Applied Mechanics and Materials Vols. 501-504

Abstract: The soil over the bedrock in the city of Guangzhou is thin, with a depth of only about 11 m. Under such conditions, excessive exploitation of the underground space is very likely to affect the groundwater environment. In this paper, the impact of intensive underground structures, which act as barriers, on the groundwater flow in Guangzhou is investigated. The emphasis is on the impacts in terms of hydraulic head, Darcy velocity and groundwater balance. The study finds that: (1) Under the current underground structure density, the impact on the hydraulic head is small, and most of the change is in the range of ±0.5 m. (2) The Darcy velocity appears to be more susceptible to being affected by the structures. (3) The barrier effect of the intensive structures increases the overflow at the foot of the hills and reduces the transmissivity of the aquifer.

Abstract: Mining method inevitably causes a certain degree of damage on the shaft and surrounding rock, and severe vibration can effect on the ground buildings. The Sectional blasting design was discussed on the base of stratigraphic features, field condition and the nearest distance from surrounding buildings to Cuchun Shaft of Dalian Subway 202 construction which is taken as blasting safety control distance in this paper. The control blasting technology with short footage, weak blasting was put forward to reducing blasting vibration. The ground vibration monitoring was carried through during shaft blasting. Particle vibration velocity was from 0.28 to 1.85 cm/s and main vibration frequency was from 16.97 to 42.24 Hz at different level blasting of the surrounding rock. The monitoring results show the blasting parameters and damping measures can meet requirements of Engineering and standardization of the industry. It can provide the scientific basis and technical support for subway construction damping optimization design.

Abstract: According to the relationship of tunnel depth, the foundation forms of adjacent building (structures), the importance and the location of the tunnel in Nanjing Metro Line 3, the formation properties of the site is combined to carry out the analysis of key and difficult points on the worksite monitoring objects, the implementation methods of the interval shield monitoring is studied, which provides reference for similar engineering projects.

Abstract: Based on theories of finite element method, universal software ANSYS, by use of common software ANSYS as a platform, the influence degrees of transient temperature load and reservoir water load on arch dam stress are analyzed and computed. The result indicates that when the water level is same, the maximum tensile stress on arch dam has a close correlation with the variation of temperature, and the sensitivity of maximum tensile stress of arch dam for water temperature is higher than air temperature. The maximum tensile stress on arch dam does not correlate well with reservoir water level changes when the temperature is same. Through the non-dimensional processing on influencing factors which are temperature load and reservoir water level, the sensitivity of maximum tensile stress on arch dam for reservoir water pressure is higher than temperature load.

Abstract: Based on the monthly monitoring data in the Xinlicheng Reservoir from 2008 to 2011 in 3 zones (fluvial, transitional and lacustrine), 6 water quality variables were selected as evaluation indicators to evaluate the water environmental quality by improved Nemerow comprehensive pollution index method. The results indicated the reservoir water quality reached classII or III during the study period and met the requirements of centralized drinking water. No significant differences (P > 0.05) for Nemerow indexes were detected among seasons and zones. However, that Nemerow indexes slightly decreased along the longitudinal axis of reservoir showed the water quality in the lacustrine zone was better than that in the fluvial zone, which implied the reservoir ecological system had self-purification function. The improved Nemerow index method based on weight is objective, and the pollution factor with maximum weight is total phosphorus (TP) which is followed by ammonia nitrogen (NH₃-N) and total nitrogen (TN). Water quality protection strategies should focus on controlling nutrient emissions and prevent eutrophication, including exogenous governance and endogenous control.

Abstract: In this paper, the deformation monitoring of empirical mode decomposition method is applied to the embankment, and accordingly to evaluate dike reinforcement effect. Based on empirical mode decompositionof the endpoint effect makes the decomposition results of distortion, put forward to properly control point by using the window function method.effectively ensure the accuracy of the results of decomposition. Reference for peers and staff.

Abstract: In recent years, along with the state of water conservancy investment increases, more and more water conservancy project started construction, and how to construct the process of rational management, in reaching the target at the same time, to play a good economic efficiency, it is urgent to solve the problem. Based on the current construction of water conservancy project the problems existing in the management of serious analysis, put forward corresponding methods to solve the problems. Reference reference..

Abstract: The technique of curvilinear boundary-fitted coordinate system is used for the mathematical model of pressure underground seepage flow and the boundary conditions and the method of solving the transformed equations have been presented. The computing example shows that the computed hydraulic parameters conform to the physical laws. Compared with the finite element method, the presented method need not solve the large matrix equations, and the computer memories and the time for computing are less. The mathematical model is effective for numerical solution of pressure underground seepage flows with complicated boundaries, and can be used in practice hydraulic engineering. Keywords-curvilinear boundary-fitted coordinate, pressure underground seepage flow, mathematical model

Abstract: In the process of shaped charge ice-breaking , the response of piers is great under the impact of air, ice, water etc, and relates to integral security of the bridge. For the impact on the pier with burst points of the different distances is simulated by ANSYS / DYNA software, summarizes the impact on the pier of shaped charge ice-breaking, and obtains the maximum stress curves of the pier at different distances. Simultaneously, the paper analyses critical damaging- model of the C30 reinforced concrete piers in detail. The conclusion has a major role in guiding when shaped charge ice-breaking appears.

Abstract: Intake tower is a complex structure, which has complex boundary conditions and has complex loading situation. Intake tower is made up of reinforced concrete ,which is thin-wall hollow structure. It builds in the near the shore in the reservoir, its top bridge connects to the banks of the river, The tower is in the water and is under pressure, intake towers safety is very important under the action of earthquake. Based on the large finite element software ANSYS, the dynamic properties of the intake tower is studied, and the intake tower+ foundation is also studied. The research conclusions can be used as reference for engineering design.