Study On Test Facility Of Differential Water Pressure Test In Grouting Engineering

Water pressure test is a kind of permeability test done in drill holeswhich is commonly used in grouting engineering to expose the relativepermeability and groutability of rocks, the width of rock fissures andcharacteristics of materials filled. It was also used in checking thegrouting effect.Based on the analysis on a great number of engineering practices theauthor found that the relationship between grout quantity and unitpermeating ratio (i.e. the Lu number) deduced from pump-in test wasundeterminable, and the author presents that the limit in the principle ofthe pump-in test was the main reason.In this paper, a new method of gaining the permeability of rocks wasstudied and a new instrument named drill-hole turbine flow velocitymeter was. developed. The instrument could test permeating flow of anysections larger than 5 centimeters in length of the hole. Test data could besorted out to a distribution curve of grout quantity, from which sections ofneeding grout or not could be determined. Results above present aobjectivebasis for dam grouting design and construction.This paper also presents a high accurate controllable electric whichforms a complete set with the turbine flow velocity meter.It was proved that the research achievements in this paper are betterthan the pump-in test in finding out the true permeability of rocks.