2. The main factor of the crack formation in concrete of pump stations is analyzed and the mechanism of the crack on concrete of pump stations is studied.

Based on the introduction of basic geological characteristics and relaxed-tension crack feature of a typical bank slope with relaxed-tension crack, the state and trend of bank slope stress are analyzed before and after tension crack formation as well as after water storage of the reservoir.

2. The main factor of the crack formation in concrete of pump stations is analyzed and the mechanism of the crack on concrete of pump stations is studied.

Based on the introduction of basic geological characteristics and relaxed-tension crack feature of a typical bank slope with relaxed-tension crack, the state and trend of bank slope stress are analyzed before and after tension crack formation as well as after water storage of the reservoir.

(4) Deformation and stress evolution mechanism of gravity arch dams under the influence of geological defects is drawn out by the above numerical methods. And the rules how the strength, creep and seepage of geological defects influence on deformation and cracks evolution of the dams are derived.

In the end, after analyzing temperature control and slit data of high arch dam constructed in the world, according to sort of concrete dam slit and reason of it produces, the paper discuss temperature control criterion, some common temperature stress control and slit prevention measures at present are put forward.

The design and results of the tests performed with this setup for AE-technique-based monitoring of the crack formation are presented.

Some estimates are obtained for the interaction between the acoustic emission pulses caused by the crack formation in the Arctic ice cover and a high-frequency test wave.

The high-frequency range (4-11 kHz) is most informative for the observation of geoacoustic noise caused by the crack formation processes.

It is proposed that h reflects not only the deformation heterogeneity, but also influences crack formation during the creep process.

In the limit, this condition coincides with the condition of crack formation at the tip of a single twin boundary with the same total number of dislocations.

The benefit of this technique over traditional curvature analysis is that the structural evolution is taken into account, a factor that mostly dominates fracture formation.

Fractal and information characteristics of the stressed state of a massif and their effect on the process of fracture formation

Fracture formation and void filling of the first generation of neptunian dikes is dated as Pliensbachian and is interpreted to be caused by the Julian carbonate platform dissection due to widely recognized Lower Jurassic Tethyan rifting.

It is suggested that observed scale effects in JRC and joint dilation can be explained by small differential strain discontinuities across fractures, which originate at the time of fracture formation.

In this study acoustic emission (AE) techniques were employed to investigate the process of fracture formation in large, shear-critical, reinforced concrete beams and to gain improved insight into the mechanisms of shear failure.

The design and results of the tests performed with this setup for AE-technique-based monitoring of the crack formation are presented.

Some estimates are obtained for the interaction between the acoustic emission pulses caused by the crack formation in the Arctic ice cover and a high-frequency test wave.

The high-frequency range (4-11 kHz) is most informative for the observation of geoacoustic noise caused by the crack formation processes.

It is proposed that h reflects not only the deformation heterogeneity, but also influences crack formation during the creep process.

In the limit, this condition coincides with the condition of crack formation at the tip of a single twin boundary with the same total number of dislocations.

For the surveillance of dam safety,it is necessary to determine the exact young's modulus(E),linear dilatation coefficient((?))and fracture toughness of concrete in dam body. This article taking Fu Ziling Multiple-Arch Dam as an example introduces the calculations of these parameters. The Young's modulus of concrete is obtained from the water pressure component of horizontal displacement in dam crest in statistical model(ΔδH) and the same component calculated by FEM(Δδ'H): E_c=E_c′ΔδH'/ΔδH (1) here E_c′ is the...

For the surveillance of dam safety,it is necessary to determine the exact young's modulus(E),linear dilatation coefficient((?))and fracture toughness of concrete in dam body. This article taking Fu Ziling Multiple-Arch Dam as an example introduces the calculations of these parameters. The Young's modulus of concrete is obtained from the water pressure component of horizontal displacement in dam crest in statistical model(ΔδH) and the same component calculated by FEM(Δδ'H): E_c=E_c′ΔδH'/ΔδH (1) here E_c′ is the pre-assumed young′s modulus of dam concrete. The linear dilatation coefficient((?))is obtained from the thermal component of vertical displacement in dam crest in statistical model(ΔδT) and the same component calculated by FEM(ΔδT′): α=α′ΔδT/ΔδT′ (2) here α′is the pre-assumed linear dilatation coefficient of dam concrete. The governing condition of crack occurrence can be foundout from the analysis of measured data and the stress in dam under this condition can be calculated by FEM. The stress intensity factor of a certain crack developed under minimum stress condition is Considered approximately as the fracture toughness of dam concrete[K_c]: [K_c]=K_Ⅰcos~3 Q_o/2-3K Ⅱ sin Q_o/2 cos~2 Q_o/2 (3) here, K_Ⅰ and K_Ⅱ are stress intensity factors on the tips of type Ⅰ and type Ⅱ crack respectively, Q. is the direction angle of crack propagation. Applying above mentioned formulus to Fuziling Multiple Arch Dam, weget E_c=3×10~(5kg)/cm~2, α=0.8×10~(-5)/℃, [K_c]=110~(kg)/cm~2.

Combining the theory of damage mechanics with experiments,two damage model—bicurvlinear model and bilinear model are proposed. Calculations of typical examples show that the behaviour of concrete can be well described by these two models.Then the bicurvlinear model is extended to the problems which take the temperature effect into account and the surface crack forming in Zhexi diamond head buttress dam is calculated using this model and the finite element method.The results of calculation basically agree with...

Combining the theory of damage mechanics with experiments,two damage model—bicurvlinear model and bilinear model are proposed. Calculations of typical examples show that the behaviour of concrete can be well described by these two models.Then the bicurvlinear model is extended to the problems which take the temperature effect into account and the surface crack forming in Zhexi diamond head buttress dam is calculated using this model and the finite element method.The results of calculation basically agree with the actual state.

The reservoir area of the Guanyinge Reservoir is located in severe cold zone. The climate is poor. There are 5 months in winter every year in which the concrete pouring could not be conducted. From February to April in1994, it was found in site that the horizontal construction joints opened in some dam sections, with the maximum joint depth is up to 3-6m. In order to study the fissure form process and its development trend and ensure that no fissure could be occurred in overwintering surface from now on, the...

The reservoir area of the Guanyinge Reservoir is located in severe cold zone. The climate is poor. There are 5 months in winter every year in which the concrete pouring could not be conducted. From February to April in1994, it was found in site that the horizontal construction joints opened in some dam sections, with the maximum joint depth is up to 3-6m. In order to study the fissure form process and its development trend and ensure that no fissure could be occurred in overwintering surface from now on, the finite element method has been used, in linewith actual field conditions, for the emulation analysis and prediction calculation analysis of temperature and creep stress by temperature for typical dam section of Guanyinge Dam during construction and operation have been studied.