Research On Application Of Jet Grouting Piles Water-stop Curtain At Coastal Fly Ash Fill Dredger Area

There is strong compression of foundation, low ground bearing capacity, strongpermeability, ease to liquefaction and loss at coastal fly ash dredger fill area. Whenhigh-pressure jet grouting piles water-stop curtain is adopted in these place, problems not onlyappear in application such as that the foundation can not support construction machines, dustis serious, or the pit is easy to leak, but also come out in theory that there is no unified theoryin calculation of the curtain thickness. People seldom analyze the curtain thickness from theperspective of the force, but always follow engineering experience and depend onconservative construction, which at last result in tremendous waste of materials while thequality is unsatisfactory. These issues are researched in depth in this paper.Firstly, there is analysis of the conventional jet grouting piles water-stop curtain,including development, construction technology, scope of application, jet structure, seepagemechanism and problems to be solved of the technology. Then the design process andrequirements of the water-stop curtain in complex geological conditions such as coastal flyash dredger fill area is researched, especially on new solution to problems such as poorbearing capacity of the foundation, fly ash liquefaction and dust, and new theory ofcomputation of the curtain thickness——The maximum shear of curtain should be calculatedonly considering lateral pressure of water, active earth pressure and passive earth pressure inthe case of that curtain depth is beyond depth of supporting piles. The shear strength ofsoil-cement curtain can be combined with the maximum shear by a safety factor to achievethe thickness of the curtain. At last, the new computation theory and technology is used in akey project in Qingdao. It proves that the new computation theory and technology meet theneeds of project because there was no seepage during construction and the theory results ofcurtain thickness is close to the value in specification.