Advanced Materials Research Vols. 250-253

Abstract: During the tunnel’s construction, pre-inject to form loop in wall rock of the fault fracture and karst-developed area where there is abundant water. To reduce the quantity of seepage for lining, simultaneity, set up drainage system to drain the rest of water to achieve its purpose that reduce the press of external water and control drainage with effort. According to the principle of elastic-plastic, the paper analyses and designs the thickness optimization based on the status change of plastic zone during excavating tunnel. The result indicates that the pre-injection loop of the single electrified railway tunnel with standard V level is ranging between 4m and 8m when leave out of consideration of external water load. Otherwise the thickness optimization is around 6m for the deep-buried 200m tunnel.

Abstract: Yellow River-Crossing Project in South-to-North Water Transfer approach through the use of shield tunnel and its north bank departure shaft adopts diaphragm wall as enclosure structure. The depth of continuous wall of its shielding starting shaft is 76.6m, which is the deepest at present in china. The continuous diaphragm wall travels through the layer of silver sand, medium sand and loam from top to bottom, where the geological conditions are poor with large difficulty of construction. This paper sets forth construction of guide wall, reinforcing measures before construction, Trenching process, groove segment connections, innovative technologies of uplifting huge reinforcing cage and so on, which will provide guidance and lessons for the similar project

Abstract: Based on practice road tunnel engineering in Gansu province and near areas in west china, the main construction technology and emphasis of quality monitoring of waterproof and drainage of loess road tunnel are analyzed. Requirements of waterproof and drainage construction and methods of quality monitoring are obtained. Principle of design for waterproof and drainage in highway tunnels construction is provided. The analysis results provide technical guidance for the waterproof construction optimization of loess tunnels.

Abstract: The large deflection behavior of prismatic cantilever beams subjected to uniformly distributed load is investigated. An approximate analytical solution is obtained using the homotopy analysis method (HAM). The solution is validated by the nonlinear shooting method. This reveals that the solution is accurate, efficient and convenient for cantilever beams with uniformly distributed loads.

Abstract: Field test and analysis were carried out for dynamic responses on a continuous bridge under open traffic. The inspection, testing and analysis for the tested bridge mainly consist of the measurement of pavement roughness and analysis on power spectral density, the testing and analysis on natural vibration characteristics, the observation of traffic loads under open traffic and the corresponding measurements of dynamic displacement and acceleration on bridge. To determine impact factors in terms of measured dynamic displacement responses, low pass Butterworth filter is used for filtering the dynamic part of measured dynamic displacement and the static extreme values are reserved. Finally, the relationship between impact factors and vehicle weight, vehicle speed is studied. It was found that impact factor tends to decrease with increasing vehicle weight, and integrally speaking, the impact factor increases gradually as the vehicle speed is increased within a wide range.

Abstract: This paper deals with large deflection problem of a cantilever beam with a constant section under the action of a transverse tip load. The differential transformation method (DTM) is used to solve the nonlinear differential equation governing the problem. An approach treats trigonometric nonlinearity is used in DTM. The results obtained from DTM are compared with those results obtained by the finite difference method and they agree well.

Abstract: Digital Elevation Models (DEM) implies numbers of geomorphologic spatial information. It not only includes the three-dimensional coordinate but also has unique texture information, which can describe the ‘true’ land surface adequately at relation of neighbors (plan) and relative (amplitude). We will use a method to study the wavelength characters by data mining and distribution of slope and local relief on the altitude steps through a local window. The Shuttle Radar Topography Mission (SRTM) collect detailed Digital Elevation Models(DEM) data between 60°N and 57°S, 80 percent for all land masses, and it provides reliable, high precision surface elevation data for us, suits to analyze efficiently landscape pattern. SRTM-DEM data simulate three-dimensional land surface with regular gridded matrix, and these discrete points are fit for spatial neighbors’ analysis and statistics, and convenient to geomorphologic pattern computation and analysis in digital computer. Geomorphologic pattern is influenced by Physical properties and human activities in a most direct way, but whilst it record numbers of geological evolution evidence, and these records provide some important information for climate change, geological and geographical processes and ecological environment researches in science. In this study, making the whole Jilin province as study object, we propose a fourth-order equation to approximate land as a continuous curved surface, association neighbors’ analysis method, utilize digital elevation matrix to validate an optimal statistic window, and subsequent study the area spatial distribution by parameterization and classification, get a satisfactory effect.

Abstract: Beijing subway Huangzhuang stations is cross-transfer station. It has a complex tunneling structure. The characteristics of the reverse construction vertical well was been thinking in the course of excavation design. The vertical well excavation and support method, horizontal wells channel excavation and support methods, the main station pilot tunnel excavation and support methods were researched to determine in detail. In order to analysis and evaluation the feasibility of excavation and getting into hole, FLAC3D numerical simulation analysis method was applied to do simulation of the vertical well, horizontal channel and the main cavern excavation. All detail construction course of these three-part were been studied. Excavation and supporting method and progress were all included. The ground surface subsidence, deformation of support structure and strengthen structure were been got. On the condition of the vertical well support structure destruction caused by the horizontal guide hole excavation and the group cave effect caused by guiding cave excavation in main station underground building, the support structure and ground soil stability were studied. The research result gave the base technical support for the project optimization design and construction security.

Abstract: Damage detection in civil engineering structures using the dynamic system parameters has become an important area of research. The sensitivity of damage indicator is of great value to structural damage identification. The curvature mode is an excellent parameter in damage detection of structures, while in case that certain curvature mode curve can’t show existence of damage. In this paper, numerical studies are conducted to demonstrate the deficiency of curvature mode to damage detection. Then a new damage indicator called “curvature mode changing rate” (CMCR) is introduced which is processed by numerical differentiation of curvature mode curve. The simulation results show that the new index is superior to curvature mode for structural damage identification, and it is still sensitive to the damaged location in the mode node.

Abstract: In order to achieve the setting and hardening of mine shaft lining concrete under the minus temperature in freezing construction and to meet the demands of every performance of concrete, the technique of compounding air entraining admixture and antifreezing admixture and early strength water reducing admixture was applied in this research. Based on the orthogonal experimental design, several mix proportions of compound admixture for early strength liquid mine shaft lining concrete were developed in the laboratory. The data collected in this research provide reference for the optimum mix proportion of the adulteration quantity of the concrete admixture. The results show that the 2.1％ amount of compound antifreezing admixture achieves favorable effects of liquid, early strength, freezing prevention and antifreezing.