A Study On The Parameters Analysis Of Flat Dilatometer Test In Kunming

The flat dilatometer test (DMT) was invented in Italy by Silvano Marchetti in 1980. The new in-situ test has many obvious advantages. It has been extensively used and calibrated all over the world, and widely accepted by engineers in our China after it was imported since the turn of last century. However, one chief problem for DMT in China, which restricts its practical application, is that its theory research is low-level. Some existing empirical formulas and conclusions of Shanghai and other countries are still used in most analysis of research results in our country. Because the test equipments are different among countries and the performance of the solid is strongly regional, these two points make the parameters significantly different from that of the actual situation. For the issue of the DMT in Kunming, this paper presents some research works on the following aspects.First, the DMT data is combined with the Geotechnical Engineering Investigation Report, and then the chief soil of sites is chosen as a basic unit and a set of database is established. Based on the results of the DMT, the relative division standard of the solids in Kunming is developed. This paper tests some calculation formulas of current software and amends parameters of part formulas regionally, including the undrained shear strength, internal friction angle of sand and modulus of compressibility. Meanwhile, the parameters, such as gravity density and standard value of subgrade bearing capacity, are not given detailed form in the software. For this point, this paper presents some new calculation formulas according to the practical meanings of these parameters and movement rules shown by statistical materials.Second, an indoor large sample test is done in this study. During the experiment, the imposition of load promotes physical and mechanical properties of soil change. At different stages of loading, a set of separate flat dilatometer tests and soil tests were done. The reliability and accuracy of the test parameters relationship is tested through comparing two testing results.Third, the paper presents the relationships of the main parameters between the DMT and the other in-situ soil test, through the corresponding result data of DMT and other in-site soil test (Static Cone Penetration Test, Standard Penetration Test and Vane Shear Test, etc.). The result is tested to improve the reliability and the application scope of in-situ testing technology is enlarged.Fourth, this paper researches on the technology application of flat dilatometer test for foundation treatment. Test data is combined with monitoring data during the soft clay drainage consolidation. It researches on the relativity between main parameters of DMT and the soft soil consolidation change rules, and then proposes some experience computational formulas. These formulas create conditions for more comprehensive understanding of degree of consolidation and physical and mechanical properties of soil during the drainage consolidation process of soft clay.