Semi-positive Cutoffs for Embankment Dams
Semi-positive cutoffs for dams are constructed by mixing the materials from the existing ground with an engineered hydraulic binder.There are mainly two methods in use, namely jet grouting and deep mixing.With both procedures column-like or wall-like elements of soilcrete (a mixture of soil, cement, bentonite and water) can be.created in the ground.Overlapping columns can be used to construct watertight barriers as alternatives to positive cutoffs (e.g.slurry walls, plastic concrete walls, etc.).This paper focusses on the jet grouting technology where mixing is accomplished with hydraulic power through a rotating high pressure fluid jet stream, which erodes and destructures the soil and mixes it with grout whereby a columnar element is formed.Jet grouting can be used with any type of soil.The diameter of a jet-grouted column is related to the energy of the jetting fluids and to the erodibility of the soil being treated.The paper reviews briefly the relevant issues for the successful use of jet grouting for cutoff constiuction in dam projects and points out some recent developments.Selected case histories illustrate the challenges which have to be faced in difficult subsurface and environmental situations and the lessons learnt.
cutoff wall jet grouting cofferdam seepage control
R.Peter Brenner
Independent Consultant, CH-8570 Weinfelden, Switzerland,brenner
国际会议
昆明
英文
361-370
2013-11-01（万方平台首次上网日期，不代表论文的发表时间）