Papers by Keyword: Tide

Abstract: The paper brings out the stability analysis of the earth embankments subjected to specific natural cyclic processes such as tides in India and freeze-thaw in Romania. The Sundarban, along the Bay of Bengal, is a low tide-dominated deltaic plain of the Ganga-Brahmaputra-Meghna basin (GBM) spreading over India and Bangladesh around 25,500 sq.km. The 3520km of riverside embankments had been erected to protect the deltaic plain from tidal flooding. The tidal cycle in this region is twice high tide and low tide daily. Presently, the Indian Sundarban Delta is under the threat to embankment failure. The study analyses the stability of an 8 m height embankment in the Gosaba region of Sundarban considering a 2m wide earth filled berm at 6m from the bottom of varying clay core thickness under the transient groundwater flow. Pore pressure, Flow net and Phreatic surface have been obtained by numerical models using FLAC 2D software, thus the factor of safety being analysed. In Romania, built on the of the highway A1 Orăştie-Sibiu section crossing the clayey hills from Aciliu and Apoldu known for their instability, the embankment around the abutment pier from Apoldu broke up at the entry to the Aciliu Viaduct. The layers of permeable soil soaked with water become heavy instead the waterproof layers keep the water above them creating sliding surfaces. The water is channelled to dozens of springs that appear or disappear depending on each micro-slip or fallen water amount. By freezing the water expands on the ground determining additional efforts, the cycle iterating with each rain and freeze-thaw.

Abstract: The key of constructing cast-in-situ bored piles in filled-sea ground area is how to bore through loose and uneven stratum filled with a great amount of large hard rubble, how to overcome the affection of ocean tide and how to prevent the accident of hole’s collapsing, shrinking or irregular shape, thick sedimentary cinder. This paper introduces the practice of constructing cast-in-situ bored piles in the filled-sea ground area in Yantai.

Abstract: Background: Saphan Hin is well known park located in the southern east coast of Phuket. Marine litter, especially light and floatable litter such as plastic, is known to be the cause of death in marine animals. Therefore, prediction of light floatable marine litter will greatly help to understand behavior of marine litter transportation at Saphan Hin and leads to proper waste management in vulnerable areas.

Abstract: The observation wave induced setup can be separated from observed total water level which combines tide level, weather induced setup and wave induced setup. SandyDuck ’97 experiment provides lots of observation data. Separation of tide level form preliminary data is using the nearest tide station’s predicted tide. The weather induced setup is given by numerical model which includes the effects of air pressure and wind blows. The residual water level, wave induced setup, seems reasonable and available, and the time series trend match with wave high trend at same location.

Abstract: In this paper, a 2-D tidal river flow-sediment mathematical model is established by irregular triangular element calculation mesh and finite element numerical method. And verification is done through the comparison of measured value and the calculated. The result shows good agreement is obtained.

Abstract: We analyzed the relationship of groundwater level of wetlands at the Yellow River mouth to the ocean tide responses, as well as its impact on the spatial distribution of wetland types by field positioning observations of coastal wetland groundwater levels. The results showed that, the groundwater level is significantly affected by the tides. Its fluctuation has a negative polynomial relationship with its distance to the coast. Their correlation reached maximum during spring tide (R2=0.79); the closer to the coast, the greater the groundwater level fluctuation is, the greater the interaction between the seawater and the groundwater, the smaller the groundwater depth; In contrast, the further from the coast, the smaller the level fluctuation is, the greater the groundwater depth level. The spatial distribution of coastal wetlands is greatly affected by groundwater level and ocean tide. Thus reasonable protection of the region is of importance for protection of both the seawater and groundwater qualities.

Abstract: The paper studied the effect of tide on the removal rate of COD, NH₃-N and TP in the dosing pool in order to provide data to simulate disorderly discharged sewage in tidal rivers. Due to the dilute effect of rivers, the removal rate of COD, NH₃-N and TP at the tidal state was higher than that at no tidal state. At the tidal state, the average removal rate of COD, NH₃-N and TP was 60.8%, 55.7%, 55.6%. At no tidal state, the average removal rate of COD, NH₃-N and TP was 57.5%, 47.5%, 8.6%. At the tidal state, the upper bio-film was exposed to air and the activity of microorganism decreased, and the activity of microorganism was high at middle-level bio-film. Therefore, the utilization of bio-film at the tidal state was lower than that at no tidal state. However, due to the tidal action, rivers entered into the dosing pool and the dilute effect of rivers on the pollutants was obvious.

Abstract: Caofeidian harbor is a large size deep-water harbor currently under construction in the Bohai Bay, the eastern coast of north China. The construction began in 2003. The characteristics of tides and tidal currents in the Caofeidian area are analyzed with field data from comprehensive field observations from 2008 to 2010. The field observations and analysis show that the tide is the irregular semi-diurnal and tidal current is characterized as a type of reverse flow with moving west during flood tides and east during ebb tides. In general, the flood current is slightly stronger than the ebb current, and the strongest tidal current appears in the Caofeidian foreland, which is the predominant driving force to maintain the deep water depth.

Abstract: The paper studied enhanced treatment of sewage from discharging points of rivers by bio-film process dosing with enzyme and investigated the promotion effect of enzyme on treatment of sewage by bio-film process. The removal of phenol in sewage was also researched. The experiments results indicated that during the ebb tide, the remove rate of phenol was stable (33%) on the eighth day in the dosing pools and it was stable (31.6%) on the eighth day in the contrast pool. During the rising tide, the remove rate of phenol was stable (30%) on the eighth day in the dosing pools and it was stable (27.2%) on the eighth day in the contrast pool. It indicated that enzyme had good promotion effect on bio-film process during the sewage treatment process. Biological accelerator-bio-film process could effectively reduce the impact of sewage on river and it had a good application prospect as the auxiliary means for water restore.

Abstract: The in situ treatment of disorderly discharged sewage by bio-film process with multiple enzymes stimulant was carried out in this study. The removal of the phenol in sewage was studied. The promotion of multiple enzymes stimulant on treatment of sewage by biofilm process was also investigated. The experiments results indicated that during the ebb tide, the remove rate of phenol was stable (88%) on the sixth day in the dosing pools and it was stable (83%) on the seventh day in the contrast pool. During the rising tide, the remove rate of phenol was stable (78%) on the sixth day in the dosing pools and it was stable (74%) on the seventh day in the contrast pool. It indicated that the bio-film process enhanced by dosing multiple enzymes stimulant possessed the promotion effect of pollutant removal. The bio-film process enhanced by bio-stimulant had good performance in treating the wastewater from discharging points of rivers, which had a broad practical application as assistant means of water body remediation.