Applied Mechanics and Materials Vols. 638-640

Abstract: The construction of Hurongxi highway is the one of the most difficult highway in the world. Slopes of Hurongxi highway are studied in this paper. Comprehensive three-dimensional (3D) modeling and visual analysis technique based on rock stratum model and skirt weathering model are put forward. The comprehensive model consists of slope multi-information, such as 3D accurate terrain, excavation, engineering measures, monitoring facilities, underground water, bridges and tunnels. An information analysis system of slopes along the highway is established combining database platform. It provides an effective visualization support platform for the analysis of the geological conditions of slope during the construction, decision making of excavation and protection and deformation warning, meanwhile, it also contributes a lot to some other similar slope engineering.

Abstract: Irregularity is the locomotive and the main excitation source of vibration, is directly related to the smooth running of the train, safety and comfort, is to control the maximum operating speed of the train one of the main factors. The statistic specimen was collected by track geometry inspection car from Wuhan-Guangzhou high-speed rail. Based on the stationarity test of the specimen, Fast Fourier Transform (FFT) method was used to evaluate the spectrum of the whole specimen space. The power spectrum density (PSD) and related functions of track irregularity were obtained by MATLAB program. We analyzed it by comparing the fitting curve of the national speed lines and fitting curve of Qinhuangdao-Shenyang dedicated passenger railway line, by comparison, the Wuhan-Guangzhou high-speed railway track irregularity is much better than the national speed lines and Qinhuangdao-Shenyang dedicated passenger railway line. The parameter values of PSD fitting curve for track irregularity are obtained by the nonlinear curve-fitting algorithm in the least-squares sense, which has referencing value to maintenance high-speed rail.

Abstract: Based on the Abaqus parallel computing cluster system platform, the three-dimensional finite element model of train-track-viaduct/embankment-foundation-soil coupling is established. The three-dimensional space-time variation and Fourier spectrums characters of ground surface vibration vertical accelerations by high-speed train running on viaduct and embankment are simulated. The result shows that ground surface vibration is mainly excited by periodic axle force of the train in the site near the viaduct pier. In the site far from the viaduct pier, ground surface vibration is mainly from the transmission of the site near the viaduct pier. With the increased distance between the viaduct pier, the peak value of ground surface vibration vertical acceleration decreases, and decreases significantly when the distance is within 10m. There are two main frequency bands of Fourier spectrum of ground surface vibration vertical acceleration: low-frequency band 0-12Hz and high-frequency band 35-47Hz of viaduct route, and low-frequency band 0-21Hz and high-frequency band 25-45Hz of embankment route. In general, with the increased distance between viaduct/embankment, Fourier spectrum amplitude of every frequency band decrease, and attenuation speed of high-frequency band is much faster than-frequency band’s.

Abstract: 2D wave model test was in common use for the verification of structure stability in coastal design in past decades. However, only positive wave could be simulated in 2D model and in practical many coastal engineering were damaged by oblique wave. The revetment stability was tested through 3D wave physical model for a coastal engineering in Dalian city. The result show that wave height in shallow water area would be larger than that in deep area under specific terrain. The stability of revetment armor block in shallow area may be worse than deep area under action of breaking wave in surf zone. The blocks in bottom fail in stability first and then the upper slide down. Oblique wave is more dangerous than positive wave. The necessity of 3D stability model test on verification and optimization of revetment design is reflected once more in this research.

Abstract: China has been the country which is suffering serious coastal erosion that primarily caused by the increase of hydrodynamic force and the unbalance between input and output sediment. Comparing with the traditional revetment, most of which were made of reinforced concrete, the ecological shoreline protection can prevent coastal erosion in an ecological method. In this article, a biodegradable coastline protection mat (BCP-mat) was proposed and different arrangement methods direct to various areas was presented to solve the problems such as high cost, complicated construction caused by existing ecological method. In the end, the existing technology problems and promotion difficulties was discussed in the perspective of design and management.

Abstract: This paper introduces a coastal structure design to protect a reclamation site, which will be fixed at a level of +8 m above the chart datum. A jetty will be also used for loading and unloading of materials from the plant that will be developed on the nearby reclamation site. From the given site contours and water depth data, the bottom slope of the sandy foreshore can be determined. In order to design the coastal structure, the wave climate must be considered and analyzed in priority. For the vertical breakwater to be located on the other side of the berth jetty, the required base and height was determined. In addition, the seawalls for the reclamation platform were analyzed at different water depths.

Abstract: For two sampling sediment take from the-3m and-5m depth water in the main channel of Xuwei port, Lianyungang, the experiment of sediment incipient motion under wave-current interaction is carried out in a wave-current flume. The results show that the wet density of bed sediment is 1.4 t/m³ and 1.5 t/m³ respectively, the critical incipient shear stress at the bottom of the bed is between 0.21 N/m²~ 0.29 N/m² and 0.35 N/m² ~ 0.46 N/m² respectively; the critical incipient shear stress of sediment from-3m depth water is greater than from the-5m depth water for the same wet density of bed sediment. The results can provide parameters and basis to the research of engineering sediment problem.

Abstract: How to treat dredged sediment is one of the main environmental problems and the recycling technique is the best way to deal with this problem. This paper deals with the feasibility of beach protection project alternative materials-dredged sand, applies cement and addition to solidify it. The components of dredged sediment and the physical properties were analyzed. Specimens with a designed mix ratio of the cement and dredged sediment were made by means of instant formation. The specimens were cured under standard condition and room temperature. The unconfined compressive strength of specimens were measured after curing for 7, 14 and 28 days. Using solidified dredged sediment as construction material has advantages of technology, economy and environment protection.

Abstract: The surrounding area of the Dachan Bay in the Pearl River Estuary has one of the highest economic development rates of China. Rapid industrialization and urbanization has resulted in extensive changes in land use, including the tidal flat reclamation and harbor construction. For the analysis of the morphological changes of the Dachan Bay, multi-temporal Landsat images have been digitized by using the integrated RS and GIS technique, and the digital elevation modes in different years were set up in combination with topographical and nautical data. From the change analysis, it can be concluded that the sea area of the Dachan Bay decreases to 6.0 km², by 87.6% between 1907a and 2011a due to the large-scale tidal flat reclamation, and the maximum downcutting depth of the seabed in the entrance area is over 10m mainly caused by extensive harbor construction. Based on the research of the morphological change in recent decades, it is suggested that the human activities have become one of the major factors affecting the morphological processes of the Dachan Bay.

Abstract: This paper presents a spectral wave action model to simulate random wave deformation and transformation. The wave model is based on the wave action balance equation and can simulate wave fields by accounting for wave breaking, shoaling, refraction, diffraction and wind effect in coastal waters. It is a finite-difference, phase averaged model for the steady-state wave spectral transformation. The wave model is applied to verify different experimental cases and real life case of considering the several factor effects. The calculated results agree with the experimental and field data. The results show that the wave model presented herein should be useful in simulating the wave transformation processes in complicated coastal waters.