Advanced Materials Research Vols. 446-449

Abstract: An comparison research on the effect of pozzolanic reactions of fly ashes in architectural wastes recycle is described in the paper. In the experiment, NaOH and Na2SO4-Ca(OH)2 were used to activate the pozzolanic activities in the fly ashes—cement system to solidify the architectural wastes. The macro and micro testing methods were used to test the compressive strength, phase and electronic micro morphology of the hydration of alkali-activated fly ashes—cement cementitious system. The testing result shows that proper alkali-activated fly ashes—cement cementitious architectural wastes can shorten the incubation time of the pozzolanic reactions of fly ashes, whi ch make the reactions of fly ashes more sufficient. So the hydration products of fly ashes —cement cementitious system with alkali additions were more than those of without alkali add itions, and the compressive strength of the alkali-activated fly ashes—cement cementitious system is higher than that of non alkali-activated fly ashes—cement cementitious system.

Abstract: Safe analysis of the progressive slide is used to estimate the stability of arch dam. The space stochastic parameters are surveyed through considering the relativity of parameter. The stability reliability analysis can be divided into element, sub-structure or sub-system, system.etc. From element to system calculate abutment’s ability. Sub-structure is composed by elements parallel connection. System is composed by sub-structures in series. The substructure method is applied to study the interaction between arch dam and its abutment. In this paper, the weakness part of abutment was found by cracking analysis of the progressive slide, and the safe evaluation was given.

Abstract: During urbanization, large areas of soil are exposed to the risk of soil erosion due to extensive earthworks and construction activities. Runoff from construction sites is known by far the largest source of sediment clogging our waterways. Erosion occurred from the study area due to removal of vegetation, high rainfall intensity, alteration of existing topography, and the covering of previously vegetated surfaces with impervious cover such as roads, driveways and buildings. The main objective of this study is to evaluate the soil loss due to storm rainfall and runoff on a construction site located at Sungai Ara, Penang State of Malaysia. A purpose-built hydraulic structure namely Sharp Crested Rectangular Weir was constructed and installed on site for more reliable estimates of flow during storms. The soil loss was then evaluated by using an empirical modeling known as the Modified Universal Soil Loss Equation (MUSLE). Results showed that large amount of sediment has being eroded from the study area during these activities. The highest soil loss rate was estimated was 64 ton/ha during a storm event.

Abstract: The underground cavities of the Guandi Hydropower Station are Complex large-scale underground caverns. The quality of the surrounding rock masses of the underground cavities of the Guandi Hydropower Station is good and the deformation is normally less than 30mm. The structure surfaces have noticeable action for controlling the surrounding rock mass deformation. The time characteristic of the surrounding rock mass deformation is not noticeable.

Abstract: The correlation of chloride penetration experiment for hydraulic concrete of indoor artificial-climate accelerated tests with field expose tests result was analyzed. The results show that there’s a good similarity of chlorine ion erosion characteristics in hydraulic concrete between the natural environment and artificial-climate environment, indoor artificial-climate accelerated tests can simulate the chloride ions erosion processes of hydraulic concrete under natural environment.

Abstract: Following the thick-walled cylinder theory, a design progress of pressure tunnel with reinforcement concrete lining is carried out in the condition of water flow continuity. When rock consolidation grouting is adopted to increase rock mass deformation module and to decrease tunnel water leakage, the equivalent permeability coefficient is introduced to tell the influence of consolidation grouting. And the results of a certain tunnel show that the method of consolidation grouting can sharply lower the tunnel water leakage, and the quality of consolidation grouting is more important than the depth of grouting to control water leakage.

Abstract: Based on the character of the penetrated cracks in the sluice piers of a overflow dam, the reasons inducing cracks are investigated. The results of the finite element (FE) nonlinear analysis on a representative cracked sluice pier indicate that the current cracks will expend, and the piers need to be strengthened. Four strengthening schemes with prestressed anchorage cables are designed, and their effects are analyzed and compared with FE method, the best strengthening scheme is found.

Abstract: Aeration facility is widely used to reduce cavitation erosion of discharge works caused by high speed flows and it has proved to be an economical, effective and successful measure. For a flow chute with complex boundary conditions, the air pressure and backwater in an aerator cavity are important factors that influence the flow aeration, and there are numerous and complex hydraulic factors to affect them. By the jet trajectory equation and a series of experimental tests, the air pressure and backwater in different aerator cavities are investigated. How these factors such as the size and style of aerator, the arc radius of the chute and flow discharge to influence the air pressure and backwater in an aerator cavity are revealed. These results can be referenced in designing aerators on the chute with a concave surface.

Abstract: Abstract. According to the characteristics of large bending deformation produced in the process of vibration due to big high-thickness ratio of arch dam, the principle of total potential energy with stationary value is employed to establish the nonlinear vibration equation based on cantilever beam model to calculate arch dam. By means of catastrophe theory, the jumping and hysteresis phenomena of the vibration amplitude of the dam are analyzed, and the factors which cause instability and the parameter range of stable region are discussed. The analysis results show that response behaviors of dam are very sensitive to the change of system parameters, but catastrophic behaviors disappear and pseudo-linear characteristics arise when system parameters are selected rationally. The results obtained in the paper are of significant value for understanding the damage mechanism of arch dams subjected to earthquake, as well as guiding the design of arch dams

Abstract: To research the actual resistance for excavator in digging process, the relationship between manipulator motion, cylinder pressure and digging resistance was analyzed. On this basis, the equation for calculating digging resistance of excavator was proposed. By using tension sensor, a digging resistance test was done under the actual digging movement environment. And the obtained inclination angle and hydraulic cylinder signal data were imported into digging resistance calculation equation to get a calculation resistance. After comparing the calculation resistance with the tension sensor readings, the following conclusions can be derived: this calculation equation can reflect effectively the size and dynamic process of actual resistance during digging operation, and it can describe the instantaneous changes and impact status of real resistance much better can the empirical equation in which the resistance is directly proportional to the digging depth.