Research Of A New Soil Improvement For Sand And Gravel EPB Shield

EPB(Earth Pressure Balance) shield as a shield method, with the merits like wide applicable ground type, fast driving speed, satisfactory construction quality etc, has been more and more widely used. The plastic flow of soil technology is the key to the EPB shield to success. Naturally,the soil is difficult to achieve the state of plastic flow, so it is must to be improved.At the present stage, the common foam or slurry and other materials to the pre-cutter and the earth pressure tank. The performance is not enough excellent, expensive or cause serious pollution problems etc. Considering the universality of slurry, relying on the 9th Line, addressing to the formation characteristics for Beijing (Sand and Gravel), the main following method is adopted to study the new shield slurry.⑴、Drawing on knowledge of drilling fluid, combined with the characteristics of shield plastic flow soil, introduction of guar gum, clay tablets and other new materials is a innovation. Through a series of tests, while testing the new shield slurry, find a reasonable slurry preparation programs.⑵、According to the characteristics of the layer on the 9th, using specially designed test equipment for soil improvement, evaluate the effect of slurry.⑶、On the basis of the interior tests, in order to evaluate the performance of the new shield slurry and the improvement effect on soil.⑷、Based on laboratory tests and field tests of soil improvement, optimize the new shield slurry preparation programs and he preparation method.The new low-solids polymer shield slurry is a combination of improvement materials of mineral and water-soluble polymer type and other biological materials, has superior performance, reasonable price and wide applicability, security, environmental protection.