Research Of Mechanical Properties And Reinforcement Methods Of Shell Sand

The Bohai Bay Shell Embankment, one of the three largest shell embankments in the world, is important in the study of Quaternary geology. Unfortunately, due to economic limitation and inadequate recognition, the Bohai Bay Shell Embankment is facing damage both from nature and by human activities. To rescue the ocean cultural relics, as well as provide a science popularization base, the Tianjin municipal government decided to establish Tianjin Ancient Forest and Coast Museum.The museum will be founded on the shell embankment and the first underground floor, as the profile exhibition district of the shell embankment, should be in harmony in architectural style with the existing museums and should also minimize the disturbance to the relics. The height of the display pit should be greater than 3m to show the existing relics adequately and to satisfy science education and research. The above-mentioned requirements present four questions to be studied as following:First, the shell sand making up the shell embankment is the mixture of shell and its fragments, fine sand, silt sand, peat and silt clay film. Its geotechnical properties need to be deeply researched.Secondly, we should make out that how to make the profile exhibition districts in concordance with the existing museums in the architectural style and how to reduce the disturbance on the heritage from the constructionThirdly, the shell sand has the characters such as high permeability, high water content, bad structure, eugeogenous,low stability. We need a reliable reinforce method to display the cross-section in such soil.Finally, Tianjin is earthquake multiple and the protected seismic intensity is 7 degree. The long-term stability of the display districts under the earthquake should be guaranteed.The paper take Tianjin accent shell embankment as the background, through theatrics analysis, numerical calculation, indoor test and field test, we can gained the following achievement:1. Make the analysis to the shell content of the shell sand, and test the capability of the geotechnical mechanics, so that we gain the displacement and shearing strength of the shell sand to offer mechanics parameter to the analysis of the shell embankment.2. The exhibition cross-section of the shell embankment should combine with the interior design and the visiting route, make the exhibition cross-section harmonious to with the existing museum in architecture style.3. It should be ensured that the piling process and the foundation ditch excavation can protect the original core exhibition appearance through the research to the basis style of the major structure, so that the natural historical remains can avoid being disturbed.The practice proved that optimized base style being on the safe side. Laying reinforced concrete in the bottom of the foundation ditch can make the base as a visiting pathway and can also make the foundation and its bottom integral; this can keep the exhibition foundation ditch stable and lessen the displacement of the bottom.4. On the base of the shell sand geotechnical mechanic research, the paper analyzed the stress characteristic, compared the advantages and drawbacks of deferent grouting material. Innocuous, anti-ultraviolet materials were chosen as the basic materials. The paper brrought forward the amount of the grouting and reinforce range through field test and also debase the cost and advance the reinforce effect.The project practice proved the method as being feasible.5. Finite Method was used to analysis the slope stability and the stability under the earthquake. The result indicated that the stability of the reinforced shell embankment and the exhibition foundation ditch improved. The displacement and stress decade obviously and it satisfies the stability demand.