepage, stress and displacement fields of the dam were analyzed for discussing the coupled effect. The results show the similar distribution of seepage, stress and displacement fields in the two conditions. However, compared to the uncoupled one, the potential distribution of seepage field is close to downstream, each displacement component increases at different rates, the tensile stress of the upstream rock and the compressive stress of the downstream rock both increases in the coupled condition, which enhances the uplift pressure in the foundation. So the coupled effect of seepage and stress is not beneficial for the dam safety, which cannot be ignored under high water pressure.

Considering topographic and geologic conditions, project layout and investments, concret arch dam is adopted in a hydropower plant and underground powerhouses are arranged in mountains on left and right banks. However, the minimum distance between the excavation boundary of abutment of arch dam on elevation 850m and underground powerhouse is only 110m. Abutment load created by reservoir storage, permeability and earthquake may affect general stability of underground caverns in operation period. Thus, using elasto-plastic finite difference method, three dimensional numerical simulation models of underground caverns and slope of abutment of arch dam is establised and proposed key issues are systemly studied. The calculation results show that, under reservoir storage and dam vibration subject to earthquke, abutment load has small effect on plastic zone, displacement and stress around opennings and the caverns would be stable in operation period.

Arch dam is a water retaining structure which has beautiful bodily form and reasonable structure form, in recent years, arch dam has been widely used. This paper adopts finite element method to carry out three-dimensional finite element simulation analysis for Haierwa reservoir concrete hyperbolic arch dam, researching variation law of the dams stress and displacement in operating process. Research results show that, Haierwa reservoir concrete hyperbolic arch dam is reasonable structure, good mechanical performance, every index meets the requirements for design.

According to the existing arch dam design specification, the temperature load is obtained based on analytic solution of infinite long free plate, it only considers the average temperature and the equivalent linear temperature difference of dam section in operation period, the influence of non-linear temperature difference has not been considered. This kind of simplification has some approximation; especially it can not reflect spatial effect of larger temperature gradient changes in the upstream and downstream water level change area. This paper first takes the free plate as an example, has calculated the temperature field corresponding to analytical method, finite element method, standard method, explains the rationality of using written program to carry on finite element analysis. On this basis, take Xiluodu arch dam as an example, the dam temperature load and temperature stress has been analyzed by using finite element method and standard method, the difference between both has been discussed

In this paper, the crack stability and crack propagation regularity of the upstream surface of super-high arch dam along the water-stop structure were analyzed in the framework of fracture mechanics. According to fracture toughness of dam concrete, the relationship between the crack propagation length and the allowable water pressure was studied. Finally, two main specific engineering suggestions for avoiding this kind of crack on the upstream surface of super-high arch dam were given: (1) the value of checking water pressure should not exceed 0.4 MPa; (2) the flange of the water-stop structure near the upstream surface of dam should be changed toward the downstream.

In this paper, a 3-dimension finite element with dummy nodes for calculating and outputting the stress energy release (SERR) at the crack tip was built up based on virtual crack closure technique (VCCT), it is presented to demonstrate the virtual crack closure technique has high accuracy and good feasibility. The calculation results curve and the analytical solution curve are in good agreement. The results show that the proposed interface elements can be used to calculate to get accurate results by finite element analysis. It can give us some new ideas for Hydraulic structure crack research.

For virtue of small volume and fast speed of construction, arch dam is the most suitable dam type in cold region, where construction period is relatively short each year. Low average value and large amplitude of atmospheric temperature make temperature stress distribution of arch affect directly by thickness of permanent insulation material as while as the time of thermal insulation. Extreme climate lead to stricter external insulation requirement for cold region arch than these in common district, however, thermal insulation will increase the burden of artificial cooling and extend the construction period. Therefore, it is complicated and critical for arch dam crack prevention to study on permanent thermal insulation. In view of this, finite element method was applied for simulation of construction processes of a practical project in cold region. Influence of permanent thermal insulation layer thickness and selection of insulation time is analyzed, in order to provide basis for permanent thermal insulation optimization.

A three-dimensional model of dam-water-interaction system was built. Three different materials were used to model the dam, and the acceleration response of arch dam under the observed seismic waves was simulated. The results show that the dynamic reactions of the arch dam under observed earthquakes can well match the monitoring values, which means the established model of the arch dam is reliable. In the future, when great earthquakes happen, the stress strain situation of the key positions can be quickly obtained by the finite element calculation, which could provide scientific support for post-earthquake safety evaluation and decision-making.

A kind of crack with similar characteristics has been discovered on the upstream surface of super-high arch dam. In this paper, the reason of cracking was analyzed by the three-dimensional finite element method. It is found that the stress concentration of concrete near the water-stop structure led to the concrete initial cracking in the process of transverse joint open.

This study main focuses on a real-time Zigbee-based localization system to provide prompt support for safety management in dam construction sites. The system accounts for a wireless sensor tracking technology and a set of servers running software for handling collected data, real-time site state visualization and remote interaction communications with other system such as ERP, CRM. The low-level tracking technology is a ZigBee-based network hardware utilizing fingerprinting software technology. The proposed real-time monitoring system for employer has been successfully implemented in Xiluodu arch dam construction site. The field tests also show that the RSSI-based localization algorithm implemented by ZigBee devices is reliable and is accurate (3 to 5 meters) enough. This real-time monitoring system was proven to be very useful for field safety management of high arch dam, and in similar hydraulic projects.

The calculation method of the minimum aperture of transverse joints with spherical surface key groove was introduced in this study. Based on the computation theory of allowable height difference between adjacent monoliths proposed by Bofang Zhu, the analytical model of allowable height difference of Xiluodu arch dam was established with consideration of the effect of main factors on the transverse joints deformation, including the temperature, autogenous volume deformation, self-weight and foundation. After the horizontal and vertical deformations of transverse joints was required, according to the form of spherical surface key groove, the aperture of each part of key groove and the minimum aperture were obtained at several height difference between adjacent monoliths. The allowable height difference was determined on the condition of meeting the grouting requirements of transverse joints. The result shows that the allowable height difference for Xiluodu arch dam should not be more than 30m.

In order to effectively predict aspects of dam deformation, taking effective and timely measures against the problem to ensure the safety of the dam .As a result, LS-SVM-Mc model is proposed . Namely, Markov chain based on LS-SVM prediction corrects the error, and ultimately improves the prediction accuracy. By the analysis and calculation of deformation prediction of an arch dam, you can find that the method is more in line with the actual situation, showing predictive superiority and a high prediction accuracy.so the method can serve as a new ways of dam deformation prediction,some promotional value can be gained in later work.

A hybrid prediction model based on the simulation of the complete process in high arch dams is proposed because of capacity shortage in the prediction of and early warning for deformation and stress in such dams during the first impounding stage. An early warning system for dam body deformation as well as dam heel and dam toe stress is established in this model. The warning thresholds are also clarified. Applications in the first impounding stage of the Xiaowan Arch Dam show that the model is practical and effective, and can provide highly accurate predictions. Early warning indicator thresholds for deformation and stress are reasonably set to provide warnings for abnormal situations. The model provides accurate predictions and effective warning methods for the safe impounding and operation of high arch dams.

To reduce the tensile stress at dam heel, inducing joints have been set in Xiaowan arch dam; they were designed to work without water pressure. After the reservoir was impounded to the normal water level of E.L.1240m, monitoring data showed that almost half of the inducing joints were working with water pressure, but leakage remained small. It also indicated the opening and shear deformation of all the inducing joints were small, and the joint surface remained in compression although the compressive stress was decreased by 2.03MPa~9.29MPa. So it can be concluded that the inducing joints are generally working at closing and compressive state. However, some abnormalities were detected: large seepage pressure and increasing crack width in block No.16 which is at the right end of the inducing joints; 5 small cracks appeared with leakage water at the downstream inner surface of the inspection gallery of the inducing joint in block No.22. Therefore, close attention has to be paid to the crack propagation around the inducing joints for the safety monitoring in future.

Based on nonlinear finite element analysis, three-dimensional elastoplastic numerical simulation of Jinping I high arch dam is developed. By using the method of multiply mesh, the stress result of FEM is transferred to any sliding surface (flat or curved), and the safety factors of sliding blocks are computed. The elastic-plastic calculation results indicate that the stress and displacement distributions are basically symmetrical to the river valley. The minimal safety factor of the left abutment under the basic condition is 4.88(larger than 3.5), which appears in the 1740m elevation in the temperature drop condition. However, the minimal safety factor of the right abutment under the basic condition is 3.41(less than 3.5), appearing in the 1710m elevation in the temperature rise condition, which means the necessity of the reinforcement measures to the right abutment.

Reservoir basin deformation monitoring data of some high arch dams has shown that the upstream of the dam subsided while the downstream warped upward slightly. Therefore, combining reservoir basin with high arch dam and foundation, the widespread finite element model is built and the reservoir basin deformation and its influence factor weight are determined through the simulation of the bedrock depth, the extending length of the upstream and downstream and different water levels based on an improved entropy method. The engineering simulation model has proved the reservoir basin deformation mechanism. Moreover, the reservoir basin deformation will tend to converge when the simulation model expands to certain extent. The research can provide suggestions for deformation doubts occurring during the high arch dam operation.

Considering the true mechanical states of roller compacted gravity and arch dams, the strength experiments of the roller compacted concrete (RCC) specimens with two graded-aggregates made from a high arch dam are carried out. These specimens are of three kinds: body specimens, layer-treated specimens and layer-untreated specimens and the tests include direct shear and triaxial compressive-compressive-shear, tensile-compressive-shear tests. The shear strength of three kinds of specimens under different stress states is analyzed systematically. By regression of the tests results, respective failure criterions for RCC under different combined loads are proposed.

This paper presents the experimental investigations into the seismic failure for high arch dam with shaking table test. The similitude scale of high arch dam was studied firstly. Then we developed a like concrete material to simulate the mechanical behavior of the structural concrete in high arch dam. The shaking table tests have been performed on the scale model. The experimental results reveal the failure process of high arch dam with respect to the different earthquake intensities.

Arch dam has gradually evolved as one of dam type as main large-scale hydraulic project, dam deformation prediction is an important part of dam safety monitoring, and it is difficult to forecast because of the complicated nonlinear characteristics of the monitoring data. Support Vector Machine (SVM) could solve the small sample, nonlinear high dimension problem due to the excellent generalization ability, and hence it has been widely used in the forecast of arch dam deformation. However, the forecast results considerably depend on the choice of SVM model parameters. In this paper, Particle Swarm Optimization (PSO), which has the characteristic of fast global optimization, was applied to optimize the parameters in SVM, and then the dam deformation prediction model based on PSO-SVM could be established. The model is applied to a certain arch dam foundation prediction. The accuracy of this employed approach was examined by comparing it with multiple regression method. In a word, the experimental results indicate that the proposed method based on PSO-SVM can be used in arch dam deformation prediction.

Experiments of two graded-aggregates concrete used for RCC arch dam are conducted. The experiment includes three states: direct shear state, compressive-compressive-shear state and tensile-compressive-shear state. Comparison and analysis of the deformation characteristics of body specimens and layer specimens are carried out. Influences of different stress states on body specimens and layer specimens are also studied in this paper.

Seismic risk analysis is greatly helpful to seismic safety evaluation of dams. A preliminary study on seismic risk analysis of arch dam based on numerical simulation is presented. The numerical procedure approximately takes into account the influence of concrete heterogeneity, it can model the response of the dam from elastic vibration to ultimate failure. Five seismic damage levels including no damage, minor damage, medium damage, serious damage and collapse of dam are defined. Through Monte-Carlo analysis of nonlinear response of the dam, which considers uncertainty persistent in ground motion input as well as material properties of concrete, status of the dam after subjected to earthquakes is obtained. The final seismic risk of the dam, which conforms to the norm distribution, is reached based on data fitting. The results provide meaningful reference to seismic safety evaluation of the dam.

As the highest RCC(Roller Compacted Concrete) arch dam under construction around the world, Wanjiakouzi adopted advanced distributed temperature system (DTS). This paper summarizes the network design, technical requirements as well as the protection precautions of fiber connector and monitoring port of temperature measurement system of optical fiber in high RCC arch dam in Wanjiakouzi. It can be indicated that the accuracy and reliability of DTS by comparing fiber optic temperature values with the conventional thermometer measured values. The analysis and monitoring results show that the temperature measurement system of optical fiber can truly monitor and reflect the change process of heat of hydration of RCC, gradation and the cooling water pipe to temperature.

Super concrete dam is threatened by dynamic brittle damage. In this paper, the fuzzy stochastic damping function was established for the seismic damping computation. According to the simulation results, there lives high level of fuzzy stochastic damage stress at the abutments and slope concrete sections of Xiluodu arch dam. Particularly, the stress level in downstream direction and transverse direction is higher than that in vertical direction.

In this paper, the key parameters and functions for quantification of temperature creep stress were offered. These key parameters established the creep-heat-change fluctuation on fully graded concrete. The information is helpful for simulation of super arch dam concrete pouring process.

Super dam construction under high steep slope is threatened by the uncertainty of shear strength development of rock-concrete joints. With numerical theory, the shear stress vector distribution of interface was studied. The simulation results show that dam section 23 of Xiluodu arch dam has enough safety reservation at rock-concrete joints zones with 4-lift separate pouring.

On the basis of the analysis of the displacement of concrete dam and its related influential factors, based on the evolvement of nonlinear dynamics of concrete dam, it can effectively identify the mutations position of measured value and the attribute interval of dynamical system applied with the wavelet analysis, dynamic structural mutation theory and other numerical analysis methods. When detecting after separating structural mutation sequence, it can finally get the relative stable displacement time series of dynamical structure, so it can realize the diagnostic separation of the monitoring information effective interval. At the end of the paper, through applying a certain concrete arch dam, it is proved that the proposed method of concrete dam mutations diagnosis of is of great significance for the real-time monitoring of the workability state of a dam.

Concrete arch dams are critical structures, the failure of which would lead to catastrophic effects on a regional scale. Considering the uncertainty characteristics of earthquake and the self-adjustment of inner force of arch dams, it’s necessary to investigate the seismic performance index of arch dam for holistically evaluating the seismic safety of arch dam-foundation system subjected to high intensity seismic excitations. By considering the contraction joints movement and concrete material nonlinearity, a series of dynamic response-history analyses of arch dam were carried out under increasing levels of earthquakes. Based on these analyses, the performance index of crest deformation is recommended for the seismic safety assessment of arch dam. And several performance stages of seismic response including the opening of contraction joints and the distribution of concrete damage are also investigated.

Due to the massive volume of body and complex structure, the dynamic reliability analysis on arch dam under earthquake action draws more attention. In this paper calculated seismic dynamic action on arch dam by applying mode superposition response spectrum method. By taking the elastic modulus of the dam concrete and the rock foundation beneath the dam, and concrete tensile and compressive strength as random variables, adapting response surface method to establish limit state equation. The reliability index of each element in the dam was calculated via gradient optimization method, as a result to obtain the variation law of reliability index of dam body. The calculation of real case shows that the tensile index is comparatively low at some region of dam heel and abutment upstream, which requires the measure for aseismic measures, while the reliability index for tensile and compressive stress on other part of dam generally meets requirement.

The loads on the arch dam and the materials physical properties of the dam and the bedrock are uncertain, and can be described with random variable. Due to the huge volume, the complex structure of the dam and excessive random variable, the reliability analysis of the dam is difficult. The dam is a higher order statically indeterminate structure, and the variation of the temperature obviously affects the stress and displacement of the structure, therefore, it is very important to consider the randomness of the temperature change load in the reliability analysis of arch dam. Based on the analysis of the stable temperature field, temperature rise and temperature drop field of the dam, the calculation method of temperature change field is further studied and applied in the reliability analysis of the arch dam. Considering random variables such as temperature change, water pressure, elastic modulus and strength of the materials, the stress and displacement of the arch dam and bedrock are calculated with a three dimensional finite element method, the limit state equations are established by RSM. Then the tension and compression reliability of the arch dam are analyzed using gradient optimization method. The results indicate that the temperature change field significantly influences the tension and compression reliability of the dam, and should be seriously considered in the reliability analysis of arch dams.

The proposed Jinping-I hydropower station is located on the middle reach of the Yalongjiang River, Sichuan Province, P.R. China. It consists of a double-curvature arch dam with a maximum height of 305 m, which will be the highest in the world. Excavation disturbed zone (EDZ) in the left bank slope is one of the most important aspects in slope stability and deformation evaluation. This paper is focused on estimation of EDZ in the left bank slope of Jinping-I hydropower station based on numerical simulation. Geological conditions of the left bank slope are firstly analyzed. Then, displacement field of the slope during excavation is calculated by finite element method (FEM). It can be indicated that the model and parameters in this paper is reasonable by comparing observed results with calculated ones. EDZ in the left bank slope can be estimated based on the calculated displacement field. It can be inferred that the range of EDZ is related to the controlling discontinuities such as fault f42-9 and Lamprophyre X etc. which are adjacent to the excavation line.

In arch dam design, every country has it own technical design standard. In Vietnam, the standard is far lessconprehensive compared with those of the United States and China. This research focus on analysis of the differences between three above standard systems, in order to give some suggestions to improve the Vietnamese standard for arch dam. Differnces in stability and strength analysis under static and seismic conditions is discussed in depth. A case study of Namchien arch dam in Vietnam, which has being constructed in Vietnam, is presented. The results show that if arch dam design based on the Vietnamese standard, stability and strength analysis should be paid more attention on the discussed differences. The research aims atcontributing constructive suggestions concerning to existing Vietnamese standard and providing some technical specifications for designer in arch dam design.

The dam concrete material properties wre influenced by the implementation of temperature control measures on site. The weekly temperature evaluation system has been set up in order to evaluate current temperature control measures, combining with the distributed optical fiber temperature control techniques and construction technical requirements. The system has been applied to a concrete arch dam under construction in southwest China which established multi-objective fuzzy mathematical model by synthetic weighting method that was a combination of experts scoring method and entropy weight method. Practice shows that the system can estimate weak link of this week and give guidance to the temperature control’s adjustment of the following week.

Taking all the effects into account of thermal and mechanical properties, construction process, environment temperature, arch-closure and reservoir impounding orders, three dimension (3D) finite element methods(FEM) was adopted to simulate the whole construction process for temperature changing and thermal stress distribution of the dam. Typically, the results of the highest 22nd monolith were analyzed, from which the general law for both temperature field and thermal stress was acquired. And the results are valuable for temperature control of Xiaowan high arch dam.

Although real-time tracking and feedback were carried out for the dam concrete construction process, there was still certain blindness in the construction units. The temperature double-control index, which is the allowable temperature and temperature gradient under typical age before concrete block reaching its maximum temperature, was proposed in this paper on the basis of the analysis of measured temperature process curves of concrete blocks. The probabilistic method was applied to draft the temperature double-control index of different sections and periods based on the measured temperature process curve of the poured block of a constructing extra-high arch dam in southwest China. Furthermore, the prediction model was also provided and applied in the dynamic feedback of new pouring block. It is demonstrated by the practice that the prediction model proposed in this paper has better pertinence and maneuverability for the construction units to control the maximum temperature of concrete block, i.e. the maximum temperature in high temperature season and in low temperature season are both controllable.

A research on numerical modeling of arch dam with contraction joints under static and seismic conditions is performed in this study. Discussions on the use of the adaptive finite element method with consideration of the “equivalent stress” and simulating technique for the contact between dam segments are presented. A case study of stress analysis for the Namchien hydropower arch dam in Vietnam is given. The results showed that the numerical model established in this paper is effective to simulate complex physical models. The stability analysis is easily performed by using the self-adapting technique with consideration of equivalent stress, and the contraction joints between dam segments can be successfully simulated by assigning zero-thickness contact elements to control complex contact behaviors, such as slip, opening or closing of the contact surfaces. The results of this study will be a useful reference for the assessment of the dam safety in the future.