Applied Mechanics and Materials Vols. 405-408

Abstract: A procedure for evaluating liquefaction resistance of soils based on the shear wave velocity measurements is outlined in the paper. The procedure follows the general formal of the Seed-Idriss simplified procedure. In addition, it was developed following suggestions from industry, researchers, and practitioners. The procedure correctly predicts moderate to high liquefaction potential for over 95% of the liquefaction case histories. The case study for the site of offshore wind farm in Jiangsu province is provided to illustrate the application of the proposed procedure. The feature of the soils and the shear wave velocity in-situ tested in site are discussed and the liquefaction potential of the layer is evaluated. The application shows that the layers of the non-cohesive soils in the depths 3-11m may be liquefiable according to the procedure.

Abstract: Prestressed concrete hollow retaining pile in lateral force resistance can effectively increase the bending height because of their hollow, so it can play a good effect in the pit maintenance .We will research and explore some problems about the innovative structure ,such as the suitable value of tension control stress , reasonable calculation method for flexural bearing capacity, shear lag effect causing by the hollow and using finite element analysis to verify. Do some preliminary research on some basic properties of the structure and lay the foundation for follow-up studies.

Abstract: Structure and anisotropy are two fundamental aspects of natural clays. They cant be ignored because of their significant influences on soils strength and stress-strain behavior, etc. Therefore, anisotropic tensor and structural parameters are introduced in Modified Cam Clay Model which is only suitable for isotropic remolded clays, and evolution laws of them are given in this paper. Thus, an elasto-plastic constitutive model considering the influences of natural soil structure and anisotropy is established. Most parameters involved in this model have explicit physical meaning and are easily determined through geotechnical tests, which makes this model more flexible, practical and applicable to practical engineering.

Abstract: The large-scale models of core rock-fill dam were constructed firstly, and the model dams were vibrated on large shaking table. In this paper, the dynamic analysis methods of earth-rock fill dam were verified base on the results of large-scale shaking model test, including the equivalent linear analysis method base on equivalent linear visco-elastic model and the effective stress analysis method of earth-rock fill dam. Study results show that: the value of natural vibration frequency of model dam which was calculated though characteristic value method using maximum dynamic shear modulus is close to the value which obtained from shaking model test; the acceleration response of the model dam under earthquake were simulated well by the equivalent linear analysis method base on equivalent linear visco-elastic model, and the calculated acceleration response values of model dam are close to the experiment results; because the finite element method (FEM) base on continuum media theory can not well reflect the loosening phenomenon of soil in vibration, the calculated acceleration response values are lower than experiment results; the effective stress analysis method of earth-rock fill dam can consider the dissipation and diffusion of dynamic pore water pressure during earthquake, and the calculated acceleration response values of model dam are close to the experiment results when the reservoir before dam was full of water.

Abstract: This paper, using 3-D numerical simulation and the hydraulic model tests, presents an analysis on hydraulic performance of pumped storage plant inlet/outlet. It discusses the uneven flow coefficient, coefficient of orifice flow distribution and head loss coefficient of inlet/outlet in different sizes. The optimized size has a uniform flow distribution, with less to produce unwanted eddies.

Abstract: Aerator is often used in the spillways or tunnels to protect these discharge release works from cavitation damage. But for the flow chutes with mild bottom slope, the backwater may occur easily in the aerators cavity. There are a lot of factors to influence the backwater in the cavity. Based on the model experiments and analysis, the backwater in the bottom aerators cavity on the chutes with mild bottom slope and some influence factor to the backwater are investigated. The research presented in this paper provides some laws of how backwater exists in the aerators cavity and how to reduce backwater in the cavity. Results show, in the case of other conditions remain unchanged, flow discharge is inversely proportion to the depth of backwater, and the takeoff angle of aerator affects the depth of backwater larger than the slope of chute; the greater the flow discharge is, the lower the depth of backwater. And the depth of backwater increases with aerator height. More attention should be paid to the backwater in the cavity for the chute with small bottom slope.

Abstract: 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.

Abstract: The inlet and outlet of the aqueduct and the inverted siphon, standing a gradual transition linked to the channel, make water gradually change along the cross section of the gradual transition, to improve the water flow pattern. This paper aims to research the deformation of the gradual transition under the water load in static water conditions, to make ANSYS finite element analysis to the engineering gradual transition for preventing deformation, and finally to optimize the overall style design on the basis of its analysis. The developed techniques have been successfully used in designing the gradual transition of a practical aqueduct project. The results of this study on the gradual transition have strong theoretical and practical significance.

Abstract: 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.

Abstract: The geotechnical consolidation test is used to detect the soil deformation under all levels of vertical load. Consolidation parameters play a vital role in the basal design of the buildings. But the lever consolidometer covers too large area, and needs high labor intensity. The pressure consolidometer is not convenient to find leak, noisy, and is affected by the power supply. We developed the hydraulic consolidation system, which is aid to make consolidation tests of the soil samples. The hydraulic consolidation system is composed of the hydraulic pump used as a pressure source, the hydraulic piston cylinder used as the load transfer device, intelligent instrument and solenoid valve. Through the comparison of the test by three methods, it proved that the test results are identical. The coefficient of variation of the parameters is less than 0.1, while its efficiency is 31.33 times higher than the lever test, 6.86 times higher than the pressure method.